|
1
|
Schröder CM, Zissel L, Mersiowsky SL, Tekman M, Probst S, Schüle KM, Preissl S, Schilling O, Timmers HTM, Arnold SJ. EOMES establishes mesoderm and endoderm differentiation potential through SWI/SNF-mediated global enhancer remodeling. Dev Cell 2025; 60:735-748.e5. [PMID: 39662466 DOI: 10.1016/j.devcel.2024.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 09/17/2024] [Accepted: 11/14/2024] [Indexed: 12/13/2024]
Abstract
Mammalian pluripotent cells first segregate into neuroectoderm (NE), or mesoderm and endoderm (ME), characterized by lineage-specific transcriptional programs and chromatin states. To date, the relationship between transcription factor activities and dynamic chromatin changes that guide cell specification remains ill-defined. In this study, we employ mouse embryonic stem cell differentiation toward ME lineages to reveal crucial roles of the Tbx factor Eomes to globally establish ME enhancer accessibility as the prerequisite for ME lineage competence and ME-specific gene expression. EOMES cooperates with the SWItch/sucrose non-fermentable (SWI/SNF) complex to drive chromatin rewiring that is essential to overcome default NE differentiation, which is favored by asymmetries in chromatin accessibility at pluripotent state. Following global ME enhancer remodeling, ME-specific gene transcription is controlled by additional signals such as Wnt and transforming growth factor β (TGF-β)/NODAL, as a second layer of gene expression regulation, which can be mechanistically separated from initial chromatin remodeling activities.
Collapse
Affiliation(s)
- Chiara M Schröder
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Lea Zissel
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Sophie-Luise Mersiowsky
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Mehmet Tekman
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Simone Probst
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Katrin M Schüle
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Sebastian Preissl
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Oliver Schilling
- Institute for Surgical Pathology, Medical Centre, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - H Th Marc Timmers
- Department of Urology, Medical Centre, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; German Cancer Consortium (DKTK), partner site Freiburg, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Sebastian J Arnold
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| |
Collapse
|
|
2
|
Negrón-Piñeiro LJ, Di Gregorio A. Single-cell Transcriptomic Studies Unveil Potential Nodes of the Notochord Gene Regulatory Network. Integr Comp Biol 2024; 64:1194-1213. [PMID: 38914463 PMCID: PMC11579531 DOI: 10.1093/icb/icae084] [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: 03/31/2024] [Revised: 06/01/2024] [Accepted: 06/16/2024] [Indexed: 06/26/2024] Open
Abstract
Transcription factors (TFs) are DNA-binding proteins able to modulate the timing, location, and levels of gene expression by binding to regulatory DNA regions. Therefore, the repertoire of TFs present in the genome of a multicellular organism and the expression of variable constellations of TFs in different cellular cohorts determine the distinctive characteristics of developing tissues and organs. The information on tissue-specific assortments of TFs, their cross-regulatory interactions, and the genes/regulatory regions targeted by each TF is summarized in gene regulatory networks (GRNs), which provide genetic blueprints for the specification, development, and differentiation of multicellular structures. In this study, we review recent transcriptomic studies focused on the complement of TFs expressed in the notochord, a distinctive feature of all chordates. We analyzed notochord-specific datasets available from organisms representative of the three chordate subphyla, and highlighted lineage-specific variations in the suite of TFs expressed in their notochord. We framed the resulting findings within a provisional evolutionary scenario, which allows the formulation of hypotheses on the genetic/genomic changes that sculpted the structure and function of the notochord on an evolutionary scale.
Collapse
Affiliation(s)
- Lenny J Negrón-Piñeiro
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Anna Di Gregorio
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| |
Collapse
|
|
3
|
Negrón-Piñeiro LJ, Wu Y, Popsuj S, José-Edwards DS, Stolfi A, Di Gregorio A. Cis-regulatory interfaces reveal the molecular mechanisms underlying the notochord gene regulatory network of Ciona. Nat Commun 2024; 15:3025. [PMID: 38589372 PMCID: PMC11001920 DOI: 10.1038/s41467-024-46850-3] [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: 11/03/2022] [Accepted: 03/12/2024] [Indexed: 04/10/2024] Open
Abstract
Tissue-specific gene expression is fundamental in development and evolution, and is mediated by transcription factors and by the cis-regulatory regions (enhancers) that they control. Transcription factors and their respective tissue-specific enhancers are essential components of gene regulatory networks responsible for the development of tissues and organs. Although numerous transcription factors have been characterized from different organisms, the knowledge of the enhancers responsible for their tissue-specific expression remains fragmentary. Here we use Ciona to study the enhancers associated with ten transcription factors expressed in the notochord, an evolutionary hallmark of the chordate phylum. Our results illustrate how two evolutionarily conserved transcription factors, Brachyury and Foxa2, coordinate the deployment of other notochord transcription factors. The results of these detailed cis-regulatory analyses delineate a high-resolution view of the essential notochord gene regulatory network of Ciona, and provide a reference for studies of transcription factors, enhancers, and their roles in development, disease, and evolution.
Collapse
Affiliation(s)
- Lenny J Negrón-Piñeiro
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Yushi Wu
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Sydney Popsuj
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Diana S José-Edwards
- Post-Baccalaureate Premedical Program, Washington University, St. Louis, MO, 63130, USA
| | - Alberto Stolfi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Anna Di Gregorio
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA.
| |
Collapse
|
|
4
|
Cheng C, Cong Q, Liu Y, Hu Y, Liang G, Dioneda KMM, Yang Y. Yap controls notochord formation and neural tube patterning by integrating mechanotransduction with FoxA2 and Shh expression. SCIENCE ADVANCES 2023; 9:eadf6927. [PMID: 37315133 PMCID: PMC10266736 DOI: 10.1126/sciadv.adf6927] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/04/2023] [Indexed: 06/16/2023]
Abstract
Correct notochord and neural tube (NT) formation is crucial to the development of the central nervous system and midline structures. Integrated biochemical and biophysical signaling controls embryonic growth and patterning; however, the underlying mechanisms remain poorly understood. Here, we took the opportunities of marked morphological changes during notochord and NT formation and identified both necessary and sufficient roles of Yap, a key mechanosensor and mechanotransducer, in biochemical signaling activation during formation of notochord and floor plate, the ventral signaling centers that pattern the dorsal-ventral axis of NT and the surrounding tissues. We showed that Yap activation by a gradient of mechanical stress and tissue stiffness in the notochord and ventral NT induces FoxA2 and Shh expression. Hedgehog signaling activation rescued NT patterning defects caused by Yap deficiency, but not notochord formation. Therefore, mechanotransduction via Yap activation acts in feedforward mechanisms to induce FoxA2 expression for notochord formation and activate Shh expression for floor plate induction by synergistically interacting with FoxA2.
Collapse
Affiliation(s)
| | | | - Yuchen Liu
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, 188 Longwood Ave., Boston, MA 02115, USA
| | - Yizhong Hu
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, 188 Longwood Ave., Boston, MA 02115, USA
| | - Guoyan Liang
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, 188 Longwood Ave., Boston, MA 02115, USA
| | - Kevin Marc Manquiquis Dioneda
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard Stem Cell Institute, 188 Longwood Ave., Boston, MA 02115, USA
| | | |
Collapse
|
|
5
|
Feng R, Liebe R, Weng HL. Transcription networks in liver development and acute liver failure. LIVER RESEARCH 2023; 7:47-55. [PMID: 39959701 PMCID: PMC11791834 DOI: 10.1016/j.livres.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/10/2022] [Accepted: 11/27/2022] [Indexed: 12/05/2022]
Abstract
Acute liver failure (ALF) is a medical emergency due to massive hepatocyte loss. In such a harsh condition, maintaining transcriptional regulation in the remaining hepatocytes while activating similar transcription factor networks in liver progenitor cells (LPCs) to ensure essential liver functions are two critical processes to rescue patients from liver failure and death. In this review, we discuss the formation and functions of transcription networks in ALF and liver development. We focus on a hierarchical network of transcription factors that responds to different pathophysiological circumstances: (1) Under normal circumstances, pioneer factor forkhead box protein A2 (FOXA2) coordinates several constitutive hepatic transcription factors, such as hepatic nuclear factor 4 alpha (HNF4α) and CCAAT-enhancer binding protein α (C/EBPα), which ensure normal liver function; (2) When the expression of both HNF4α and C/EBPα in hepatocytes are disrupted by severe inflammation, retinoic acid receptor (RAR) is the alternative transcription factor that compensates for their absence; (3) When massive hepatic necrosis occurs, a similar transcription network including FOXA2 and HNF4α, is activated as a "rescue network" in LPCs to maintain vital liver functions when hepatocytes fail, and thus ensures survival. Expression of these master transcription factors in hepatocytes and LPCs is tightly regulated by hormone signals and inflammation. The performance of this hierarchical transcription network, in particularly the "rescue network" described above, significantly affects the clinical outcome of ALF.
Collapse
Affiliation(s)
- Rilu Feng
- Department of Medicine II, Section Molecular Hepatology, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Roman Liebe
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University, Düsseldorf, Germany
- Department of Medicine II, Saarland University Medical Centre, Saarland University, Homburg, Germany
| | - Hong-Lei Weng
- Department of Medicine II, Section Molecular Hepatology, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| |
Collapse
|
|
6
|
Guo SS, Au TYK, Wynn S, Aszodi A, Chan D, Fässler R, Cheah KSE. β1 Integrin regulates convergent extension in mouse notogenesis, ensures notochord integrity and the morphogenesis of vertebrae and intervertebral discs. Development 2020; 147:dev192724. [PMID: 33051257 DOI: 10.1242/dev.192724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/01/2020] [Indexed: 12/17/2022]
Abstract
The notochord drives longitudinal growth of the body axis by convergent extension, a highly conserved developmental process that depends on non-canonical Wnt/planar cell polarity (PCP) signaling. However, the role of cell-matrix interactions mediated by integrins in the development of the notochord is unclear. We developed transgenic Cre mice, in which the β1 integrin gene (Itgb1) is ablated at E8.0 in the notochord only or in the notochord and tail bud. These Itgb1 conditional mutants display misaligned, malformed vertebral bodies, hemi-vertebrae and truncated tails. From early somite stages, the notochord was interrupted and displaced in these mutants. Convergent extension of the notochord was impaired with defective cell movement. Treatment of E7.25 wild-type embryos with anti-β1 integrin blocking antibodies, to target node pit cells, disrupted asymmetric localization of VANGL2. Our study implicates pivotal roles of β1 integrin for the establishment of PCP and convergent extension of the developing notochord, its structural integrity and positioning, thereby ensuring development of the nucleus pulposus and the proper alignment of vertebral bodies and intervertebral discs. Failure of this control may contribute to human congenital spine malformations.
