FIG. 2.

Binding of proteins to the HIF-1 site. EMSAs were performed with the L24-HIF probe with the addition of nuclear extract from HeLa cells incubated in normoxia (N) or hypoxia (H). Inducible (Ind) and constitutive (Const) complexes, as well as the free probe (Pr), are labeled. The addition of competitor (Comp) or antibody (Ab) is noted. OZ12 and OZ15 are monoclonal antibodies to HIF-1α; the combination of both antibodies caused an additive supershift. Supershifts were also observed with an ARNT polyclonal and a p300/CBP monoclonal antibody (AC240) (4) but not with an ATF-1/CREB-1 monoclonal antibody (25C10G; Santa Cruz). WT, wild type; mut, mutant.