Polar Localization of Chemotactic Proteins in Vibrio parahaemolyticus

Chemotaxis is the process by which bacteria bias their flagella-assisted swimming in response to their environment. Recent work in the rod-shaped bacterium Vibrio cholerae revealed that ParC, a homologue of a protein important for chromosome partitioning, plays a key role in promoting the polar localization and segregation of chemotaxis proteins. The purpose of my work is to study ParC and chemotaxis protein localization in Vibrio parahaemolyticus, another enteric pathogen, which unlike V. cholerae has lateral as well as polar flagellae. To detect the subcellular localization of ParC and chemotaxis proteins within V. parahaemolyticus, we fused genes encoding fluorescent proteins (either YFP or CFP) to the genes encoding ParC and to chemotaxis proteins, including CheW. In wild-type V. parahaemolyticus, time-lapse fluorescence microscopy revealed that ParC and CheW exhibit specific spatio-temporal patterns of localization. In newborn cells, ParC and CheW form single foci at the ‘old’ flagellated cell pole. As the cell cycle progresses, ParC and CheW are recruited to the new cell pole, resulting in a bipolar pattern of localization, which at cell division ensures inheritance of a ParC/chemotaxis cluster to each daughter cell. Ongoing experiments include analyses of cells containing both YFP-ParC and CFP-CheW to explore whether they co-localize in a cell-cycle dependent manner. We have constructed a V. parahaemolyticus parC deletion mutant and analyses of this strain will reveal if ParC is required for proper localization and segregation of chemotaxis proteins in V. parahaemolyticus. Finally, we will test if ParC is required for both of V. parahaemolyticus’ flagellar systems.