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RpoS and quorum sensing control expression and polar localization of V ibrio cholerae chemotaxis cluster III proteins in vitro and in vivo
Author(s) -
Ringgaard Simon,
Hubbard Troy,
Mandlik Anjali,
Davis Brigid M.,
Waldor Matthew K.
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13053
Subject(s) - biology , vibrio cholerae , rpos , chemotaxis , quorum sensing , microbiology and biotechnology , in vivo , gene cluster , gene expression , gene , genetics , promoter , bacteria , virulence , receptor
Summary The diarrheal pathogen V ibrio cholerae contains three gene clusters that encode chemotaxis‐related proteins, but only cluster II appears to be required for chemotaxis. Here, we present the first characterization of V . cholerae 's ‘cluster III’ chemotaxis system. We found that cluster III proteins assemble into foci at bacterial poles, like those formed by cluster II proteins, but the two systems assemble independently and do not colocalize. Cluster III proteins are expressed in vitro during stationary phase and in conjunction with growth arrest linked to carbon starvation. This expression, as well as expression in vivo in suckling rabbits, is dependent upon RpoS . V . cholerae 's CAI ‐1 quorum sensing ( QS ) system is also required for cluster III expression in stationary phase and modulates its expression in vivo , but is not required for cluster III expression in response to carbon starvation. Surprisingly, even though the CAI ‐1 and AI ‐2 QS systems are thought to feed into the same signaling pathway, the AI ‐2 system inhibited cluster III gene expression, revealing that the outputs of the two QS systems are not always the same. The distinctions between genetic determinants of cluster III expression in vitro and in vivo highlight the distinctive nature of the in vivo environment.