History of the GeneSwitch System
GeneSwitch Regulator Protein, version 2.0
(GS 2.0, GL914VPC)
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.
/ EFPGVDQ / hPR-LBD D19
(640-914) / GST / VP16
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.