Copyright ©The Author(s) 2015.
World J Biol Chem. Aug 26, 2015; 6(3): 48-56
Published online Aug 26, 2015. doi: 10.4331/wjbc.v6.i3.48
Table 1 Components and regulators of DNA damage tolerance1
Rad6/Rad18E2 ubiquitin conjugase/E3 ubiquitin ligase complex; promotes mono-ubiquitination of PCNA at lysine 164 (PCNA-K164)
Rad5/Mms2/Ubc13E3 ubiquitin ligase/E2 ubiquitin conjugase complex; promotes poly-ubiquitination of PCNA-K164; has ATPase activity
Pol30Forms a homotrimer (PCNA); its ubiquitination and sumoylation regulates the choice of DDT mechanism
Ubc9/Siz1E2 SUMO conjugase/E3 SUMO ligase complex; promotes PCNA sumoylation
DNA polymerase ζTLS polymerase; consists of subunits Rev3, Rev7, Pol31 and Pol32 with Rev3 being the catalytic subunit
Rev1dCMP transferase; required for TLS by Pol ζ
DNA polymerase η (Rad30)TLS polymerase
DNA polymerase δ (Pol3/Pol31/Pol32)Lagging strand DNA polymerase; Pol3 is the catalytic subunit; promotes repair synthesis in error-free DDT; Pol32 is not essential for DNA replication but is required for repair synthesis
Rad51Components of HR responsible for homology search and strand invasion; Rad51 molecules bind ssDNA to form a presynaptic filament important for subsequent strand invasion; both Rad55 and Rad57 are paralogs of Rad51; Rad55/Rad57 stabilizes Rad51 nucleoprotein filament and inhibits Srs2 helicase activity
Srs23′-5′ helicase and translocase; disrupts Rad51 nucleoprotein filaments; inhibits salvage HR pathway thereby channeling DNA lesions to Rad5 pathway
Sgs1/Top3/Rmi1Resolves SCJ intermediates generated in error-free DDT
RFA (replication factor A) (Rfa1/Rfa2/Rfa3)ssDNA binding complex; is involved in DNA replication, repair and recombination; RFA-ssDNA nucleofilament helps recruit Rad18
Exo15’-3’ exonuclease; promotes resection of dsDNA break ends; functions in DNA damage repair, recombination, replication, and telomere integrity; is required for SCJ formation in error-free DDT
9-1-1 complex (Ddc1/Mec3/Rad17)Ring shaped DNA clamp; is involved in DNA check point signaling; facilitates Pol ζ recruitment; is required for SCJ formation in error-free DDT; interacts with Exo1
MRX complex (Mre11-Rad50-Xrs2)3’-5’ exonuclease and ssDNA endonuclease; is potentially involved in both TLS and TS branches of DDT; interacts with Rad18
Shu complex (Shu1/Shu2/ Csm2/Psy3)Is involved in error-free DDT; interacts with Rad55/Rad57
Ino80Chromatin remodeler; associates with replication forks and promotes fork progression; required for Rad18 and Rad51 recruitment to replications forks, PCNA poly-ubiquitination and SCJ formation
Elg1Unloads PCNA from chromatin during DNA replication; regulates choice of DDT pathway
Hmo1HMGB homolog; binds ssDNA and DNA with an altered conformation; bends DNA; interacts with Elg1; may help channel DNA lesions to Rad5 pathway; required for SCJ formation in S phase
Fun30Chromatin remodeler; facilitates long-range resection of dsDNA ends; potentially regulates choice of DDT pathway