Skip to Main content Skip to Navigation

Fonctions et régulations des protéines PARP2 et de XRCC1 dans la réparation des dommages à l’ADN

Abstract : Post-translational modifications of proteins by polymers of ADP-ribose (PAR) or by phosphorylation allow the assembly of DNA repair protein complexes at damaged chromatin and are crucial to ensure genome stability. In response to DNA insults, the synthesis of PAR by the PARP1 and PARP2 proteins is strongly induced. PAR act as a signaling platform for the recruitment of multiples proteins at the sites of DNA damages, including the scaffold protein XRCC1. Research conducted during this PhD have been focused on studying the regulation of PARP1 and PARP2 functions in double-strands break repair (DSBR), and in investigating the role of XRCC1 modifications by phosphorylation in response to DNA damage.Using DNA repair assay allowing us to assess the accuracy of the different DSBR pathways, we demonstrated that PARP2, and not PARP1, is involved in the regulation of DNA double-strands break repair pathway choice. More precisely, we showed that PARP2 stimulates CtIP dependent initiation of end-resection at DSB, independently of its catalytic activity. By live cell imaging, we were able to determine that PARP2 limit 53BP1 accumulation at DNA damage sites induced by laser-microirradiation. We propose that by limiting 53BP1 accumulation at DNA damage sites, PARP2 stimulate DSB repair pathway that depend on DNA end-resection, thus counteracting the canonical end-joining pathway. These results are the first demonstrating a role for PARP2 in DNA DBSR pathway choice.In addition, we analyzed how the functions of XRCC1 are regulated by phosphorylation. Using in vitro and in vivo approaches, we were able to demonstrate that the linker 1 region of XRCC1 is phosphorylated by the CDK5 kinase. XRCC1 is actively dephosphorylated in response to DNA damage induced by an alkylating agent in vivo. We also observed that when the linker 1 cannot be phosphorylated, the XRCC1 interaction between the PAR synthetized by PARP1 and PARP2 is stimulated, and XRCC1 recruitement at the sites of DNA damage is far more efficient. These evidences indicate for the first time that the dephosphorylation of XRCC1 actively participate in its recruitment at the site of DNA damage. Put together, this work contributed to strengthen our fundamental knowledge of the protein network involved in the DNA damage response. Knowledge of those mechanisms is crucial since they participate in maintaining genome stability, and because new antitumoral drugs targeting DNA repair pathways in the attempt to specifically killed tumor cells are exponentially released.
Complete list of metadatas

Cited literature [994 references]  Display  Hide  Download
Contributor : Abes Star :  Contact
Submitted on : Friday, September 21, 2018 - 1:03:17 AM
Last modification on : Wednesday, October 14, 2020 - 4:11:46 AM
Long-term archiving on: : Saturday, December 22, 2018 - 1:02:11 PM


Version validated by the jury (STAR)


  • HAL Id : tel-01878353, version 1



Alexis Fouquin. Fonctions et régulations des protéines PARP2 et de XRCC1 dans la réparation des dommages à l’ADN. Biochimie, Biologie Moléculaire. Université Paris-Saclay, 2017. Français. ⟨NNT : 2017SACLS236⟩. ⟨tel-01878353⟩



Record views


Files downloads