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Zhang W, Cheng L, Li K, Xie L, Ji J, Lei X, Jiang A, Chen C, Li H, Li P, Sun Q. Evolutional heterochromatin condensation delineates chromocenter formation and retrotransposon silencing in plants. NATURE PLANTS 2024; 10:1215-1230. [PMID: 39014153 DOI: 10.1038/s41477-024-01746-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 06/20/2024] [Indexed: 07/18/2024]
Abstract
Heterochromatic condensates (chromocenters) are critical for maintaining the silencing of heterochromatin. It is therefore puzzling that the presence of chromocenters is variable across plant species. Here we reveal that variations in the plant heterochromatin protein ADCP1 confer a diversity in chromocenter formation via phase separation. ADCP1 physically interacts with the high mobility group protein HMGA to form a complex and mediates heterochromatin condensation by multivalent interactions. The loss of intrinsically disordered regions (IDRs) in ADCP1 homologues during evolution has led to the absence of prominent chromocenter formation in various plant species, and introduction of IDR-containing ADCP1 with HMGA promotes heterochromatin condensation and retrotransposon silencing. Moreover, plants in the Cucurbitaceae group have evolved an IDR-containing chimaera of ADCP1 and HMGA, which remarkably enables formation of chromocenters. Together, our work uncovers a coevolved mechanism of phase separation in packing heterochromatin and silencing retrotransposons.
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Affiliation(s)
- Weifeng Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Lingling Cheng
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Kuan Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Leiming Xie
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinyao Ji
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xue Lei
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Anjie Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Chunlai Chen
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haitao Li
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- State Key Laboratory of Molecular Oncology, MOE Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing, China
| | - Pilong Li
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qianwen Sun
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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2
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Gopinathan G, Xu Q, Luan X, Diekwisch TGH. CFDP1 regulates the stability of pericentric heterochromatin thereby affecting RAN GTPase activity and mitotic spindle formation. PLoS Biol 2024; 22:e3002574. [PMID: 38630655 PMCID: PMC11023358 DOI: 10.1371/journal.pbio.3002574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 03/02/2024] [Indexed: 04/19/2024] Open
Abstract
The densely packed centromeric heterochromatin at minor and major satellites is comprised of H3K9me2/3 histones, the heterochromatin protein HP1α, and histone variants. In the present study, we sought to determine the mechanisms by which condensed heterochromatin at major and minor satellites stabilized by the chromatin factor CFDP1 affects the activity of the small GTPase Ran as a requirement for spindle formation. CFDP1 colocalized with heterochromatin at major and minor satellites and was essential for the structural stability of centromeric heterochromatin. Loss of CENPA, HP1α, and H2A.Z heterochromatin components resulted in decreased binding of the spindle nucleation facilitator RCC1 to minor and major satellite repeats. Decreased RanGTP levels as a result of diminished RCC1 binding interfered with chromatin-mediated microtubule nucleation at the onset of mitotic spindle formation. Rescuing chromatin H2A.Z levels in cells and mice lacking CFDP1 through knock-down of the histone chaperone ANP32E not only partially restored RCC1-dependent RanGTP levels but also alleviated CFDP1-knockout-related craniofacial defects and increased microtubule nucleation in CFDP1/ANP32E co-silenced cells. Together, these studies provide evidence for a direct link between condensed heterochromatin at major and minor satellites and microtubule nucleation through the chromatin protein CFDP1.
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Affiliation(s)
- Gokul Gopinathan
- School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Qian Xu
- School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Xianghong Luan
- School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Thomas G. H. Diekwisch
- School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
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Packiaraj J, Thakur J. DNA satellite and chromatin organization at mouse centromeres and pericentromeres. Genome Biol 2024; 25:52. [PMID: 38378611 PMCID: PMC10880262 DOI: 10.1186/s13059-024-03184-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 02/12/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND Centromeres are essential for faithful chromosome segregation during mitosis and meiosis. However, the organization of satellite DNA and chromatin at mouse centromeres and pericentromeres is poorly understood due to the challenges of assembling repetitive genomic regions. RESULTS Using recently available PacBio long-read sequencing data from the C57BL/6 strain, we find that contrary to the previous reports of their homogeneous nature, both centromeric minor satellites and pericentromeric major satellites exhibit a high degree of variation in sequence and organization within and between arrays. While most arrays are continuous, a significant fraction is interspersed with non-satellite sequences, including transposable elements. Using chromatin immunoprecipitation sequencing (ChIP-seq), we find that the occupancy of CENP-A and H3K9me3 chromatin at centromeric and pericentric regions, respectively, is associated with increased sequence enrichment and homogeneity at these regions. The transposable elements at centromeric regions are not part of functional centromeres as they lack significant CENP-A enrichment. Furthermore, both CENP-A and H3K9me3 nucleosomes occupy minor and major satellites spanning centromeric-pericentric junctions and a low yet significant amount of CENP-A spreads locally at centromere junctions on both pericentric and telocentric sides. Finally, while H3K9me3 nucleosomes display a well-phased organization on major satellite arrays, CENP-A nucleosomes on minor satellite arrays are poorly phased. Interestingly, the homogeneous class of major satellites also phase CENP-A and H3K27me3 nucleosomes, indicating that the nucleosome phasing is an inherent property of homogeneous major satellites. CONCLUSIONS Our findings reveal that mouse centromeres and pericentromeres display a high diversity in satellite sequence, organization, and chromatin structure.
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Affiliation(s)
- Jenika Packiaraj
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA, 30322, USA
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA, 30322, USA.
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4
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Bogolyubova IO, Sailau ZK, Bogolyubov DS. Nuclear Distribution of the Chromatin-Remodeling Protein ATRX in Mouse Early Embryos during Normal Development and Developmental Arrest In Vitro. Life (Basel) 2023; 14:5. [PMID: 38276254 PMCID: PMC10817635 DOI: 10.3390/life14010005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/12/2023] [Accepted: 12/17/2023] [Indexed: 01/27/2024] Open
Abstract
The chromatin-remodeling protein ATRX, which is currently recognized as one of the key genome caretakers, plays an important role in oogenesis and early embryogenesis in mammals. ATRX distribution in the nuclei of mouse embryos developing in vivo and in vitro, including when the embryos are arrested at the two-cell stage-the so-called two-cell block in vitro-was studied using immunofluorescent labeling and FISH. In normally developing two- and four-cell embryos, ATRX was found to be closely colocalized with pericentromeric DNA sequences detected with a probe to the mouse major satellite DNA. The association of ATRX with pericentromeric heterochromatin is mediated by nuclear actin and reduced after the treatment of embryos with latrunculin B. When culturing embryos in vitro, the distribution pattern of ATRX changes, leading to a decrease in the association of this protein with major satellite DNA especially under the two-cell block in vitro. Taken together, our data suggest that the intranuclear distribution of ATRX reflects the viability of mouse embryos and their probability of successful preimplantation development.
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Affiliation(s)
- Irina O. Bogolyubova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia;
| | - Zhuldyz K. Sailau
- PERSONA International Clinical Center for Reproductology, Almaty 050060, Kazakhstan;
| | - Dmitry S. Bogolyubov
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia;
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5
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Malla AB, Yu H, Farris D, Kadimi S, Lam TT, Cox AL, Smith ZD, Lesch BJ. DOT1L bridges transcription and heterochromatin formation at mammalian pericentromeres. EMBO Rep 2023; 24:e56492. [PMID: 37317657 PMCID: PMC10398668 DOI: 10.15252/embr.202256492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 04/28/2023] [Accepted: 05/26/2023] [Indexed: 06/16/2023] Open
Abstract
Repetitive DNA elements are packaged in heterochromatin, but many require bursts of transcription to initiate and maintain long-term silencing. The mechanisms by which these heterochromatic genome features are transcribed remain largely unknown. Here, we show that DOT1L, a conserved histone methyltransferase that modifies lysine 79 of histone H3 (H3K79), has a specialized role in transcription of major satellite repeats to maintain pericentromeric heterochromatin and genome stability. We find that H3K79me3 is selectively enriched relative to H3K79me2 at repetitive elements in mouse embryonic stem cells (mESCs), that DOT1L loss compromises pericentromeric satellite transcription, and that this activity involves possible coordination between DOT1L and the chromatin remodeler SMARCA5. Stimulation of transcript production from pericentromeric repeats by DOT1L participates in stabilization of heterochromatin structures in mESCs and cleavage-stage embryos and is required for preimplantation viability. Our findings uncover an important role for DOT1L as a bridge between transcriptional activation of repeat elements and heterochromatin stability, advancing our understanding of how genome integrity is maintained and how chromatin state is set up during early development.
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Affiliation(s)
- Aushaq B Malla
- Department of GeneticsYale School of MedicineNew HavenCTUSA
| | - Haoming Yu
- Department of GeneticsYale School of MedicineNew HavenCTUSA
| | - Delaney Farris
- Department of GeneticsYale School of MedicineNew HavenCTUSA
| | | | - TuKiet T Lam
- Keck MS & Proteomics ResourceYale School of MedicineNew HavenCTUSA
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
| | - Andy L Cox
- Department of GeneticsYale School of MedicineNew HavenCTUSA
| | - Zachary D Smith
- Department of GeneticsYale School of MedicineNew HavenCTUSA
- Yale Stem Cell CenterYale School of MedicineNew HavenCTUSA
| | - Bluma J Lesch
- Department of GeneticsYale School of MedicineNew HavenCTUSA
- Yale Cancer CenterYale School of MedicineNew HavenCTUSA
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6
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Packiaraj J, Thakur J. DNA satellite and chromatin organization at house mouse centromeres and pericentromeres. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549612. [PMID: 37503200 PMCID: PMC10370071 DOI: 10.1101/2023.07.18.549612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Centromeres are essential for faithful chromosome segregation during mitosis and meiosis. However, the organization of satellite DNA and chromatin at mouse centromeres and pericentromeres is poorly understood due to the challenges of sequencing and assembling repetitive genomic regions. Using recently available PacBio long-read sequencing data from the C57BL/6 strain and chromatin profiling, we found that contrary to the previous reports of their highly homogeneous nature, centromeric and pericentromeric satellites display varied sequences and organization. We find that both centromeric minor satellites and pericentromeric major satellites exhibited sequence variations within and between arrays. While most arrays are continuous, a significant fraction is interspersed with non-satellite sequences, including transposable elements. Additionally, we investigated CENP-A and H3K9me3 chromatin organization at centromeres and pericentromeres using Chromatin immunoprecipitation sequencing (ChIP-seq). We found that the occupancy of CENP-A and H3K9me3 chromatin at centromeric and pericentric regions, respectively, is associated with increased sequence abundance and homogeneity at these regions. Furthermore, the transposable elements at centromeric regions are not part of functional centromeres as they lack CENP-A enrichment. Finally, we found that while H3K9me3 nucleosomes display a well-phased organization on major satellite arrays, CENP-A nucleosomes on minor satellite arrays lack phased organization. Interestingly, the homogeneous class of major satellites phase CENP-A and H3K27me3 nucleosomes as well, indicating that the nucleosome phasing is an inherent property of homogeneous major satellites. Overall, our findings reveal that house mouse centromeres and pericentromeres, which were previously thought to be highly homogenous, display significant diversity in satellite sequence, organization, and chromatin structure.
