Stress response and biofilm formation in E. coli

Stéphan Lacour

Study of the stress response in E. coli

RpoS is a key regulator of the generalized stress response in the bacterium Escherichia coli. Its regulon has been studied using microarrays, RNA-seq ChIP and individual gene expression measurements using reporter proteins such as GFP. We are trying to understand the function of other proteins that affect the activity of this alternative sigma factor of the RNA polymerase. Our previous studies focused initially on the function of the Crl protein, whose regulation we are also investigating. We are now studying other transcription modulators lacking a DNA-binding motif, to understand their mode of action on RpoS and/or on the expression of its regulon.

Regulation of biofilm formation by E. coli

We are studying the regulation of the expression of csgBA genes encoding short fimbriae called "curli", which enable E. coli to adhere to abiotic surfaces. Using a collection of mutants, we have identified numerous protein factors modulating curli expression. We are currently seeking to understand how certain genes positively regulate the expression of the csg operon and the formation of biofilm by this bacterium. We are also studying the regulation of these same operons by small non-coding RNAs (7 known and others yet to be discovered) and the function of the 5'UTR of csgD (activator of csgBA curli structural genes).