title: Repair of thymine dimers and (6-4) photoproducts in group A xeroderma pigmentosum cell lines harboring a transferred normal chromosome 9.
abstract: Transfer of a normal chromosome 9 into a xeroderma pigmentosum (XP)-A cell line partially restored its DNA repair activity. XP-A cell lines harboring a transferred chromosome were much more UV-resistant than parental XP-A cells but still more UV-sensitive than normal cells. The amount of UV-induced unscheduled DNA synthesis was only one-third of that in normal cells. The repair of thymine dimers and (6-4) photoproducts in these cell lines was analyzed by using monoclonal antibodies raised against them. Although these XP-A cell lines carrying a normal chromosome 9 could repair (6-4) photoproduct with a little lower efficiency than normal cells, the repair of thymine dimers was completely absent in these cells. The present results suggest a gene-dosage effect in DNA excision repair mechanisms in human cells or a rather complicated mechanism which involves two or more pathways.
authors.affiliation: Radiation Biology Center, Kyoto University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishizaki
authors.forename: T
authors.initials: T
authors.lastname: Matsunaga
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: O
authors.initials: O
authors.lastname: Nikaido
authors.forename: M
authors.initials: M
authors.lastname: Ikenaga
mesh_terms: D002460:Cell Line; D002899:Chromosomes, Human, Pair 9; D004247:DNA / Q000235:genetics / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D006801:Humans; D011740:Pyrimidine Dimers; D014162:Transfection; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics*
chemical_list: D011740:Pyrimidine Dimers; D004247:DNA