The Vibrio cholerae ToxR Regulon Encodes Host- Specific Chemotaxis Proteins that Function in Intestinal Colonization

Abstract

Virulence gene regulation in cholerae. V . cholerae toxR V ibrio cholerae is under the control of the T oxR -ToxT regulatory cascade. Chemotaxis and net motility have been shown to influence the infectivity of V mutants do not synthesize proteins required for chemotaxis towards ibrio mucus. The inability of the mutant strain to recognize and swim towards mucus is due to their failure to synthesize AcfB, a methyl–accepting chemotaxis protein. AcfB has previously been toxR cholerae acfB shown to be involved in intestinal colonization using the infant mouse model of cholera infection. Wild type V . cholerae recognizes galactose-6-sulfate in the capillary tube assay whereas V . mutants fail to migrate into the capillary tubes. Vibrio strains carrying a mutation in tcpI , a T oxR regulated gene found within the Vibrio Pathogenicity Island (VPI), which encodes a methyl accepting chemotaxis protein are fully chemotactic towards mucus and galactose-6-sulfate.