Characterization of the σ^E-dependent rpoEp3 promoter of Salmonella enteric serovar Typhimurium

Skovierova, H., Rezuchova, B., Homerova, D., Roberts, M. and Kormanec, J. (2006) Characterization of the σ^E-dependent rpoEp3 promoter of Salmonella enteric serovar Typhimurium. FEMS Microbiology Letters, 261(1), pp. 53-59. (doi: 10.1111/j.1574-6968.2006.00325.x)

Abstract

Using a two-plasmid system, we recently identified σ^E-dependent promoters directing expression of the σ^E regulon genes in <i>Salmonella enteric</i> serovar Typhimurium (<i>S</i>. Typhimurium). Comparison of the promoters revealed a consensus sequence almost identical to the σ^E-dependent <i>rpoEp3</i> promoter directing expression of <i>rpoE</i>. This two-plasmid system was previously optimized to identify nucleotides critical for the <i>rpoEp3</i> promoter activity. However, two highly conserved nucleotides in the σ^E consensus sequence were not identified by this screening. In the present study, we have improved the two-plasmid screening system using a new optimized error-prone PCR mutagenesis. Together with site-directed mutagenesis, we further identified nucleotides critical for activity of the <i>rpoEp3</i> promoter and quantified the effect of the particular mutation upon promoter activity. All the identified critical nucleotides of the <i>rpoEp3</i> promoter (in capital) were located in the −35 (ggAACtt) and −10 (gTCtaA) regions and corresponded to the most conserved nucleotides in the σ^E consensus sequence. The expression of the wild-type and mutated <i>rpoEp3</i> promoters was confirmed in <i>S</i>. Typhimurium and was found to exhibit a different pattern of σ^E activation compared with <i>Escherichia coli</i>, with a peak <i>rpoEp3</i> promoter activity in early stationary phase followed by a decrease in late stationary phase.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Roberts, Professor Mark
• Authors: Skovierova, H., Rezuchova, B., Homerova, D., 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: 08 June 2006