Gene Regulation Systems for Gene Therapy Applications in the Central Nervous System

Figure 3

Schematic of the rapamycin regulation system. The constitutively active human cytomegalovirus (hCMV) promoter drives expression of two fusion transcription factors. (Top left) A transcription factor consisting of three copies of the FKBP protein fused to a ZFHD1 DNA binding domain. (Top right) A transcription factor consisting of a FRAP protein with a p65 activation domain. Rapamycin enables dimerization of the transcription factors, with enable binding to 12xZFHD1 binding sites and activation, respectively, driving expression of a transgene upstream of a minimal CMV promoter. ZFHD1: zinc finger homeodomain-1; FKBP: FK-binding protein; FRAP: FKBP-rapamycin associated protein [23].