Title: Heterogeneous gene expression of T3SS between individual cells: a lifestyle choice for ecological success

Presenter: Ching-Hong Yang，Associate Professor

University: Department of Biological Sciences，University of Wisconsin, Milwaukee

Time: 9:00-12:00, June 15, 2012

Venue: Room A203, Institute of Microbiology, Chinese Academy of Sciences

Abstract: Transcriptional bistability (bimodal expression) is a type of gene expression that, in a total bacterial population, a subpopulation of cells expresses a target gene at a relatively high level, while the rest of the population expresses the target gene at the basal level. Bistability is considered a critical strategy to maximize bacterial survival under adverse conditions. By inhibiting a proportion of cells from responding to a certain environmental signal, bacteria hedge their bets so that once the environmental conditions revert, the rest of the population would still be able to survive. The type III secretion system (T3SS) is a major virulence determinant common among many bacterial pathogens that translocates virulence factors from the bacteria through a needle-like pilus directly into host cells. In this talk, the bistable expression of T3SS at the single-cell level will be introduced. In addition, the key mechanism on bimodal regulation and how individuality contributes to fitness of unicellular pathogens in spatially and temporally varying environments and hosts will be discussed.