FIGURE 6.

Knockdown of p23 augments HIF-1α target genes. A–E, HeLa cells were treated with the indicated siRNA for 72 h and then maintained under normoxia (NX) or subjected to 2% O₂ (HX) for 16 h. mRNA levels for the indicated genes were measured by real time PCR and normalized to that of 18 S rRNA. Shown are the means ± S.D., n = 3. *, p < 0.05 compared with the respective normoxic or hypoxic control; **, p < 0.01 compared with the respective normoxic or hypoxic control; ns, not significant compared with the respective normoxic or hypoxic control. F, HEK293FT cells were transfected with 50 ng of (eHRE)3-Luc, 50 ng of pRL-TK, and either 5 or 15 ng of either pcDNA3-FLAG-PHD2 or pcDNA3-HA-PHD2 (C36S/C42S). DNA doses were held constant by the addition of pcDNA3. After 8 h, cells were exposed to 1% O₂ (HX) for an additional 16 h or maintained under normoxia (NX). Cells were lysed, and luciferase activity was measured and normalized to that of Renilla luciferase. Shown are the means ± S.D., n = 3. *, p < 0.05 compared with the respective normoxic or hypoxic control; **, p < 0.01 compared with the respective normoxic or hypoxic control; ns, not significant compared with the respective normoxic or hypoxic control.