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Induced mutagenesis in dam − mutants of Escherichia coli: A role for 6-methyladenine residues in mutation avoidance

✍ Scribed by Glickman, Barry ;van den Elsen, Peter ;Radman, Miroslav


Publisher
Springer
Year
1978
Tongue
English
Weight
547 KB
Volume
163
Category
Article
ISSN
0026-8925

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✦ Synopsis


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.