Fig. 1. Binding of ZEB to the two E-boxes present in the VDR promoter region. GMSAs were performed as described in "Materials and Methods" using digoxigenin-labeled probes containing the Z1 site (Lanes 1–4) or the Z2 site (Lanes 5–8). Lanes 1 and 5, the probes alone; Lanes 2 and 6, the probes incubated with recombinant ZEB protein; Lanes 3 and 7, the same binding reactions as in Lanes 2 and 6, except that a 100-fold molar excess of unlabeled probe was added; and Lanes 4 and 8, the binding reactions of probes with mutated E-boxes and recombinant ZEB protein. Arrow, the ZEB-binding complex. A representative gel of the GMSA is shown.