Fig. 5.

CITCO enhances the recruitment of coactivator SRC-1 to hPXR. (A) Dose-response curves for T0901317, RIF, and CITCO in the hPXR TR-FRET coactivator recruitment assay. The TR-FRET signal (fold-to-DMSO), as described in Materials and Methods, is used to represent hPXR–SRC-1 interaction. Results are expressed as the means ± S.D. of three independent experiments performed in quadruplicate. (B) Mammalian two-hybrid assay in HepG2 cells. “Normalized luciferase (percentage of DMSO)” represents the interaction of hPXR with SRC-1 and is calculated by normalizing firefly luciferase activity to Renilla luciferase activity. Data are shown as the means ± S.D. (n = 3) (**P < 0.005; ***P < 0.001). The asterisks indicate significant difference between ligand treated (RIF and CITCO) compared with DMSO control samples (Gal4-SRC-1 + VP16-hPXR). VP16-AD, pACT which contains the herpes simplex virus protein 16 (VP16) activation domain (AD).