Nuclear extracts (NE) from uterine arteries were incubated with double-stranded oligonucleotide probes containing unmethylated (UM) or methylated (M) Sp1-520 binding site (A) or USF-15 binding site (B), in the absence or presence of antibodies (Ab) against Sp1, USF1, or USF2. Cold competition (CC) was performed with unlabeled competitor oligonucleotide at a 200-fold molar excess. Free oligo, no nuclear extracts were added. S, shift; SS, supershift.