title: Unscheduled DNA synthesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Hela cells.
abstract: N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced repair (unscheduled) DNA synthesis was studied in intact HeLa cells as well as in the cell lysate. The incorporation of dTTP[methyl-3H] in vitro by the cell lysate was dependent on the dose of MNNG, and as linear for 2 min, reaching the maximum at 4 min. The optimum conditions were the same as for UV-induced in vitro repair synthesis. The presence of hydroxyurea and arabinofuranosyl cytosine during in vivo incubation with MNNG was necessary for enhancement of in vitro DNA synthesis. This MNNG-induced in vitro DNA synthesis was inhibited by aphidicolin, but not by 2',3'-dideoxythymidine-5'-triphosphate. It thus appears that DNA polymerase alpha participates in MNNG-induced unscheduled DNA synthesis in vitro.
mesh_terms: D016590:Aphidicolin; D003561:Cytarabine / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis*; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors; D054306:Dideoxynucleotides; D004224:Diterpenes / Q000494:pharmacology; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D019384:Nucleic Acid Synthesis Inhibitors; D013942:Thymine Nucleotides / Q000494:pharmacology
chemical_list: D054306:Dideoxynucleotides; D004224:Diterpenes; D019384:Nucleic Acid Synthesis Inhibitors; D013942:Thymine Nucleotides; D003561:Cytarabine; D008769:Methylnitronitrosoguanidine; D016590:Aphidicolin; D004247:DNA; D004257:DNA Polymerase II; C017216:2',3'-dideoxythymidine triphosphate; D006918:Hydroxyurea