FIG. 9.

Expression of a DNA-binding-defective HIF-2α mutant (HIF-2αmBHLH) but not a similarly mutated HIF-1α construct rescues the function of endogenous HIF-2α in the Hif-1α^−/− ES cells. (A) Both HIF-2αmBHLH and HIF-1αmBHLH mutants do not induce a cotransfected WT-HRE reporter in HEK293 cells under normoxia, while the same amount of WT HIF-α plasmids induces WT-HRE reporter. Results were plotted as change relative to that of empty vector under normoxia. (B) Hypoxia induces Glut-1 and ADM (HIF-1α and HIF-2α common genes) expression in WT and Hif-1α^−/−/HIF-2αmBHLH ES cells as assessed by real-time PCR but not in Hif-1α^−/−/HIF-1αmBHLH or Hif-1α^−/−/vector ES cells. Results are the averages for three independent experiments and are plotted as changes relative to that in Hif-1α^−/−/vector cells under normoxia.