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Affiliation(s)
- Jenika Packiaraj
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA 30322
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA 30322
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Wang Y, Yao X, Xu Y, Cheng X, Peng J, Pan Q, Hu K, Li L, Zhang Y, Yin D. Visual assessment of global chromatin intranuclear localization and its cellular diversification in mouse cells. Acta Biochim Biophys Sin (Shanghai) 2023; 55:518-520. [PMID: 36891816 PMCID: PMC10160228 DOI: 10.3724/abbs.2023034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/02/2022] [Indexed: 03/05/2023] Open
Affiliation(s)
- Yongqiang Wang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Xinyi Yao
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Yuanyuan Xu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Xu Cheng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Jiangyun Peng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Qimei Pan
- Institute of Rocket Force MedicineState Key Laboratory of TraumaBurns and Combined InjuryThird Military Medical University (Army Medical University)Chongqing400038China
| | - Kaishun Hu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Lu Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Yin Zhang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
| | - Dong Yin
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene RegulationSun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhou510000China
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8
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Siouda M, Dujardin AD, Dekeyzer B, Schaeffer L, Mulligan P. Chromodomain on Y-like 2 (CDYL2) implicated in mitosis and genome stability regulation via interaction with CHAMP1 and POGZ. Cell Mol Life Sci 2023; 80:47. [PMID: 36658409 PMCID: PMC11072993 DOI: 10.1007/s00018-022-04659-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 01/21/2023]
Abstract
Histone H3 trimethylation on lysine 9 (H3K9me3) is a defining feature of mammalian pericentromeres, loss of which results in genome instability. Here we show that CDYL2 is recruited to pericentromeres in an H3K9me3-dependent manner and is required for faithful mitosis and genome stability. CDYL2 RNAi in MCF-7 breast cancer cells and Hela cervical cancer cells inhibited their growth, induced apoptosis, and provoked both nuclear and mitotic aberrations. Mass spectrometry analysis of CDYL2-interacting proteins identified the neurodevelopmental disease-linked mitotic regulators CHAMP1 and POGZ, which are associated with a central non-conserved region of CDYL2. RNAi rescue assays identified both the CDYL2 chromodomain and the CHAMP1-POGZ interacting region as required and, together, sufficient for CDYL2 regulation of mitosis and genome stability. CDYL2 RNAi caused loss of CHAMP1 localization at pericentromeres. We propose that CDYL2 functions as an adaptor protein that connects pericentromeric H3K9me3 with CHAMP1 and POGZ to ensure mitotic fidelity and genome stability.
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Affiliation(s)
- Maha Siouda
- Centre Léon Bérard, Cancer Research Center of Lyon, Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Lyon, France
| | - Audrey D Dujardin
- Centre Léon Bérard, Cancer Research Center of Lyon, Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Lyon, France
| | - Blanche Dekeyzer
- Centre Léon Bérard, Cancer Research Center of Lyon, Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Lyon, France
| | - Laurent Schaeffer
- Faculté de Médecine, Physiopathology and Genetics of Neurons and Muscles Division, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, INSERM U1217, CNRS, UMR5310, 3ème étage, Aile B, 8 Avenue Rockefeller, 69008, Lyon, France
- Centre de Biotechnologie Cellulaire, CBC Biotec, CHU de Lyon - HCL Groupement Est, 59 Bvd Pinel, 69677, Cedex Bron, France
| | - Peter Mulligan
- Centre Léon Bérard, Cancer Research Center of Lyon, Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Lyon, France.
- Faculté de Médecine, Physiopathology and Genetics of Neurons and Muscles Division, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, INSERM U1217, CNRS, UMR5310, 3ème étage, Aile B, 8 Avenue Rockefeller, 69008, Lyon, France.
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Prakash Yadav R, Leskinen S, Ma L, Mäkelä JA, Kotaja N. Chromatin remodelers HELLS, WDHD1 and BAZ1A are dynamically expressed during mouse spermatogenesis. Reproduction 2023; 165:49-63. [PMID: 36194437 PMCID: PMC9782464 DOI: 10.1530/rep-22-0240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022]
Abstract
In brief Proper regulation of heterochromatin is critical for spermatogenesis. This study reveals the dynamic localization patterns of distinct chromatin regulators during spermatogenesis and disrupted sex chromatin status in spermatocytes in the absence of DICER. Abstract Heterochromatin is dynamically formed and organized in differentiating male germ cells, and its proper regulation is a prerequisite for normal spermatogenesis. While heterochromatin is generally transcriptionally silent, we have previously shown that major satellite repeat (MSR) DNA in the pericentric heterochromatin (PCH) is transcribed during spermatogenesis. We have also shown that DICER associates with PCH and is involved in the regulation of MSR-derived transcripts. To shed light on the heterochromatin regulation in the male germline, we studied the expression, localization and heterochromatin association of selected testis-enriched chromatin regulators in the mouse testis. Our results show that HELLS, WDHD1 and BAZ1A are dynamically expressed during spermatogenesis. They display limited overlap in expression, suggesting involvement in distinct heterochromatin-associated processes at different steps of differentiation. We also show that HELLS and BAZ1A interact with DICER and MSR chromatin. Interestingly, deletion of Dicer1 affects the sex chromosome heterochromatin status in late pachytene spermatocytes, as demonstrated by mislocalization of Polycomb protein family member SCML1 to the sex body. These data substantiate the importance of dynamic heterochromatin regulation during spermatogenesis and emphasize the key role of DICER in the maintenance of chromatin status in meiotic male germ cells.
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Affiliation(s)
- Ram Prakash Yadav
- 1Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Turku, Finland
| | - Sini Leskinen
- 1Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Turku, Finland
| | - Lin Ma
- 1Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Turku, Finland
| | - Juho-Antti Mäkelä
- 1Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Turku, Finland
| | - Noora Kotaja
- 1Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Turku, Finland
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10
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Johann to Berens P, Schivre G, Theune M, Peter J, Sall SO, Mutterer J, Barneche F, Bourbousse C, Molinier J. Advanced Image Analysis Methods for Automated Segmentation of Subnuclear Chromatin Domains. EPIGENOMES 2022; 6:epigenomes6040034. [PMID: 36278680 PMCID: PMC9624336 DOI: 10.3390/epigenomes6040034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/19/2022] [Accepted: 10/01/2022] [Indexed: 11/07/2022] Open
Abstract
The combination of ever-increasing microscopy resolution with cytogenetical tools allows for detailed analyses of nuclear functional partitioning. However, the need for reliable qualitative and quantitative methodologies to detect and interpret chromatin sub-nuclear organization dynamics is crucial to decipher the underlying molecular processes. Having access to properly automated tools for accurate and fast recognition of complex nuclear structures remains an important issue. Cognitive biases associated with human-based curation or decisions for object segmentation tend to introduce variability and noise into image analysis. Here, we report the development of two complementary segmentation methods, one semi-automated (iCRAQ) and one based on deep learning (Nucl.Eye.D), and their evaluation using a collection of A. thaliana nuclei with contrasted or poorly defined chromatin compartmentalization. Both methods allow for fast, robust and sensitive detection as well as for quantification of subtle nucleus features. Based on these developments, we highlight advantages of semi-automated and deep learning-based analyses applied to plant cytogenetics.
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Affiliation(s)
| | - Geoffrey Schivre
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Inserm, Université PSL, 75230 Paris, France
- Université Paris-Saclay, 91190 Orsay, France
| | - Marius Theune
- FB 10 / Molekulare Pflanzenphysiologie, Bioenergetik in Photoautotrophen, Universität Kassel, 34127 Kassel, Germany
| | - Jackson Peter
- Institut de Biologie Moléculaire des Plantes du CNRS, 67000 Strasbourg, France
| | | | - Jérôme Mutterer
- Institut de Biologie Moléculaire des Plantes du CNRS, 67000 Strasbourg, France
| | - Fredy Barneche
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Inserm, Université PSL, 75230 Paris, France
| | - Clara Bourbousse
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Inserm, Université PSL, 75230 Paris, France
- Correspondence: (C.B.); (J.M.)
| | - Jean Molinier
- Institut de Biologie Moléculaire des Plantes du CNRS, 67000 Strasbourg, France
- Correspondence: (C.B.); (J.M.)
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11
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Singh PB, Newman AG. HP1-Driven Micro-Phase Separation of Heterochromatin-Like Domains/Complexes. Epigenet Insights 2022; 15:25168657221109766. [PMID: 35813402 PMCID: PMC9260563 DOI: 10.1177/25168657221109766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022] Open
Affiliation(s)
- Prim B Singh
- Department of Medicine, Nazarbayev University School of Medicine, Nur-Sultan, Kazakhstan
| | - Andrew G Newman
- Institute of Cell and Neurobiology, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
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12
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Unveiling RCOR1 as a rheostat at transcriptionally permissive chromatin. Nat Commun 2022; 13:1550. [PMID: 35322029 PMCID: PMC8943175 DOI: 10.1038/s41467-022-29261-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/01/2022] [Indexed: 12/23/2022] Open
Abstract
RCOR1 is a known transcription repressor that recruits and positions LSD1 and HDAC1/2 on chromatin to erase histone methylation and acetylation. However, there is currently an incomplete understanding of RCOR1’s range of localization and function. Here, we probe RCOR1’s distribution on a genome-wide scale and unexpectedly find that RCOR1 is predominantly associated with transcriptionally active genes. Biochemical analysis reveals that RCOR1 associates with RNA Polymerase II (POL-II) during transcription and deacetylates its carboxy-terminal domain (CTD) at lysine 7. We provide evidence that this non-canonical RCOR1 activity is linked to dampening of POL-II productive elongation at actively transcribing genes. Thus, RCOR1 represses transcription in two ways—first, via a canonical mechanism by erasing transcriptionally permissive histone modifications through associating with HDACs and, second, via a non-canonical mechanism that deacetylates RNA POL-II’s CTD to inhibit productive elongation. We conclude that RCOR1 is a transcription rheostat. The classical neuronal-gene corepressor RCOR1/CoREST is paradoxically enriched in transcriptionally active chromatin. Here the authors show RCOR1 is recruited during promoter-proximal pausing and negatively regulates the nascent-transcript synthesis. They also show that an RCOR1-LSD1- HDAC1 complex removes lysine acetylation from RNA polymerase II to repress transcription.
