The roles of two-component systems in virulence of pathogenic escherichia coli and shigella spp.

Abstract

Two-component systems (TCSs) are well conserved among E. coli strains, including pathogenic E. coli and also closely related Shigella spp. Although 25% of the genome of pathogenic E. coli is strain-specific, only small number of strain-specific TCSs is found. Regulation of virulence genes in response to environmental stimuli is partly dependett on TCSs commonly present in nonpathogenic E. coli strains. Some virulence genes are directly regulated by response regulator of TCS but some are affected at posttranscriptional steps of production or assembly of macromolecule by TCS-induced products. In the process of acquiring virulence traits, regulatory systems for virulence genes expression seem to be built by integrating E. coli backbone TCSs with the virulence regulatory network via transcription regulatory gene. © 2008 Springer New York.