title: Escherichia coli response to hydrogen peroxide: a role for DNA supercoiling, topoisomerase I and Fis.
abstract: Bacterial cells respond to the deleterious effects of reactive oxygen species by inducing the expression of antioxidant defence genes. Here we show that treatment with hydrogen peroxide leads to a transient decrease in DNA negative supercoiling. We also report that hydrogen peroxide activates topA P1 promoter expression. The peroxide-dependent topA P1 activation is independent of oxyR, but is mediated by Fis. This nucleoid-associated protein binds to the promoter region of topA. We also show that a fis deficient mutant strain is extremely sensitive to hydrogen peroxide. Our results suggest that topA activation by Fis is an important component of the Escherichia coli response to oxidative stress.
authors.affiliation: Department of Molecular Genetics and Biotechnology, The Hebrew University-Hadassah Medical School, 91120 Jerusalem, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Weinstein-Fischer
authors.forename: M
authors.initials: M
authors.lastname: Elgrably-Weiss
authors.forename: S
authors.initials: S
authors.lastname: Altuvia
mesh_terms: D001483:Base Sequence; D002352:Carrier Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects; D004264:DNA Topoisomerases, Type I / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D034982:Integration Host Factors; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D018384:Oxidative Stress; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; C440502:integration host factor, E coli; D006861:Hydrogen Peroxide; D004264:DNA Topoisomerases, Type I