title: Induction of temperature-sensitive 6-thioguanine-resistant mutants as a measure of base-pair substitution mutations in Chinese hamster ovary cells.
abstract: A method which allows quantification of the frequency of temperature-sensitive (ts) 6-thioguanine-resistant mutants of Chinese hamster ovary cells is described. These mutants, as well as non-ts type of mutant, contain altered hypoxanthine-guanine phosphoribosyl transferase (HGPRT) enzyme activity. The frequency of these altered enzyme mutants allows estimation of the fraction of total mutagenic events in the hgprt gene which results from base-pair substitution and thus provides a measure of the type of lesions induced by mutagenic agents. With an alkylating agent, ethyl methanesulfonate, 16-22% of the total induced mutants show these altered protein phenotypes, while none were found with the putative frameshift mutagen, ICR-191.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004351:Drug Resistance; D005260:Female; D009153:Mutagens; D009154:Mutation; D013866:Thioguanine / Q000494:pharmacology
chemical_list: D009153:Mutagens; D013866:Thioguanine