Collapse
Affiliation(s)
- Shiny Shengzhen Guo
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Max Planck Institute of Biochemistry, Department of Molecular Medicine, 82152 Martinsried, Germany
| | - Tiffany Y K Au
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sarah Wynn
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Attila Aszodi
- Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Ludwig-Maximilians-University, Fraunhoferstraβe 20, 82152 Planegg-Martinsried, Germany
| | - Danny Chan
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Reinhard Fässler
- Max Planck Institute of Biochemistry, Department of Molecular Medicine, 82152 Martinsried, Germany
| | - Kathryn S E Cheah
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| |
Collapse
|
|
7
|
Au TYK, Lam T, Peng Y, Wynn SL, Cheung KMC, Cheah KSE, Leung VYL. Transformation of resident notochord-descendent nucleus pulposus cells in mouse injury-induced fibrotic intervertebral discs. Aging Cell 2020; 19:e13254. [PMID: 33084203 PMCID: PMC7681061 DOI: 10.1111/acel.13254] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 09/09/2020] [Accepted: 09/15/2020] [Indexed: 02/06/2023] Open
Abstract
Intervertebral disc degeneration (IDD), a major cause of low back pain, occurs with ageing. The core of the intervertebral disc, the nucleus pulposus (NP), embedded in a proteoglycan‐rich and gelatinous matrix, is derived from the embryonic notochord. With IDD, the NP becomes fibrous, containing fewer cells, which are fibroblastic and of unknown origin. Here, we used a lineage tracing strategy to investigate the origin of cells in the NP in injury‐induced mouse IDD. We established a Foxa2 notochord‐specific enhancer‐driven Cre transgenic mouse model (Foxa2mNE‐Cre) that acts only in the embryonic to foetal period up to E14.5, to genetically label notochord cells with enhanced green fluorescent protein (EGFP). When this mouse is crossed to one carrying a Cre recombinase reporter, Z/EG, EGFP‐labelled NP cells are present even at 2 years of age, consistent with their notochordal origin. We induced tail IDD in Foxa2mNE‐Cre; Z/EG mice by annulus puncture and observed the degenerative changes for 12 weeks. Soon after puncture, EGFP‐labelled NP cells showed strong Col2a1+ expression unlike uninjured control NP. Later, accompanying fibrotic changes, EGFP‐positive NP cells expressed fibroblastic and myofibroblastic markers such as Col1a1, ASMA, FAPA and FSP‐1. The number of EGFP+ cells co‐expressing the fibroblastic markers increased with time after puncture. Our findings suggest resident NP cells initially upregulate Col2a1+ and later transform into fibroblast‐like cells during injury‐mediated disc degeneration and remodelling. This important discovery concerning the cellular origin of fibrotic pathology in injury‐induced IDD has implications for management in disease and ageing.
Collapse
Affiliation(s)
- Tiffany Y. K. Au
- School of Biomedical Sciences The University of Hong Kong Hong Kong China
- Centre for Reproduction Development, and Growth Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong China
| | - To‐Kam Lam
- Department of Orthopaedics and Traumatology The University of Hong Kong Hong Kong China
| | - Yan Peng
- Department of Orthopaedics and Traumatology The University of Hong Kong Hong Kong China
| | - Sarah L. Wynn
- School of Biomedical Sciences The University of Hong Kong Hong Kong China
| | - Kenneth M. C. Cheung
- Centre for Reproduction Development, and Growth Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong China
- Department of Orthopaedics and Traumatology The University of Hong Kong Hong Kong China
| | - Kathryn S. E. Cheah
- School of Biomedical Sciences The University of Hong Kong Hong Kong China
- Centre for Reproduction Development, and Growth Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong China
| | - Victor Y. L. Leung
- Centre for Reproduction Development, and Growth Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong China
- Department of Orthopaedics and Traumatology The University of Hong Kong Hong Kong China
| |
Collapse
|
|
8
|
An Evolutionarily Conserved Mesodermal Enhancer in Vertebrate Zic3. Sci Rep 2018; 8:14954. [PMID: 30297839 PMCID: PMC6175831 DOI: 10.1038/s41598-018-33235-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/25/2018] [Indexed: 11/08/2022] Open
Abstract
Zic3 encodes a zinc finger protein essential for the development of meso-ectodermal tissues. In mammals, Zic3 has important roles in the development of neural tube, axial skeletons, left-right body axis, and in maintaining pluripotency of ES cells. Here we characterized cis-regulatory elements required for Zic3 expression. Enhancer activities of human-chicken-conserved noncoding sequences around Zic1 and Zic3 were screened using chick whole-embryo electroporation. We identified enhancers for meso-ectodermal tissues. Among them, a mesodermal enhancer (Zic3-ME) in distant 3' flanking showed robust enhancement of reporter gene expression in the mesodermal tissue of chicken and mouse embryos, and was required for mesodermal Zic3 expression in mice. Zic3-ME minimal core region is included in the DNase hypersensitive region of ES cells, mesoderm, and neural progenitors, and was bound by T (Brachyury), Eomes, Lef1, Nanog, Oct4, and Zic2. Zic3-ME is derived from an ancestral sequence shared with a sequence encoding a mitochondrial enzyme. These results indicate that Zic3-ME is an integrated cis-regulatory element essential for the proper expression of Zic3 in vertebrates, serving as a hub for a gene regulatory network including Zic3.
Collapse
|
|
9
|
Saitsu H. Folate receptors and neural tube closure. Congenit Anom (Kyoto) 2017; 57:130-133. [PMID: 28244241 DOI: 10.1111/cga.12218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/18/2017] [Accepted: 02/22/2017] [Indexed: 12/29/2022]
Abstract
Neural tube defects (NTD) are among the most common human congenital malformations, affecting 0.5-8.0/1000 of live births. Human clinical trials have shown that periconceptional folate supplementation significantly decreases the occurrence of NTD in offspring. However, the mechanism by which folate acts on NTD remains largely unknown. Folate receptor (Folr) is one of the three membrane proteins that mediate cellular uptake of folates. Recent studies suggest that mouse Folr1 (formerly referred to as Fbp1) is essential for neural tube closure. Therefore, we examined spatial and temporal expression patterns of Folr1 in developing mouse embryos, showing a close association between Folr1 and anterior neural tube closure. Transient transgenic analysis was performed using lacZ as a reporter; we identified a 1.1-kb enhancer that directs lacZ expression in the neural tube and optic vesicle in a manner that is similar to endogenous Folr1. The 1.1-kb enhancer sequences were highly conserved between humans and mice, suggesting that human FOLR1 is associated with anterior neural tube closure in humans. Several experimental studies in mice and human epidemiological and genetics studies have suggested that folate receptor abnormalities are involved in a portion of human NTDs, although the solo defect of FOLR1 did not cause NTD.
Collapse
Affiliation(s)
- Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu, Japan
| |
Collapse
|
|
10
|
Simon CS, Downes DJ, Gosden ME, Telenius J, Higgs DR, Hughes JR, Costello I, Bikoff EK, Robertson EJ. Functional characterisation of cis-regulatory elements governing dynamic Eomes expression in the early mouse embryo. Development 2017; 144:1249-1260. [PMID: 28174238 PMCID: PMC5399628 DOI: 10.1242/dev.147322] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/25/2017] [Indexed: 12/28/2022]
Abstract
The T-box transcription factor (TF) Eomes is a key regulator of cell fate decisions during early mouse development. The cis-acting regulatory elements that direct expression in the anterior visceral endoderm (AVE), primitive streak (PS) and definitive endoderm (DE) have yet to be defined. Here, we identified three gene-proximal enhancer-like sequences (PSE_a, PSE_b and VPE) that faithfully activate tissue-specific expression in transgenic embryos. However, targeted deletion experiments demonstrate that PSE_a and PSE_b are dispensable, and only VPE is required for optimal Eomes expression in vivo. Embryos lacking this enhancer display variably penetrant defects in anterior-posterior axis orientation and DE formation. Chromosome conformation capture experiments reveal VPE-promoter interactions in embryonic stem cells (ESCs), prior to gene activation. The locus resides in a large (500 kb) pre-formed compartment in ESCs and activation during DE differentiation occurs in the absence of 3D structural changes. ATAC-seq analysis reveals that VPE, PSE_a and four additional putative enhancers display increased chromatin accessibility in DE that is associated with Smad2/3 binding coincident with transcriptional activation. By contrast, activation of the Eomes target genes Foxa2 and Lhx1 is associated with higher order chromatin reorganisation. Thus, diverse regulatory mechanisms govern activation of lineage specifying TFs during early development. Summary: Expression of the mouse T-box factor Eomes is controlled by a key gene-proximal enhancer-like element, with changes in chromatin accessibility influencing its activity in definitive endoderm.
Collapse
Affiliation(s)
- Claire S Simon
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Damien J Downes
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Matthew E Gosden
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Jelena Telenius
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Ita Costello
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Elizabeth K Bikoff
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | | |
Collapse
|
|
11
|
Tsujimura T, Idei M, Yoshikawa M, Takase O, Hishikawa K. Roles and regulation of bone morphogenetic protein-7 in kidney development and diseases. World J Stem Cells 2016; 8:288-296. [PMID: 27679685 PMCID: PMC5031890 DOI: 10.4252/wjsc.v8.i9.288] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/12/2016] [Accepted: 07/22/2016] [Indexed: 02/07/2023] Open
Abstract
The gene encoding bone morphogenetic protein-7 (BMP7) is expressed in the developing kidney in embryos and also in the mature organ in adults. During kidney development, expression of BMP7 is essential to determine the final number of nephrons in and proper size of the organ. The secreted BMP7 acts on the nephron progenitor cells to exert its dual functions: To maintain and expand the progenitor population and to provide them with competence to respond to differentiation cues, each relying on distinct signaling pathways. Intriguingly, in the adult organ, BMP7 has been implicated in protection against and regeneration from injury. Exogenous administration of recombinant BMP7 to animal models of kidney diseases has shown promising effects in counteracting inflammation, apoptosis and fibrosis evoked upon injury. Although the expression pattern of BMP7 has been well described, the mechanisms by which it is regulated have remained elusive and the processes by which the secretion sites of BMP7 impinge upon its functions in kidney development and diseases have not yet been assessed. Understanding the regulatory mechanisms will pave the way towards gaining better insight into the roles of BMP7, and to achieving desired control of the gene expression as a therapeutic strategy for kidney diseases.
