Special Seminar Hosted by the Bacterial Communities Class and Shrout Lab:
Penelope Higgs, Wayne State University
“A complex regulatory network controls cell fate segregation in the Myxococcus xanthus biofilm”
Abstract: Myxococcus xanthus are ubiquitous environmental bacteria that produce a specialized biofilm in response to nutrient-limitation. During biofilm maturation, cells are segregated into spatially distinct fates: 1) differentiation into quiescent spores inside matrix-encased fruiting bodies or 2) formation persister-like cells which remain outside fruiting bodies. Thus, production of different quiescent states, a hallmark of biofilm resistance, can be readily characterized. We have demonstrated that cell fate segregation correlates with heterologous accumulation of an important transcriptional factor, MrpC. MrpC is subject to complex regulation including negative transcriptional autoregulation, proteolytic turnover, and phosphorylation. We have characterized several atypical His-Asp phosphorelay (aka two component signal transduction) systems which converge to modulate distinct aspects of MrpC regulation. Our current working model suggests these signaling systems are enriched in distinct subpopulations and serve to tune the M. xanthus biofilm to different environmental conditions.