The Tetracycline Responsive System.

Constitutive gene expression is not always the appropriate expression system because the unphysiological levels of expressed protein could be detrimental in studies examining biological roles of proteins, or continued expression may be unnecessary after therapeutic effects have been achieved in gene therapy . We have utilized pharmacologically regulated gene expression systems to achieve fine control of gene expression levels which facilitate research in basic biology and translates to use in experimental gene therapy studies. In this chapter, we outline the application of a tightly controlled tetracycline responsive gene expression system.