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13
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Arrastia MV, Jachowicz JW, Ollikainen N, Curtis MS, Lai C, Quinodoz SA, Selck DA, Ismagilov RF, Guttman M. Single-cell measurement of higher-order 3D genome organization with scSPRITE. Nat Biotechnol 2022; 40:64-73. [PMID: 34426703 PMCID: PMC11588347 DOI: 10.1038/s41587-021-00998-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 06/25/2021] [Indexed: 02/07/2023]
Abstract
Although three-dimensional (3D) genome organization is central to many aspects of nuclear function, it has been difficult to measure at the single-cell level. To address this, we developed 'single-cell split-pool recognition of interactions by tag extension' (scSPRITE). scSPRITE uses split-and-pool barcoding to tag DNA fragments in the same nucleus and their 3D spatial arrangement. Because scSPRITE measures multiway DNA contacts, it generates higher-resolution maps within an individual cell than can be achieved by proximity ligation. We applied scSPRITE to thousands of mouse embryonic stem cells and detected known genome structures, including chromosome territories, active and inactive compartments, and topologically associating domains (TADs) as well as long-range inter-chromosomal structures organized around various nuclear bodies. We observe that these structures exhibit different levels of heterogeneity across the population, with TADs representing dynamic units of genome organization across cells. We expect that scSPRITE will be a critical tool for studying genome structure within heterogeneous populations.
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Affiliation(s)
- Mary V Arrastia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Joanna W Jachowicz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Noah Ollikainen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Matthew S Curtis
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Charlotte Lai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sofia A Quinodoz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - David A Selck
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Rustem F Ismagilov
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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14
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Fioriniello S, Csukonyi E, Marano D, Brancaccio A, Madonna M, Zarrillo C, Romano A, Marracino F, Matarazzo MR, D'Esposito M, Della Ragione F. MeCP2 and Major Satellite Forward RNA Cooperate for Pericentric Heterochromatin Organization. Stem Cell Reports 2021; 15:1317-1332. [PMID: 33296675 PMCID: PMC7724518 DOI: 10.1016/j.stemcr.2020.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/20/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) has historically been linked to heterochromatin organization, and in mouse cells it accumulates at pericentric heterochromatin (PCH), closely following major satellite (MajSat) DNA distribution. However, little is known about the specific function of MeCP2 in these regions. We describe the first evidence of a role in neurons for MeCP2 and MajSat forward (MajSat-fw) RNA in reciprocal targeting to PCH through their physical interaction. Moreover, MeCP2 contributes to maintenance of PCH by promoting deposition of H3K9me3 and H4K20me3. We highlight that the MeCP2B isoform is required for correct higher-order PCH organization, and underline involvement of the methyl-binding and transcriptional repression domains. The T158 residue, which is commonly mutated in Rett patients, is directly involved in this process. Our findings support the hypothesis that MeCP2 and the MajSat-fw transcript are mutually dependent for PCH organization, and contribute to clarify MeCP2 function in the regulation of chromatin architecture.
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Affiliation(s)
- Salvatore Fioriniello
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | - Eva Csukonyi
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | - Domenico Marano
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | - Arianna Brancaccio
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | | | - Carmela Zarrillo
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | | | | | - Maria R Matarazzo
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, Naples 80131, Italy
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15
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Remnant L, Kochanova NY, Reid C, Cisneros-Soberanis F, Earnshaw WC. The intrinsically disorderly story of Ki-67. Open Biol 2021; 11:210120. [PMID: 34375547 PMCID: PMC8354752 DOI: 10.1098/rsob.210120] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/13/2021] [Indexed: 01/14/2023] Open
Abstract
Ki-67 is one of the most famous marker proteins used by histologists to identify proliferating cells. Indeed, over 30 000 articles referring to Ki-67 are listed on PubMed. Here, we review some of the current literature regarding the protein. Despite its clinical importance, our knowledge of the molecular biology and biochemistry of Ki-67 is far from complete, and its exact molecular function(s) remain enigmatic. Furthermore, reports describing Ki-67 function are often contradictory, and it has only recently become clear that this proliferation marker is itself dispensable for cell proliferation. We discuss the unusual organization of the protein and its mRNA and how they relate to various models for its function. In particular, we focus on ways in which the intrinsically disordered structure of Ki-67 might aid in the assembly of the still-mysterious mitotic chromosome periphery compartment by controlling liquid-liquid phase separation of nucleolar proteins and RNAs.
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Affiliation(s)
- Lucy Remnant
- Wellcome Centre for Cell Biology, University of Edinburgh, ICB, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Natalia Y. Kochanova
- Wellcome Centre for Cell Biology, University of Edinburgh, ICB, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Caitlin Reid
- Wellcome Centre for Cell Biology, University of Edinburgh, ICB, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Fernanda Cisneros-Soberanis
- Wellcome Centre for Cell Biology, University of Edinburgh, ICB, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - William C. Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, ICB, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
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16
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Rachez C, Legendre R, Costallat M, Varet H, Yi J, Kornobis E, Muchardt C. HP1γ binding pre-mRNA intronic repeats modulates RNA splicing decisions. EMBO Rep 2021; 22:e52320. [PMID: 34312949 DOI: 10.15252/embr.202052320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 12/30/2022] Open
Abstract
HP1 proteins are best known as markers of heterochromatin and gene silencing. Yet, they are also RNA-binding proteins and the HP1γ/CBX3 family member is present on transcribed genes together with RNA polymerase II, where it regulates co-transcriptional processes such as alternative splicing. To gain insight in the role of the RNA-binding activity of HP1γ in transcriptionally active chromatin, we have captured and analysed RNAs associated with this protein. We find that HP1γ is specifically targeted to hexameric RNA motifs and coincidentally transposable elements of the SINE family. As these elements are abundant in introns, while essentially absent from exons, the HP1γ RNA association tethers unspliced pre-mRNA to chromatin via the intronic regions and limits the usage of intronic cryptic splice sites. Thus, our data unveil novel determinants in the relationship between chromatin and co-transcriptional splicing.
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Affiliation(s)
- Christophe Rachez
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Rachel Legendre
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, USR 3756 CNRS, Paris, France.,Biomics Technological Platform, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Mickaël Costallat
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Hugo Varet
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, USR 3756 CNRS, Paris, France.,Biomics Technological Platform, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Jia Yi
- Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France.,Sorbonne Université, Ecole Doctorale Complexité du Vivant (ED515), Paris, France
| | - Etienne Kornobis
- Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Christian Muchardt
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
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17
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Transcriptomic and Epigenomic Landscape in Rett Syndrome. Biomolecules 2021; 11:biom11070967. [PMID: 34209228 PMCID: PMC8301932 DOI: 10.3390/biom11070967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 12/13/2022] Open
Abstract
Rett syndrome (RTT) is an extremely invalidating, cureless, developmental disorder, and it is considered one of the leading causes of intellectual disability in female individuals. The vast majority of RTT cases are caused by de novo mutations in the X-linked Methyl-CpG binding protein 2 (MECP2) gene, which encodes a multifunctional reader of methylated DNA. MeCP2 is a master epigenetic modulator of gene expression, with a role in the organization of global chromatin architecture. Based on its interaction with multiple molecular partners and the diverse epigenetic scenario, MeCP2 triggers several downstream mechanisms, also influencing the epigenetic context, and thus leading to transcriptional activation or repression. In this frame, it is conceivable that defects in such a multifaceted factor as MeCP2 lead to large-scale alterations of the epigenome, ranging from an unbalanced deposition of epigenetic modifications to a transcriptional alteration of both protein-coding and non-coding genes, with critical consequences on multiple downstream biological processes. In this review, we provide an overview of the current knowledge concerning the transcriptomic and epigenomic alterations found in RTT patients and animal models.
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18
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Morrison O, Thakur J. Molecular Complexes at Euchromatin, Heterochromatin and Centromeric Chromatin. Int J Mol Sci 2021; 22:6922. [PMID: 34203193 PMCID: PMC8268097 DOI: 10.3390/ijms22136922] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023] Open
Abstract
Chromatin consists of a complex of DNA and histone proteins as its core components and plays an important role in both packaging DNA and regulating DNA metabolic pathways such as DNA replication, transcription, recombination, and chromosome segregation. Proper functioning of chromatin further involves a network of interactions among molecular complexes that modify chromatin structure and organization to affect the accessibility of DNA to transcription factors leading to the activation or repression of the transcription of target DNA loci. Based on its structure and compaction state, chromatin is categorized into euchromatin, heterochromatin, and centromeric chromatin. In this review, we discuss distinct chromatin factors and molecular complexes that constitute euchromatin-open chromatin structure associated with active transcription; heterochromatin-less accessible chromatin associated with silencing; centromeric chromatin-the site of spindle binding in chromosome segregation.
