Transcriptional analysis of the rpoE gene encoding extracytoplasmic stress response sigma factor σE in Salmonella enteric serovar Typhimurium

Miticka, H., Rowley, G., Rezuchova, B., Homerova, D., Humphreys, S., Farn, J., Roberts, M. and Kormanec, J. (2003) Transcriptional analysis of the rpoE gene encoding extracytoplasmic stress response sigma factor σE in Salmonella enteric serovar Typhimurium. FEMS Microbiology Letters, 226(2), pp. 307-314. (doi: 10.1016/S0378-1097(03)00600-1)

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Abstract

The <i>rpoE</i> gene of <i>Salmonella enterica</i> serovar Typhimurium (<i>S</i>. Typhimurium), which encodes the extracytoplasmic stress response sigma factor σ<sup>E</sup>, is critically important for the virulence of <i>S</i>. Typhimurium. We analysed expression of <i>rpoE</i> by wild-type and mutant bacteria grown in different conditions by S1-nuclease mapping using RNA, and using in vivo reporter gene fusions. Three promoters, <i>rpoEp1, rpoEp2</i> and <i>rpoEp3</i>, were located upstream of the <i>S</i>. Typhimurium <i>rpoE</i> gene. The promoters were differentially expressed during growth and under several stress conditions including cold shock. Expression from the <i>rpoEp3</i> promoter was absent in an <i>S</i>. Typhimurium <i>rpoE</i> mutant, demonstrating its dependence upon σE. The level of mRNA corresponding to <i>rpoEp3</i> was also higher in a <i>cpxR</i> mutant, indicating a negative regulation of the promoter by the Cpx system. Using this <i>rpoE</i>-dependent promoter, we optimised a two-plasmid system for identification of promoters recognised by <i>S</i>. Typhimurium σE. The <i>rpoEp3</i> promoter was active in the <i>Escherichia coli</i> two-plasmid system and has an identical transcription start point as in <i>S</i>. Typhimurium but only after induction of <i>S</i>. Typhimurium <i>rpoE</i> expression.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Roberts, Professor Mark
Authors: Miticka, H., Rowley, G., Rezuchova, B., Homerova, D., Humphreys, S., Farn, J., Roberts, M., and Kormanec, J.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:FEMS Microbiology Letters
Publisher:Wiley
ISSN:0378-1097
ISSN (Online):1574-6968
Published Online:09 January 2006

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