title: Induced mutagenesis in dam- mutants of Escherichia coli: a role for 6-methyladenine residues in mutation avoidance.
abstract: E. coli strains carrying the dam-3 and dam-4 mutations resulting in reduced levels of 6-methyladenine in the DNA have been found to be more sensitive to base analogue mutagenesis than dam+ strains. Mutagenesis by EMS was also found to be enhanced in dam- strains. Dam- mutants however were not found to be hypermutable by UV light. It is concluded that the dam- strains are deficient in the correct repair of mispairing lesions. The data are consistent with the hypothesis that 6-methyladenine residues in the DNA are involved in strand discrimination during mismatch correction.
mesh_terms: D015075:2-Aminopurine / Q000494:pharmacology; D000225:Adenine / Q000031:analogs & derivatives*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D009154:Mutation / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D015075:2-Aminopurine; D000225:Adenine; D004269:DNA, Bacterial; D005020:Ethyl Methanesulfonate; C000730567:6-methyladenine