title: On the mechanism of induction of resistance to 6-thioguanine in Chinese hamster V79 cells by 3-methylcholanthrene-diolepoxide.
abstract: V79 Chinese hamster cells were cultured in the presence of 3-methylcholanthrene-diolepoxide (10r,9t-dihydroxy-7,8t-epoxy-tetrahydro-3-methylcholanthrene, MCDE) and mutants were selected in medium containing 6-thioguanine (TG). Of 22 TG-resistant mutants examined, 18 were devoid of HPRT (hypoxanthine-guanine phosphoribosyltransferase, EC 2.4.2.8) activity. Two mutants had suffered a total and one a partial gene deletion. The 1.6-kb HPRT mRNA was not detected in these three mutants nor in two others. The remaining mutants did not, however, have a readily demonstrable lesion.
mesh_terms: D000818:Animals; D002273:Carcinogens; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000235:genetics; D004262:DNA Restriction Enzymes; D004351:Drug Resistance; D005796:Genes; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007526:Isoelectric Point; D008748:Methylcholanthrene / Q000031:analogs & derivatives* / Q000494:pharmacology; D009154:Mutation / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics; D013866:Thioguanine / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D012333:RNA, Messenger; D008748:Methylcholanthrene; C038099:9,10-dihydroxy-7,8-epoxy-7,8,9,10-tetrahydro-3-methylcholanthrene; D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase; D004262:DNA Restriction Enzymes; D013866:Thioguanine