The role of HIF-1αin PlGF-mediated ET-1 mRNA expression. HPMVECs were transfected with indicated plasmids followed by PlGF treatment for 6 hours. (A) RPA. (B) Western blot analysis of nuclear extracts (20 μg) using antibodies to HIF-1α and HIF-1β. Data are representative of 3 different experiments. Where indicated, the vertical lines show the repositioned gel lanes.