Two-polymerase mechanisms dictate error-free and error-prone translesion DNA synthesis in mammals.
DNA replication across blocking lesions occurs by translesion DNA synthesis (TLS), involving a multitude of mutagenic DNA polymerases that operate to protect the mammalian genome. Using a quantitative TLS assay, we identified three main classes of TLS in human cells: two rapid and error-free, and the third slow and error-prone. A single gene, REV3L, encoding the catalytic subunit of DNA polymerase zeta (pol zeta), was found to have a pivotal role in TLS, being involved in TLS across all lesions examined, except for a TT cyclobutane dimer. Genetic epistasis siRNA analysis indicated that discrete two-polymerase combinations with pol zeta dictate error-prone or error-free TLS across the same lesion. These results highlight the central role of pol zeta in both error-prone and error-free TLS in mammalian cells, and show that bypass of a single lesion may involve at least three different DNA polymerases, operating in different two-polymerase combinations.
Shachar
Sigal
S
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.
Ziv
Omer
O
Avkin
Sharon
S
Adar
Sheera
S
Wittschieben
John
J
Reissner
Thomas
T
Chaney
Stephen
S
Friedberg
Errol C
EC
Wang
Zhigang
Z
Carell
Thomas
T
Geacintov
Nicholas
N
Livneh
Zvi
Z
D000818:Animals; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004249:DNA Damage; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D004843:Epistasis, Genetic; D006801:Humans; D007700:Kinetics; D051379:Mice; D016296:Mutagenesis; D011740:Pyrimidine Dimers / Q000737:chemistry; D034741:RNA, Small Interfering / Q000378:metabolism; D051760:Xeroderma Pigmentosum Group A Protein / Q000378:metabolism
D011740:Pyrimidine Dimers; D034741:RNA, Small Interfering; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; D004247:DNA; D004259:DNA-Directed DNA Polymerase