title: Notable reduction in illegitimate integration mediated by a PPT-deleted, nonintegrating lentiviral vector.
abstract: Nonintegrating lentiviral vectors present a means of reducing the risk of insertional mutagenesis in nondividing cells and enabling short-term expression of potentially hazardous gene products. However, residual, integrase-independent integration raises a concern that may limit the usefulness of this system. Here we present a novel 3' polypurine tract (PPT)-deleted lentiviral vector that demonstrates impaired integration efficiency and, when packaged into integrase-deficient particles, significantly reduced illegitimate integration. Cells transduced with PPT-deleted vectors exhibited predominantly 1-long terminal repeat (LTR) circles and a low level of linear genomes after reverse transcription (RT). Importantly, the PPT-deleted vector exhibited titers and in vitro and in vivo expression levels matching those of conventional nonintegrating lentiviral vectors. This safer nonintegrating lentiviral vector system will support emerging technologies, such as those based on transient expression of zinc-finger nucleases (ZFNs) for gene editing, as well as reprogramming factors for inducing pluripotency.
authors.affiliation: Gene Therapy Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Kantor
authors.forename: Matthew
authors.initials: M
authors.lastname: Bayer
authors.forename: Hong
authors.initials: H
authors.lastname: Ma
authors.forename: Jude
authors.initials: J
authors.lastname: Samulski
authors.forename: Chengwen
authors.initials: C
authors.lastname: Li
authors.forename: Thomas
authors.initials: T
authors.lastname: McCown
authors.forename: Tal
authors.initials: T
authors.lastname: Kafri
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D017353:Gene Deletion; D005786:Gene Expression Regulation / Q000235:genetics; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D019426:Integrases / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011995:Recombination, Genetic; D020079:Terminal Repeat Sequences / Q000235:genetics; D019562:Viral Load; D016662:Virus Integration / Q000235:genetics*
chemical_list: D019426:Integrases