Antimutagenic action of methionine in Chinese hamster fibroblasts: an opposite of methionine mutagenicity.
Serially propagated fibroblast clones were treated with 25-mM methionine and a thioguanine resistance assay was performed at each passage to measure mutagenesis at the HGPRT locus. The spontaneous frequency of thioguanine resistant mutants before treatment was less than 5 X 10(-6) in four clones and 22 X 10(-6) in one clone. These values dropped 10- to 100-fold and remained so until the methionine was withdrawn, then returned to, or overshot, the initial values. It is proposed that these fibroblasts, unlike their previously described RSV-transformed counterparts, possess a repair enzyme capable of an adaptive response to S-adenosylmethionine, the metabolite thought to be responsible for methionine mutagenicity in vivo.
Hill
M
M
Laboratory of Cellular and Molecular Biology, C.N.R.S., I.C.I.G., Hôpital Paul-Brousse, Villejuif, France.
Hillova
J
J
Mariage-Samson
R
R
Brada
Z
Z
D000818:Animals; D015139:Blotting, Southern; D002460:Cell Line; D002999:Clone Cells; D006224:Cricetinae; D003412:Cricetulus; D004351:Drug Resistance / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D008715:Methionine / Q000494:pharmacology*; D009153:Mutagens; D009154:Mutation; D013866:Thioguanine / Q000494:pharmacology
D009153:Mutagens; D008715:Methionine; D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine