Original Article
Molecular Therapy (2000) 2, 276–287; doi: 10.1006/mthe.2000.0115
Ligand-Dependent Regulation of Vascular Endothelial Growth Factor and Erythropoietin Expression by a Plasmid-Based Autoinducible GeneSwitch System
Ronald V. Abruzzese*, Debra Godin*, Vidya Mehta*, Jerry L. Perrard*, Martha French*, Wendy Nelson*, Gaylen Howell*, Michael Coleman*, Bert W. O'Malley† and Jeffrey L. Nordstrom*
- *Valentis, Inc. The Woodlands, Texas 77381
- †Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030
Correspondence: Jeffrey L. Nordstrom, Valentis, Inc., 8301 New Trails Drive, The Woodlands, TX 77381-4248. Fax: 281-364-0858. E-mail: nordsj@valentis.com
Received 27 March 2000; Accepted 18 July 2000.
Abstract
We investigated the ability of an improved mifepristone-dependent GeneSwitch system to regulate the expression of genes for two therapeutic proteins: vascular endothelial growth factor (VEGF) and erythropoietin. The GeneSwitch system consisted of two plasmids, one encoding the chimeric GeneSwitch protein, the other an inducible transgene. When the constitutive CMV promoter of the GeneSwitch plasmid was replaced by an autoinducible promoter consisting of four copies of GAL4 DNA binding sites linked to a minimal thymidine kinase promoter, the tightness of transgene regulation was improved by an order of magnitude. Quantitative RT-PCR analysis of GeneSwitch mRNA confirmed that the autoinducible promoter was responsive to mifepristone. We demonstrated the ability of the improved GeneSwitch system to regulate the expression of VEGF or erythropoietin in a biologically relevant manner after delivery of plasmids to the hind-limb muscle of adult mice. This ability of the autoinducible GeneSwitch system to regulate the expression of therapeutic proteins in mice indicates its potential for use in human gene therapy applications.
Keywords:
GeneSwitch, mifepristone, regulation, autoinducible, erythropoietin, VEGF, gene therapy, nonviral