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Affiliation(s)
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd #2006, Atlanta, GA 30322, USA;
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19
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Tet1 regulates epigenetic remodeling of the pericentromeric heterochromatin and chromocenter organization in DNA hypomethylated cells. PLoS Genet 2021; 17:e1009646. [PMID: 34166371 PMCID: PMC8263065 DOI: 10.1371/journal.pgen.1009646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 07/07/2021] [Accepted: 06/04/2021] [Indexed: 01/04/2023] Open
Abstract
Pericentromeric heterochromatin (PCH), the constitutive heterochromatin of pericentromeric regions, plays crucial roles in various cellular events, such as cell division and DNA replication. PCH forms chromocenters in the interphase nucleus, and chromocenters cluster at the prophase of meiosis. Chromocenter clustering has been reported to be critical for the appropriate progression of meiosis. However, the molecular mechanisms underlying chromocenter clustering remain elusive. In this study, we found that global DNA hypomethylation, 5hmC enrichment in PCH, and chromocenter clustering of Dnmt1-KO ESCs were similar to those of the female meiotic germ cells. Tet1 is essential for the deposition of 5hmC and facultative histone marks of H3K27me3 and H2AK119ub at PCH, as well as chromocenter clustering. RING1B, one of the core components of PRC1, is recruited to PCH by TET1, and PRC1 plays a critical role in chromocenter clustering. In addition, the rearrangement of the chromocenter under DNA hypomethylated condition was mediated by liquid-liquid phase separation. Thus, we demonstrated a novel role of Tet1 in chromocenter rearrangement in DNA hypomethylated cells.
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20
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The Multiple Facets of ATRX Protein. Cancers (Basel) 2021; 13:cancers13092211. [PMID: 34062956 PMCID: PMC8124985 DOI: 10.3390/cancers13092211] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary The gene encoding for the epigenetic regulator ATRX is gaining a prominent position among the most important oncosuppressive genes of the human genome. ATRX gene somatic mutations are found across a number of diverse cancer types, suggesting its relevance in tumor induction and progression. In the present review, the multiple activities of ATRX protein are described in the light of the most recent literature available highlighting its multifaceted role in the caretaking of the human genome. Abstract ATRX gene codifies for a protein member of the SWI-SNF family and was cloned for the first time over 25 years ago as the gene responsible for a rare developmental disorder characterized by α-thalassemia and intellectual disability called Alpha Thalassemia/mental Retardation syndrome X-linked (ATRX) syndrome. Since its discovery as a helicase involved in alpha-globin gene transcriptional regulation, our understanding of the multiple roles played by the ATRX protein increased continuously, leading to the recognition of this multifaceted protein as a central “caretaker” of the human genome involved in cancer suppression. In this review, we report recent advances in the comprehension of the ATRX manifold functions that encompass heterochromatin epigenetic regulation and maintenance, telomere function, replicative stress response, genome stability, and the suppression of endogenous transposable elements and exogenous viral genomes.
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21
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Thakur J, Packiaraj J, Henikoff S. Sequence, Chromatin and Evolution of Satellite DNA. Int J Mol Sci 2021; 22:ijms22094309. [PMID: 33919233 PMCID: PMC8122249 DOI: 10.3390/ijms22094309] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/15/2022] Open
Abstract
Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protection. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embedded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.
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Affiliation(s)
- Jitendra Thakur
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
- Correspondence:
| | - Jenika Packiaraj
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Fred Hutchinson Cancer Research Center, Howard Hughes Medical Institute, Seattle, WA 98109, USA
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22
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Thakur J, Henikoff S. Architectural RNA in chromatin organization. Biochem Soc Trans 2020; 48:1967-1978. [PMID: 32897323 PMCID: PMC7609026 DOI: 10.1042/bst20191226] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022]
Abstract
RNA plays a well-established architectural role in the formation of membraneless interchromatin nuclear bodies. However, a less well-known role of RNA is in organizing chromatin, whereby specific RNAs have been found to recruit chromatin modifier proteins. Whether or not RNA can act as an architectural molecule for chromatin remains unclear, partly because dissecting the architectural role of RNA from its regulatory role remains challenging. Studies that have addressed RNA's architectural role in chromatin organization rely on in situ RNA depletion using Ribonuclease A (RNase A) and suggest that RNA plays a major direct architectural role in chromatin organization. In this review, we will discuss these findings, candidate chromatin architectural long non-coding RNAs and possible mechanisms by which RNA, along with RNA binding proteins might be mediating chromatin organization.
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Affiliation(s)
- Jitendra Thakur
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
- Howard Hughes Medical Institute, Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
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23
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Yadav RP, Mäkelä JA, Hyssälä H, Cisneros-Montalvo S, Kotaja N. DICER regulates the expression of major satellite repeat transcripts and meiotic chromosome segregation during spermatogenesis. Nucleic Acids Res 2020; 48:7135-7153. [PMID: 32484548 PMCID: PMC7367195 DOI: 10.1093/nar/gkaa460] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/23/2020] [Accepted: 05/22/2020] [Indexed: 12/16/2022] Open
Abstract
Constitutive heterochromatin at the pericentric regions of chromosomes undergoes dynamic changes in its epigenetic and spatial organization during spermatogenesis. Accurate control of pericentric heterochromatin is required for meiotic cell divisions and production of fertile and epigenetically intact spermatozoa. In this study, we demonstrate that pericentric heterochromatin is expressed during mouse spermatogenesis to produce major satellite repeat (MSR) transcripts. We show that the endonuclease DICER localizes to the pericentric heterochromatin in the testis. Furthermore, DICER forms complexes with MSR transcripts, and their processing into small RNAs is compromised in Dicer1 knockout mice leading to an elevated level of MSR transcripts in meiotic cells. We also show that defective MSR forward transcript processing in Dicer1 cKO germ cells is accompanied with reduced recruitment of SUV39H2 and H3K9me3 to the pericentric heterochromatin and meiotic chromosome missegregation. Altogether, our results indicate that the physiological role of DICER in maintenance of male fertility extends to the regulation of pericentric heterochromatin through direct targeting of MSR transcripts.
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Affiliation(s)
- Ram Prakash Yadav
- Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Finland
| | - Juho-Antti Mäkelä
- Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Finland
| | - Hanna Hyssälä
- Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Finland
| | - Sheyla Cisneros-Montalvo
- Institute of Biomedicine, Integrative Physiology and Pharmacology Unit, University of Turku, Finland
| | - Noora Kotaja
- To whom correspondence should be addressed. Tel: +358 44 2539225;
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24
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Martins NMC, Cisneros-Soberanis F, Pesenti E, Kochanova NY, Shang WH, Hori T, Nagase T, Kimura H, Larionov V, Masumoto H, Fukagawa T, Earnshaw WC. H3K9me3 maintenance on a human artificial chromosome is required for segregation but not centromere epigenetic memory. J Cell Sci 2020; 133:jcs242610. [PMID: 32576667 PMCID: PMC7390644 DOI: 10.1242/jcs.242610] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/11/2020] [Indexed: 12/24/2022] Open
Abstract
Most eukaryotic centromeres are located within heterochromatic regions. Paradoxically, heterochromatin can also antagonize de novo centromere formation, and some centromeres lack it altogether. In order to investigate the importance of heterochromatin at centromeres, we used epigenetic engineering of a synthetic alphoidtetO human artificial chromosome (HAC), to which chimeric proteins can be targeted. By tethering the JMJD2D demethylase (also known as KDM4D), we removed heterochromatin mark H3K9me3 (histone 3 lysine 9 trimethylation) specifically from the HAC centromere. This caused no short-term defects, but long-term tethering reduced HAC centromere protein levels and triggered HAC mis-segregation. However, centromeric CENP-A was maintained at a reduced level. Furthermore, HAC centromere function was compatible with an alternative low-H3K9me3, high-H3K27me3 chromatin signature, as long as residual levels of H3K9me3 remained. When JMJD2D was released from the HAC, H3K9me3 levels recovered over several days back to initial levels along with CENP-A and CENP-C centromere levels, and mitotic segregation fidelity. Our results suggest that a minimal level of heterochromatin is required to stabilize mitotic centromere function but not for maintaining centromere epigenetic memory, and that a homeostatic pathway maintains heterochromatin at centromeres.This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
| | | | - Elisa Pesenti
- Wellcome Trust Centre for Cell Biology, Edinburgh, UK
| | | | - Wei-Hao Shang
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Tetsuya Hori
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | | | - Hiroshi Kimura
- Cell Biology Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Vladimir Larionov
- National Cancer Institute, National Institutes of Health, Bethesda, USA
| | | | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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25
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Epigenetic Factors That Control Pericentric Heterochromatin Organization in Mammals. Genes (Basel) 2020; 11:genes11060595. [PMID: 32481609 PMCID: PMC7349813 DOI: 10.3390/genes11060595] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Pericentric heterochromatin (PCH) is a particular form of constitutive heterochromatin that is localized to both sides of centromeres and that forms silent compartments enriched in repressive marks. These genomic regions contain species-specific repetitive satellite DNA that differs in terms of nucleotide sequences and repeat lengths. In spite of this sequence diversity, PCH is involved in many biological phenomena that are conserved among species, including centromere function, the preservation of genome integrity, the suppression of spurious recombination during meiosis, and the organization of genomic silent compartments in the nucleus. PCH organization and maintenance of its repressive state is tightly regulated by a plethora of factors, including enzymes (e.g., DNA methyltransferases, histone deacetylases, and histone methyltransferases), DNA and histone methylation binding factors (e.g., MECP2 and HP1), chromatin remodeling proteins (e.g., ATRX and DAXX), and non-coding RNAs. This evidence helps us to understand how PCH organization is crucial for genome integrity. It then follows that alterations to the molecular signature of PCH might contribute to the onset of many genetic pathologies and to cancer progression. Here, we describe the most recent updates on the molecular mechanisms known to underlie PCH organization and function.
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26
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Cappelli C, Sepulveda H, Rivas S, Pola V, Urzúa U, Donoso G, Sagredo E, Carrero D, Casanova-Ortiz E, Sagredo A, González M, Manterola M, Nardocci G, Armisén R, Montecino M, Marcelain K. Ski Is Required for Tri-Methylation of H3K9 in Major Satellite and for Repression of Pericentromeric Genes: Mmp3, Mmp10 and Mmp13, in Mouse Fibroblasts. J Mol Biol 2020; 432:3222-3238. [PMID: 32198114 DOI: 10.1016/j.jmb.2020.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/23/2020] [Accepted: 03/11/2020] [Indexed: 11/27/2022]
Abstract
Several mechanisms directing a rapid transcriptional reactivation of genes immediately after mitosis have been described. However, little is known about the maintenance of repressive signals during mitosis. In this work, we address the role of Ski in the repression of gene expression during M/G1 transition in mouse embryonic fibroblasts (MEFs). We found that Ski localises as a distinct pair of dots at the pericentromeric region of mitotic chromosomes, and the absence of the protein is related to high acetylation and low tri-methylation of H3K9 in pericentromeric major satellite. Moreover, differential expression assays in early G1 cells showed that the presence of Ski is significantly associated with repression of genes localised nearby to pericentromeric DNA. In mitotic cells, chromatin immunoprecipitation assays confirmed the association of Ski to major satellite and the promoters of the most repressed genes: Mmp3, Mmp10 and Mmp13. These genes are at pericentromeric region of chromosome 9. In these promoters, the presence of Ski resulted in increased H3K9 tri-methylation levels. This Ski-dependent regulation is also observed during interphase. Consequently, Mmp activity is augmented in Ski-/- MEFs. Altogether, these data indicate that association of Ski with the pericentromeric region of chromosomes during mitosis is required to maintain the silencing bookmarks of underlying chromatin.
