Heather Kamp

Listeria monocytogenes uses flagellar-based motility for chemotaxis and biofilm formation in extracellular environments. However, when bacteria enter the intracellular environment of the host cell cytosol, L. monocytogenes switches from flagellar-based motility to actin-based motility. Previous studies have shown that flagellar motility gene expression is also down-regulated at temperatures of 37˚C and above, resulting in the loss of flagellar-based motility at physiological temperatures.
 
Recent work in our lab revealed that a transcriptional repressor, MogR, regulates temperature-dependent expression of flagellar motility genes.  MogR represses transcription of flagellar motility genes at all temperatures examined, although repression by MogR is less stringent at low temperatures allowing for flagellar gene expression. It is unclear what factors and mechanisms are involved in relieving MogR repression at low temperatures allowing for the production of flagella. Epistasis analysis revealed that the DegU response regulator is involved in antagonizing MogR repression activity. I am using biochemical and genetic approaches to identify and further understand the mechanism by which DegU, DegU-regulated, or DegU-interacting factors relieve MogR transcriptional repression at low temperatures.