Nucleotide excision repair proteins may be involved in the fixation of glyoxal-induced mutagenesis in Escherichia coli.
To investigate the influence of nucleotide excision repair (NER) on glyoxal-induced mutations, we treated wild-type and NER-deficient (uvrC) Escherichia coli strains with glyoxal, and analyzed mutations in the chromosomal lacI gene. In both strains, the cell death and the mutation frequency increased according to the dose of glyoxal added to the culture medium, and cell death was induced to a similar level in both strains. Interestingly, the frequency of glyoxal-induced mutations in the wild-type strain was higher than that in the uvrC strain. Particularly, the frequency of base-pair substitutions was 4.7-fold higher in the wild-type strain. In the wild-type strain, G:C-->T:A transversions were predominant, followed by G:C-->A:T and A:T-->T:A mutations. In the uvrC strain, G:C-->A:T transitions were predominant, followed by G:C-->T:A transversions. All the base-pair substitutions except for G:C-->A:T transitions were >4-fold higher in the wild-type strain than in the uvrC strain. These results suggest that NER may be involved in the fixation of glyoxal-induced base-pair substitutions.
Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan.
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Murata-Kamiya
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Kamiya
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Kaji
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H
Kasai
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001482:Base Composition / Q000235:genetics; D001483:Base Sequence; D004260:DNA Repair / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D006037:Glyoxal / Q000494:pharmacology*; D056968:Lac Repressors; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D009154:Mutation / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D056968:Lac Repressors; C539064:LacI protein, E coli; D012097:Repressor Proteins; D006037:Glyoxal