Polymerase chain reaction-based deletion screening of bisulfite (sulfur dioxide) enhanced gpt-mutants in CHO-AS52 cells

In this study, we have examined the mutagenicity of bisulfite (sulfur dioxi de) at the xathine-guanine phosphoribosyl transferase locus (gpt) in the pS V2 gpt-transformed CHO cell line, AS52, Our results provide evidence for bi sulfite as a weak gene mutagen because the chemical at high doses and at hi gh cytotoxicity causes a 4-fold increase in mutant frequency (MF) and less than a doubling of the gpt gene deletion frequency compared to central We s uggest that the increase of MF in bisulfite-treated cells results from bisu lfite activity,as a comutagen, enhancing the induction effect of unknown en dogenous or exogenous factors on spontaneous mutagenesis of AS52 cells. For the spontaneous, 5 mM bisulfite- and 10 mM bisulfite-enhanced spontaneous mutants in AS52 cells, the percentage al total deletion mutations of the gp t gene is 36%, 44% and 65%, respectively. (C) 1999 Elsevier Science B.V. Al l rights reserved.