Telomeric dysfunctions

Our aim is to gain understanding into the proteins that, depending on their state (wild type, variant, isoform) contribute to telomere stability or instability.

In the past years, we have studied how the single-stranded DNA-binding proteins human RPA (hRPA) and human POT1-TPP1 (hPOT1-TPP1) deal with secondary structures (G-quadruplexes) formed by the telomeric DNA. In the framework of a collaborative research project funded by ANR (TeloRPA), we started a new research axis aimed at characterising variants hRPA and hPOT1 found in patients affected by telomeres biology disorders (TBDs). We have already contributed to an international collaborative study that has led to the identification of germline RPA1 variants as a cause of a telomeropathy (doi: 10.1182/blood.2021011980).

End to end chromosome fusions between short dysfunctional telomeres can cause genomic instability and massive cell death, referred to as telomere crisis. Telomere fusions can lead to the acquisition of large-scale genomic rearrangements detected in cancers, and telomere crisis is thought to be involved in cellular transformation. Our research aims to identify new factors implicated in telomere crisis.

We and our collaborators have discovered a new player involved in the induction of telomere fusions. This player is an isoform of a protein involved in genome stability. We are currently investigating how this newly discovered factor affects telomere stability and its potential contribution to cancer initiation.

The compartmentalisation of biomolecules in cells is involved in the regulation of a wide range of cellular processes. The proteins we study contain modular domains and intrinsically disordered regions that make them susceptible to form condensates via liquid-liquid phase separation. One of the aspects we are investing is how mutations or variant forms associated with telomeres biology disorders dysregulate their ability to form condensates via liquid-liquid phase separation.