Thanks to its 3 different phases (in silico, in vitro and in cellulo), our approach allowed us to evaluate the global role of G-quadruplexes of RNA in the cell, more precisely at the level of untranslated regions of mRNAs.
Our research results allow the identification of new G-quadruplexes, notably through the use of artificial intelligence. By automated learning, we are now able to identify new G-quadruplexes in any genome. After identifying a G-quadruplex of interest, it is necessary to check whether the structure can be formed by in vitro assays on a synthetic RNA. We use a technique called "in line probing" which allows to highlight the formation of a G-quadruplex in different salt conditions. Biophysical methods such as circular dichroism and fluorescence methods using G-quadruplex specific fluorescent ligands are also used. Subsequently, we use luciferase assays in cells to demonstrate the effect of these G-quadruplexes on gene expression.
The formation / deformation of G-quadruplexes thus makes it possible to control certain cellular mechanisms such as a switch. We have developed a technique that can promote or prevent the formation of a G-quadruplex in cell using specific oligonucleotides. More recently, we have begun studying the proteins that can bind G-quadruplexes and their effects on gene expression. As a result, RNA G-quadruplexes become potential new therapeutic targets.