Escherichia coli mutator mutants deficient in methylation-instructed DNA mismatch correction.
Open Access
- 1 February 1980
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 77 (2) , 1063-1067
- https://doi.org/10.1073/pnas.77.2.1063
Abstract
Our approach to the isolation of DNA mismatch-correction-deficient mutants was based upon the isolation of 2-aminopurine-resistant second-site revertants of Escherichia coli dam- mutants. We isolated such second-site revertants which, when separated from the dam- mutation, have a mutator character of their own. These new mutators all mapped at three known mutator loci, mutH, mutL, and mutS, which exhibit the same mutagenic spectrum as the dam- mutator: increased levels of base substitution and frameshift mutations. The mutator potencies of double and triple mut- mutants suggest that these mutators are involved in the same general mismatch-repair pathway. All these mutations result in a hyper-recombination phenotype, but in four-factor crosses among lambda phages, a specific loss of intragenic recombination (Pam3 X Pam80) was found in mutL and mutS mutants, as would be predicted from the postulated role of mismatch correction in gene conversion and high negative interference phenomena.This publication has 25 references indexed in Scilit:
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