Simultaneous disruption of two DNA polymerases, Polη and Polζ, in Avian DT40 cells unmasks the role of Polη in cellular response to various DNA lesions.
Replicative DNA polymerases are frequently stalled by DNA lesions. The resulting replication blockage is released by homologous recombination (HR) and translesion DNA synthesis (TLS). TLS employs specialized TLS polymerases to bypass DNA lesions. We provide striking in vivo evidence of the cooperation between DNA polymerase η, which is mutated in the variant form of the cancer predisposition disorder xeroderma pigmentosum (XP-V), and DNA polymerase ζ by generating POLη(-/-)/POLζ(-/-) cells from the chicken DT40 cell line. POLζ(-/-) cells are hypersensitive to a very wide range of DNA damaging agents, whereas XP-V cells exhibit moderate sensitivity to ultraviolet light (UV) only in the presence of caffeine treatment and exhibit no significant sensitivity to any other damaging agents. It is therefore widely believed that Polη plays a very specific role in cellular tolerance to UV-induced DNA damage. The evidence we present challenges this assumption. The phenotypic analysis of POLη(-/-)/POLζ(-/-) cells shows that, unexpectedly, the loss of Polη significantly rescued all mutant phenotypes of POLζ(-/-) cells and results in the restoration of the DNA damage tolerance by a backup pathway including HR. Taken together, Polη contributes to a much wide range of TLS events than had been predicted by the phenotype of XP-V cells.
CREST Research Project, Japan Science and Technology, Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Kouji
K
Hirota
Eiichiro
E
Sonoda
Takuo
T
Kawamoto
Akira
A
Motegi
Chikahide
C
Masutani
Fumio
F
Hanaoka
Dávid
D
Szüts
Shigenori
S
Iwai
Julian E
JE
Sale
Alan
A
Lehmann
Shunichi
S
Takeda
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D002645:Chickens; D002945:Cisplatin / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D057809:HEK293 Cells; D006801:Humans; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D012689:Sequence Homology, Nucleic Acid; D013489:Suppression, Genetic; D014466:Ultraviolet Rays; D000099270:Y-Family DNA Polymerases
D000970:Antineoplastic Agents; D002945:Cisplatin; D004259:DNA-Directed DNA Polymerase; D008741:Methyl Methanesulfonate; C425929:DNA polymerase zeta; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases