complete control system for inducible mammalian expression
Denise Wyborski Peter Vaillancourt
The complete control mammalian expression system allows tight control of gene expression in a wide range of mammalian cell types. The inducible promoter used in the system is naturally repressed in the absence of the ecdysone analog ponasterone A (ponA). In a double-stable cell line, a linear dose-response is achieved over a wide range of ponA concentrations (4 fold to >500 fold) and, in a time-course experiment, a linear increase was achieved from 1 hour post induction (5 fold) to 20 hours (1,030 fold). Coexpression of both receptors from a single dicistronic transcript from the vector pERV3 facilitates replacement of the CMV promoter with a cell type-specific promoter of interest. The inducible vector pEGSH is engineered so that expression of the gene of interest can be monitored by Western blot analysis or RNA detection.
DNA vector-based systems that allow precise control of gene expression in vivo are invaluable for studying gene function in a variety of organisms, particularly when studying developmental and other biological processes for which the timing or dosage of gene expression is critical to gene function. Such systems are successfully used to overexpress toxic or disease-causing genes, induce gene targeting, and express antisense RNA. Pharmaceutical companies currently use inducible systems to facilitate screening for inhibitors of clinically relevant biological pathways and to explore potential applications for gene therapy.1
Most inducible mammalian systems currently available employ either natural
promoters that are induced by heavy-metal ions, heat shock,