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Affiliation(s)
- Claudio Cappelli
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile; Instituto de Bioquimica y Microbiologia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Hugo Sepulveda
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Solange Rivas
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Víctor Pola
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ulises Urzúa
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gerardo Donoso
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Eduardo Sagredo
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile; Centro de Genética y Genómica, Instituto de Ciencias e Innovación en Medicina, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - David Carrero
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Emmanuel Casanova-Ortiz
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Alfredo Sagredo
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marisel González
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marcia Manterola
- Instituto de Ciencias Biomédicas. Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gino Nardocci
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile; FONDAP Center for Genome Regulation, Santiago, Chile
| | - Ricardo Armisén
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile; Centro de Genética y Genómica, Instituto de Ciencias e Innovación en Medicina, Facultad de Medicina Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Martin Montecino
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile; FONDAP Center for Genome Regulation, Santiago, Chile
| | - Katherine Marcelain
- Departamento de Oncología Básico Clínica. Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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Strom AR, Brangwynne CP. The liquid nucleome - phase transitions in the nucleus at a glance. J Cell Sci 2019; 132:132/22/jcs235093. [PMID: 31754043 DOI: 10.1242/jcs.235093] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cells organize membrane-less internal compartments through a process called liquid-liquid phase separation (LLPS) to create chemically distinct compartments, referred to as condensates, which emerge from interactions among biological macromolecules. These condensates include various cytoplasmic structures such as P-granules and stress granules. However, an even wider array of condensates subcompartmentalize the cell nucleus, forming liquid-like structures that range from nucleoli and Cajal bodies to nuclear speckles and gems. Phase separation provides a biophysical assembly mechanism underlying this non-covalent form of fluid compartmentalization and functionalization. In this Cell Science at a Glance article and the accompanying poster, we term these phase-separated liquids that organize the nucleus the liquid nucleome; we discuss examples of biological phase transitions in the nucleus, how the cell utilizes biophysical aspects of phase separation to form and regulate condensates, and suggest interpretations for the role of phase separation in nuclear organization and function.
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Affiliation(s)
- Amy R Strom
- Department of Chemical and Biological Engineering, Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA
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28
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Marano D, Fioriniello S, Fiorillo F, Gibbons RJ, D'Esposito M, Della Ragione F. ATRX Contributes to MeCP2-Mediated Pericentric Heterochromatin Organization during Neural Differentiation. Int J Mol Sci 2019; 20:E5371. [PMID: 31671722 PMCID: PMC6862095 DOI: 10.3390/ijms20215371] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a multi-function factor involved in locus-specific transcriptional modulation and the regulation of genome architecture, e.g., pericentric heterochromatin (PCH) organization. MECP2 mutations are responsible for Rett syndrome (RTT), a devastating postnatal neurodevelopmental disorder, the pathogenetic mechanisms of which are still unknown. MeCP2, together with Alpha-thalassemia/mental retardation syndrome X-linked protein (ATRX), accumulates at chromocenters, which are repressive PCH domains. As with MECP2, mutations in ATRX cause ATR-X syndrome which is associated with severe intellectual disability. We exploited two murine embryonic stem cell lines, in which the expression of MeCP2 or ATRX is abolished. Through immunostaining, chromatin immunoprecipitation and western blot, we show that MeCP2 and ATRX are reciprocally dependent both for their expression and targeting to chromocenters. Moreover, ATRX plays a role in the accumulation of members of the heterochromatin protein 1 (HP1) family at PCH and, as MeCP2, modulates their expression. Furthermore, ATRX and HP1 targeting to chromocenters depends on an RNA component. 3D-DNA fluorescence in situ hybridization (FISH) highlighted, for the first time, a contribution of ATRX in MeCP2-mediated chromocenter clustering during neural differentiation. Overall, we provide a detailed dissection of the functional interplay between MeCP2 and ATRX in higher-order PCH organization in neurons. Our findings suggest molecular defects common to RTT and ATR-X syndrome, including an alteration in PCH.
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Affiliation(s)
- Domenico Marano
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Salvatore Fioriniello
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Francesca Fiorillo
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Richard J Gibbons
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
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29
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Kruszka P, Hu T, Hong S, Signer R, Cogné B, Isidor B, Mazzola SE, Giltay JC, van Gassen KLI, England EM, Pais L, Ockeloen CW, Sanchez-Lara PA, Kinning E, Adams DJ, Treat K, Torres-Martinez W, Bedeschi MF, Iascone M, Blaney S, Bell O, Tan TY, Delrue MA, Jurgens J, Barry BJ, Engle EC, Savage SK, Fleischer N, Martinez-Agosto JA, Boycott K, Zackai EH, Muenke M. Phenotype delineation of ZNF462 related syndrome. Am J Med Genet A 2019; 179:2075-2082. [PMID: 31361404 DOI: 10.1002/ajmg.a.61306] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/30/2019] [Accepted: 07/09/2019] [Indexed: 12/20/2022]
Abstract
Zinc finger protein 462 (ZNF462) is a relatively newly discovered vertebrate specific protein with known critical roles in embryonic development in animal models. Two case reports and a case series study have described the phenotype of 10 individuals with ZNF462 loss of function variants. Herein, we present 14 new individuals with loss of function variants to the previous studies to delineate the syndrome of loss of function in ZNF462. Collectively, these 24 individuals present with recurring phenotypes that define a multiple congenital anomaly syndrome. Most have some form of developmental delay (79%) and a minority has autism spectrum disorder (33%). Characteristic facial features include ptosis (83%), down slanting palpebral fissures (58%), exaggerated Cupid's bow/wide philtrum (54%), and arched eyebrows (50%). Metopic ridging or craniosynostosis was found in a third of study participants and feeding problems in half. Other phenotype characteristics include dysgenesis of the corpus callosum in 25% of individuals, hypotonia in half, and structural heart defects in 21%. Using facial analysis technology, a computer algorithm applying deep learning was able to accurately differentiate individuals with ZNF462 loss of function variants from individuals with Noonan syndrome and healthy controls. In summary, we describe a multiple congenital anomaly syndrome associated with haploinsufficiency of ZNF462 that has distinct clinical characteristics and facial features.
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Affiliation(s)
- Paul Kruszka
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Tommy Hu
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Sungkook Hong
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Rebecca Signer
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Benjamin Cogné
- Service de génétique médicale, Hôtel-Dieu, Nantes, France
| | - Betrand Isidor
- Service de génétique médicale, Hôtel-Dieu, Nantes, France
| | - Sarah E Mazzola
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Jacques C Giltay
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eleina M England
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Lynn Pais
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Charlotte W Ockeloen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pedro A Sanchez-Lara
- Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Esther Kinning
- West of Scotland Genetics Service, Queen Elizabeth Hospitals, Glasgow, Scotland
| | - Darius J Adams
- Personalized Genomic Medicine and Pediatric Genetics, Atlantic Health System, Morristown, New Jersey
| | - Kayla Treat
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | | | - Maria F Bedeschi
- Medical Genetic Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Iascone
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Stephanie Blaney
- Genetics, Vaccine Preventable Diseases, and Sexual Health, Algoma Public Health, Sault Ste. Marie, Ontario, Canada
| | - Oliver Bell
- Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Tiong Y Tan
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Victorian Clinical Genetics Services, Melbourne, Victoria, Australia
| | - Marie-Ange Delrue
- Département de pédiatrie, Service de génétique médicale, Centre Hospitalier Universitaire Ste-Justine, Université de Montréal, Montréal, Québec, Canada
| | - Julie Jurgens
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Brenda J Barry
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Elizabeth C Engle
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland.,Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | | | - Julian A Martinez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Kym Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Elaine H Zackai
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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30
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Mahmood N, Rabbani SA. DNA Methylation Readers and Cancer: Mechanistic and Therapeutic Applications. Front Oncol 2019; 9:489. [PMID: 31245293 PMCID: PMC6579900 DOI: 10.3389/fonc.2019.00489] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/23/2019] [Indexed: 12/14/2022] Open
Abstract
DNA methylation is a major epigenetic process that regulates chromatin structure which causes transcriptional activation or repression of genes in a context-dependent manner. In general, DNA methylation takes place when methyl groups are added to the appropriate bases on the genome by the action of "writer" molecules known as DNA methyltransferases. How these methylation marks are read and interpreted into different functionalities represents one of the main mechanisms through which the genes are switched "ON" or "OFF" and typically involves different types of "reader" proteins that can recognize and bind to the methylated regions. A tightly balanced regulation exists between the "writers" and "readers" in order to mediate normal cellular functions. However, alterations in normal methylation pattern is a typical hallmark of cancer which alters the way methylation marks are written, read and interpreted in different disease states. This unique characteristic of DNA methylation "readers" has identified them as attractive therapeutic targets. In this review, we describe the current state of knowledge on the different classes of DNA methylation "readers" identified thus far along with their normal biological functions, describe how they are dysregulated in cancer, and discuss the various anti-cancer therapies that are currently being developed and evaluated for targeting these proteins.
