This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cordone, A. Articles by Ricca, E. Search for Related Content PubMed PubMed Citation Articles by Cordone, A. Articles by Ricca, E.

 Previous Article  |  Next Article 

Journal of Bacteriology, October 2005, p. 7009-7017, Vol. 187, No. 20
0021-9193/05/$08.00+0     doi:10.1128/JB.187.20.7009-7017.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

The lrp Gene and Its Role in Type I Fimbriation in Citrobacter rodentium

Dipartimento di Biologia Strutturale e Funzionale, Università Federico II, Naples, Italy,¹ The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, United Kingdom²

Received 11 April 2005/ Accepted 23 June 2005

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.

^¶ These two authors contributed equally to the work.

This article has been cited by other articles:

• Wu, X., Vallance, B. A., Boyer, L., Bergstrom, K. S. B., Walker, J., Madsen, K., O'Kusky, J. R., Buchan, A. M., Jacobson, K. (2008). Saccharomyces boulardii ameliorates Citrobacter rodentium-induced colitis through actions on bacterial virulence factors. Am. J. Physiol. Gastrointest. Liver Physiol. 294: G295-G306 [Abstract] [Full Text]