Figure 1

EMSA with HeLa nuclear extracts using -537G and -537A oligonucleotides. Binding activities of [γ-³²P] ATP-labeled -537G (lane 1–6) and -537A (lane 7–12) oligonucleotides. The assay was performed in the presence (+) or absence (-) of HeLa nuclear extracts. Unlabeled -537G or -537A oligonucleotides were used in competition assays. Each binding reaction contained 5 mg of HeLa nuclear extracts and labeled -537G (lanes 2–6) or -537A (lanes 8–12) oligonucleotides. Excess unlabeled oligonucleotides (10-, 50- and 100-fold) were included in the binding reactions as competitors (Lanes 3–5 and 9–11, respectively). In addition, we added a 100-fold excess of unlabeled -537A and -537G oligonucleotides to compete with -537G (Lane 6) and -537A (Lane 12) oligonucleotides. The binding activity of -537G was unaffected, even in the presence of a 100-fold excess of -537A competitor (lane 6). However, the -537A oligonucleotide could not bind transcription factor (lane 12), and displayed no band in the presence of a 100-fold excess of -537G probe.