Reduction of GC --> TA transversion mutation by overexpression of MutS in Escherichia coli K-12.
Overexpression of the MutS repair protein significantly decreased the rate of lacZ GC --> TA transversion mutation in stationary-phase and exponentially growing bacteria and in mutY and mutM mutants, which accumulate mismatches between 8-oxoguanine (8-oxoG) and adenine residues in DNA. Conversely, GC --> TA transversion increased in mutL or mutS mutants in stationary phase. In contrast, overexpression of MutS did not appreciably reduce lacZ AT --> CG transversion mutation in a mutT mutant. These results suggest that MutS-dependent repair can correct 8-oxoG:A mismatches in Escherichia coli cells but may not be able to compete with mutation fixation by MutY in mutT mutants.
Department of Microbiology and Molecular Genetics, University of Texas Houston Medical School, Houston, Texas 77030, USA.
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Zhao
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Winkler
D000225:Adenine; D000251:Adenosine Triphosphatases; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020137:Base Pair Mismatch; D003553:Cystine; D004260:DNA Repair; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D006147:Guanine; D051719:MutS DNA Mismatch-Binding Protein; D009154:Mutation; D013941:Thymine
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D003553:Cystine; D006147:Guanine; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli; D000225:Adenine; D013941:Thymine