title: Robust and efficient regulation of transgene expression in vivo by improved tetracycline-dependent lentiviral vectors.
abstract: We developed a panel of lentiviral vectors that displayed tetracycline-regulated transgene expression over two orders of magnitude in bulk, non-selected populations of transduced cells in vitro and in vivo. The robust expression and homogeneous response indicated that most transduced vector genomes were transcription competent and responsive to regulation, providing the lentiviral vector with a novel competitive advantage for gene transfer. After ex vivo transduction and transplantation of cord blood CD34+ cells into NOD/SCID mice, reporter gene expression could be switched "on" and "off" in human hematopoietic cells in vivo for prolonged times, proving integration of the regulated expression system into long-term repopulating cells. By vector injection into established tumor grafts, we achieved efficient delivery and quantitative regulation of transgene expression in vivo. By these approaches, gene function studies can now be performed in in vivo models of human hematopoiesis and cancer. In the future, regulated lentiviral vectors will improve the safety and efficacy of gene therapy.
authors.affiliation: Institute for Cancer Research and Treatment, University of Torino Medical School, Strada Provinciale 142, 10060 Candiolo, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Vigna
authors.forename: Simona
authors.initials: S
authors.lastname: Cavalieri
authors.forename: Laurie
authors.initials: L
authors.lastname: Ailles
authors.forename: Massimo
authors.initials: M
authors.lastname: Geuna
authors.forename: Rainer
authors.initials: R
authors.lastname: Loew
authors.forename: Hermann
authors.initials: H
authors.lastname: Bujard
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldini
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D016086:Lentivirus; D008164:Luminescent Proteins; D051379:Mice; D008819:Mice, Nude; D011401:Promoter Regions, Genetic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology; D014161:Transduction, Genetic; D019076:Transgenes
chemical_list: D008164:Luminescent Proteins; D011500:Protein Synthesis Inhibitors; D049452:Green Fluorescent Proteins; D013752:Tetracycline