ArticleGlickman B, van den Elsen P, Radman M.
Mol Gen Genet. 1978 Jul 25;163(3):307-12.
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.