Caulobacter crescentus is a Gram-negative bacterium member of the alpha subdivision of proteobacteria, which live in aquatic environments of low nutrient conditions. C crescentus is a major model system for study of the bacterial cell cycle and cell differentiation, and the molecular mechanisms involved have been detailed extensively in recent years. The adaptation of C. crescentus for survival in oligotrophic conditions include the ability to grow in low nutrient conditions and halt cell cycle progression when starved for carbon and nitrogen. C. crescentus is equipped with environmental sensors, transporters and metabolic pathways to explore low concentrations of metabolites, using organic material as food source. The cells of C. crescentus suffer drastic changes in morphology and physiology in long periods of stationary phase, becoming more resistant to stresses. Gene regulation on stationary phase is very poorly known in Caulobacter crescentus. Caulobacter does not present a single master regulator of stationary phase similar to ÃS described in E. coli, and other transcription factors must play this role. A response regulator that belongs to a two-component system called SpdR (Stationary phase cspD regulator) was identified, that binds directly to the cspD regulatory region, activating its transcription in stationary phase. Thus, this project proposes to identify the genes regulated by SpdR, determine which cell signals are important for its activation and study its role in the onset of stationary phase of C. crescentus. To achieve this, we propose to identify the genes regulated by SpdR by DNA microarrays; to inactivate other regulatory systems regulated by SpdR that coordinate the expression of genes in stationary phase; to identify the signals that trigger the activation of the SpdR/SpdS system; and to determine the role of SpdR in stationary phase by phenotypic analyses of the knockout mutant.
News published in Agência FAPESP Newsletter about the scholarship: