title: Fanconi anemia FANCG protein in mitigating radiation- and enzyme-induced DNA double-strand breaks by homologous recombination in vertebrate cells.
abstract: The rare hereditary disorder Fanconi anemia (FA) is characterized by progressive bone marrow failure, congenital skeletal abnormality, elevated susceptibility to cancer, and cellular hypersensitivity to DNA cross-linking chemicals and sometimes other DNA-damaging agents. Molecular cloning identified six causative genes (FANCA, -C, -D2, -E, -F, and -G) encoding a multiprotein complex whose precise biochemical function remains elusive. Recent studies implicate this complex in DNA damage responses that are linked to the breast cancer susceptibility proteins BRCA1 and BRCA2. Mutations in BRCA2, which participates in homologous recombination (HR), are the underlying cause in some FA patients. To elucidate the roles of FA genes in HR, we disrupted the FANCG/XRCC9 locus in the chicken B-cell line DT40. FANCG-deficient DT40 cells resemble mammalian fancg mutants in that they are sensitive to killing by cisplatin and mitomycin C (MMC) and exhibit increased MMC and radiation-induced chromosome breakage. We find that the repair of I-SceI-induced chromosomal double-strand breaks (DSBs) by HR is decreased approximately 9-fold in fancg cells compared with the parental and FANCG-complemented cells. In addition, the efficiency of gene targeting is mildly decreased in FANCG-deficient cells, but depends on the specific locus. We conclude that FANCG is required for efficient HR-mediated repair of at least some types of DSBs.
authors.affiliation: Department of Immunology and Molecular Genetics, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ishiai
authors.forename: Nobuko
authors.initials: N
authors.lastname: Matsushita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Arakawa
authors.forename: Jane E
authors.initials: JE
authors.lastname: Lamerdin
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Buerstedde
authors.forename: Mitsune
authors.initials: M
authors.lastname: Tanimoto
authors.forename: Mine
authors.initials: M
authors.lastname: Harada
authors.forename: Larry H
authors.initials: LH
authors.lastname: Thompson
authors.forename: Minoru
authors.initials: M
authors.lastname: Takata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019313:BRCA1 Protein / Q000378:metabolism; D024682:BRCA2 Protein / Q000378:metabolism; D015153:Blotting, Western; D002455:Cell Division; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002645:Chickens; D002869:Chromosome Aberrations; D002945:Cisplatin / Q000494:pharmacology; D003001:Cloning, Molecular; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000187:drug effects / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004351:Drug Resistance; D052241:Fanconi Anemia Complementation Group G Protein; D005434:Flow Cytometry; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D016685:Mitomycin / Q000494:pharmacology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014965:X-Rays
chemical_list: D019313:BRCA1 Protein; D024682:BRCA2 Protein; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C499909:FANCG protein, human; C499910:Fancg protein, mouse; D052241:Fanconi Anemia Complementation Group G Protein; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D016685:Mitomycin; D004247:DNA; D002945:Cisplatin