Transactivation by EPAS-1 and HIF-1α in Ka13 cells. Histogram showing the relative luciferase expression from transient cotransfections of CHO Ka13 cells with reporter plasmids containing a multiple HRE (p24x6TKLuc), the LDH-A promoter (pLDH-ALuc), or the VEGF promoter (pVEGFLuc) and an expression plasmid for either HIF-1α, EPAS-1, or an empty vector control. Values shown represent averaged data from seven experiments, with normalization to the normoxic value for LDH-A (1 arbitrary unit).