TY - JOUR AU - Mamar, Hasan AU - Fajka-Boja, Roberta AU - Mórocz, Mónika AU - Pinto, Eva AU - Zentout, Siham AU - Mihut, Alexandra AU - Kopasz, Anna Georgina AU - Mérey, Mihály AU - Smith, Rebecca AU - Haracska, Lajos AU - Huet, Sébastien AU - Timinszky, Gyula TI - The loss of DNA polymerase epsilon accessory subunits POLE3-POLE4 leads to BRCA1-independent PARP inhibitor sensitivity JF - NUCLEIC ACIDS RESEARCH J2 - NUCLEIC ACIDS RES VL - 52 PY - 2024 IS - 12 SP - 6994 EP - 7011 PG - 18 SN - 0305-1048 DO - 10.1093/nar/gkae439 UR - https://m2.mtmt.hu/api/publication/34169536 ID - 34169536 AB - The clinical success of PARP1/2 inhibitors (PARPi) prompts the expansion of their applicability beyond homologous recombination deficiency. Here, we demonstrate that the loss of the accessory subunits of DNA polymerase epsilon, POLE3 and POLE4, sensitizes cells to PARPi. We show that the sensitivity of POLE4 knockouts is not due to compromised response to DNA damage or homologous recombination deficiency. Instead, POLE4 loss affects replication speed leading to the accumulation of single-stranded DNA gaps behind replication forks upon PARPi treatment, due to impaired post-replicative repair. POLE4 knockouts elicit elevated replication stress signaling involving ATR and DNA-PK. We find POLE4 to act parallel to BRCA1 in inducing sensitivity to PARPi and counteracts acquired resistance associated with restoration of homologous recombination. Altogether, our findings establish POLE4 as a promising target to improve PARPi driven therapies and hamper acquired PARPi resistance. LA - English DB - MTMT ER - TY - JOUR AU - Smith, Rebecca AU - Zentout, Siham AU - Rother, Magdalena AU - Bigot, Nicolas AU - Chapuis, Catherine AU - Mihut, Alexandra AU - Zobel, Florian Franz AU - Ahel, Ivan AU - van Attikum, Haico AU - Timinszky, Gyula AU - Huet, Sebastien TI - HPF1-dependent histone ADP-ribosylation triggers chromatin relaxation to promote the recruitment of repair factors at sites of DNA damage JF - NATURE STRUCTURAL & MOLECULAR BIOLOGY J2 - NAT STRUCT MOL BIOL VL - 30 PY - 2023 SP - 678 EP - 691 PG - 35 SN - 1545-9993 DO - 10.1038/s41594-023-00977-x UR - https://m2.mtmt.hu/api/publication/33955642 ID - 33955642 N1 - Funding Agency and Grant Number: French National Research Agency [ANR-10-INBS-04]; Agence Nationale de la Recherche [PRC-2018 REPAIRCHROM]; Institut National du Cancer [PLBIO-2019]; Institut Universitaire de France; Fondation ARC pour la recherche sur le cancer [PDF20181208405]; Hungarian Academy of Sciences [LP2017-11/2017]; National Research Development and Innovation Office [K128239]; Wellcome Trust [210634, 223107]; Biotechnology and Biological Sciences Research Council [BB/R007195/1]; Ovarian Cancer Research Alliance [813369]; Cancer Research United Kingdom [C35050/A22284]; Dutch Research Council (NWO) [VI.C.182.052] Funding text: We thank the Microscopy-Rennes Imaging Center (BIOSIT, Universite Rennes 1), a member of the national infrastructure France-BioImaging supported by the French National Research Agency (ANR-10-INBS-04), for providing access to the imaging setups, as well as S.?Dutertre and X.?Pinson for technical assistance on the microscopes. We also thank the Cytometrie en flux et tri cellulaire (BIOSIT, Universite Rennes 1), specifically L.?Deleurme and A.?Aime for technical assistance with flow cytometry. We also thank M.?Suskiewicz for thoughtful discussions and generously sharing the HPF1 plasmid DNA. For this work, S.H.'s group received financial support from the Agence Nationale de la Recherche (PRC-2018 REPAIRCHROM), the Institut National du Cancer (PLBIO-2019) and the Institut Universitaire de France. R.S. is supported by the Fondation ARC pour la recherche sur le cancer (PDF20181208405). The work in G.T.'s laboratory was supported by the Hungarian Academy of Sciences (LP2017-11/2017) and the National Research Development and Innovation Office (K128239). The work in I.A.'s laboratory is supported by the Wellcome Trust (210634 and 223107), Biotechnology and Biological Sciences Research Council (BB/R007195/1), Ovarian Cancer Research Alliance (813369) and Cancer Research United Kingdom (C35050/A22284). H.v.A.'s laboratory is financially supported by a NWO-VICI grant (VI.C.182.052) from the Dutch Research Council (NWO). AB - Poly(ADP-ribose) polymerase 1 (PARP1) activity is regulated by its co-factor histone poly(ADP-ribosylation) factor 1 (HPF1). The complex formed by HPF1 and PARP1 catalyzes ADP-ribosylation of serine residues of proteins near DNA breaks, mainly PARP1 and histones. However, the effect of HPF1 on DNA repair regulated by PARP1 remains unclear. Here, we show that HPF1 controls prolonged histone ADP-ribosylation in the vicinity of the DNA breaks by regulating both the number and length of ADP-ribose chains. Furthermore, we demonstrate that HPF1-dependent histone ADP-ribosylation triggers the rapid unfolding of chromatin, facilitating access to DNA at sites of damage. This process promotes the assembly of both the homologous recombination and non-homologous end joining repair machineries. Altogether, our data highlight the key roles played by the PARP1/HPF1 complex in regulating ADP-ribosylation signaling as well as the conformation of damaged chromatin at early stages of the DNA damage response.Smith, Zentout et al. investigate the role of HPF1 in DNA repair using live-cell imaging methods and find that HPF1-dependent histone ADP-ribosylation drives early process in DNA repair, including chromatin relaxation and repair factor recruitment. LA - English DB - MTMT ER -