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.
Zhao
J
J
Department of Microbiology and Molecular Genetics, University of Texas Houston Medical School, Houston, Texas 77030, USA.
Winkler
M E
ME
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