Regulatory interplay of RpoS and RssB controls motility and colonization in Vibrio cholerae

Area of Science:

• Microbiology
• Bacterial Physiology
• Regulatory Networks

Background:

• Cholera, caused by Vibrio cholerae, requires bacterial adaptation for host colonization.
• Alternative sigma factors, like RpoS, and their anti-sigma factors, like RssB, regulate bacterial responses.
• RpoS/RssB regulation differs between V. cholerae and Enterobacteriaceae, impacting distinct survival strategies.

Purpose of the Study:

• To characterize the starvation-induced interaction model of RpoS and RssB in V. cholerae.
• To investigate the role of rssB in bacterial phenotypes, including motility, growth, and virulence.
• To identify mechanisms of RssB regulation, including proteolysis and mutations affecting its function.

Main Methods:

• Genotypic and phenotypic analyses of V. cholerae strains.
• Characterization of RpoS/RssB interaction under starvation conditions.
• Identification and analysis of mutations in rssB impacting RpoS interaction.

Main Results:

• A negative feedback loop between RpoS and RssB expression was identified.
• rssB significantly influences V. cholerae motility, growth, colonization fitness, and post-infectious survival.
• RssB was found to be a substrate for proteolysis, with a specific Asp mutation altering its function and RpoS interaction.

Conclusions:

• The RpoS/RssB regulatory interaction is active during V. cholerae in vivo colonization.
• RssB proteolysis represents an extension to the feedback regulation circuit.
• Understanding this system provides insights into V. cholerae adaptation and pathogenesis.