Bacterial gene regulation in response to stress

Project Overview: Bacteria respond to stressful changes in their environment by changing their patterns of gene expression. The RpoS protein coordinates E. coli’s general stress response, allowing the cell to survive a variety of stresses, including starvation, pH, osmotic stress, and high and low temperatures. RpoS does this by altering the expression of about ¼ of the genes in the E. coli genome. RpoS is thought to also be important for stress responses in related species, including important pathogens like Salmonella and Klebsiella, but we know much less about it.

In the laboratory strain of E. coli, the major way that RpoS is regulated is not at the level of transcription. Instead, the amount of RpoS protein in the cell depends on the action of small RNAs that regulate how much the RpoS mRNA is translated, and small proteins that regulate how much the RpoS protein gets degraded. 

The major focus of this research project is to determine if factors that regulate RpoS in E. coli are important for the regulation of RpoS in other species.

Students working on this project will genetically modify regulators of RpoS in relatives of E. coli, and then use western blotting to study how the RpoS protein is regulated in response to a variety of stress conditions. These tests will be guided by our detailed knowledge of this system in E. coli, and by predictions based on genome content of relatives. In addition, students working on this project will create reporter genes to study the transcription of some of the regulators of RpoS in response to stress. Students working on this project should expect to learn microbiological and molecular biology techniques.