title: Impact of the MRN Complex on Adeno-Associated Virus Integration and Replication during Coinfection with Herpes Simplex Virus 1.
abstract: Adeno-associated virus (AAV) is a helper-dependent parvovirus that requires coinfection with adenovirus (AdV) or herpes simplex virus 1 (HSV-1) to replicate. In the absence of the helper virus, AAV can persist in an episomal or integrated form. Previous studies have analyzed the DNA damage response (DDR) induced upon AAV replication to understand how it controls AAV replication. In particular, it was shown that the Mre11-Rad50-Nbs1 (MRN) complex, a major player of the DDR induced by double-stranded DNA breaks and stalled replication forks, could negatively regulate AdV and AAV replication during coinfection. In contrast, MRN favors HSV-1 replication and is recruited to AAV replication compartments that are induced in the presence of HSV-1. In this study, we examined the role of MRN during AAV replication induced by HSV-1. Our results indicated that knockdown of MRN significantly reduced AAV DNA replication after coinfection with wild-type (wt) HSV-1 or HSV-1 with the polymerase deleted. This effect was specific to wt AAV, since it did not occur with recombinant AAV vectors. Positive regulation of AAV replication by MRN was dependent on its DNA tethering activity but did not require its nuclease activities. Importantly, knockdown of MRN also negatively regulated AAV integration within the human AAVS1 site, both in the presence and in the absence of HSV-1. Altogether, this work identifies a new function of MRN during integration of the AAV genome and demonstrates that this DNA repair complex positively regulates AAV replication in the presence of HSV-1.
  
  
  OBJECTIVE
  Viral DNA genomes trigger a DNA damage response (DDR), which can be either detrimental or beneficial for virus replication. Adeno-associated virus (AAV) is a defective parvovirus that requires the help of an unrelated virus such as adenovirus (AdV) or herpes simplex virus 1 (HSV-1) for productive replication. Previous studies have demonstrated that the cellular Mre11-Rad50-Nbs1 (MRN) complex, a sensor and regulator of the DDR, negatively regulates AAV replication during coinfection with AdV, which counteracts this effect by inactivating the complex. Here, we demonstrate that MRN positively regulates AAV replication during coinfection with HSV-1. Importantly, our study also indicates that MRN also favors integration of AAV genomes within the human AAVS1 site. Altogether, this work indicates that MRN differentially regulates AAV replication depending on the helper virus which is present and identifies a new function of this DNA repair complex during AAV integration.
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France.
authors.forename: Rachel
authors.initials: R
authors.lastname: Millet
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France.
authors.forename: Nelly
authors.initials: N
authors.lastname: Jolinon
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France.
authors.forename: Xuan-Nhi
authors.initials: XN
authors.lastname: Nguyen
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France.
authors.forename: Gregory
authors.initials: G
authors.lastname: Berger
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cimarelli
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Greco
authors.affiliation: INSERM U967, CEA, Université Paris Diderot, Université Paris Sud, CEA DSV, Institut de Radiobiologie Moléculaire et Cellulaire, Fontenay-aux-Roses, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Bertrand
authors.affiliation: Institute for Pathology, University Hospital of Cologne, Cologne, Germany Center for Molecular Medicine of Cologne, University of Cologne, Cologne, Germany.
authors.forename: Margarete
authors.initials: M
authors.lastname: Odenthal
authors.affiliation: Center for Molecular Medicine of Cologne, University of Cologne, Cologne, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany German Center for Infection Research, Bonn-Cologne Partner Site, Bonn-Cologne, Germany.
authors.forename: Hildegard
authors.initials: H
authors.lastname: Büning
authors.affiliation: International Center for Research in Infectiology, INSERM U1111, CNRS UMR5308, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université de Lyon, UCB-Lyon 1, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France anna.salvetti@inserm.fr.
authors.forename: Anna
authors.initials: A
authors.lastname: Salvetti
mesh_terms: D017766:Acid Anhydride Hydrolases; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000229:Dependovirus / Q000502:physiology*; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D018259:Herpesvirus 1, Human / Q000502:physiology*; D006801:Humans; D000076228:MRE11 Homologue Protein; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D016662:Virus Integration; D014779:Virus Replication
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; C112156:NBN protein, human; D009687:Nuclear Proteins; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D045643:DNA Repair Enzymes