CpxR/OmpR Interplay Regulates Curli Gene Expression in Response to Osmolarity in<i>Escherichia coli</i>
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- Gregory Jubelin
- Unité de Microbiologie et Génétique Composante INSA
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- Anne Vianney
- Unité de Microbiologie et Génétique, Université Claude Bernard Lyon I, Villeurbanne
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- Christophe Beloin
- Groupe de Génétique des Biofilms, Institut Pasteur, Paris, France
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- Jean-Marc Ghigo
- Groupe de Génétique des Biofilms, Institut Pasteur, Paris, France
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- Jean-Claude Lazzaroni
- Unité de Microbiologie et Génétique, Université Claude Bernard Lyon I, Villeurbanne
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- Philippe Lejeune
- Unité de Microbiologie et Génétique Composante INSA
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- Corinne Dorel
- Unité de Microbiologie et Génétique Composante INSA
説明
<jats:title>ABSTRACT</jats:title><jats:p>Curli fibers could be described as a virulence factor able to confer adherence properties to both abiotic and eukaryotic surfaces. The ability to adapt rapidly to changing environmental conditions through signal transduction pathways is crucial for the growth and pathogenicity of bacteria. OmpR was shown to activate<jats:italic>csgD</jats:italic>expression, resulting in curli production. The CpxR regulator was shown to negatively affect curli gene expression when binding to its recognition site that overlaps the<jats:italic>csgD</jats:italic>OmpR-binding site. This study was undertaken to clarify how the interplay between the two regulatory proteins, OmpR and CpxR, can affect the transcription of the curli gene in response to variation of the medium osmolarity. Band-shift assays with purified CpxR proteins indicate that CpxR binds to the<jats:italic>csgD</jats:italic>promoter region at multiple sites that are ideally positioned to explain the<jats:italic>csg</jats:italic>repression activity of CpxR. To understand the physiological meaning of this in vitro molecular phenomenon, we analyzed the effects of an osmolarity shift on the two-component pathway CpxA/CpxR. We establish here that the Cpx pathway is activated at both transcriptional and posttranscriptional levels in response to a high osmolarity medium and that CpxR represses<jats:italic>csgD</jats:italic>expression in high-salt-content medium, resulting in low curli production. However,<jats:italic>csgD</jats:italic>repression in response to high sucrose content is not mediated by CpxR but by the global regulatory protein H-NS. Therefore, multiple systems (EnvZ/OmpR, Cpx, Rcs, and H-NS) appear to be involved in sensing environmental osmolarity, leading to sophisticated regulation of the curli genes.</jats:p>
収録刊行物
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- Journal of Bacteriology
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Journal of Bacteriology 187 (6), 2038-2049, 2005-03-15
American Society for Microbiology
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詳細情報 詳細情報について
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- CRID
- 1363107370269877120
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- NII論文ID
- 30021054603
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- ISSN
- 10985530
- 00219193
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