Collapse
|
|
12
|
Takemoto T, Abe T, Kiyonari H, Nakao K, Furuta Y, Suzuki H, Takada S, Fujimori T, Kondoh H. R26-WntVis reporter mice showing graded response to Wnt signal levels. Genes Cells 2016; 21:661-9. [PMID: 27030109 DOI: 10.1111/gtc.12364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/29/2016] [Indexed: 02/06/2023]
Abstract
The canonical Wnt signaling pathway plays a major role in the regulation of embryogenesis and organogenesis, where signal strength-dependent cellular responses are of particular importance. To assess Wnt signal levels in individual cells, and to circumvent the integration site-dependent bias shown in previous Wnt reporter lines, we constructed a new Wnt signal reporter mouse line R26-WntVis. Heptameric TCF/LEF1 binding sequences were combined with a viral minimal promoter to confer a graded response to the reporter depending on Wnt signal strengths. The histone H2B-EGFP fusion protein was chosen as the fluorescent reporter to facilitate single-cell resolution analyses. This WntVis reporter gene was then inserted into the ROSA26 locus in an orientation opposite to that of the endogenous gene. The R26-WntVis allele was introduced into Wnt3a(-/-) and Wnt3a(vt/-) mutant mouse embryos and compared with wild-type embryos to assess its performance. The R26-WntVis reporter was activated in known Wnt-dependent tissues and responded in a graded fashion to signal intensity. This analysis also indicated that the major Wnt activity early in embryogenesis switched from Wnt3 to Wnt3a around E7.5. The R26-WntVis mouse line will be widely useful for the study of Wnt signal-dependent processes.
Collapse
Affiliation(s)
- Tatsuya Takemoto
- Fujii Memorial Institute of Medical Sciences, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.,Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takaya Abe
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan
| | - Hiroshi Kiyonari
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan.,Animal Resource Development Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan
| | - Kazuki Nakao
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan.,Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yasuhide Furuta
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan.,Animal Resource Development Unit, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan
| | - Hitomi Suzuki
- Fujii Memorial Institute of Medical Sciences, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Shinji Takada
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Toshihiko Fujimori
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, 2-2-3 Minatojima Minami-machi, Chuou-ku, Kobe, 650-0047, Japan.,Division of Embryology, National Institute for Basic Biology (NIBB), Okazaki, Aichi, 444-8787, Japan
| | - Hisato Kondoh
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8555, Japan
| |
Collapse
|
|
13
|
Integration of Orthogonal Signaling by the Notch and Dpp Pathways in Drosophila. Genetics 2016; 203:219-40. [PMID: 26975664 PMCID: PMC4858776 DOI: 10.1534/genetics.116.186791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/08/2016] [Indexed: 11/18/2022] Open
Abstract
The transcription factor Suppressor of Hairless and its coactivator, the Notch intracellular domain, are polyglutamine (pQ)-rich factors that target enhancer elements and interact with other locally bound pQ-rich factors. To understand the functional repertoire of such enhancers, we identify conserved regulatory belts with binding sites for the pQ-rich effectors of both Notch and BMP/Dpp signaling, and the pQ-deficient tissue selectors Apterous (Ap), Scalloped (Sd), and Vestigial (Vg). We find that the densest such binding site cluster in the genome is located in the BMP-inducible nab locus, a homolog of the vertebrate transcriptional cofactors NAB1/NAB2 We report three major findings. First, we find that this nab regulatory belt is a novel enhancer driving dorsal wing margin expression in regions of peak phosphorylated Mad in wing imaginal discs. Second, we show that Ap is developmentally required to license the nab dorsal wing margin enhancer (DWME) to read out Notch and Dpp signaling in the dorsal compartment. Third, we find that the nab DWME is embedded in a complex of intronic enhancers, including a wing quadrant enhancer, a proximal wing disc enhancer, and a larval brain enhancer. This enhancer complex coordinates global nab expression via both tissue-specific activation and interenhancer silencing. We suggest that DWME integration of BMP signaling maintains nab expression in proliferating margin descendants that have divided away from Notch-Delta boundary signaling. As such, uniform expression of genes like nab and vestigial in proliferating compartments would typically require both boundary and nonboundary lineage-specific enhancers.
Collapse
|
|
14
|
Costello I, Nowotschin S, Sun X, Mould AW, Hadjantonakis AK, Bikoff EK, Robertson EJ. Lhx1 functions together with Otx2, Foxa2, and Ldb1 to govern anterior mesendoderm, node, and midline development. Genes Dev 2016; 29:2108-22. [PMID: 26494787 PMCID: PMC4617976 DOI: 10.1101/gad.268979.115] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Costello et al. demonstrate that Smad4/Eomes-dependent Lhx1 expression in the epiblast marks the entire definitive endoderm lineage, the anterior mesendoderm, and midline progenitors. In proteomic experiments, they characterize a complex comprised of Lhx1, Otx2, and Foxa2 as well as the chromatin-looping protein Ldb1. Gene regulatory networks controlling functional activities of spatially and temporally distinct endodermal cell populations in the early mouse embryo remain ill defined. The T-box transcription factor Eomes, acting downstream from Nodal/Smad signals, directly activates the LIM domain homeobox transcription factor Lhx1 in the visceral endoderm. Here we demonstrate Smad4/Eomes-dependent Lhx1 expression in the epiblast marks the entire definitive endoderm lineage, the anterior mesendoderm, and midline progenitors. Conditional inactivation of Lhx1 disrupts anterior definitive endoderm development and impedes node and midline morphogenesis in part due to severe disturbances in visceral endoderm displacement. Transcriptional profiling and ChIP-seq (chromatin immunoprecipitation [ChIP] followed by high-throughput sequencing) experiments identified Lhx1 target genes, including numerous anterior definitive endoderm markers and components of the Wnt signaling pathway. Interestingly, Lhx1-binding sites were enriched at enhancers, including the Nodal-proximal epiblast enhancer element and enhancer regions controlling Otx2 and Foxa2 expression. Moreover, in proteomic experiments, we characterized a complex comprised of Lhx1, Otx2, and Foxa2 as well as the chromatin-looping protein Ldb1. These partnerships cooperatively regulate development of the anterior mesendoderm, node, and midline cell populations responsible for establishment of the left–right body axis and head formation.
Collapse
Affiliation(s)
- Ita Costello
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Sonja Nowotschin
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Xin Sun
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Arne W Mould
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | | | - Elizabeth K Bikoff
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Elizabeth J Robertson
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| |
Collapse
|
|
15
|
Sun L, Tang XJ, Luo FM. Forkhead box protein A2 and T helper type 2-mediated pulmonary inflammation. World J Methodol 2015; 5:223-229. [PMID: 26713283 PMCID: PMC4686420 DOI: 10.5662/wjm.v5.i4.223] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/24/2015] [Accepted: 09/30/2015] [Indexed: 02/06/2023] Open
Abstract
The transcription factor forkhead box protein A2 (FOXA2, also known as hepatocyte nuclear factor 3β or transcription factor 3β), has been found to play pivotal roles in multiple phases of mammalian life, from the early development to the organofaction, and subsequently in homeostasis and metabolism in the adult. In the embryonic development period, FOXA2 is require d for the formation of the primitive node and notochord, and its absence results in embryonic lethality. Moreover, FOXA2 plays an important role not only in lung development, but also in T helper type 2 (Th2)-mediated pulmonary inflammation and goblet cell hyperplasia. In this article, the role of FOXA2 in lung development and Th2-mediated pulmonary inflammation, as well as in goblet cell hyperplasia, is reviewed. FOXA2 deletion in airway epithelium results into Th2-mediated pulmonary inflammation and goblet cell hyperplasia in developing lung. Leukotriene pathway and signal transducers and activators of transcription 6 pathway may mediate this inflammation through recruitment and activation of denditric cell during lung developments. FOXA2 is a potential treatment target for lung diseases with Th2 inflammation and goblet cell hyperplasia, such as asthma and chronic obstructive pulmonary disease.
Collapse
|
|
16
|
Identification of transcriptional regulatory elements for Ntng1 and Ntng2 genes in mice. Mol Brain 2014; 7:19. [PMID: 24642214 PMCID: PMC4000137 DOI: 10.1186/1756-6606-7-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/09/2014] [Indexed: 11/17/2022] Open
Abstract
Background Higher brain function is supported by the precise temporal and spatial regulation of thousands of genes. The mechanisms that underlie transcriptional regulation in the brain, however, remain unclear. The Ntng1 and Ntng2 genes, encoding axonal membrane adhesion proteins netrin-G1 and netrin-G2, respectively, are paralogs that have evolved in vertebrates and are expressed in distinct neuronal subsets in a complementary manner. The characteristic expression patterns of these genes provide a part of the foundation of the cortical layer structure in mammals. Results We used gene-targeting techniques, bacterial artificial chromosome (BAC)-aided transgenesis techniques, and in vivo enhancer assays to examine transcriptional mechanisms in vivo to gain insight into how the characteristic expression patterns of these genes are acquired. Analysis of the gene expression patterns in the presence or absence of netrin-G1 and netrin-G2 functional proteins allowed us to exclude the possibility that a feedback or feedforward mechanism mediates their characteristic expression patterns. Findings from the BAC deletion series revealed that widely distributed combinations of cis-regulatory elements determine the differential gene expression patterns of these genes and that major cis-regulatory elements are located in the 85–45 kb upstream region of Ntng2 and in the 75–60 kb upstream region and intronic region of Ntng1. In vivo enhancer assays using 2-kb evolutionarily conserved regions detected enhancer activity in the distal upstream regions of both genes. Conclusions The complementary expression patterns of Ntng1 and Ntng2 are determined by transcriptional cis-regulatory elements widely scattered in these loci. The cis-regulatory elements characterized in this study will facilitate the development of novel genetic tools for functionally dissecting neural circuits to better understand vertebrate brain function.
