History of the GeneSwitch System

GeneSwitch Regulator Protein, version 2.0
(GS 2.0, GL₉₁₄VP_C’)

The potency of the GeneSwitch regulator protein was improved by restoring some of the amino acids in the truncated human progesterone ligand binding domain. This restores helix 12, which contains an activation function, AF2, that enables a greater dynamic range of transgene regulation. The potency of the GeneSwitch regulator protein was further increased by changing the position of the VP16 activation domain from the N-terminus to the C-terminus of the chimeric protein (Wang et al., 1997b). The structure of GS 2.0, including the amino acid sequence of the linker regions, is shown.

MDSQQPDL / yGAL4 (2-93) / EFPGVDQ / hPR-LBD D19 (640-914) / GST / VP16 (401-476)

In transient transfection studies, basal transgene expression with GS 2.0 was higher than with GS 1.0. The level of induced expression in response to mifepristone was extremely high, however, often exceeding the level of expression achieved by the CMV promoter.