Role of the Extracytoplasmic Function Protein Family Sigma Factor RpoE in Metal Resistance of Escherichia coli
| Autor: | Gregor Grass, Monique Egler, Cornelia Grosse, Dietrich H. Nies |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Mutant
Down-Regulation Gene Expression Sigma Factor Genetics and Molecular Biology Biology medicine.disease_cause Microbiology Sigma factor Gene expression Escherichia coli medicine Molecular Biology Escherichia coli Proteins Wild type Promoter Periplasmic space Molecular biology Up-Regulation Zinc Metals Bacterial outer membrane Copper Cadmium Transcription Factors |
| Zdroj: | Journal of Bacteriology. 187:2297-2307 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.187.7.2297-2307.2005 |
| Popis: | RpoE of Escherichia coli is a sigma factor of the extracytoplasmic function protein family and is required for the expression of proteins involved in maintaining the integrity of periplasmic and outer membrane components. RpoE of E. coli was needed for full resistance to Zn(II), Cd(II), and Cu(II). Promoter gene fusion and quantitative real time reverse transcription (RT)-PCR (qRT-PCR) assays demonstrated that expression of RpoE was induced by metals. Global gene expression profiles upon metal treatment of a Δ rpoE mutant strain and its wild-type strain were analyzed with microarrays, and selected genes were confirmed by qRT-PCR. The absolute number of genes that were changed in their expression upon metal stress was similar in both strains, but the increase or decrease in transcript levels upon metal treatment was smaller in the Δ rpoE mutant strain than in the wild type. Genes showing increased expression in the Δ rpoE mutant strain encoded proteins that belong to general defense systems against protein-denaturing agents. Genes showing decreased expression were part of the RpoE modulon itself plus the ompC gene, encoding a major outer membrane protein. A Δ ompC deletion strain was as sensitive to Cu(II) and Cd(II) as the Δ rpoE mutant or a Δ rpoE Δ ompC double mutant strain. In the case of Zn(II), the double mutant was more sensitive than either single mutant. This indicates that increased expression of OmpC contributes to the RpoE modulon-mediated response to metals. |
| Databáze: | OpenAIRE |
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