Collapse
|
|
17
|
Kondo T, Isono K, Kondo K, Endo T, Itohara S, Vidal M, Koseki H. Polycomb Potentiates Meis2 Activation in Midbrain by Mediating Interaction of the Promoter with a Tissue-Specific Enhancer. Dev Cell 2014; 28:94-101. [DOI: 10.1016/j.devcel.2013.11.021] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 09/04/2013] [Accepted: 11/22/2013] [Indexed: 12/21/2022]
|
|
18
|
Irvine SQ. Study of Cis-regulatory Elements in the Ascidian Ciona intestinalis. Curr Genomics 2013; 14:56-67. [PMID: 23997651 PMCID: PMC3580780 DOI: 10.2174/138920213804999192] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 12/30/2012] [Accepted: 01/01/2013] [Indexed: 01/31/2023] Open
Abstract
The ascidian (sea squirt) C. intestinalis has become an important model organism for the study of cis-regulation. This is largely due to the technology that has been developed for assessing cis-regulatory activity through the use of transient reporter transgenes introduced into fertilized eggs. This technique allows the rapid and inexpensive testing of endogenous or altered DNA for regulatory activity in vivo. This review examines evidence that C. intestinaliscis-regulatory elements are located more closely to coding regions than in other model organisms. I go on to compare the organization of cis-regulatory elements and conserved non-coding sequences in Ciona, mammals, and other deuterostomes for three representative C.intestinalis genes, Pax6, FoxAa, and the DlxA-B cluster, along with homologs in the other species. These comparisons point out some of the similarities and differences between cis-regulatory elements and their study in the various model organisms. Finally, I provide illustrations of how C. intestinalis lends itself to detailed study of the structure of cis-regulatory elements, which have led, and promise to continue to lead, to important insights into the fundamentals of transcriptional regulation.
Collapse
Affiliation(s)
- Steven Q Irvine
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
| |
Collapse
|
|
19
|
Yu K, McGlynn S, Matise MP. Floor plate-derived sonic hedgehog regulates glial and ependymal cell fates in the developing spinal cord. Development 2013; 140:1594-604. [PMID: 23482494 DOI: 10.1242/dev.090845] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cell fate specification in the CNS is controlled by the secreted morphogen sonic hedgehog (Shh). At spinal cord levels, Shh produced by both the notochord and floor plate (FP) diffuses dorsally to organize patterned gene expression in dividing neural and glial progenitors. Despite the fact that two discrete sources of Shh are involved in this process, the individual contribution of the FP, the only intrinsic source of Shh throughout both neurogenesis and gliogenesis, has not been clearly defined. Here, we have used conditional mutagenesis approaches in mice to selectively inactivate Shh in the FP (Shh(FP)) while allowing expression to persist in the notochord, which underlies the neural tube during neurogenesis but not gliogenesis. We also inactivated Smo, the common Hh receptor, in neural tube progenitors. Our findings confirm and extend prior studies suggesting an important requirement for Shh(FP) in specifying oligodendrocyte cell fates via repression of Gli3 in progenitors. Our studies also uncover a connection between embryonic Shh signaling and astrocyte-mediated reactive gliosis in adults, raising the possibility that this pathway is involved in the development of the most common cell type in the CNS. Finally, we find that intrinsic spinal cord Shh signaling is required for the proper formation of the ependymal zone, the epithelial cell lining of the central canal that is also an adult stem cell niche. Together, our studies identify a crucial late embryonic role for Shh(FP) in regulating the specification and differentiation of glial and epithelial cells in the mouse spinal cord.
Collapse
Affiliation(s)
- Kwanha Yu
- Department of Neuroscience and Cell Biology, UMDNJ/Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08840, USA
| | | | | |
Collapse
|
|
20
|
Fibroblast growth factor 10 gene regulation in the second heart field by Tbx1, Nkx2-5, and Islet1 reveals a genetic switch for down-regulation in the myocardium. Proc Natl Acad Sci U S A 2012; 109:18273-80. [PMID: 23093675 DOI: 10.1073/pnas.1215360109] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
During cardiogenesis, Fibroblast Growth Factor (Fgf10) is expressed in the anterior second heart field. Together with Fibroblast growth factor 8 (Fgf8), Fgf10 promotes the proliferation of these cardiac progenitor cells that form the arterial pole of the heart. We have identified a 1.7-kb region in the first intron of Fgf10 that is necessary and sufficient to direct transgene expression in this cardiac context. The 1.7-kb sequence is directly controlled by T-box transcription factor 1 (Tbx1) in anterior second heart field cells that contribute to the outflow tract. It also responds to both NK2 transcription factor related, locus 5 (Nkx2-5) and ISL1 transcription factor, LIM/homeodomain (Islet1), acting through overlapping sites. Mutation of these sites reduces transgene expression in the anterior second heart field where the Fgf10 regulatory element is activated by Islet1 via direct binding in vivo. Analysis of the response to Nkx2-5 loss- and Isl1 gain-of-function genetic backgrounds indicates that the observed up-regulation of its activity in Nkx2-5 mutant hearts, reflecting that of Fgf10, is due to the absence of Nkx2-5 repression and to up-regulation of Isl1, normally repressed in the myocardium by Nkx2-5. ChIP experiments show strong binding of Nkx2-5 in differentiated myocardium. Molecular and genetic analysis of the Fgf10 cardiac element therefore reveals how key cardiac transcription factors orchestrate gene expression in the anterior second heart field and how genes, such as Fgf10, normally expressed in the progenitor cell population, are repressed when these cells enter the heart and differentiate into myocardium. Our findings provide a paradigm for transcriptional mechanisms that underlie the changes in regulatory networks during the transition from progenitor state to that of the differentiated tissue.
Collapse
|
|
21
|
A novel mammal-specific three partite enhancer element regulates node and notochord-specific Noto expression. PLoS One 2012; 7:e47785. [PMID: 23110100 PMCID: PMC3478275 DOI: 10.1371/journal.pone.0047785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/17/2012] [Indexed: 11/19/2022] Open
Abstract
The vertebrate organizer and notochord have conserved, essential functions for embryonic development and patterning. The restricted expression of developmental regulators in these tissues is directed by specific cis-regulatory modules (CRMs) whose sequence conservation varies considerably. Some CRMs have been conserved throughout vertebrates and likely represent ancestral regulatory networks, while others have diverged beyond recognition but still function over a wide evolutionary range. Here we identify and characterize a mammalian-specific CRM required for node and notochord specific (NNC) expression of NOTO, a transcription factor essential for node morphogenesis, nodal cilia movement and establishment of laterality in mouse. A 523 bp enhancer region (NOCE) upstream the Noto promoter was necessary and sufficient for NNC expression from the endogenous Noto locus. Three subregions in NOCE together mediated full activity in vivo. Binding sites for known transcription factors in NOCE were functional in vitro but dispensable for NOCE activity in vivo. A FOXA2 site in combination with a novel motif was necessary for NOCE activity in vivo. Strikingly, syntenic regions in non-mammalian vertebrates showed no recognizable sequence similarities. In contrast to its activity in mouse NOCE did not drive NNC expression in transgenic fish. NOCE represents a novel, mammal-specific CRM required for the highly restricted Noto expression in the node and nascent notochord and thus regulates normal node development and function.
Collapse
|
|
22
|
β-Catenin signaling regulates Foxa2 expression during endometrial hyperplasia formation. Oncogene 2012; 32:3477-82. [PMID: 22945641 DOI: 10.1038/onc.2012.376] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 06/20/2012] [Accepted: 07/09/2012] [Indexed: 01/10/2023]
Abstract
The Wnt/β-catenin signaling is essential for various organogenesis and is often implicated during tumorigenesis. Dysregulated β-catenin signaling is associated with the formation of endometrial adenocarcinomas (EACs), which is considered as the common form of endometrial cancer in women. In the current study, we investigate the downstream target of Wnt/β-catenin signaling in the uterine epithelia and the mechanism leading to the formation of endometrial hyperplasia. We report that conditional ablation and activation of β-catenin in the uterine epithelia lead to aberrant epithelial structures and endometrial hyperplasia formation, respectively. We demonstrate that β-catenin regulates Foxa2 with its candidate upstream region for the uterine epithelia. Furthermore, knockdown of Foxa2 leads to defects in cell cycle regulation, suggesting a possible function of Foxa2 in the control of cell proliferation. We also observe that β-catenin and Foxa2 expression levels are augmented in the human specimens of complex atypical endometrial hyperplasia, which is considered to have a greater risk of progression to EACs. Thus, our study indicates that β-catenin regulates Foxa2 expression, and this interaction is possibly essential to control cell cycle progression during endometrial hyperplasia formation. Altogether, the augmented expression levels of β-catenin and Foxa2 are essential features during the formation of endometrial hyperplasia.
Collapse
|
|
23
|
Metzakopian E, Lin W, Salmon-Divon M, Dvinge H, Andersson E, Ericson J, Perlmann T, Whitsett JA, Bertone P, Ang SL. Genome-wide characterization of Foxa2 targets reveals upregulation of floor plate genes and repression of ventrolateral genes in midbrain dopaminergic progenitors. Development 2012; 139:2625-34. [PMID: 22696295 DOI: 10.1242/dev.081034] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The transcription factors Foxa1 and Foxa2 promote the specification of midbrain dopaminergic (mDA) neurons and the floor plate. Whether their role is direct has remained unclear as they also regulate the expression of Shh, which has similar roles. We characterized the Foxa2 cis-regulatory network by chromatin immunoprecipitation followed by high-throughput sequencing of mDA progenitors. This identified 9160 high-quality Foxa2 binding sites associated with 5409 genes, providing mechanistic insights into Foxa2-mediated positive and negative regulatory events. Foxa2 regulates directly and positively key determinants of mDA neurons, including Lmx1a, Lmx1b, Msx1 and Ferd3l, while negatively inhibiting transcription factors expressed in ventrolateral midbrain such as Helt, Tle4, Otx1, Sox1 and Tal2. Furthermore, Foxa2 negatively regulates extrinsic and intrinsic components of the Shh signaling pathway, possibly by binding to the same enhancer regions of co-regulated genes as Gli1. Foxa2 also regulates the expression of floor plate factors that control axon trajectories around the midline of the embryo, thereby contributing to the axon guidance function of the floor plate. Finally, this study identified multiple Foxa2-regulated enhancers that are active in the floor plate of the midbrain or along the length of the embryo in mouse and chick. This work represents the first comprehensive characterization of Foxa2 targets in mDA progenitors and provides a framework for elaborating gene regulatory networks in a functionally important progenitor population.
