DNA damaging by physical or chemical agents induces in our cells complex pathways. In the forefront of these processes are proteins bound to double helix alterations. The cartography of these proteins is far to be exhaustive. In order to complement the list of already identified DNA lesion-protein interactions, “ligand fishing” tools have been optimized.
The principle consists in immobilizing modified DNA fragments on magnetic beads; these traps are used to isolate from a complex nuclear extract factors bound to damaged DNA. The following stage aims at giving a name to these proteins using proteomics approaches (partnerships with our institute and DSV-iBEB). Using this strategy, we demonstrated that DNA damaged by platinating compounds (anticancer drugs) is recognized by the PTW complex, a regulator of chromatin structure modifications taking place during the cell cycle. We also applied these methods to epigenetic DNA modifications which are known to switch on or off gene expression (Epigenome ANR project, partnership with the Gustave Roussy Institute).
Finally, a recent collaborative work with DSV-iBEB and Paris-Sud University (Gammatolerans ANR project) will use our traps to unravel new members of this DNA damage interactome in the radioresistant Archaea Thermococcus gammatolerans which is able to withstand kilograys of ionizing radiations.