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Affiliation(s)
- Niaz Mahmood
- Department of Medicine, McGill University Health Centre, Montréal, QC, Canada
| | - Shafaat A Rabbani
- Department of Medicine, McGill University Health Centre, Montréal, QC, Canada
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31
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Spirkoski J, Shah A, Reiner AH, Collas P, Delbarre E. PML modulates H3.3 targeting to telomeric and centromeric repeats in mouse fibroblasts. Biochem Biophys Res Commun 2019; 511:882-888. [PMID: 30850162 DOI: 10.1016/j.bbrc.2019.02.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 02/16/2019] [Indexed: 10/27/2022]
Abstract
Targeted deposition of histone variant H3.3 into chromatin is paramount for proper regulation of chromatin integrity, particularly in heterochromatic regions including repeats. We have recently shown that the promyelocytic leukemia (PML) protein prevents H3.3 from being deposited in large heterochromatic PML-associated domains (PADs). However, to what extent PML modulates H3.3 loading on chromatin in other areas of the genome remains unexplored. Here, we examined the impact of PML on targeting of H3.3 to genes and repeat regions that reside outside PADs. We show that loss of PML increases H3.3 deposition in subtelomeric, telomeric, pericentric and centromeric repeats in mouse embryonic fibroblasts, while other repeat classes are not affected. Expression of major satellite, minor satellite and telomeric non-coding transcripts is altered in Pml-null cells. In particular, telomeric Terra transcripts are strongly upregulated, in concordance with a marked reduction in H4K20me3 at these sites. Lastly, for most genes H3.3 enrichment or gene expression outcomes are independent of PML. Our data argue towards the importance of a PML-H3.3 axis in preserving a heterochromatin state at centromeres and telomeres.
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Affiliation(s)
- Jane Spirkoski
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway
| | - Akshay Shah
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway
| | - Andrew H Reiner
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway; Oslo Center for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway; Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway.
| | - Erwan Delbarre
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway.
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32
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Ferreira D, Escudeiro A, Adega F, Chaves R. DNA Methylation Patterns of a Satellite Non-coding Sequence - FA-SAT in Cancer Cells: Its Expression Cannot Be Explained Solely by DNA Methylation. Front Genet 2019; 10:101. [PMID: 30809250 PMCID: PMC6379292 DOI: 10.3389/fgene.2019.00101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 01/29/2019] [Indexed: 02/05/2023] Open
Abstract
Satellite ncRNAs are emerging as key players in cell and cancer pathways. Cancer-linked satellite DNA hypomethylation seems to be responsible for the overexpression of satellite non-coding DNAs in several tumors. FA-SAT is the major satellite DNA of Felis catus and recently, its presence and transcription was described across Bilateria genomes. This satellite DNA is GC-rich and includes a CpG island, what is suggestive of transcription regulation via DNA methylation. In this work, it was studied for the first time the FA-SAT methylation profile in cat primary cells, in four passages of the cat tumor cell line FkMTp and in eight feline mammary tumors and the respective disease-free tissues. Contrary to what was expected, we found that in most of the tumor samples analyzed, FA-SAT DNA was not hypomethylated. Furthermore, in these samples the transcription of FA-SAT does not correlate with the methylation status. The use of a global demethylating agent, 5-Azacytidine, in cat primary cells caused an increase in the FA-SAT non-coding RNA levels. However, global demethylation in the tumor FkMTp cells only resulted in the increased levels of the FA-SAT small RNA fraction. Our data suggests that DNA methylation of FA-SAT is involved in the regulation of this satellite DNA, however, other mechanisms are certainly contributing to the transcriptional status of the sequence, specifically in cancer.
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Affiliation(s)
- Daniela Ferreira
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Ana Escudeiro
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
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33
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Nicetto D, Donahue G, Jain T, Peng T, Sidoli S, Sheng L, Montavon T, Becker JS, Grindheim JM, Blahnik K, Garcia BA, Tan K, Bonasio R, Jenuwein T, Zaret KS. H3K9me3-heterochromatin loss at protein-coding genes enables developmental lineage specification. Science 2019; 363:294-297. [PMID: 30606806 PMCID: PMC6664818 DOI: 10.1126/science.aau0583] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/23/2018] [Accepted: 12/20/2018] [Indexed: 12/22/2022]
Abstract
Gene silencing by chromatin compaction is integral to establishing and maintaining cell fates. Trimethylated histone 3 lysine 9 (H3K9me3)-marked heterochromatin is reduced in embryonic stem cells compared to differentiated cells. However, the establishment and dynamics of closed regions of chromatin at protein-coding genes, in embryologic development, remain elusive. We developed an antibody-independent method to isolate and map compacted heterochromatin from low-cell number samples. We discovered high levels of compacted heterochromatin, H3K9me3-decorated, at protein-coding genes in early, uncommitted cells at the germ-layer stage, undergoing profound rearrangements and reduction upon differentiation, concomitant with cell type-specific gene expression. Perturbation of the three H3K9me3-related methyltransferases revealed a pivotal role for H3K9me3 heterochromatin during lineage commitment at the onset of organogenesis and for lineage fidelity maintenance.
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Affiliation(s)
- Dario Nicetto
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Greg Donahue
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tanya Jain
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tao Peng
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Simone Sidoli
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Lihong Sheng
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas Montavon
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Justin S Becker
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jessica M Grindheim
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly Blahnik
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin A Garcia
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kai Tan
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Roberto Bonasio
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas Jenuwein
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Kenneth S Zaret
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
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34
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Benoit M, Simon L, Desset S, Duc C, Cotterell S, Poulet A, Le Goff S, Tatout C, Probst AV. Replication-coupled histone H3.1 deposition determines nucleosome composition and heterochromatin dynamics during Arabidopsis seedling development. THE NEW PHYTOLOGIST 2019; 221:385-398. [PMID: 29897636 DOI: 10.1111/nph.15248] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/01/2018] [Indexed: 05/23/2023]
Abstract
Developmental phase transitions are often characterized by changes in the chromatin landscape and heterochromatin reorganization. In Arabidopsis, clustering of repetitive heterochromatic loci into so-called chromocenters is an important determinant of chromosome organization in nuclear space. Here, we investigated the molecular mechanisms involved in chromocenter formation during the switch from a heterotrophic to a photosynthetically competent state during early seedling development. We characterized the spatial organization and chromatin features at centromeric and pericentromeric repeats and identified mutant contexts with impaired chromocenter formation. We find that clustering of repetitive DNA loci into chromocenters takes place in a precise temporal window and results in reinforced transcriptional repression. Although repetitive sequences are enriched in H3K9me2 and linker histone H1 before repeat clustering, chromocenter formation involves increasing enrichment in H3.1 as well as H2A.W histone variants, hallmarks of heterochromatin. These processes are severely affected in mutants impaired in replication-coupled histone assembly mediated by CHROMATIN ASSEMBLY FACTOR 1 (CAF-1). We further reveal that histone deposition by CAF-1 is required for efficient H3K9me2 enrichment at repetitive sequences during chromocenter formation. Taken together, we show that chromocenter assembly during post-germination development requires dynamic changes in nucleosome composition and histone post-translational modifications orchestrated by the replication-coupled H3.1 deposition machinery.
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Affiliation(s)
- Matthias Benoit
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
- The Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Lauriane Simon
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, 75007, Sweden
| | - Sophie Desset
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Céline Duc
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Sylviane Cotterell
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Axel Poulet
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA, 30322, USA
| | - Samuel Le Goff
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Christophe Tatout
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Aline V Probst
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
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Bao K, Shan CM, Moresco J, Yates J, Jia S. Anti-silencing factor Epe1 associates with SAGA to regulate transcription within heterochromatin. Genes Dev 2018; 33:116-126. [PMID: 30573453 PMCID: PMC6317313 DOI: 10.1101/gad.318030.118] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/19/2018] [Indexed: 12/11/2022]
Abstract
In this study, Bao et al. investigated how transcription is regulated within heterochromatin in fission yeast. They show that overexpressed Epe1 associates with SAGA and recruits SAGA to heterochromatin regions (which leads to an increase in histone acetylation, transcription of repeats, and the disruption of heterochromatin) and that Epe1 recruits SAGA to regulate transcription within heterochromatin when expressed at normal levels. Heterochromatin is a highly condensed form of chromatin that silences gene transcription. Although high levels of transcriptional activities disrupt heterochromatin, transcription of repetitive DNA elements and subsequent processing of the transcripts by the RNAi machinery are required for heterochromatin assembly. In fission yeast, a JmjC domain protein, Epe1, promotes transcription of DNA repeats to facilitate heterochromatin formation, but overexpression of Epe1 leads to heterochromatin defects. However, the molecular function of Epe1 is not well understood. By screening the fission yeast deletion library, we found that heterochromatin defects associated with Epe1 overexpression are alleviated by mutations of the SAGA histone acetyltransferase complex. Overexpressed Epe1 associates with SAGA and recruits SAGA to heterochromatin regions, which leads to increased histone acetylation, transcription of repeats, and the disruption of heterochromatin. At its normal expression levels, Epe1 also associates with SAGA, albeit weakly. Such interaction regulates histone acetylation levels at heterochromatin and promotes transcription of repeats for heterochromatin assembly. Our results also suggest that increases of certain chromatin protein levels, which frequently occur in cancer cells, might strengthen relatively weak interactions to affect the epigenetic landscape.
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Affiliation(s)
- Kehan Bao
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Chun-Min Shan
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James Moresco
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - John Yates
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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36
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Pace L, Goudot C, Zueva E, Gueguen P, Burgdorf N, Waterfall JJ, Quivy JP, Almouzni G, Amigorena S. The epigenetic control of stemness in CD8+T cell fate commitment. Science 2018; 359:177-186. [DOI: 10.1126/science.aah6499] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/01/2017] [Accepted: 11/16/2017] [Indexed: 12/11/2022]
Abstract
After priming, naïve CD8+T lymphocytes establish specific heritable transcription programs that define progression to long-lasting memory cells or to short-lived effector cells. Although lineage specification is critical for protection, it remains unclear how chromatin dynamics contributes to the control of gene expression programs. We explored the role of gene silencing by the histone methyltransferase Suv39h1. In murine CD8+T cells activated afterListeria monocytogenesinfection, Suv39h1-dependent trimethylation of histone H3 lysine 9 controls the expression of a set of stem cell–related memory genes. Single-cell RNA sequencing revealed a defect in silencing of stem/memory genes selectively inSuv39h1-defective T cell effectors. As a result,Suv39h1-defective CD8+T cells show sustained survival and increased long-term memory reprogramming capacity. Thus, Suv39h1 plays a critical role in marking chromatin to silence stem/memory genes during CD8+T effector terminal differentiation.