Collapse
|
|
24
|
Trask MC, Tremblay KD, Mager J. Yin-Yang1 is required for epithelial-to-mesenchymal transition and regulation of Nodal signaling during mammalian gastrulation. Dev Biol 2012; 368:273-82. [PMID: 22669107 DOI: 10.1016/j.ydbio.2012.05.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 05/14/2012] [Accepted: 05/22/2012] [Indexed: 12/15/2022]
Abstract
The ubiquitously expressed Polycomb Group protein Yin-Yang1 (YY1) is believed to regulate gene expression through direct binding to DNA elements found in promoters or enhancers of target loci. Additionally, YY1 contains diverse domains that enable a plethora of protein-protein interactions, including association with the Oct4/Sox2 pluripotency complex and Polycomb Group silencing complexes. To elucidate the in vivo role of YY1 during gastrulation, we generated embryos with an epiblast specific deletion of Yy1. Yy1 conditional knockout (cKO) embryos initiate gastrulation, but both primitive streak formation and ingression through the streak is severely impaired. These streak descendants fail to repress E-Cadherin and are unable to undergo an appropriate epithelial to mesenchymal transition (EMT). Intriguingly, overexpression of Nodal and concomitant reduction of Lefty2 are observed in Yy1 cKO embryos, suggesting that YY1 is normally required for proper Nodal regulation during gastrulation. Furthermore, definitive endoderm is specified but fails to properly integrate into the outer layer. Although anterior neuroectoderm is specified, mesoderm production is severely restricted. We show that YY1 directly binds to the Lefty2 locus in E7.5 embryos and that pharmacological inhibition of Nodal signaling partially restores mesoderm production in Yy1 cKO mutant embryos. Our results reveal critical requirements for YY1 during several important developmental processes, including EMT and regulation of Nodal signaling. These results are the first to elucidate the diverse role of YY1 during gastrulation in vivo.
Collapse
Affiliation(s)
- Mary C Trask
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, 661 North Pleasant Street, Amherst, MA 01003, United States
| | | | | |
Collapse
|
|
25
|
Sato S, Ikeda K, Shioi G, Nakao K, Yajima H, Kawakami K. Regulation of Six1 expression by evolutionarily conserved enhancers in tetrapods. Dev Biol 2012; 368:95-108. [PMID: 22659139 DOI: 10.1016/j.ydbio.2012.05.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 05/16/2012] [Accepted: 05/21/2012] [Indexed: 11/16/2022]
Abstract
The Six1 homeobox gene plays critical roles in vertebrate organogenesis. Mice deficient for Six1 show severe defects in organs such as skeletal muscle, kidney, thymus, sensory organs and ganglia derived from cranial placodes, and mutations in human SIX1 cause branchio-oto-renal syndrome, an autosomal dominant developmental disorder characterized by hearing loss and branchial defects. The present study was designed to identify enhancers responsible for the dynamic expression pattern of Six1 during mouse embryogenesis. The results showed distinct enhancer activities of seven conserved non-coding sequences (CNSs) retained in tetrapod Six1 loci. The activities were detected in all cranial placodes (excluding the lens placode), dorsal root ganglia, somites, nephrogenic cord, notochord and cranial mesoderm. The major Six1-expression domains during development were covered by the sum of activities of these enhancers, together with the previously identified enhancer for the pre-placodal region and foregut endoderm. Thus, the eight CNSs identified in a series of our study represent major evolutionarily conserved enhancers responsible for the expression of Six1 in tetrapods. The results also confirmed that chick electroporation is a robust means to decipher regulatory information stored in vertebrate genomes. Mutational analysis of the most conserved placode-specific enhancer, Six1-21, indicated that the enhancer integrates a variety of inputs from Sox, Pax, Fox, Six, Wnt/Lef1 and basic helix-loop-helix proteins. Positive autoregulation of Six1 is achieved through the regulation of Six protein-binding sites. The identified Six1 enhancers provide valuable tools to understand the mechanism of Six1 regulation and to manipulate gene expression in the developing embryo, particularly in the sensory organs.
Collapse
Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | | | | | | | | | | |
Collapse
|
|
26
|
Barolo S. Shadow enhancers: frequently asked questions about distributed cis-regulatory information and enhancer redundancy. Bioessays 2012; 34:135-41. [PMID: 22083793 PMCID: PMC3517143 DOI: 10.1002/bies.201100121] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper, in the form of a frequently asked questions page (FAQ), addresses outstanding questions about "shadow enhancers", quasi-redundant cis-regulatory elements, and their proposed roles in transcriptional control. Questions include: What exactly are shadow enhancers? How many genes have shadow/redundant/distributed enhancers? How redundant are these elements? What is the function of distributed enhancers? How modular are enhancers? Is it useful to study a single enhancer in isolation? In addition, a revised definition of "shadow enhancers" is proposed, and possible mechanisms of shadow enhancer function and evolution are discussed.
Collapse
Affiliation(s)
- Scott Barolo
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.
| |
Collapse
|
|
27
|
Integrated microarray and ChIP analysis identifies multiple Foxa2 dependent target genes in the notochord. Dev Biol 2011; 360:415-25. [DOI: 10.1016/j.ydbio.2011.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 09/26/2011] [Accepted: 10/01/2011] [Indexed: 11/20/2022]
|
|
28
|
Wang H, Lei Q, Oosterveen T, Ericson J, Matise MP. Tcf/Lef repressors differentially regulate Shh-Gli target gene activation thresholds to generate progenitor patterning in the developing CNS. Development 2011; 138:3711-21. [PMID: 21775418 DOI: 10.1242/dev.068270] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During neural tube development, Shh signaling through Gli transcription factors is necessary to establish five distinct ventral progenitor domains that give rise to unique classes of neurons and glia that arise in specific positions along the dorsoventral axis. These cells are generated from progenitors that display distinct transcription factor gene expression profiles in specific domains in the ventricular zone. However, the molecular genetic mechanisms that control the differential spatiotemporal transcriptional responses of progenitor target genes to graded Shh-Gli signaling remain unclear. The current study demonstrates a role for Tcf/Lef repressor activity in this process. We show that Tcf3 and Tcf7L2 (Tcf4) are required for proper ventral patterning and function by independently regulating two Shh-Gli target genes, Nkx2.2 and Olig2, which are initially induced in a common pool of progenitors that ultimately segregate into unique territories giving rise to distinct progeny. Genetic and functional studies in vivo show that Tcf transcriptional repressors selectively elevate the strength and duration of Gli activity necessary to induce Nkx2.2, but have no effect on Olig2, and thereby contribute to the establishment of their distinct expression domains in cooperation with graded Shh signaling. Together, our data reveal a Shh-Gli-independent transcriptional input that is required to shape the precise spatial and temporal response to extracellular morphogen signaling information during lineage segregation in the CNS.
Collapse
Affiliation(s)
- Hui Wang
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | | | | | | | | |
Collapse
|
|
29
|
Foxa1 and Foxa2 positively and negatively regulate Shh signalling to specify ventral midbrain progenitor identity. Mech Dev 2011; 128:90-103. [DOI: 10.1016/j.mod.2010.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 09/27/2010] [Accepted: 11/05/2010] [Indexed: 11/24/2022]
|
|
30
|
Iwafuchi-Doi M, Yoshida Y, Onichtchouk D, Leichsenring M, Driever W, Takemoto T, Uchikawa M, Kamachi Y, Kondoh H. The Pou5f1/Pou3f-dependent but SoxB-independent regulation of conserved enhancer N2 initiates Sox2 expression during epiblast to neural plate stages in vertebrates. Dev Biol 2010; 352:354-66. [PMID: 21185279 DOI: 10.1016/j.ydbio.2010.12.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 12/09/2010] [Accepted: 12/16/2010] [Indexed: 12/30/2022]
Abstract
The transcription factor Sox2 is a core component of the pluripotency control circuits in the early embryo, and later controls many aspects of neural development. Here, we demonstrate that Sox2 expression in the epiblast (mouse blastoderm) and anterior neural plate (ANP) is determined by the upstream enhancer N2. The mouse enhancer N2 exhibits strong activity in mouse ES cells, epiblast and ANP, and is regulated correctly in chicken and zebrafish embryos. Targeted deletion of this enhancer in mouse embryos caused a large reduction of Sox2 expression to 10% of that of wild-type levels in epiblast and ANP. However, this was tolerated by mouse embryo, probably due to functional compensation by Sox3. The activity of enhancer N2 depends on phylogenetically conserved bipartite POU factor-binding motifs in a 73-bp core sequence that function synergistically, but this activation does not involve Sox2. The major POU factor expressed at the epiblastic stage is Pou5f1 (Oct3/4), while those in the anterior neural plate are Pou3f factors (Oct6, Brn2 etc.). These factors are gradually exchanged during the transition from epiblast to ANP stages in mouse embryos and epiblast stem cells (EpiSC). Consistently, enhancer N2 activity changes from full Pou5f1 dependence to Pou3f dependence during the development of neural plate cells (NPC) from EpiSC, as assessed by specific POU factor knockdown in these cells. Zebrafish mutant embryos completely devoid of Pou5f1 activity failed to activate enhancer N2 and to express Sox2 in the blastoderm and ANP, and these defects were rescued by exogenous supply of pou5f1. Previously, Pou5f1-Sox2 synergism-dependent Sox2 activation through enhancer SRR2 in ES cells has been highlighted, but this mechanism is limited to ES cells and amniotes. In contrast, the enhancer N2-mediated, POU factor-dependent activation of Sox2, without involvement of Sox2, is a phylogenetically conserved core mechanism that functions in gene regulatory networks at early embryonic stages.
