Protection of Chinese hamster cells against the cytotoxic and mutagenic effects of alkylating agents by transfection of the Escherichia coli alkyltransferase gene and a truncated derivative.
AffiliationDepartment of Biochemical Genetics, Paterson Institute for Cancer Research, Withington, Manchester, UK.
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AbstractThe cytotoxic and mutagenic effects of various monofunctional and bifunctional alkylating agents have been assessed in V79 Chinese hamster cells that express either the entire O6-alkylguanine (O6AG) and alkylphosphotriester alkyltransferase (ATase) gene (clone 8 cells) or a truncated form that codes only for O6AG ATase activity (clone SB cells). Protection ratios, as determined by D37 values, were greater for clone 8 cells than for SB cells. Significant protection against the mutagenic effects of N-methyl-N-nitrosourea and ethylmethanesulphonate at the hypoxanthine phosphoribosyltransferase (HPRT) locus was observed in clone 8 and SB cells. Streptozotocin and the haloethyl nitrosoureas, chlorozotocin and bis-chloroethylnitrosourea were less efficient in inducing HPRT-deficient mutants and a smaller degree of protection was afforded by the transfected genes. This is possibly due to the propensity of these compounds to induce multi-locus deletions. Southern analysis of DNA from clone 8 and SB cells indicated the presence of multiple copies of the plasmid integrated into clone 8 cells but few copies in clone SB cells. The copy number did not change but ATase levels fell when cells were grown in the absence of G418.
CitationProtection of Chinese hamster cells against the cytotoxic and mutagenic effects of alkylating agents by transfection of the Escherichia coli alkyltransferase gene and a truncated derivative. 1987, 2 (6):491-6 Mutagenesis