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37
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Sas-Nowosielska H, Bernas T. Spatial relationship between chromosomal domains in diploid and autotetraploid Arabidopsis thaliana nuclei. Nucleus 2017; 7:216-31. [PMID: 27310308 DOI: 10.1080/19491034.2016.1182277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Polyploids constitute more than 80% of angiosperm plant species. Their DNA content is often further increased by endoreplication, which occurs as a part of cell differentiation. Here, we explore the relationship between 3D chromatin architecture, number of genome copies and their origin in the model plant, Arabidopsis thaliana. Spatial proximity between pericentromeric, interstitial and subtelomeric domains of chromosomes 1 and 4 was quantified over a range of distances. The results indicate that average nuclear volume as well as chromatin density increase with the genome copy number. Similar dependence is observed when association of homologous chromosomes (in 2C/ endopolyploid nuclei) and sister chromatid separation (in endopolyploid nuclei) is studied. Moreover, clusters of chromosomal domains are detectable at the spatial scale above microscopy resolution. Subtelomeric, interstitial and pericentromeric chromosomal domains are affected to different extent by these processes, which are modulated by endopolyploidy. This factor influences fusion of heterochromatin as well. Nonetheless, local chromatin architecture of Arabidopsis thaliana depends mainly on endopolyploidy level, and to lesser extend on polyploidy.
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Affiliation(s)
- H Sas-Nowosielska
- a Laboratory of Imaging Tissue Structure and Function , Nencki Institute of Experimental Biology , Polish Academy of Sciences , Warszawa , Poland.,b Department of Plant Anatomy and Cytology , Faculty of Biology , University of Silesia , Katowice , Poland
| | - T Bernas
- b Department of Plant Anatomy and Cytology , Faculty of Biology , University of Silesia , Katowice , Poland
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38
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DNA sequence homology induces cytosine-to-thymine mutation by a heterochromatin-related pathway in Neurospora. Nat Genet 2017; 49:887-894. [PMID: 28459455 PMCID: PMC5474309 DOI: 10.1038/ng.3857] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 03/31/2017] [Indexed: 12/16/2022]
Abstract
Eukaryotic genomes contain substantial amounts of repetitive DNA organized in the form of constitutive heterochromatin and associated with repressive epigenetic modifications, such as H3K9me3 and C5-cytosine methylation (5mC). In the fungus Neurospora crassa, H3K9me3 and 5mC are catalyzed, respectively, by a conserved SUV39 histone methyltransferase DIM-5 and a DNMT1-like cytosine methyltransferase DIM-2. Here we show that DIM-2 can also mediate Repeat-Induced Point mutation (RIP) of repetitive DNA in N. crassa. We further show that DIM-2-dependent RIP requires DIM-5, HP1, and other known heterochromatin factors, implying the role of a repeat-induced heterochromatin-related process. Our previous findings suggest that the mechanism of repeat recognition for RIP involves direct interactions between homologous double-stranded (ds) DNA segments. We thus now propose that, in somatic cells, homologous dsDNA/dsDNA interactions between a small number of repeat copies can nucleate a transient heterochromatic state, which, on longer repeat arrays, may lead to the formation of constitutive heterochromatin.
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39
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Mutazono M, Morita M, Tsukahara C, Chinen M, Nishioka S, Yumikake T, Dohke K, Sakamoto M, Ideue T, Nakayama JI, Ishii K, Tani T. The intron in centromeric noncoding RNA facilitates RNAi-mediated formation of heterochromatin. PLoS Genet 2017; 13:e1006606. [PMID: 28231281 PMCID: PMC5322907 DOI: 10.1371/journal.pgen.1006606] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 01/25/2017] [Indexed: 12/20/2022] Open
Abstract
In fission yeast, the formation of centromeric heterochromatin is induced through the RNA interference (RNAi)-mediated pathway. Some pre-mRNA splicing mutants (prp) exhibit defective formation of centromeric heterochromatin, suggesting that splicing factors play roles in the formation of heterochromatin, or alternatively that the defect is caused by impaired splicing of pre-mRNAs encoding RNAi factors. Herein, we demonstrate that the splicing factor spPrp16p is enriched at the centromere, and associates with Cid12p (a factor in the RNAi pathway) and the intron-containing dg ncRNA. Interestingly, removal of the dg intron, mutations of its splice sites, or replacement of the dg intron with an euchromatic intron significantly decreased H3K9 dimethylation. We also revealed that splicing of dg ncRNA is repressed in cells and its repression depends on the distance from the transcription start site to the intron. Inefficient splicing was also observed in other intron-containing centromeric ncRNAs, dh and antisense dg, and splicing of antisense dg ncRNA was repressed in the presence of the RNAi factors. Our results suggest that the introns retained in centromeric ncRNAs work as facilitators, co-operating with splicing factors assembled on the intron and serving as a platform for the recruitment of RNAi factors, in the formation of centromeric heterochromatin. Formation of centromeric heterochromatin is required for correct segregation of sister chromatids during mitosis. In fission yeast, formation of heterochromatin at centromeres is performed through the RNA interference (RNAi) system, which involves processing of noncoding RNAs transcribed from the centromeres. We found that the intron in the centromeric dg ncRNAs facilitates formation of centromeric heterochromatin in fission yeast. We showed that the splicing factor spPrp16p associates with the RNAi factor and intron-containing dg ncRNA. Removal of or mutations in the dg intron significantly decreased H3K9 dimethylation, suggesting that the intron and associated splicing factors serve as a platform for recruitment of RNAi factors. Inefficient splicing is a hallmark of intron-containing centromeric ncRNAs. Such repression of splicing seems to be important for facilitation of heterochromatin formation. Introns in euchromatic regions are removed by splicing to generate functional RNAs, whereas centromeric introns are retained in ncRNAs by splicing repression and play roles in gene silencing. Our findings shed light on the novel roles of introns in epigenetic regulation of gene expression and heterochromatin formation.
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Affiliation(s)
- Masatoshi Mutazono
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Misato Morita
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Chihiro Tsukahara
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Madoka Chinen
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Shiori Nishioka
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Tatsuhiro Yumikake
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Kohei Dohke
- Laboratory of Chromosome Function and Regulation, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Misuzu Sakamoto
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Takashi Ideue
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
| | - Jun-Ichi Nakayama
- Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan.,Division of Chromatin Regulation, National Institute for Basic Biology, Okazaki, Japan
| | - Kojiro Ishii
- Laboratory of Chromosome Function and Regulation, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Tokio Tani
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kurokami, Chuo-ku, Kumamoto, Japan
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40
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Abstract
Centromeric chromatin undergoes major changes in composition and architecture during each cell cycle. These changes in specialized chromatin facilitate kinetochore formation in mitosis to ensure proper chromosome segregation. Thus, proper orchestration of centromeric chromatin dynamics during interphase, including replication in S phase, is crucial. We provide the current view concerning the centromeric architecture associated with satellite repeat sequences in mammals and its dynamics during the cell cycle. We summarize the contributions of deposited histone variants and their chaperones, other centromeric components - including proteins and their post-translational modifications, and RNAs - and we link the expression and deposition timing of each component during the cell cycle. Because neocentromeres occur at ectopic sites, we highlight how cell cycle processes can go wrong, leading to neocentromere formation and potentially disease.
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Affiliation(s)
- Sebastian Müller
- Institut Curie, PSL Research University, CNRS, UMR3664, Equipe Labellisée Ligue contre le Cancer, F-75005 Paris, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, UMR3664, Equipe Labellisée Ligue contre le Cancer, F-75005 Paris, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR3664, F-75005 Paris, France
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41
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DNA methylation is dispensable for changes in global chromatin architecture but required for chromocentre formation in early stem cell differentiation. Chromosoma 2017; 126:605-614. [PMID: 28084535 DOI: 10.1007/s00412-017-0625-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 01/05/2023]
Abstract
Epiblast stem cells (EpiSCs), which are pluripotent cells isolated from early post-implantation mouse embryos (E5.5), show both similarities and differences compared to mouse embryonic stem cells (mESCs), isolated earlier from the inner cell mass (ICM) of the E3.5 embryo. Previously, we have observed that while chromatin is very dispersed in E3.5 ICM, compact chromatin domains and chromocentres appear in E5.5 epiblasts after embryo implantation. Given that the observed chromatin re-organization in E5.5 epiblasts coincides with an increase in DNA methylation, in this study, we aimed to examine the role of DNA methylation in chromatin re-organization during the in vitro conversion of ESCs to EpiSCs. The requirement for DNA methylation was determined by converting both wild-type and DNA methylation-deficient ESCs to EpiSCs, followed by structural analysis with electron spectroscopic imaging (ESI). We show that the chromatin re-organization which occurs in vivo can be re-capitulated in vitro during the ESC to EpiSC conversion. Indeed, after 7 days in EpiSC media, compact chromatin domains begin to appear throughout the nuclear volume, creating a chromatin organization similar to E5 epiblasts and embryo-derived EpiSCs. Our data demonstrate that DNA methylation is dispensable for this global chromatin re-organization but required for the compaction of pericentromeric chromatin into chromocentres.
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42
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Dumont M, Fachinetti D. DNA Sequences in Centromere Formation and Function. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:305-336. [PMID: 28840243 DOI: 10.1007/978-3-319-58592-5_13] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Faithful chromosome segregation during cell division depends on the centromere, a complex DNA/protein structure that links chromosomes to spindle microtubules. This chromosomal domain has to be marked throughout cell division and its chromosomal localization preserved across cell generations. From fission yeast to human, centromeres are established on a series of repetitive DNA sequences and on specialized centromeric chromatin. This chromatin is enriched with the histone H3 variant, named CENP-A, that was demonstrated to be the epigenetic mark that maintains centromere identity and function indefinitely. Although centromere identity is thought to be exclusively epigenetic, the presence of specific DNA sequences in the majority of eukaryotes and of the centromeric protein CENP-B that binds to these sequences, suggests the existence of a genetic component as well. In this review, we will highlight the importance of centromeric sequences for centromere formation and function, and discuss the centromere DNA sequence/CENP-B paradox.
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Affiliation(s)
- M Dumont
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, 75005, Paris, France
| | - D Fachinetti
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, 75005, Paris, France.
