Although small regulatory RNAs are numerous (~100 sRNAs in E. coli) and play significant functions in the physiology of living organisms, their mechanisms of action remain largely unknown. sRNAs are usually shorter than 300 nucleotides, non-coding, and found in both eukaryotic and prokaryotic organisms. Because they can directly regulate virulence factors and antibiotic resistance in bacterial pathogens, sRNAs are extremely potent modulators of gene expression. Our recent work with E. coli has revealed unique features of sRNAs; (1) a single sRNA can rapidly silence mRNAs by recruiting the RNA chaperone Hfq to block translation; (2) sRNAs can recruit ribonucleases such as RNase E to induce sRNA-mediated mRNA decay; (3) sponge RNAs can regulate sRNA functions and dramatically change response to stress.
Combining a pull-down assay and RNA sequencing in an approach called MAPS (MS2 Affinity Purification coupled with RNA Sequencing), we are able to uncover unsuspected RNA interactions.
Global screening such as MAPS exposes novel types of cellular RNA transactions, which are being further investigated to evaluate their impact on the cell. Since the MAPS approach is quite flexible, we are also investigating the sRNA targetomes of other bacterial species.
Colorectal cancer (CRC) is the third most common cause of cancer mortality in the world. Early detection and removal of polyps at the precancerous stage is critical for patient survival. Recent studies demonstrated that the microbiome, bacteria living in the human gut, is an important risk factor for colon cancer and can directly foster tumorigenesis by interacting with the immune system.
Pr Eric Massé
Eric Massé - Office