Collapse
Affiliation(s)
- Makiko Iwafuchi-Doi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
|
31
|
Rojas A, Schachterle W, Xu SM, Martín F, Black BL. Direct transcriptional regulation of Gata4 during early endoderm specification is controlled by FoxA2 binding to an intronic enhancer. Dev Biol 2010; 346:346-55. [PMID: 20692247 DOI: 10.1016/j.ydbio.2010.07.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 07/22/2010] [Accepted: 07/27/2010] [Indexed: 10/19/2022]
Abstract
The embryonic endoderm is a multipotent progenitor cell population that gives rise to the epithelia of the digestive and respiratory tracts, the liver and the pancreas. Among the transcription factors that have been shown to be important for endoderm development and gut morphogenesis is GATA4. Despite the important role of GATA4 in endoderm development, its transcriptional regulation is not well understood. In this study, we identified an intronic enhancer from the mouse Gata4 gene that directs expression to the definitive endoderm in the early embryo. The activity of this enhancer is initially broad in all endodermal progenitors, as demonstrated by fate mapping analysis using the Cre/loxP system, but becomes restricted to the dorsal foregut and midgut, and associated organs such as dorsal pancreas and stomach. The function of the intronic Gata4 enhancer is dependent upon a conserved Forkhead transcription factor-binding site, which is bound by recombinant FoxA2 in vitro. These studies identify Gata4 as a direct transcriptional target of FoxA2 in the hierarchy of the transcriptional regulatory network that controls the development of the definitive endoderm.
Collapse
Affiliation(s)
- Anabel Rojas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CIBERDEM, Sevilla, Spain.
| | | | | | | | | |
Collapse
|
|
32
|
Sato S, Ikeda K, Shioi G, Ochi H, Ogino H, Yajima H, Kawakami K. Conserved expression of mouse Six1 in the pre-placodal region (PPR) and identification of an enhancer for the rostral PPR. Dev Biol 2010; 344:158-71. [PMID: 20471971 DOI: 10.1016/j.ydbio.2010.04.029] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 04/24/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
All cranial sensory organs and sensory neurons of vertebrates develop from cranial placodes. In chick, amphibians and zebrafish, all placodes originate from a common precursor domain, the pre-placodal region (PPR), marked by the expression of Six1/4 and Eya1/2. However, the PPR has never been described in mammals and the mechanism involved in the formation of PPR is poorly defined. Here, we report the expression of Six1 in the horseshoe-shaped mouse ectoderm surrounding the anterior neural plate in a pattern broadly similar to that of non-mammalian vertebrates. To elucidate the identity of Six1-positive mouse ectoderm, we searched for enhancers responsible for Six1 expression by in vivo enhancer assays. One conserved non-coding sequence, Six1-14, showed specific enhancer activity in the rostral PPR of chick and Xenopus and in the mouse ectoderm. These results strongly suggest the presence of PPR in mouse and that it is conserved in vertebrates. Moreover, we show the importance of the homeodomain protein-binding sites of Six1-14, the Six1 rostral PPR enhancer, for enhancer activity, and that Dlx5, Msx1 and Pax7 are candidate binding factors that regulate the level and area of Six1 expression, and thereby the location of the PPR. Our findings provide critical information and tools to elucidate the molecular mechanism of early sensory development and have implications for the development of sensory precursor/stem cells.
Collapse
Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
| | | | | | | | | | | | | |
Collapse
|
|
33
|
Le Lay J, Kaestner KH. The Fox genes in the liver: from organogenesis to functional integration. Physiol Rev 2010; 90:1-22. [PMID: 20086072 DOI: 10.1152/physrev.00018.2009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Formation and function of the liver are highly controlled, essential processes. Multiple signaling pathways and transcriptional regulatory networks cooperate in this complex system. The evolutionarily conserved FOX, for Forkhead bOX, class of transcriptional regulators is critical to many aspects of liver development and function. The FOX proteins are small, mostly monomeric DNA binding factors containing the so-called winged helix DNA binding motif that distinguishes them from other classes of transcription factors. We discuss the biochemical and genetic roles of Foxa, Foxl1, Foxm1, and Foxo, as these have been shown to regulate many processes throughout the life of the organ, controlling both formation and function of the liver.
Collapse
Affiliation(s)
- John Le Lay
- Department of Genetics and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA
| | | |
Collapse
|
|
34
|
Ukita K, Hirahara S, Oshima N, Imuta Y, Yoshimoto A, Jang CW, Oginuma M, Saga Y, Behringer RR, Kondoh H, Sasaki H. Wnt signaling maintains the notochord fate for progenitor cells and supports the posterior extension of the notochord. Mech Dev 2009; 126:791-803. [PMID: 19720144 PMCID: PMC2757446 DOI: 10.1016/j.mod.2009.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 08/20/2009] [Accepted: 08/24/2009] [Indexed: 11/15/2022]
Abstract
The notochord develops from notochord progenitor cells (NPCs) and functions as a major signaling center to regulate trunk and tail development. NPCs are initially specified in the node by Wnt and Nodal signals at the gastrula stage. However, the underlying mechanism that maintains the NPCs throughout embryogenesis to contribute to the posterior extension of the notochord remains unclear. Here, we demonstrate that Wnt signaling in the NPCs is essential for posterior extension of the notochord. Genetic labeling revealed that the Noto-expressing cells in the ventral node contribute the NPCs that reside in the tail bud. Robust Wnt signaling in the NPCs was observed during posterior notochord extension. Genetic attenuation of the Wnt signal via notochord-specific beta-catenin gene ablation resulted in posterior truncation of the notochord. In the NPCs of such mutant embryos, the expression of notochord-specific genes was down-regulated, and an endodermal marker, E-cadherin, was observed. No significant alteration of cell proliferation or apoptosis of the NPCs was detected. Taken together, our data indicate that the NPCs are derived from Noto-positive node cells, and are not fully committed to a notochordal fate. Sustained Wnt signaling is required to maintain the NPCs' notochordal fate.
Collapse
Affiliation(s)
- Kanako Ukita
- Laboratory for Embryonic Induction, RIKEN Center for Developmental Biology, Chuo, Kobe, Hyogo 650-0047, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
|
35
|
A transposon-based chromosomal engineering method to survey a large cis-regulatory landscape in mice. Nat Genet 2009; 41:946-52. [DOI: 10.1038/ng.397] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 05/12/2009] [Indexed: 11/08/2022]
|
|
36
|
Nishi Y, Ji H, Wong WH, McMahon AP, Vokes SA. Modeling the spatio-temporal network that drives patterning in the vertebrate central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:299-305. [PMID: 19445894 DOI: 10.1016/j.bbagrm.2009.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 11/18/2008] [Accepted: 01/12/2009] [Indexed: 10/21/2022]
Abstract
In this review, we discuss the gene regulatory network underlying the patterning of the ventral neural tube during vertebrate embryogenesis. The neural tube is partitioned into domains of distinct cell fates by inductive signals along both anterior-posterior and dorsal-ventral axes. A defining feature of the dorsal-ventral patterning is the graded distribution of Sonic hedgehog (Shh), which acts as a morphogen to specify several classes of ventral neurons in a concentration-dependent fashion. These inductive signals translate into patterned expressions of transcription factors that define different neural progenitor subtypes. Progenitor boundaries are sharpened by repressive interactions between these transcription factors. The progenitor-expressed transcription factors induce another set of transcription factors that are thought to contribute to neural identities in post-mitotic neural precursors. Thus, the gene regulatory network of the ventral neural tube patterning is characterized by hierarchical expression [inductive signal-->progenitor specifying factors (mitotic)--> precursor specifying factors (post mitotic)--> differentiated neural markers] and cross-repression between progenitor-expressed regulatory factors. Although a number of transcriptional regulators have been identified at each hierarchical level, their precise regulatory relationships are not clear. Here we discuss approaches aimed at clarifying and extending our understanding of the formation and propagation of this network.
Collapse
Affiliation(s)
- Yuichi Nishi
- Department of Molecular and Cellular Biology, Harvard University , Cambridge, MA 02138, USA
| | | | | | | | | |
Collapse
|
|
37
|
Kamachi Y, Iwafuchi M, Okuda Y, Takemoto T, Uchikawa M, Kondoh H. Evolution of non-coding regulatory sequences involved in the developmental process: reflection of differential employment of paralogous genes as highlighted by Sox2 and group B1 Sox genes. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2009; 85:55-68. [PMID: 19212098 PMCID: PMC3524295 DOI: 10.2183/pjab.85.55] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 01/05/2009] [Indexed: 05/27/2023]
Abstract
In higher vertebrates, the expression of Sox2, a group B1 Sox gene, is the hallmark of neural primordial cell state during the developmental processes from embryo to adult. Sox2 is regulated by the combined action of many enhancers with distinct spatio-temporal specificities. DNA sequences for these enhancers are conserved in a wide range of vertebrate species, corresponding to a majority of highly conserved non-coding sequences surrounding the Sox2 gene, corroborating the notion that the conservation of non-coding sequences mirrors their functional importance. Among the Sox2 enhancers, N-1 and N-2 are activated the earliest in embryogenesis and regulate Sox2 in posterior and anterior neural plates, respectively. These enhancers differ in their evolutionary history: the sequence and activity of enhancer N-2 is conserved in all vertebrate species, while enhancer N-1 is fully conserved only in amniotes. In teleost embryos, Sox19a/b play the major pan-neural role among the group B1 Sox paralogues, while strong Sox2 expression is limited to the anterior neural plate, reflecting the absence of posterior CNS-dedicated enhancers, including N-1. In Xenopus, neurally expressed SoxD is the orthologue of Sox19, but Sox3 appears to dominate other B1 paralogues. In amniotes, however, Sox19 has lost its group B1 Sox function and transforms into group G Sox15 (neofunctionalization), and Sox2 assumes the dominant position by gaining enhancer N-1 and other enhancers for posterior CNS. Thus, the gain and loss of specific enhancer elements during the evolutionary process reflects the change in functional assignment of particular paralogous genes, while overall regulatory functions attributed to the gene family are maintained.
