title: Characteristics of adenovirus-mediated tetracycline-controllable expression system.
abstract: The combination of recombinant adenovirus (Ad) vectors and the tetracycline-controllable expression system is clearly an advantage in gene therapy and gene transfer experiment. In this study, we examined the characteristics of Ad vectors containing the tet-off or tet-on system. The Ad vector containing the tet-off system showed tightly regulatable transgene expression even at low MOI (multiplicity of infection). In contrast, regulation of gene expression by the Ad vector containing the tet-on system was not tight at low MOI, while it showed moderate regulation at high MOI (MOI=100). The Ad vector-mediated tet-on system showed lower inducible and higher background (basal) luciferase production than that of the Ad vector-mediated tet-off system. Moreover, the former system required a concentration of doxycycline, a derivative of tetracycline, approx. 2-3 log orders higher than that of the latter system to switch the luciferase expression. A combination of the vector containing the tet-on system and the vector containing the tetracycline-controlled transcriptional silencer (tTS) gene reduced the background luciferase production and improved regulation. These results suggest that the Ad vector containing the tet-off system is considered to be functionally superior to the vector containing the tet-on system. Care should be taken regarding regulation (especially lower inducibility and higher background), which is decreased in the Ad vector-mediated tet-on system in comparison with the tet-off system. The Ad vector containing the tetracycline-controllable expression system should offer a powerful tool for gene therapy and gene transfer experimentation.
authors.affiliation: Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan. mizuguch@nihs.go.jp
authors.forename: H
authors.initials: H
authors.lastname: Mizuguchi
authors.forename: T
authors.initials: T
authors.lastname: Hayakawa
mesh_terms: D000256:Adenoviridae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004268:DNA-Binding Proteins; D004318:Doxycycline; D005786:Gene Expression Regulation / Q000187:drug effects*; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000187:drug effects*; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011500:Protein Synthesis Inhibitors; D012097:Repressor Proteins / Q000235:genetics; D013752:Tetracycline; D015534:Trans-Activators / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; C111027:NKRF protein, human; D011500:Protein Synthesis Inhibitors; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D008156:Luciferases; D013752:Tetracycline; D004318:Doxycycline