title: Inability of Chinese hamster ovary cells to excise O6-alkylguanine.
abstract: The capacity of Chinese hamster ovary cells for excising alkylated bases from their DNA was investigated. Cells were treated with N-methyl-N-nitrosourea or N-ethyl-N-nitrosourea, and the amounts of 3-alkyladenine, 7-alkylguanine, and O6-alkylguanine in DNA were compared immediately after the treatment and after a 20-hr incubation. Cells were able to excise 3-alkyladenine and 7-alkylguanine, but there was no loss of O6-alkylguanine, after correction for dilution, due to DNA synthesis during posttreatment incubation. The inability of Chinese hamster ovary cells fail to show growing point mutagenesis after treatment with N-ethyl-N-nitrosourea.
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000032:analysis; D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D005038:Ethylnitrosourea / Q000494:pharmacology; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis; D008770:Methylnitrosourea / Q000494:pharmacology; D010053:Ovary / Q000166:cytology; D011740:Pyrimidine Dimers; D013997:Time Factors
chemical_list: D000477:Alkylating Agents; D011740:Pyrimidine Dimers; D006147:Guanine; D008770:Methylnitrosourea; D004247:DNA; D000225:Adenine; D005038:Ethylnitrosourea