Dual roles for DNA polymerase eta in homologous DNA recombination and translesion DNA synthesis.
Chicken B lymphocyte precursors and DT40 cells diversify their immunoglobulin-variable (IgV) genes through homologous recombination (HR)-mediated Ig gene conversion. To identify DNA polymerases that are involved in Ig gene conversion, we created DT40 clones deficient in DNA polymerase eta (poleta), which, in humans, is defective in the variant form of xeroderma pigmentosum (XP-V). Poleta is an error-prone translesion DNA synthesis polymerase that can bypass UV damage-induced lesions and is involved in IgV hypermutation. Like XP-V cells, poleta-disrupted (poleta) clones exhibited hypersensitivity to UV. Remarkably, poleta cells showed a significant decrease in the frequency of both Ig gene conversion and double-strand break-induced HR when compared to wild-type cells, and these defects were reversed by complementation with human poleta. Our findings identify a DNA polymerase that carries out DNA synthesis for physiological HR and provides evidence that a single DNA polymerase can play multiple cellular roles.
Kawamoto
Takuo
T
CREST, Japan Science and Technology Agency, Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Japan.
Araki
Kasumi
K
Sonoda
Eiichiro
E
Yamashita
Yukiko M
YM
Harada
Kouji
K
Kikuchi
Koji
K
Masutani
Chikahide
C
Hanaoka
Fumio
F
Nozaki
Kazuhiko
K
Hashimoto
Nobuo
N
Takeda
Shunichi
S
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002645:Chickens; D003001:Cloning, Molecular; D004247:DNA / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000235:genetics / Q000528:radiation effects; D004260:DNA Repair / Q000235:genetics / Q000502:physiology; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000502:physiology* / Q000528:radiation effects; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007136:Immunoglobulins / Q000235:genetics / Q000528:radiation effects; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic; D014466:Ultraviolet Rays / Q000009:adverse effects; D014983:Xeroderma Pigmentosum / Q000235:genetics; D000099270:Y-Family DNA Polymerases
D004247:DNA; D004259:DNA-Directed DNA Polymerase; D007135:Immunoglobulin Variable Region; D007136:Immunoglobulins; D051135:Rad51 Recombinase; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases