Exploring the role of VpsT in Vibrio cholerae

Vibrio cholerae is an aquatic bacterium and the cause of cholera, an acute and potentially fatal diarrheal infection. Throughout human history cholera has been a significant cause of morbidity and mortality and remains so (particularly for under 5s) in endemic regions or areas devastated by natural disaster or war.
The ability of V. cholerae to switch lifestyles (ie. between a motile planktonic or colonial biofilm state) allows it to adapt to different environmental conditions and persist in aquatic environments between epidemics. In such environments, V. cholerae can colonise alternative hosts (such as fish) or form biofilms on biotic and abiotic chitinous surfaces. The production of vibrio polysaccharide (or VPS, an exopolysaccharide) is necessary for the formation of biofilms, and its production is coordinated by a complex regulatory network that links quorum sensing with the bacterial second messenger cyclic-di-GMP. C-di-GMP is understood to up-regulate the expression of genes involved in biofilm formation and repress virulence in several bacterial pathogens. In V. cholerae the transcriptional regulator VpsT requires c-di-GMP to bind DNA and regulate the expression of vps genes.
Preliminary data from chromatin immunoprecipitation and sequencing (ChIP-seq) experiments suggests that VpsT might bind to and potentially regulate other targets in the genome. This project aims to confirm the interaction of VpsT with these new targets and characterise the activity and function of its interaction, using a combination of biochemical, genetic, molecular biology and bioinformatic techniques. To understand the role of VpsT in controlling lifestyle switching the project will also involve work with zebrafish that serve as a model for host colonisation. Hence, we will determine the role of VpsT and its target genes in mediating colonisation of aquatic environments and the orginisms therein.