Effects of aphidicolin and/or 2‘,3‘-dideoxythymidine on DNA repair induced in HeLa cells by four types of DNA-damaging agents.
1985; Elsevier BV; Volume: 260; Issue: 19 Linguagem: Inglês
10.1016/s0021-9258(19)85098-6
ISSN1083-351X
AutoresKouichi Yamada, Fumio Hanaoka, Masa-atsu Yamada,
Tópico(s)DNA Repair Mechanisms
ResumoThe alkaline sucrose density gradient centrifugation method was modified to permit detection of 1 lesion/ 10' daltons of DNA.With this technique, the involvements of DNA polymerases in DNA repair of damage by dimethyl sulfate, UV irradiation, neocarzinostatin, and bleomycin were studied in HeLa cells with the aid of the DNA polymerase inhibitors aphidicolin and 2',3'-dideoxythymidine.DNA repair after UV-induced damage seemed to involve only polymerase a, while repair of damage by the other three agents involved both polymerase a and a non-a polymerase, probably polymerase B. But repair after damage by dimethyl sulfate differed from that after damage by neocarzinostatin or bleomycin with respect to the co- operations of polymerase a and polymerase 8: in repair of dimethyl sulfate-induced damage, both polymerases operated on the same lesions, whereas after damage by neocarzinostatin or bleomycin, polymerase a and polymerase t9 functioned independently on different lesions.Excision repair of damaged DNA is important in mammalian cells for efficient removal of chemical-and ultravioletinduced promutagenic, procarcinogenic, and potentially lethal lesions from the DNA.As in many other areas of eukaryotic molecular biology, much less information on the enzymology of DNA repair is available than for similar processes in prokaryotes.This is mainly because very few repair mutants of eukaryotic cells are available, in contrast to those of prokaryotes.However, the three known mammalian DNA polymerases (a, 0, and y) have been extensively characterized (1) and relatively specific inhibitors of each have been reported.Thus, the functions of these polymerases in DNA excision repair in mammals can now be examined (2).We previously described a HeLa cell lysate system for detection of unscheduled DNA synthesis after DNA damage by UV irradiation or MNNG' treatment (3-5).Moreover,
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