Fig. 9. HIF-1 and VEGF mRNA expression during hypoxia. Amplification of HIF-1 (487 bp) and VEGF for 15 to 30 cycles was carried out by RT-PCR to determine the linear portion of the amplification reaction (A). Two isoforms of VEGF mRNA were amplified, VEGF₁₆₅ (627 bp) and VEGF₁₈₉ (699 bp). Caki-1 cells were exposed to 1% O₂ and total RNA was isolated. RT-PCR analysis of HIF-1 at 25 cycles and VEGF at 30 cycles using total RNA from Caki-1 cells under kinetic of hypoxia is shown (B). mRNA -tubulin (321 bp) was used as a control. HIF1-a protein expression was analyzed by its immunoprecipitation from nuclei and immunodectection (C). Two independent experiments were performed.