title: Detection of oxidative mutagens in strains of Escherichia coli deficient in the OxyR or MutY functions: dependence on SOS mutagenesis.
abstract: The Escherichia coli strain IC3821, a delta oxyR derivative of WP2 uvrA trpE65, was more sensitive to mutagenicity promoted by t-butyl hydroperoxide and cumene hydroperoxide than the isogenic oxyR+ control. Mutagenicity of menadione, a redox cycling quinone, was clearly detected in the delta oxyR strain, whereas only a slight mutagenic response was observed in the oxyR+ strain. Plumbagin, another quinone structurally similar to menadione, was not mutagenic to any of the strains. These mutagenic responses appeared to involve the SOS processing of oxidative DNA lesions and were mediated by MucA/B proteins more efficiently than by UmuD/C. In cells lacking mutagenesis proteins, induction of SOS-independent mutations by the two alkyl hydroperoxides required a deficiency in the MutY DNA glycosylase and was increased by the presence of the delta oxyR mutation. In contrast, the two quinones assayed were unable to induce SOS-independent mutations in the MutY-deficient strains.
authors.affiliation: FIB Instituto de Investigaciones Citológicas, Fundación Valenciana de Investigaciones Biomédicas, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Urios
authors.forename: G
authors.initials: G
authors.lastname: Herrera
authors.forename: M
authors.initials: M
authors.lastname: Blanco
mesh_terms: D001555:Benzene Derivatives / Q000633:toxicity*; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D045647:DNA Glycosylases; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation / Q000187:drug effects; D009699:N-Glycosyl Hydrolases / Q000235:genetics*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000633:toxicity*; D012097:Repressor Proteins / Q000235:genetics*; D013014:SOS Response, Genetics / Q000187:drug effects*; D014157:Transcription Factors / Q000235:genetics*; D020122:tert-Butylhydroperoxide
chemical_list: D001555:Benzene Derivatives; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009153:Mutagens; D010545:Peroxides; D012097:Repressor Proteins; D014157:Transcription Factors; C499299:oxyR protein, E coli; D020122:tert-Butylhydroperoxide; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; C007164:cumene hydroperoxide