Collapse
Affiliation(s)
- Yusuke Kamachi
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Makiko Iwafuchi
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yuichi Okuda
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Tatsuya Takemoto
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Masanori Uchikawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Hisato Kondoh
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| |
Collapse
|
|
38
|
Yasuhiko Y, Kitajima S, Takahashi Y, Oginuma M, Kagiwada H, Kanno J, Saga Y. Functional importance of evolutionally conserved Tbx6 binding sites in the presomitic mesoderm-specific enhancer of Mesp2. Development 2008; 135:3511-9. [PMID: 18849530 DOI: 10.1242/dev.027144] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The T-box transcription factor Tbx6 controls the expression of Mesp2, which encodes a basic helix-loop-helix transcription factor that has crucial roles in somitogenesis. In cultured cells, Tbx6 binding to the Mesp2 enhancer region is essential for the activation of Mesp2 by Notch signaling. However, it is not known whether this binding is required in vivo. Here we report that an Mesp2 enhancer knockout mouse bearing mutations in two crucial Tbx6 binding sites does not express Mesp2 in the presomitic mesoderm. This absence leads to impaired skeletal segmentation identical to that reported for Mesp2-null mice, indicating that these Tbx6 binding sites are indispensable for Mesp2 expression. T-box binding to the consensus sequences in the Mesp2 upstream region was confirmed by chromatin immunoprecipitation assays. Further enhancer analyses indicated that the number and spatial organization of the T-box binding sites are critical for initiating Mesp2 transcription via Notch signaling. We also generated a knock-in mouse in which the endogenous Mesp2 enhancer was replaced by the core enhancer of medaka mespb, an ortholog of mouse Mesp2. The homozygous enhancer knock-in mouse was viable and showed normal skeletal segmentation, indicating that the medaka mespb enhancer functionally replaced the mouse Mesp2 enhancer. These results demonstrate that there is significant evolutionary conservation of Mesp regulatory mechanisms between fish and mice.
Collapse
Affiliation(s)
- Yukuto Yasuhiko
- Division of Cellular and Molecular Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
| | | | | | | | | | | | | |
Collapse
|
|
39
|
Dessaud E, McMahon AP, Briscoe J. Pattern formation in the vertebrate neural tube: a sonic hedgehog morphogen-regulated transcriptional network. Development 2008; 135:2489-503. [PMID: 18621990 DOI: 10.1242/dev.009324] [Citation(s) in RCA: 523] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neuronal subtype specification in the vertebrate neural tube is one of the best-studied examples of embryonic pattern formation. Distinct neuronal subtypes are generated in a precise spatial order from progenitor cells according to their location along the anterior-posterior and dorsal-ventral axes. Underpinning this organization is a complex network of multiple extrinsic and intrinsic factors. This review focuses on the molecular mechanisms and general strategies at play in ventral regions of the forming spinal cord, where sonic hedgehog-based morphogen signaling is a key determinant. We discuss recent advances in our understanding of these events and highlight unresolved questions.
Collapse
Affiliation(s)
- Eric Dessaud
- Developmental Neurobiology, National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
| | | | | |
Collapse
|
|
40
|
Blank U, Seto ML, Adams DC, Wojchowski DM, Karolak MJ, Oxburgh L. An in vivo reporter of BMP signaling in organogenesis reveals targets in the developing kidney. BMC DEVELOPMENTAL BIOLOGY 2008; 8:86. [PMID: 18801194 PMCID: PMC2561030 DOI: 10.1186/1471-213x-8-86] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 09/18/2008] [Indexed: 12/22/2022]
Abstract
Background Bone morphogenetic proteins (BMPs) regulate essential processes during organogenesis, and a functional understanding of these secreted proteins depends on identification of their target cells. In this study, we generate a transgenic reporter for organogenesis studies that we use to define BMP pathway activation in the developing kidney. Results Mouse strains reporting on BMP pathway activation were generated by transgenically expressing β-galactosidase under the control of BMP responsive elements from Id1. Reporter expression corresponds well with immunoassays for pathway activation in all organs studied, validating the model. Using these reporters we have generated a detailed map of cellular targets of BMP signaling in the developing kidney. We find that SMAD dependent BMP signaling is active in collecting duct trunks, but not tips. Furthermore, glomerular endothelial cells, and proximal nephron tubules from the renal vesicle stage onward show pathway activation. Surprisingly, little activation is detected in the nephrogenic zone of the kidney, and in organ culture BMP treatment fails to activate SMAD dependent BMP signaling in nephron progenitor cells. In contrast, signaling is efficiently induced in collecting duct tips. Conclusion Transgenic reporters driven by control elements from BMP responsive genes such as Id1 offer significant advantages in sensitivity and consistency over immunostaining for studies of BMP pathway activation. They also provide opportunities for analysis of BMP signaling in organ and primary cell cultures subjected to experimental manipulation. Using such a reporter, we made the surprising finding that SMAD dependent BMP signaling is inactive in nephron progenitors, and that these cells are refractory to activation by applied growth factors. Furthermore, we find that the BMP pathway is not normally active in collecting duct tips, but that it can be ectopically activated by BMP treatment, offering a possible explanation for the inhibitory effects of BMP treatment on collecting duct growth and branching.
Collapse
Affiliation(s)
- Ulrika Blank
- Department of Molecular Medicine, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074, USA.
| | | | | | | | | | | |
Collapse
|
|
41
|
Redundant roles of Tead1 and Tead2 in notochord development and the regulation of cell proliferation and survival. Mol Cell Biol 2008; 28:3177-89. [PMID: 18332127 DOI: 10.1128/mcb.01759-07] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Four members of the TEAD/TEF family of transcription factors are expressed widely in mouse embryos and adult tissues. Although in vitro studies have suggested various roles for TEAD proteins, their in vivo functions remain poorly understood. Here we examined the role of Tead genes by generating mouse mutants for Tead1 and Tead2. Tead2(-/-) mice appeared normal, but Tead1(-/-); Tead2(-/-) embryos died at embryonic day 9.5 (E9.5) with severe growth defects and morphological abnormalities. At E8.5, Tead1(-/-); Tead2(-/-) embryos were already small and lacked characteristic structures such as a closed neural tube, a notochord, and somites. Despite these overt abnormalities, differentiation and patterning of the neural plate and endoderm were relatively normal. In contrast, the paraxial mesoderm and lateral plate mesoderm were displaced laterally, and a differentiated notochord was not maintained. These abnormalities and defects in yolk sac vasculature organization resemble those of mutants for Yap, which encodes a coactivator of TEAD proteins. Moreover, we demonstrated genetic interactions between Tead1 and Tead2 and Yap. Finally, Tead1(-/-); Tead2(-/-) embryos showed reduced cell proliferation and increased apoptosis. These results suggest that Tead1 and Tead2 are functionally redundant, use YAP as a major coactivator, and support notochord maintenance as well as cell proliferation and survival in mouse development.
Collapse
|
|
42
|
Adams D, Karolak M, Robertson E, Oxburgh L. Control of kidney, eye and limb expression of Bmp7 by an enhancer element highly conserved between species. Dev Biol 2007; 311:679-90. [PMID: 17936743 PMCID: PMC2394512 DOI: 10.1016/j.ydbio.2007.08.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 08/10/2007] [Accepted: 08/20/2007] [Indexed: 01/04/2023]
Abstract
Bmp7 is expressed in numerous tissues throughout development and is required for morphogenesis of the eye, hindlimb and kidney. In this study we show that the majority if not all of the cis-regulatory sequence governing expression at these anatomical sites during development is present in approximately 20 kb surrounding exon 1. In eye, limb and kidney, multiple distinct enhancer elements drive Bmp7 expression within each organ. In the eye, the elements driving expression in the pigmented epithelium and iris are spatially separated. In the kidney, Bmp7 expression in collecting ducts and nephron progenitors is driven by separate enhancer elements. Similarly, limb mesenchyme and apical ectodermal ridge expression are governed by separate elements. Although enhancers for pigmented epithelium, nephrogenic mesenchyme and apical ectodermal ridge are distributed across the approximately 20 kb region, an element of approximately 480 base pairs within intron 1 governs expression within the developing iris, collecting duct system of the kidney and limb mesenchyme. This element is remarkably conserved both in sequence and position in the Bmp7 locus between different vertebrates, ranging from Xenopus tropicalis to Homo sapiens, demonstrating that there is strong selective pressure for Bmp7 expression at these tissue sites. Furthermore, we show that the frog enhancer functions appropriately in transgenic mice. Interestingly, the intron 1 element cannot be found in the Bmp7 genes of vertebrates such as Danio rerio and Takifugu rubripes indicating that this modification of the Bmp7 gene might have arisen during the adaptation from aquatic to terrestrial life. Mutational analysis demonstrates that the enhancer activity of the intron 1 element is entirely dependent on the presence of a 10 base pair site within the intron 1 enhancer containing a predicted binding site for the FOXD3 transcription factor.
Collapse
Affiliation(s)
- Derek Adams
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, Maine 04074, USA
| | - Michele Karolak
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, Maine 04074, USA
| | - Elizabeth Robertson
- Wellcome Trust Center for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Leif Oxburgh
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, Maine 04074, USA
| |
Collapse
|
|
43
|
Frank DU, Elliott SA, Park EJ, Hammond J, Saijoh Y, Moon AM. System for inducible expression of cre-recombinase from the Foxa2 locus in endoderm, notochord, and floor plate. Dev Dyn 2007; 236:1085-92. [PMID: 17304540 DOI: 10.1002/dvdy.21093] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We targeted the reverse tetracycline controlled transactivator (rtTA) to the Foxa2 locus (Foxa2(ITA)) to generate a system for regulating Cre-recombinase activity within Foxa2 expression domains, including the endoderm, notochord, and floor plate of early mouse embryos. The use of an internal ribosomal entry site to obtain rtTA expression preserves Foxa2 function of the targeted allele. Cre activity with this system reflects the level of endogenous Foxa2 activity and is also tightly controlled by doxycycline. The location of Cre activity within the broader Foxa2 expression domain can be restricted by altering the timing of doxycycline administration. Isolated floor plate expression can be obtained in this manner. This system will provide a useful tool for manipulating gene expression in endoderm, notochord, and floor plate, all of which are tissues with important structural and patterning functions during embryogenesis.
Collapse
Affiliation(s)
- Deborah U Frank
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | | | | | | | | | | |
Collapse
|
|
44
|
Vokes SA, Ji H, McCuine S, Tenzen T, Giles S, Zhong S, Longabaugh WJR, Davidson EH, Wong WH, McMahon AP. Genomic characterization of Gli-activator targets in sonic hedgehog-mediated neural patterning. Development 2007; 134:1977-89. [PMID: 17442700 DOI: 10.1242/dev.001966] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sonic hedgehog (Shh) acts as a morphogen to mediate the specification of distinct cell identities in the ventral neural tube through a Gli-mediated (Gli1-3) transcriptional network. Identifying Gli targets in a systematic fashion is central to the understanding of the action of Shh. We examined this issue in differentiating neural progenitors in mouse. An epitope-tagged Gli-activator protein was used to directly isolate cis-regulatory sequences by chromatin immunoprecipitation (ChIP). ChIP products were then used to screen custom genomic tiling arrays of putative Hedgehog (Hh) targets predicted from transcriptional profiling studies, surveying 50-150 kb of non-transcribed sequence for each candidate. In addition to identifying expected Gli-target sites, the data predicted a number of unreported direct targets of Shh action. Transgenic analysis of binding regions in Nkx2.2, Nkx2.1 (Titf1) and Rab34 established these as direct Hh targets. These data also facilitated the generation of an algorithm that improved in silico predictions of Hh target genes. Together, these approaches provide significant new insights into both tissue-specific and general transcriptional targets in a crucial Shh-mediated patterning process.
