title: [Heat shock inhibits the induced expression of the SOS genes and SoxRS regulons in Escherichia coli].
abstract: Oxidative stress formed in Escherichia coli cells is known to bring about a complex induction of alternative DNA repair processes, including SOS, SoxRS, and heat-shock response (HSR). The modification by heat shock of the expression of sfiA and soxS genes induced by oxidative agents H2O2, menadione and 4-nitroquinoline-1-oxide (4NQO) was studied for the first time. Quantitative parameters of gene expression were examined in E. coli strains with fused genes (promoters) sfiA::lacZ and soxS::lacZ. The expression of these genes induced by cell treatment with H2O2, but not menadione or 4NQO, was shown to decrease selectively after exposure to heat shock. Since genetic activity of menadione and 4NQO depends mainly on the formation of superoxide anion O2-, it is assumed that the effect of selective inhibition by heat-shock of sfiA and soxS gene expression in experiments with H2O2 is connected with activity of DnaK heat shock protein, which, unlike other heat-shock proteins, cannot be induced by superoxide anion O2-.
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response / Q000235:genetics*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018085:Regulon; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013014:SOS Response, Genetics / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D024483:Vitamin K 3 / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C499299:oxyR protein, E coli; C053139:sulA protein, E coli; C070724:SoxR protein, Bacteria; C070725:SoxS protein, E coli; D015112:4-Nitroquinoline-1-oxide; D024483:Vitamin K 3; D006861:Hydrogen Peroxide; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli