Fig. 5

HIF-1α directly binds to the Tie1 promoter. a Diagram showing the two predicted HIF-1α binding sites on the Tie1 promoter and mutagenesis information of each HRE site. b A549 cells were co-transfected with pGL3-Tie1-Luc and wild-type (wt) or dominant-negative (dn) HIF-1α followed by hypoxic incubation, and luciferase activity was measured at 48 h after hypoxia. *P < 0.05, **P < 0.01 vs Normoxia + EV, ^#P < 0.05 vs Hypoxia + EV. (n = 3). c A549 cells were transfected with pGL3-Tie1-Luc or HRE mutant constructs containing the HRE1 mutation and/or HRE2 mutation, followed by hypoxic incubation, and luciferase activity was measured at 48 h after hypoxia treatment. *P < 0.05, **P < 0.01 vs Normoxia + wt Tie1-Luc, ^#P < 0.05 vs Hypoxia + wt Tie1-Luc. (n = 3). d A549 cells were incubated under hypoxic or normoxic conditions for 24 h. Cell lysate was collected for the ChIP analysis of HIF-1a binding to Tie1 promoter DNA