PARG is Essential for Pol-theta-Mediated DNA End-Joining by Removing Repressive Poly-ADP Ribose Marks

ABSTRACT: DNA polymerase theta (Pol-theta)-mediated end-joining (TMEJ) repairs DNA double-strand breaks and confers resistance to genotoxic agents. How Pol-theta is regulated at the molecular level to exert TMEJ remains unknown. We find that Pol-theta interacts with and is PARylated by PARP1 in vitro and in cells. PARP1 recruits Pol-theta to the vicinity of DNA damage via PARylation dependent liquid demixing, however, PARylated Pol-theta (PAR-Pol-theta) cannot perform TMEJ due to its inability to bind DNA. PARG-mediated de-PARylation of Pol-theta reactivates its DNA binding and end-joining activities in vitro. Consistent with this, PARG is essential for TMEJ in cells and the temporal recruitment of PARG to DNA damage corresponds with TMEJ activation and dissipation of PARP1 and PAR. These studies support a two-step spatiotemporal mechanism of TMEJ regulation. First, PARP1 PARylates Pol-theta and facilitates its recruitment to DNA damage sites in an inactivated state. PARG subsequently activates TMEJ by removing repressive PAR marks on Pol-theta.

INSTRUMENT(S): Q Exactive Plus

ORGANISM(S): Homo Sapiens (ncbitaxon:9606)

SUBMITTER: Tomasz Skorski  

PROVIDER: MSV000092839 | MassIVE |

SECONDARY ACCESSION(S): PXD045320

REPOSITORIES: MassIVE