FIG. 7.

Transient transfection of HIF3α. (A) Interaction of HIF3α and ARNT in transiently transfected COS-1 cells. COS-1 cells were cotransfected with plasmids expressing HIF3α and/or ARNT and a luciferase reporter driven by six HRE containing the TACGTG core sequence (inset). (B) Induction of HIF3α HRD1 domain by cobalt chloride and hypoxia treatment. Hep3B cells were transfected with plasmids expressing the GAL4/HRD/TAD fusion protein and a luciferase reporter driven by five GAM binding sites. The cells were treated without or with 100 μM CoCl₂ or hypoxia (1% O₂) for 20 h prior to harvest. Relative light units (RLU) were measured as described in Materials and Methods. Transfected expression plasmids and reporters are illustrated in the insets. The white, black, and striped columns represent control (C), cobalt chloride (Co), and hypoxia (H) treatments, respectively.