title: In vivo evidence that DNA polymerase kappa is responsible for error-free bypass across DNA cross-links induced by mitomycin C.
abstract: Translesion DNA synthesis (TLS) is an important pathway that avoids genotoxicity induced by endogenous and exogenous agents. DNA polymerase kappa (Polk) is a specialized DNA polymerase involved in TLS but its protective roles against DNA damage in vivo are still unclear. To better understand these roles, we have established knock-in mice that express catalytically-inactive Polk and crossbred them with gpt delta mice, which possess reporter genes for mutations. The resulting mice (inactivated Polk KI mice) were exposed to mitomycin C (MMC), and the frequency of point mutations, micronucleus formation in peripheral erythrocytes, and γH2AX induction in the bone marrow was determined. The inactivated Polk KI mice exhibited significantly higher frequency of mutations at CpG and GpG sites, micronucleated cells, and γH2AX foci-positive cells than did the Polk wild-type (Polk(+)) mice. Recovery from MMC-induced DNA damage, which was evaluated by γH2AX induction, was retarded in embryonic fibroblasts from the knock-in mice when compared to those from the Polk(+) mice. These results suggest that Polk mediates TLS, which suppresses point mutations and DNA double-strand breaks caused by intra- and interstrand cross-links induced by MMC treatment. The established knock-in mice are extremely useful to elucidate the in vivo roles of the catalytic activity of Polk in suppressing DNA damage that was induced by a variety of genotoxic stresses.
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan. Electronic address: takeiriakr@chugai-pharm.co.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Takeiri
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Naoko A
authors.initials: NA
authors.lastname: Wada
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Motoyama
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Matsuzaki
authors.affiliation: Gotemba Branch, Chugai Research Institute for Medical Science, Inc., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Tateishi
authors.affiliation: Gotemba Branch, Chugai Research Institute for Medical Science, Inc., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Niimi
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sassa
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
authors.forename: Petr
authors.initials: P
authors.lastname: Grúz
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Masumura
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Mishima
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
authors.forename: Kou-Ichi
authors.initials: KI
authors.lastname: Jishage
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya, Tokyo 158-8501, Japan. Electronic address: nohmi@nihs.go.jp.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Nohmi
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D018899:CpG Islands; D003432:Cross-Linking Reagents / Q000494:pharmacology; D053960:DNA Breaks; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects; D006657:Histones / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D015162:Micronucleus Tests; D016685:Mitomycin / Q000494:pharmacology*; D059645:Mutation Rate; D000099270:Y-Family DNA Polymerases
chemical_list: D003432:Cross-Linking Reagents; D004259:DNA-Directed DNA Polymerase; D006657:Histones; D016685:Mitomycin; C475961:gamma-H2AX protein, mouse; C498613:Polk protein, mouse; D000099270:Y-Family DNA Polymerases
keywords: Cross-links; DNA polymerase kappa; Gpt delta mice; Knock-in mice; Mitomycin C