Phenotypic analysis of salmonella enterica serovar typhimurium rpoE mutants encoding RNA polymerase extracytoplasmic stress response sigma factors σE with altered promoter specificity

Rezuchova, B., Homerova, D., Sevcikova, B., Novakova, R., Feckova, L., Roberts, M. and Kormanec, J. (2013) Phenotypic analysis of salmonella enterica serovar typhimurium rpoE mutants encoding RNA polymerase extracytoplasmic stress response sigma factors σE with altered promoter specificity. Archives of Microbiology, 195(1), pp. 27-36. (doi: 10.1007/s00203-012-0843-9)

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Abstract

We previously identified mutants in the rpoE gene of Salmonella enterica serovar Typhimurium (S. Typhimurium) encoding RNA polymerase extracytoplasmic stress response sigma factors σE with altered promoter specificity. The replacement of the conserved R171 residue in the conserved region 4.2 of σE by different amino acid residues exhibited different phenotypes. While R171A almost completely abolished sigma factor activity, R171G and R171C mutant changes imparted a relaxed recognition phenotype to the sigma factor. In the present study, we introduced these mutations into the S. Typhimurium chromosome to investigate their phenotype during ethanol stress and in promoter recognition. Both relaxed sigma factors were found to initiate transcription from a high number of artificial promoters in the S. Typhimurium genome. Both mutants had substantially decreased activity under stress conditions. However, this decreased activity and also the recognition of atypical promoters had no significant effect upon growth, even in stressful conditions.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Roberts, Professor Mark
Authors: Rezuchova, B., Homerova, D., Sevcikova, B., Novakova, R., Feckova, L., Roberts, M., and Kormanec, J.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Archives of Microbiology
ISSN:0302-8933
ISSN (Online):1432-072X
Published Online:13 September 2012

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