OmrA and OmrB are two small regulatory RNAs (sRNAs) conserved in enterobacteria. Their transcription is activated by the EnvZ-OmpR two-component system and their levels therefore increase in response to an increase in osmolarity. They both target multiple mRNAs through their conserved 5’end; these targets encode genes for outer membrane proteins (e.g. OmpT, CirA, FecA, FepA) and genes for the transcriptional regulators CsgD and FlhDC (respectively involved in adhesion/biofilm formation and in motility), but also for their own regulator EnvZ-OmpR. Interestingly, the 5’end of those sRNAs is almost identical between OmrA and OmrB and all known targets are therefore common to both OmrA and OmrB. Several data suggest however that (i) not all targets have been identified so far and (ii) that OmrA/B could also have specific targets. We want to identify a maximum of OmrA/B specific and common targets in order to apprehend the physiological role of those sRNAs.
Project in collaboration with Maude Guillier and Harald Putzer
Expression génétique microbienne, CNRS FRE3630
Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris