Biosenseurs et ARN noncodants régulateurs chez les bactéries

 

Jonathan Perreault

Institut national de la recherche scientifique [INRS]

 

Domaine : maladies infectieuses et immunitaires

Programme Chercheurs-boursiers - Junior 2

Concours 2019-2020

RNA, rather than being merely a messenger of the information contained in DNA, is now recognized as an essential player in the regulation of genes in all living organisms. This regulation applies to a multitude of processes, including the regulation of virulence in bacteria. Many opportunistic pathogens require mechanisms to change the expression of their gene when they change environment, from water or soil to a human host, for example. We are looking for RNAs involved in such genetic regulation phenomena by paying particular attention to a type of RNA that acts as a receptor: the riboswitches. These RNAs are composed of an "aptamer" portion, capable of recognizing a metabolite specifically, and an "expression platform" portion that converts metabolite binding into expression modulation, thereby acting as a genetic switch. For our first goal, we are working to discover and understand the mechanisms of riboswitches responsible for detecting the presence of metals important for bacteria.

Such systems are needed to activate the import of these metals into bacterial cells because they are known to be limiting resources, particularly in the context of infections. Some of the methods we use to find these riboswitches are based on the duality of RNA, which can both have a function (like binding a metabolite) and contains information that can be replicated (via molecular biology methods), the two essential criteria for making evolution in vitro. In addition to using this duality to discover new riboswitches, we are also using a similar approach to develop synthetic aptamers (RNA or DNA) that act as receptors for pathogen detection. Thus, for our second objective we develop biosensors based on these aptamers for diagnosis and prevention purposes.