OxyR and SoxRS Regulation of fur
| Autor: | Ming Zheng, Gisela Storz, Thomas D. Schneider, Bernard Doan |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
inorganic chemicals
Paraquat Transcription Genetic Iron Molecular Sequence Data DNA Footprinting DNA footprinting Repressor Genetics and Molecular Biology Biology Microbiology chemistry.chemical_compound Bacterial Proteins Superoxides Metalloproteins Escherichia coli RNA Messenger Promoter Regions Genetic Hydrogen peroxide Molecular Biology chemistry.chemical_classification Reactive oxygen species Base Sequence Flavoproteins Superoxide Escherichia coli Proteins Gene Expression Regulation Bacterial Hydrogen Peroxide Molecular biology DNA-Binding Proteins Repressor Proteins SOXS Oxidative Stress chemistry Biochemistry Trans-Activators bacteria Hydroxyl radical Transcription Factors |
| Zdroj: | Journal of Bacteriology. 181:4639-4643 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.181.15.4639-4643.1999 |
| Popis: | The cytotoxic effects of reactive oxygen species are largely mediated by iron. Hydrogen peroxide reacts with iron to form the extremely reactive and damaging hydroxyl radical via the Fenton reaction. Superoxide anion accelerates this reaction because the dismutation of superoxide leads to increased levels of hydrogen peroxide and because superoxide elevates the intracellular concentration of iron by attacking iron-sulfur proteins. We found that regulators of the Escherichia coli responses to oxidative stress, OxyR and SoxRS, activate the expression of Fur, the global repressor of ferric ion uptake. A transcript encoding Fur was induced by hydrogen peroxide in a wild-type strain but not in a Δ oxyR strain, and DNase I footprinting assays showed that OxyR binds to the fur promoter. In cells treated with the superoxide-generating compound paraquat, we observed the induction of a longer transcript encompassing both fur and its immediate upstream gene fldA , which encodes a flavodoxin. This polycistronic mRNA is induced by paraquat in a wild-type strain but not in a Δ soxRS strain, and SoxS was shown to bind to the fldA promoter. These results demonstrate that iron metabolism is coordinately regulated with the oxidative stress defenses. |
| Databáze: | OpenAIRE |
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