title: Methyl methanesulfonate mutagenesis in bacteriophage T4.
abstract: MMS induces diverse rII mutations from a wild-type background in bacteriophage T4. About 56% are base pair substitutions, about 30% are frameshift mutations, and the remainder is a miscellaneous set of rapidly reverting or leaky mutants of unknown composition; but deletions were not detected. MMS-induced forward mutation is sharply reduced by the mutations px and y, which also reduce ultraviolet, photodynamic and gamma-ray mutagenesis and increase killing by all of these agents. Thus, many of the mutations arise via the T4 WXY system. The induction of G:C leads to A:T transitions was detected even in a px or y background using sensitive reversion tests, and the few forward rII mutations that were induced from this background also behaved like transition mutations. Thus, some MMS-induced mutations arise independently of the WXY system, perhaps as a result of the (rather weak) ability of MMS to alkylate the O6 position of guanine.
mesh_terms: D005804:Genes, Lethal; D005814:Genes, Viral; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D009154:Mutation / Q000187:drug effects*; D013604:T-Phages / Q000235:genetics*
chemical_list: D008741:Methyl Methanesulfonate