fig4
Figure 4. Activation of PXR by HIF-1 and their interactions. (A) HIF-1 increased PXR activity. 293T cells transiently co-transfected with pGL3-PXRE, PCDH-HIF-1, and pGL3-Renilla. PXR activity was determined by luciferase assay 48 h after transfection. The results shown are from three independent experiments. Error bars represent standard deviation. *Indicates significance (P < 0.05); (B) CoCl2 increased PXR activity. 293T cells transiently co-transfected with pGL3-PXR and pGL3-Renilla and incubated with CoCl2 100 μM for 24 h. PXR activity was measured by luciferase assay; (C) Co-immunoprecipitation of overexpressed PXR and HIF-1. IP was performed with mouse anti-PXR, followed by immunoblotting with rabbit anti-HIF-1, rabbit anti-myc-tag, and mouse anti-PXR; (D) Co-IP between PXR with endogenous HIF-1 under hypoxic conditions. IP was performed with mouse anti-PXR, followed by immunoblotting with rabbit anti-HIF-1 and mouse anti-PXR. Co-IP: Co-immunoprecipitation; HIF-1: hypoxia-inducible factor-1; PCDH: pCDH vector; PXR: pregnane X receptor; pGL3-PXRE: PXR responsive element in PGL3 vector.
