Systemic and Localized Reversible Regulation of Transgene Expression by Tetracycline with tetR-Mediated Transcription Repression Switch

Academic Article

Abstract

  • Background: We recently developed a new tetracycline-inducible gene switch employing the tetracycline operator-containing hCMV major immediate-early promoter and the tetracycline repressor, tetR, rather than the previously used tetR-mammalian cell transcription factor fusion derivatives. Materials and methods: The present study demonstrates that this tetR-mediated transcription repression system can function as a powerful gene switch for On-and-Off regulation of therapeutic gene expression in ex vivo gene transfer protocols. Firstly, for achieving regulated gene expression in a localized tissue environment, R11/OEGF cells, a stable line that expresses hEGF under the control of the tetR-mediated transcription repression switch, were transplanted into porcine full-thickness wounds enclosed by wound chambers. Results: By topically applying tetracycline in wound chambers at various concentrations or at different time points post-transplantation, the levels and timing of hEGF expression in transplanted wounds could be reversibly regulated by tetracycline. Over 3000-fold induction in hEGF expression was achieved in the local wound microenvironment. Secondly, R11/OEGF cells were intramuscularly injected into NCr outbread nude mice to test the efficacy of intermittent systemic gene delivery of a soluble peptide(s). Conclusions: Basal circulating hEGF was undetectable and induced up to at least 1,500-fold after administration of tetracycline. Furthermore, the timing and duration of hEGF expression could be finely adjusted by the presence or the absence of tetracycline in the drinking water. © 2007 Elsevier Inc. All rights reserved.
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    Author List

  • Yao F; Pomahac B; Visovatti S; Chen M; Johnson S; Augustinova H; Svensjo T; Eriksson E
  • Start Page

  • 267
  • End Page

  • 274
  • Volume

  • 138
  • Issue

  • 2