Tetracycline-regulated expression of hammerhead ribozymes in vivo.

A major obstacle to achieving constitutive ribozyme expression in cells is that expression or elimination of the target gene may provide either a growth advantage or disadvantage to the cells that express ribozyme. Many approaches have been used to overcome this problem, mostly based on the effort to create conditional or inducible expression systems. In this chapter, we describe the most common choice for overcoming this problem, tetracycline-regulated ribozyme expression. This system consists of two central components: transcriptional transactivators that interact specifically with bacterial cis-regulatory elements and antibiotics that can modulate the binding of the transactivators at low and nontoxic doses. Here, we summarize protocols to generate cell lines expressing tetracycline-regulated ribozyme constructs.