The sigmaS factor of RNA polymerase in strains of diarrheagenic E. coli

• Grant number: 09/00109-7
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2009
• End date: June 30, 2011
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Beny Spira
• Grantee: Beny Spira
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

E. coli possesses 7 different known sigma factors. The principal sigma factor, sigma70, transcribes the majority of E. coli genes, while sigmaS, the second in importance, transcribes genes related to the general stress response and stationary phase.under these conditions, the bacterium produces proteins that protect the cell against possible stress sources. Under nutrient limitation, sigmaS accumulates and competes with sigma70 for the core RNA polymerase. After several days, this competition will ultimately result in mutations in the rpoS locus.That is the main reason why natural isolates of E. coli present a high proportion of rpoS mutations. On the other hand, there are several results in the literature that imply a function for RpoS in the virulence of various bacteria species. In the present project, we will evaluate the likely involvement of RpoS in the virulence of two groups of diarrheagenic E. coli- EPEC and ETEC. On top of that, the rpoS status and sequence of several clinical isolates of both EPEC and ETEC will be also evaluated. (AU)