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. 2008 Feb 11;105(7):2622–2627. doi: 10.1073/pnas.0706790105

Fig. 1.

Fig. 1.

Loss of PTEN increases transcriptional activity of HIF-1 but has no effect on HIF-1α protein levels. (A) HIF-1α protein levels were analyzed in Pten+/−, and Pten−/− cells were exposed to 21% O2 (N), 1.5% O2 (H), or 0% O2 for 2 h. (B) Pten+/− and Pten−/− cells were transfected with an HRE-Luciferase reporter gene construct and exposed to 21% O2, 1.5% O2, or 0% O2 for 16 h before being harvested. Relative luciferase expression is the ratio of luciferase/total protein levels normalized to Pten+/− cells. (C) Pten+/− and Pten−/− cells were cultured for 16 h under 21% O2, 1.5% O2, or 0% O2 and harvested, and transcription levels of the target genes Vegf A and Pgk1 were determined by quantitative real-time RT-PCR analysis. (D) Pten−/− cells were transfected with an HRE-Luciferase reporter gene construct. At 24 h after transfection, cells were infected with adenoviruses and subsequently exposed to 21% O2 or 1.5% O2 for 16 h. Relative luciferase expression is the ratio of luciferase/total protein levels normalized to cells expressing AdNull. (E) Pten+/− and Pten−/− cells were transfected with a GAL4 (amino acids 1–147) DNA-binding domain fused to HIF-1α (amino acids 531–826) construct and a reporter gene construct encoding five GAL4-binding sites. Cells were incubated at 21% O2 for 20 h, followed by 36 h at 21% O2, 1.5% O2, or 0% O2. Relative luciferase expression is the ratio of luciferase/total protein levels normalized to Pten+/− cells.