Theme n°1:
RNA based mechanisms of gene expression
Gene expression plays a key role in allowing bacteria to adapt to their environment. While transcription was the first step of gene expression to be shown as subject to regulation, later studies demonstrated the fundamental role of post-transcriptional control. RNA is a key player in the regulation of gene expression in all kingdoms of life. In particular, we have seen an explosion in the number of regulatory RNAs identified and in our understanding of the mechanisms used by these molecules to control gene expression in the last 20 years.
Our studies focus for instance on the role of cis-elements of the mRNAs in translational control, such as riboswitches or secondary structures directly affecting ribosome binding to mRNAs. We are also interested in the mechanisms of control exerted by cis- or trans-encoded antisense RNAs, often in conjunction with the study of other actors, such as ribonucleases or the RNA chaperone Hfq. 
Theme n°2:
small RNAs in cellular networks
Numerous studies point to a strong connection between sRNAs and other regulators. Indeed, the synthesis of sRNAs is highly regulated at the transcriptional level by transcription factors or alternative sigma factors. In addition, many sRNAs also directly regulate synthesis of transcriptional regulators. The biology of the resulting mixed regulatory networks is still poorly understood. We are studying several examples that point out to a previously unsuspected complexity. For instance, several small RNAs regulate the synthesis of two-component systems, and have completely different effects on the expression of their regulons. These networks likely participate to the extremely precise timing of bacterial gene expression, highlighting the need to precisely decipher their properties. 
Theme n°3:
Sugar metabolism as a tool for identifying regulatory mechanisms
Classically growth on different sugars has been a fruitful technique for understanding gene regulatory mechanisms. We are interested in mutations which have arisen in in vivo evolution spontaneously or by selection which have modified the ability of a bacteria to grow on different carbon sources. This should be the case when an enzyme exists in allosteric and non-allosteric forms or a transcription factor changes its target(s) and alters fitness or growth on several carbon sources.
