Bacillus subtilis mutants deficient in the adaptive response to simple alkylating agents.
Three mutant strains exhibiting hyper-sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine, but not to methyl methanesulfonate, were selected by a replica method from mutagenized spores of Bacillus subtilis. All three were totally deficient in the adaptive response to N-methyl-N'-nitro-N-nitrosoguanidine with regard to both lethality and mutagenesis. The activity to destroy O6-methylguanine residues in the methylated DNA was not elevated in the mutant cells by the pretreatment with sublethal concentrations of N-methyl-N'-nitro-N-nitrosoguanidine. This deficiency corresponded to the persistence of O6-methylguanine residues in the DNA of both control and pretreated mutant cells challenged with the drug. The lethal and mutagenic sensitivity of the mutant strains were observed only for methyl- or ethyl-nitroso compounds that are thought to be active as inducers and are also active in O-alkylation. Except for the insensitivity to methyl methanesulfonate, the phenotypes of these mutants look very similar to those of ada mutants isolated previously in Escherichia coli.
D000477:Alkylating Agents / Q000633:toxicity*; D001412:Bacillus subtilis / Q000235:genetics*; D004260:DNA Repair; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D008769:Methylnitronitrosoguanidine / Q000633:toxicity; D009154:Mutation
D000477:Alkylating Agents; D008769:Methylnitronitrosoguanidine; D006147:Guanine; C008449:O-(6)-methylguanine