title: Identification and elimination of replication-competent adeno-associated virus (AAV) that can arise by nonhomologous recombination during AAV vector production.
abstract: Adeno-associated virus (AAV) vector preparations are often contaminated with variable amounts of replication-competent AAV (rcAAV), which may influence the behavior of these vectors both in cultured cells and in animals. A packaging plasmid/vector plasmid system containing no significant homology and lacking the wild-type AAV p5 promoter was constructed to eliminate the production of wild-type AAV by recombination. Still, rcAAV was detected in vector produced by cotransfection of these plasmids at large scale. Sequence analysis revealed that nonhomologous recombination was responsible for the generation of these novel rcAAVs. A new AAV packaging plasmid carrying separate rep and cap expression cassettes in opposite transcriptional orientations was constructed. AAV vector preparations produced by using this packaging construct did not contain rcAAV.
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Allen
authors.forename: D J
authors.initials: DJ
authors.lastname: Debelak
authors.forename: T C
authors.initials: TC
authors.lastname: Reynolds
authors.forename: A D
authors.initials: AD
authors.lastname: Miller
mesh_terms: D000818:Animals; D002213:Capsid / Q000235:genetics; D002461:Cell Line, Transformed; D003587:Cytomegalovirus / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D000229:Dependovirus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D005822:Genetic Vectors; D006801:Humans; D008668:Metallothionein / Q000235:genetics; D051379:Mice; D011995:Recombination, Genetic; D014170:Transformation, Genetic; D014407:Tumor Cells, Cultured; D014764:Viral Proteins / Q000235:genetics; D014779:Virus Replication
chemical_list: D004268:DNA-Binding Proteins; D014764:Viral Proteins; C068734:rep proteins, Adeno-associated virus 2; D008668:Metallothionein