title: Interplay between DNA polymerases beta and lambda in repair of oxidation DNA damage in chicken DT40 cells.
abstract: DNA polymerase lambda (Pol lambda) is a DNA polymerase beta (Pol beta)-like enzyme with both DNA synthetic and 5'-deoxyribose-5'-phosphate lyase domains. Recent biochemical studies implicated Pol lambda as a backup enzyme to Pol beta in the mammalian base excision repair (BER) pathway. To examine the interrelationship between Pol lambda and Pol beta in BER of DNA damage in living cells, we disrupted the genes for both enzymes either singly or in combination in the chicken DT40 cell line and then characterized BER phenotypes. Disruption of the genes for both polymerases caused hypersensitivity to H(2)O(2)-induced cytotoxicity, whereas the effect of disruption of either polymerase alone was only modest. Similarly, BER capacity in cells after H(2)O(2) exposure was lower in Pol beta(-/-)/Pol lambda(-/-) cells than in Pol beta(-/-), wild-type, and Pol lambda(-/-) cells, which were equivalent. These results suggest that these polymerases can complement for one another in counteracting oxidative DNA damage. Similar results were obtained in assays for in vitro BER capacity using cell extracts. With MMS-induced cytotoxicity, there was no significant effect on either survival or BER capacity from Pol lambda gene disruption. A strong hypersensitivity and reduction in BER capacity was observed for Pol beta(-/-)/Pol lambda(-/-) and Pol beta(-/-) cells, suggesting that Pol beta had a dominant role in counteracting alkylation DNA damage in this cell system.
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori, Japan. tano@rri.kyoto-u.ac.jp <tano@rri.kyoto-u.ac.jp>
authors.forename: Keizo
authors.initials: K
authors.lastname: Tano
authors.forename: Jun
authors.initials: J
authors.lastname: Nakamura
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Asagoshi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Arakawa
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Sonoda
authors.forename: Elena K
authors.initials: EK
authors.lastname: Braithwaite
authors.forename: Rajendra
authors.initials: R
authors.lastname: Prasad
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Buerstedde
authors.forename: Shunichi
authors.initials: S
authors.lastname: Takeda
authors.forename: Masami
authors.initials: M
authors.lastname: Watanabe
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Wilson
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival; D002645:Chickens; D004249:DNA Damage; D019951:DNA Polymerase beta / Q000502:physiology*; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008957:Models, Genetic; D009249:NADP / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism
chemical_list: D009249:NADP; D006861:Hydrogen Peroxide; C415367:DNA polymerase beta2; D019951:DNA Polymerase beta; D010100:Oxygen