title: The MMS22L-TONSL heterodimer directly promotes RAD51-dependent recombination upon replication stress.
abstract: Homologous recombination (HR) is a key pathway that repairs DNA double-strand breaks (DSBs) and helps to restart stalled or collapsed replication forks. How HR supports replication upon genotoxic stress is not understood. Using in vivo and in vitro approaches, we show that the MMS22L-TONSL heterodimer localizes to replication forks under unperturbed conditions and its recruitment is increased during replication stress in human cells. MMS22L-TONSL associates with replication protein A (RPA)-coated ssDNA, and the MMS22L subunit directly interacts with the strand exchange protein RAD51. MMS22L is required for proper RAD51 assembly at DNA damage sites in vivo, and HR-mediated repair of stalled forks is abrogated in cells expressing a MMS22L mutant deficient in RAD51 interaction. Similar to the recombination mediator BRCA2, recombinant MMS22L-TONSL limits the assembly of RAD51 on dsDNA, which stimulates RAD51-ssDNA nucleoprotein filament formation and RAD51-dependent strand exchange activity in vitro Thus, by specifically regulating RAD51 activity at uncoupled replication forks, MMS22L-TONSL stabilizes perturbed replication forks by promoting replication fork reversal and stimulating their HR-mediated restart in vivo.
authors: Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland petr.cejka@irb.usi.ch matthias.peter@bc.biol.ethz.ch wojciech.piwko@bc.biol.ethz.ch.
authors: Wojciech
authors: 0000-0002-3779-6220
authors: W
authors: Piwko
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Lucie J
authors: LJ
authors: Mlejnkova
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Karun
authors: K
authors: Mutreja
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Lepakshi
authors: L
authors: Ranjha
authors: Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland.
authors: Diana
authors: D
authors: Stafa
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Alexander
authors: A
authors: Smirnov
authors: Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland.
authors: Mia Ml
authors: MM
authors: Brodersen
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Ralph
authors: R
authors: Zellweger
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Andreas
authors: A
authors: Sturzenegger
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Pavel
authors: P
authors: Janscak
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland.
authors: Massimo
authors: M
authors: Lopes
authors: Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland petr.cejka@irb.usi.ch matthias.peter@bc.biol.ethz.ch wojciech.piwko@bc.biol.ethz.ch.
authors: Matthias
authors: M
authors: Peter
authors: Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland petr.cejka@irb.usi.ch matthias.peter@bc.biol.ethz.ch wojciech.piwko@bc.biol.ethz.ch.
authors: Petr
authors: 0000-0002-9087-032X
authors: P
authors: Cejka
mesh_terms: D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D051135:Rad51 Recombinase / Q000378:metabolism*; D011995:Recombination, Genetic
chemical_list: D004268:DNA-Binding Proteins; C554517:MMS22L protein, human; D016328:NF-kappa B; D009687:Nuclear Proteins; C093394:TONSL protein, human; C495153:RAD51 protein, human; D051135:Rad51 Recombinase
keywords: DNA repair; DNA replication; DNA replication stress; homologous recombination