title: The effect of DNA-dependent protein kinase on adeno-associated virus replication.
abstract: BACKGROUND
  DNA-dependent protein kinase (DNA-PK) is a DNA repair enzyme and plays an important role in determining the molecular fate of the rAAV genome. However, the effect this cellular enzyme on rAAV DNA replication remains elusive.
  
  
  RESULTS
  In the present study, we characterized the roles of DNA-PK on recombinant adeno-associated virus DNA replication. Inhibition of DNA-PK by a DNA-PK inhibitor or siRNA targeting DNA-PKcs significantly decreased replication of AAV in MO59K and 293 cells. Southern blot analysis showed that replicated rAAV DNA formed head-to-head or tail-to-tail junctions. The head-to-tail junction was low or undetectable suggesting AAV-ITR self-priming is the major mechanism for rAAV DNA replication. In an in vitro replication assay, anti-Ku80 antibody strongly inhibited rAAV replication, while anti-Ku70 antibody moderately decreased rAAV replication. Similarly, when Ku heterodimer (Ku70/80) was depleted, less replicated rAAV DNA were detected. Finally, we showed that AAV-ITRs directly interacted with Ku proteins.
  
  
  CONCLUSIONS
  Collectively, our results showed that that DNA-PK enhances rAAV replication through the interaction of Ku proteins and AAV-ITRs.
authors.affiliation: Department of Pharmaceutics, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Young-Kook
authors.initials: YK
authors.lastname: Choi
authors.forename: Kevin
authors.initials: K
authors.lastname: Nash
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Byrne
authors.forename: Nicholas
authors.initials: N
authors.lastname: Muzyczka
authors.forename: Sihong
authors.initials: S
authors.lastname: Song
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D034961:Antigens, Nuclear / Q000096:biosynthesis; D015139:Blotting, Southern; D002460:Cell Line; D045744:Cell Line, Tumor; D004261:DNA Replication; D051747:DNA-Activated Protein Kinase / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D000229:Dependovirus / Q000235:genetics*; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016679:Genome, Viral; D006801:Humans; D000072200:Ku Autoantigen; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D014779:Virus Replication; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D034741:RNA, Small Interfering; D051747:DNA-Activated Protein Kinase; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen; D000077191:Wortmannin