This Article 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 Dagberg, B Articles by Uhlin, B E Search for Related Content PubMed PubMed Citation Articles by Dagberg, B Articles by Uhlin, B E

research-article

Regulation of virulence-associated plasmid genes in enteroinvasive Escherichia coli.

Department of Microbiology, University of Umeå, Sweden.

ABSTRACT

The transposon TnphoA was used for construction of gene fusions and for studies of gene regulation in an enteroinvasive strain of Escherichia coli. Several plasmid-encoded virulence genes (e.g., the ipaB and virG operons) of such enteroinvasive strains are subject to coordinated thermoregulation involving both operon-specific (the VirB and VirF activators) and global regulators. The nucleoid-associated E. coli protein H-NS was shown to be a negative regulator as judged by studies using H-NS gene deletion mutations and by increasing the level of H-NS protein in the cells. An increased gene dosage of H-NS led to enhanced repression of the ipa and virG operons, particularly at low (30 degrees C) growth temperature. The cyclic AMP receptor protein complex, which is another global transcriptional regulator in E. coli, was not required for the regulation of ipa and virG expression. The virG operon was expressed in an activator-independent manner in cells lacking H-NS protein. We suggest that the role of the VirF activator is to counteract the silencing effect of H-NS.

This article has been cited by other articles:

• Lindberg, S., Xia, Y., Sonden, B., Goransson, M., Hacker, J., Uhlin, B. E. (2008). Regulatory Interactions among Adhesin Gene Systems of Uropathogenic Escherichia coli. Infect. Immun. 76: 771-780 [Abstract] [Full Text]  
• Santapaola, D., Casalino, M., Petrucca, A., Presutti, C., Zagaglia, C., Berlutti, F., Colonna, B., Nicoletti, M. (2002). Enteroinvasive Escherichia coli virulence-plasmid-carried apyrase (apy) and ospB genes are organized as a bicistronic operon and are subject to differential expression. Microbiology 148: 2519-2529 [Abstract] [Full Text]  
• Xia, Y., Uhlin, B. E. (1999). Mutational Analysis of the PapB Transcriptional Regulator in Escherichia coli. REGIONS IMPORTANT FOR DNA BINDING AND OLIGOMERIZATION. J. Biol. Chem. 274: 19723-19730 [Abstract] [Full Text]  
• Berlutti, F., Casalino, M., Zagaglia, C., Fradiani, P. A., Visca, P., Nicoletti, M. (1998). Expression of the Virulence Plasmid-Carried Apyrase Gene (apy) of Enteroinvasive Escherichia coli and Shigella flexneri Is under the Control of H-NS and the VirF and VirB Regulatory Cascade. Infect. Immun. 66: 4957-4964 [Abstract] [Full Text]  
• Brachmann, C B, Sherman, J M, Devine, S E, Cameron, E E, Pillus, L, Boeke, J D (1995). The SIR2 gene family, conserved from bacteria to humans, functions in silencing, cell cycle progression, and chromosome stability.. Genes Dev. 9: 2888-2902 [Abstract]