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43
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Heterochromatin and the molecular mechanisms of ‘parent-of-origin’ effects in animals. J Biosci 2016; 41:759-786. [DOI: 10.1007/s12038-016-9650-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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44
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Ferreira D, Meles S, Escudeiro A, Mendes-da-Silva A, Adega F, Chaves R. Satellite non-coding RNAs: the emerging players in cells, cellular pathways and cancer. Chromosome Res 2016; 23:479-93. [PMID: 26293605 DOI: 10.1007/s10577-015-9482-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
For several decades, transcriptional inactivity was considered as one of the particular features of constitutive heterochromatin and, therefore, of its major component, satellite DNA sequences. However, more recently, succeeding evidences have demonstrated that these sequences can indeed be transcribed, yielding satellite non-coding RNAs with important roles in the organization and regulation of genomes. Since then, several studies have been conducted, trying to understand the function(s) of these sequences not only in the normal but also in cancer genomes. It is thought that the association between cancer and satncRNAs is mostly due to the influence of these transcripts in the genome instability, a hallmark of cancer. The few reports on satellite DNA transcription in cancer contexts point to its overexpression; however, this scenario may be far more complex, variable, and influenced by a number of factors and the exact role of satncRNAs in the oncogenic process remains poorly understood. The greater is the knowledge on the association of satncRNAs with cancer, the greater would be the opportunity to assist cancer treatment, either by the design of effective therapies targeting these molecules or by using them as biomarkers in cancer diagnosis, prognosis, and with predictive value.
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Affiliation(s)
- Daniela Ferreira
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal
| | - Susana Meles
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal
| | - Ana Escudeiro
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal
| | - Ana Mendes-da-Silva
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.
- Faculty of Sciences, BioISI- Biosystems & Integrative Sciences Institute, University of Lisboa, Campo Grande, Lisboa, Portugal.
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Tsouroula K, Furst A, Rogier M, Heyer V, Maglott-Roth A, Ferrand A, Reina-San-Martin B, Soutoglou E. Temporal and Spatial Uncoupling of DNA Double Strand Break Repair Pathways within Mammalian Heterochromatin. Mol Cell 2016; 63:293-305. [PMID: 27397684 DOI: 10.1016/j.molcel.2016.06.002] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 05/11/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022]
Abstract
Repetitive DNA is packaged into heterochromatin to maintain its integrity. We use CRISPR/Cas9 to induce DSBs in different mammalian heterochromatin structures. We demonstrate that in pericentric heterochromatin, DSBs are positionally stable in G1 and recruit NHEJ factors. In S/G2, DSBs are resected and relocate to the periphery of heterochromatin, where they are retained by RAD51. This is independent of chromatin relaxation but requires end resection and RAD51 exclusion from the core. DSBs that fail to relocate are engaged by NHEJ or SSA proteins. We propose that the spatial disconnection between end resection and RAD51 binding prevents the activation of mutagenic pathways and illegitimate recombination. Interestingly, in centromeric heterochromatin, DSBs recruit both NHEJ and HR proteins throughout the cell cycle. Our results highlight striking differences in the recruitment of DNA repair factors between pericentric and centromeric heterochromatin and suggest a model in which the commitment to specific DNA repair pathways regulates DSB position.
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Affiliation(s)
- Katerina Tsouroula
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France
| | - Audrey Furst
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France
| | - Melanie Rogier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France
| | - Vincent Heyer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France
| | - Anne Maglott-Roth
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France
| | - Alexia Ferrand
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Bernardo Reina-San-Martin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France.
| | - Evi Soutoglou
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Centre National de Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France.
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Della Ragione F, Vacca M, Fioriniello S, Pepe G, D'Esposito M. MECP2, a multi-talented modulator of chromatin architecture. Brief Funct Genomics 2016; 15:420-431. [PMID: 27296483 DOI: 10.1093/bfgp/elw023] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It has been a long trip from 1992, the year of the discovery of MECP2, to the present day. What is surprising is that some of the pivotal roles of MeCP2 were already postulated at that time, such as repression of inappropriate expression from repetitive elements and the regulation of pericentric heterochromatin condensation. However, MeCP2 performs many more functions. MeCP2 is a reader of epigenetic information contained in methylated (and hydroxymethylated) DNA, moving from the 'classical' CpG doublet to the more complex view addressed by the non-CpG methylation, which is a feature of the postnatal brain. MECP2 is a transcriptional repressor, although when it forms complexes with the appropriate molecules, it can become a transcriptional activator. For all of these aspects, Rett syndrome, which is caused by MECP2 mutations, is considered a paradigmatic example of a 'chromatin disorder'. Even if the hunt for bona-fide MECP2 target genes is far from concluded today, the role of MeCP2 in the maintenance of chromatin architecture appears to be clearly established. Taking a cue from the non-scientific literature, we can firmly attest that MeCP2 is a player with 'a great future behind it'*.*V. Gassmann 'Un grande avvenire dietro le spalle'. TEA Eds.
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Kalousi A, Soutoglou E. Nuclear compartmentalization of DNA repair. Curr Opin Genet Dev 2016; 37:148-157. [DOI: 10.1016/j.gde.2016.05.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 12/24/2022]
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Kilinc S, Savarino A, Coleman JH, Schwob JE, Lane RP. Lysine-specific demethylase-1 (LSD1) is compartmentalized at nuclear chromocenters in early post-mitotic cells of the olfactory sensory neuronal lineage. Mol Cell Neurosci 2016; 74:58-70. [PMID: 26947098 DOI: 10.1016/j.mcn.2016.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 01/29/2016] [Accepted: 03/02/2016] [Indexed: 12/12/2022] Open
Abstract
Mammalian olfaction depends on the development of specialized olfactory sensory neurons (OSNs) that each express one odorant receptor (OR) protein from a large family of OR genes encoded in the genome. The lysine-specific demethylase-1 (LSD1) protein removes activating H3K4 or silencing H3K9 methylation marks at gene promoters and is required for proper OR regulation. We show that LSD1 protein exhibits variable organization within nuclei of developing OSNs, and tends to consolidate into a single dominant compartment at the edges of chromocenters within nuclei of early post-mitotic cells of the mouse olfactory epithelium (MOE). Using an immortalized cell line derived from developing olfactory placode, we show that consolidation of LSD1 appears to be cell-cycle regulated, with a peak occurrence in early G1. LSD1 co-compartmentalizes with CoREST, a protein known to collaborate with LSD1 to carry out a variety of chromatin-modifying functions. We show that LSD1 compartments co-localize with 1-3 OR loci at the exclusion of most OR genes, and commonly associate with Lhx2, a transcription factor involved in OR regulation. Together, our data suggests that LSD1 is sequestered into a distinct nuclear space that might restrict a histone-modifying function to a narrow developmental time window and/or range of OR gene targets.
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Affiliation(s)
- Seda Kilinc
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06457, USA.
| | - Alyssa Savarino
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06457, USA
| | - Julie H Coleman
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - James E Schwob
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Robert P Lane
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06457, USA.
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Simon L, Voisin M, Tatout C, Probst AV. Structure and Function of Centromeric and Pericentromeric Heterochromatin in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:1049. [PMID: 26648952 PMCID: PMC4663263 DOI: 10.3389/fpls.2015.01049] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 11/09/2015] [Indexed: 05/23/2023]
Abstract
The centromere is a specific chromosomal region where the kinetochore assembles to ensure the faithful segregation of sister chromatids during mitosis and meiosis. Centromeres are defined by a local enrichment of the specific histone variant CenH3 mostly at repetitive satellite sequences. A larger pericentromeric region containing repetitive sequences and transposable elements surrounds the centromere that adopts a particular chromatin state characterized by specific histone variants and post-translational modifications and forms a transcriptionally repressive chromosomal environment. In the model organism Arabidopsis thaliana centromeric and pericentromeric domains form conspicuous heterochromatin clusters called chromocenters in interphase. Here we discuss, using Arabidopsis as example, recent insight into mechanisms involved in maintenance and establishment of centromeric and pericentromeric chromatin signatures as well as in chromocenter formation.
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Affiliation(s)
| | - Maxime Voisin
- †These authors have contributed equally to this work.
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Rapkin LM, Ahmed K, Dulev S, Li R, Kimura H, Ishov AM, Bazett-Jones DP. The histone chaperone DAXX maintains the structural organization of heterochromatin domains. Epigenetics Chromatin 2015; 8:44. [PMID: 26500702 PMCID: PMC4617904 DOI: 10.1186/s13072-015-0036-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/07/2015] [Indexed: 12/20/2022] Open
Abstract
Background The death domain-associated protein (DAXX) collaborates with accessory proteins to deposit the histone variant H3.3 into mouse telomeric and pericentromeric repeat DNA. Pericentromeric repeats are the main genetic contributor to spatially discrete, compact, constitutive heterochromatic structures called chromocentres. Chromocentres are enriched in the H3K9me3 histone modification and serve as integral, functionally important components of nuclear organization. To date, the role of DAXX as an H3.3-specific histone chaperone has been investigated primarily using biochemical approaches which provide genome-wide views on cell populations and information on changes in local chromatin structures. However, the global chromatin and subnuclear reorganization events that coincide with these changes remain to be investigated. Results Using electron spectroscopic imagine (ESI), a specialized form of energy-filtered transmission electron microscopy that allows us to visualize chromatin domains in situ with high contrast and spatial resolution, we show that in the absence of DAXX, H3K9me3-enriched domains are structurally altered and become uncoupled from major satellite DNA. In addition, the structural integrity of nucleoli and the organization of ribosomal DNA (rDNA) are disrupted. Moreover, the absence of DAXX leads to chromatin that is more sensitive, on a global level, to micrococcal nuclease digestion. Conclusions We identify a novel role of DAXX as a major regulator of subnuclear organization through the maintenance of the global heterochromatin structural landscape. As well, we show, for the first time, that the loss of a histone chaperone can have severe consequences for global nuclear organization. Electronic supplementary material The online version of this article (doi:10.1186/s13072-015-0036-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lindsy M Rapkin
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada ; Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Kashif Ahmed
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
| | - Stanimir Dulev
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
| | - Ren Li
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada
| | - Hiroshi Kimura
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-Ku, Yokohama 226-8501 Japan
| | - Alexander M Ishov
- Department of Anatomy and Cell Biology, University of Florida College of Medicine, and University of Florida Cancer Center, Gainesville, FL 32610 USA
| | - David P Bazett-Jones
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4 Canada ; Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8 Canada
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