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The lrp gene and its role in type I fimbriation in Citrobacter rodentium.
- Source :
-
Journal of bacteriology [J Bacteriol] 2005 Oct; Vol. 187 (20), pp. 7009-17. - Publication Year :
- 2005
-
Abstract
- Citrobacter rodentium is a murine pathogen that is now widely used as an in vivo model for gastrointestinal infections due to its similarities with human enteropathogens, such as the possession of a locus for enterocyte effacement (the LEE island). We studied the lrp gene of C. rodentium and found that it encodes a product highly similar to members of the Lrp (leucine-responsive regulatory protein) family of transcriptional regulators, able to recognize leucine as an effector and to repress the expression of its own structural gene. In enterobacteria, Lrp is a global regulator of gene expression, as it controls a large variety of genes, including those coding for cell appendages and other potential virulence factors. Based on the well-established role of Lrp on the expression of pilus genes in Escherichia coli, we also studied the role of Lrp in controlling the formation of the type I pilus in C. rodentium. Type I pili, produced by the fim system, are virulence factors of uropathogens, involved in mediating bacterial adhesion to bladder epithelial cells. Yeast agglutination assays showed that Lrp is needed for type I pilus formation and real-time PCR experiments indicated that Lrp has a strong leucine-mediated effect on the expression of the fimAICDFGH operon. Mutant studies indicated that this positive action is exerted mainly through a positive control of Lrp on the phase variation mechanism that regulates fimAICDFGH expression. A quantitative analysis of its expression suggested that this operon may also be negatively regulated at the level of transcription.
- Subjects :
- Citrobacter rodentium pathogenicity
Escherichia coli Proteins
Gene Expression Regulation, Bacterial
Leucine-Responsive Regulatory Protein
Mutation
Operon physiology
Phenotype
Virulence
Virulence Factors physiology
Citrobacter rodentium genetics
Citrobacter rodentium physiology
DNA-Binding Proteins genetics
DNA-Binding Proteins metabolism
Fimbriae, Bacterial genetics
Transcription Factors genetics
Transcription Factors metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9193
- Volume :
- 187
- Issue :
- 20
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 16199571
- Full Text :
- https://doi.org/10.1128/JB.187.20.7009-7017.2005