Collapse
Affiliation(s)
- Steven A Vokes
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
|
45
|
Aruga J, Yoshikawa F, Nozaki Y, Sakaki Y, Toyoda A, Furuichi T. An oligodendrocyte enhancer in a phylogenetically conserved intron region of the mammalian myelin gene Opalin. J Neurochem 2007; 102:1533-1547. [PMID: 17442045 DOI: 10.1111/j.1471-4159.2007.04583.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Opalin is a transmembrane protein detected specifically in mammalian oligodendrocytes. Opalin homologs are found only in mammals and not in the genome sequences of other animal classes. We first determined the nucleotide sequences of Opalin orthologs and their flanking regions derived from four prosimians, a group of primitive primates. A global comparison revealed that an evolutionarily conserved region exists in the first intron of Opalin. When the conserved domain was assayed for its enhancer activity in transgenic mice, oligodendrocyte-directed expression was observed. In an oligodendroglial cell line, Oli-neu, the conserved domain showed oligodendrocyte-directed expression. The conserved domain is composed of eight subdomains, some of which contain binding sites for Myt1 and cAMP-response element binding protein (CREB). Deletion analysis and cotransfection experiments revealed that the subdomains have critical roles in Opalin gene expression. Over-expression of Myt1, treatment of the cell with leukemia inhibitory factor (LIF), and cAMP analog (CREB activator) enhanced the expression of endogenous Opalin in Oli-neu cells and activated the oligodendrocyte enhancer. These results suggest that LIF, cAMP signaling cascades and Myt1 play significant roles in the differentiation of oligodendrocytes through their action on the Opalin oligodendrocyte enhancer.
Collapse
Affiliation(s)
- Jun Aruga
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| | - Fumio Yoshikawa
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| | - Yayoi Nozaki
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| | - Yoshiyuki Sakaki
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| | - Atsushi Toyoda
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| | - Teiichi Furuichi
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanLaboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama, JapanSequence Technology Team, RIKEN Genomic Science Center, Yokohama, Japan
| |
Collapse
|
|
46
|
Inoue T, Ota M, Mikoshiba K, Aruga J. Zic2 and Zic3 synergistically control neurulation and segmentation of paraxial mesoderm in mouse embryo. Dev Biol 2007; 306:669-84. [PMID: 17490632 DOI: 10.1016/j.ydbio.2007.04.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 04/04/2007] [Accepted: 04/05/2007] [Indexed: 01/10/2023]
Abstract
Zic family zinc-finger proteins play various roles in animal development. In mice, five Zic genes (Zic1-5) have been reported. Despite the partly overlapping expression profiles of these genes, mouse mutants for each Zic show distinct phenotypes. To uncover possible redundant roles, we characterized Zic2/Zic3 compound mutant mice. Zic2 and Zic3 are both expressed in presomitic mesoderm, forming and newly generated somites with differential spatiotemporal accentuation. Mice heterozygous for the hypomorphic Zic2 allele together with null Zic3 allele generally showed severe malformations of the axial skeleton, including asymmetric or rostro-caudally bridged vertebrae, and reduction of the number of caudal vertebral bones, that are not obvious in single mutants. These defects were preceded by perturbed somitic marker expression, and reduced paraxial mesoderm progenitors in the primitive streak. These results suggest that Zic2 and Zic3 cooperatively control the segmentation of paraxial mesoderm at multiple stages. In addition to the segmentation abnormality, the compound mutant also showed neural tube defects that ran the entire rostro-caudal extent (craniorachischisis), suggesting that neurulation is another developmental process where Zic2 and Zic3 have redundant functions.
Collapse
Affiliation(s)
- Takashi Inoue
- Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan
| | | | | | | |
Collapse
|
|
47
|
Wiebe PO, Kormish JD, Roper VT, Fujitani Y, Alston NI, Zaret KS, Wright CVE, Stein RW, Gannon M. Ptf1a binds to and activates area III, a highly conserved region of the Pdx1 promoter that mediates early pancreas-wide Pdx1 expression. Mol Cell Biol 2007; 27:4093-104. [PMID: 17403901 PMCID: PMC1900007 DOI: 10.1128/mcb.01978-06] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The critical pancreatic transcription factor Pdx1 is expressed throughout the pancreas early but enriched in insulin-producing beta cells postnatally. Previous studies showed that the 5' conserved promoter regions areas I and II (Pdx1(PB)) direct endocrine cell expression, while an adjacent region (Pdx1(XB)) containing conserved area III directs transient beta-cell expression. In this study, we used Cre-mediated lineage tracing to track cells that activated these regions. Pdx1(PB)Cre mediated only endocrine cell recombination, while Pdx1(XB)Cre directed broad and early recombination in the developing pancreas. Also, a reporter transgene containing areas I, II, and III was expressed throughout the embryonic day 10.5 (E10.5) pancreas and gradually became beta cell enriched, similar to endogenous Pdx1. These data suggested that sequences within area III mediate early pancreas-wide Pdx1 expression. Area III contains a binding site for PTF1, a transcription factor complex essential for pancreas development. This site contributed to area III-dependent reporter gene expression in the acinar AR42J cell line, while PTF1 specifically trans-activated area III-containing reporter expression in a nonpancreatic cell line. Importantly, Ptf1a occupied sequences spanning the endogenous PTF1 site in area III of E11.5 pancreatic buds. These data strongly suggest that PTF1 is an important early activator of Pdx1 in acinar and endocrine progenitor cells during pancreas development.
Collapse
Affiliation(s)
- Peter O Wiebe
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, 2220 Pierce Avenue, Nashville, TN 37232, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
|
48
|
Haraguchi R, Motoyama J, Sasaki H, Satoh Y, Miyagawa S, Nakagata N, Moon A, Yamada G. Molecular analysis of coordinated bladder and urogenital organ formation by Hedgehog signaling. Development 2007; 134:525-33. [PMID: 17202190 DOI: 10.1242/dev.02736] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The urogenital and reproductive organs, including the external genitalia, bladder and urethra, develop as anatomically aligned organs. Descriptive and experimental embryology suggest that the cloaca, and its derivative, the urogenital sinus, contribute to the formation of these organs. However, it is unknown how the primary tissue lineages in, and adjacent to, the cloaca give rise to the above organs, nor is bladder formation understood. While it is known that sonic hedgehog (Shh) is expressed by the cloacal epithelia, the developmental programs that regulate and coordinate the formation of the urogenital and reproductive organs have not been elucidated. Here we report that Shh mutant embryos display hypoplasia of external genitalia, internal urethra (pelvic urethra) and bladder. The importance of Shh signaling in the development of bladder and external genitalia was confirmed by analyzing a variety of mutant mouse lines with defective hedgehog signaling. By genetically labeling hedgehog-responding tissue lineages adjacent to the cloaca and urogenital sinus, we defined the contribution of these tissues to the bladder and external genitalia. We discovered that development of smooth muscle myosin-positive embryonic bladder mesenchyme requires Shh signaling, and that the bladder mesenchyme and dorsal (upper) external genitalia derive from Shh-responsive peri-cloacal mesenchyme. Thus, the mesenchymal precursors for multiple urogenital structures derive from peri-cloacal mesenchyme and the coordination of urogenital organ formation from these precursors is orchestrated by Shh signals.
Collapse
Affiliation(s)
- Ryuma Haraguchi
- Center for Animal Resources and Development, CARD and Pharmaceutical Sciences, Kumamoto University, Honjo 2-2-1, Kumamoto, Japan
| | | | | | | | | | | | | | | |
Collapse
|
|
49
|
Kumar A, Yamaguchi T, Sharma P, Kuehn MR. Transgenic mouse lines expressing Cre recombinase specifically in posterior notochord and notochord. Genesis 2007; 45:729-36. [DOI: 10.1002/dvg.20346] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
|
50
|
Hirata T, Nakazawa M, Muraoka O, Nakayama R, Suda Y, Hibi M. Zinc-finger genes Fez and Fez-like function in the establishment of diencephalon subdivisions. Development 2006; 133:3993-4004. [PMID: 16971467 DOI: 10.1242/dev.02585] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Fez and Fez-like (Fezl) are zinc-finger genes that encode transcriptional repressors expressed in overlapping domains of the forebrain. By generating Fez;Fezl-deficient mice we found that a redundant function of Fez and Fezl is required for the formation of diencephalon subdivisions. The caudal forebrain can be divided into three transverse subdivisions: prethalamus (also called ventral thalamus), thalamus (dorsal thalamus) and pretectum. Fez;Fezl-deficient mice showed a complete loss of prethalamus and a strong reduction of the thalamus at late gestation periods. Genetic marker analyses revealed that during early diencephalon patterning in Fez;Fezl-deficient mice, the rostral diencephalon (prospective prethalamus) did not form and the caudal diencephalon (prospective thalamus and pretectum) expanded rostrally. Fez;Fezl-deficient mice also displayed defects in the formation of the zona limitans intrathalamica (ZLI),which is located on the boundary between the prethalamus and thalamus. Fez and Fezl are expressed in the region rostral to the rostral limit of Irx1 expression, which marks the prospective position of the ZLI. Transgene-mediated misexpression of Fezl or Fez caudal to the ZLI repressed the caudal diencephalon fate and affected the formation of the Shh-expressing ZLI. These data indicate that Fez and Fezl repress the caudal diencephalon fate in the rostral diencephalon, and ZLI formation probably depends on Fez/Fezl-mediated formation of diencephalon subdivisions.
Collapse
Affiliation(s)
- Tsutomu Hirata
- Laboratory for Vertebrate Axis Formation, Center for Developmental Biology, RIKEN, Kobe 650-0047, Japan
| | | | | | | | | | | |
Collapse
|