Bonjour à tous,

Vous êtes invité à assister à l'examen Prédoc III de Simon Chasles, mercredi le 02 avril, à 10h30.

Jury

Abstract

The human cell can be compared to a functional city where diverse infrastructures and agents fulfill specific roles. Proteins are relatively stable constructs that can perform a variety of functions like catalyzing metabolic reactions, responding to stimuli and transporting molecules. Deoxyribonucleic acid (DNA) behaves like a secured library that encodes the information needed to build proteins, but also ribonucleic acid (RNA). RNAs, on the other hand, consist in agents that can transport genetic information (coding RNA) or carry out various functions (non-coding RNA), similarly to proteins. Just as urban order requires a dynamic management of its infrastructures, the cell is equipped with mechanisms that control the abundance and balance of proteins and RNAs. This is where microRNAs (miRNAs) come into play.
As outlined by the central dogma of molecular biology, transcription allows the flow of genetic information from DNA to messenger RNA (mRNA) and translation, from mRNA to proteins. The expression of proteins can thus be regulated at the DNA or at the RNA level, the lather being particularly interesting for RNA-based therapeutics. The process by which miRNAs bind to mRNA transcripts and mediate their translation into proteins is known as RNA interference (RNAi). Many miRNAs can interfere with a single mRNA and a single miRNA can bind to multiple mRNAs. With over 2,000 miRNAs and 80,000 mRNAs in the human genome, this results in important interaction networks, the specifics of which still need elucidation.
We therefore consider three significant research avenues. First, to determine the affinity between a given miRNA guide and a potential mRNA target, the development of specialized RNA structure prediction programs is essential: mRNA structure prediction can help in determining the avail- ability of miRNA target sites and RNA:RNA duplex structure prediction can assess the stability of miRNA:mRNA interactions. Second, using such programs, one can attempt to model the miRNA:mRNA interaction network by determining which miRNAs will bind to which mRNAs in specific cellular conditions. The third and last research avenue consists in designing artificial miRNA molecules to deliberately perturb the miRNA:mRNA network in a very specific way, with the intention to treat disorders like cancer and neurodegenerative diseases. Unraveling the mystery of miRNA activity is therefore a path to revolutionary breakthroughs in the fields of biology and medicine.