title: The PCNA-associated protein PARI negatively regulates homologous recombination via the inhibition of DNA repair synthesis.
abstract: Successful and accurate completion of the replication of damage-containing DNA requires mainly recombination and RAD18-dependent DNA damage tolerance pathways. RAD18 governs at least two distinct mechanisms: translesion synthesis (TLS) and template switching (TS)-dependent pathways. Whereas TS is mainly error-free, TLS can work in an error-prone manner and, as such, the regulation of these pathways requires tight control to prevent DNA errors and potentially oncogenic transformation and tumorigenesis. In humans, the PCNA-associated recombination inhibitor (PARI) protein has recently been shown to inhibit homologous recombination (HR) events. Here, we describe a biochemical mechanism in which PARI functions as an HR regulator after replication fork stalling and during double-strand break repair. In our reconstituted biochemical system, we show that PARI inhibits DNA repair synthesis during recombination events in a PCNA interaction-dependent way but independently of its UvrD-like helicase domain. In accordance, we demonstrate that PARI inhibits HR in vivo, and its knockdown suppresses the UV sensitivity of RAD18-depleted cells. Our data reveal a novel human regulatory mechanism that limits the extent of HR and represents a new potential target for anticancer therapy.
authors.affiliation: Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary Department of Biology, Masaryk University, 625 00 Brno, Czech Republic burkovics.peter@brc.mta.hu.
authors.forename: Peter
authors.initials: P
authors.lastname: Burkovics
authors.affiliation: Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary.
authors.forename: Lili
authors.initials: L
authors.lastname: Dome
authors.affiliation: Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary.
authors.forename: Szilvia
authors.initials: S
authors.lastname: Juhasz
authors.affiliation: Department of Biology, Masaryk University, 625 00 Brno, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Altmannova
authors.affiliation: Department of Biology, Masaryk University, 625 00 Brno, Czech Republic National Centre for Biomolecular Research, Masaryk University, 625 00 Brno, Czech Republic International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St Anne's University Hospital Brno, 656 91 Brno, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Sebesta
authors.affiliation: Department of Biology, Masaryk University, 625 00 Brno, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Pacesa
authors.affiliation: Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Fugger
authors.affiliation: Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark.
authors.forename: Claus Storgaard
authors.initials: CS
authors.lastname: Sorensen
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, 10595 NY, USA.
authors.forename: Marietta Y W T
authors.initials: MY
authors.lastname: Lee
authors.affiliation: Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Hungary.
authors.forename: Lajos
authors.initials: L
authors.lastname: Haracska
authors.affiliation: Department of Biology, Masaryk University, 625 00 Brno, Czech Republic National Centre for Biomolecular Research, Masaryk University, 625 00 Brno, Czech Republic International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St Anne's University Hospital Brno, 656 91 Brno, Czech Republic lkrejci@chemi.muni.cz.
authors.forename: Lumir
authors.initials: L
authors.lastname: Krejci
mesh_terms: D020816:Amino Acid Motifs; D004247:DNA / Q000096:biosynthesis; D004258:DNA Polymerase III / Q000037:antagonists & inhibitors; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D059767:Recombinational DNA Repair; D044767:Ubiquitin-Protein Ligases / Q000502:physiology; D014466:Ultraviolet Rays
chemical_list: D004268:DNA-Binding Proteins; C556015:PARPBP protein, human; C485954:RAD18 protein, human; D004247:DNA; D044767:Ubiquitin-Protein Ligases; D004258:DNA Polymerase III