title: Activator protein 1-mediated transcriptional regulation strategy sustains long-term expression of a xenogeneic gene product in vivo: an implication for gene therapy targeting congenital protein deficiencies.
abstract: Maintenance of high-level transgene expression is the main challenge in current gene therapy. Although the cytomegalovirus (CMV) promoter/enhancer or its derivative the CAG promoter has been harnessed in current gene therapy vectors, transgene expression by these vectors is often transient and remains at suboptimal levels due to undefined mechanisms, possibly including the shortage of transcriptional machinery. To overcome this drawback, we designed a novel transcriptional control system, designated here as transcription factor-supercharging promoter system, in which transgene expression is regulated by the positive feedback circuit consisting of cis- and trans-acting elements of gene expression machinery. Among combinations of these elements, a plasmid composed of a target gene expression cassette driven by the chimeric CMV promoter containing repetitive 12-O-tetradecanoylphorbol-13-acetate-responsive elements as cis-acting elements (CMV-TTT) and expression cassettes for c-Fos and c-Jun genes as trans-acting elements facilitated high and long-term (>10 months) expression of a transgene after its intramuscular electroporation-mediated delivery in mice. Since human secretory alkaline phosphatase was used as a reporter, it was suggested that the immune evasion mechanism elicited by the CMV-TTT and/or c-Fos/ c-Jun expression also contributed to the sustained expression in mice. Our strategy may open a new avenue for a gene therapy that involves lifelong supplementation of a deficient protein that could be targeted by the host's immune system.
authors.affiliation: Department of Molecular Biodefense Research, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Sasaki
authors.forename: James M
authors.initials: JM
authors.lastname: Smith
authors.forename: Keiko
authors.initials: K
authors.lastname: Takase
authors.forename: Kenji
authors.initials: K
authors.lastname: Okuda
authors.forename: Norihisa
authors.initials: N
authors.lastname: Ishii
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Takeshita
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D006224:Cricetinae; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011488:Protein Deficiency / Q000151:congenital*; D051381:Rats; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D019076:Transgenes
chemical_list: D018808:Transcription Factor AP-1