Fig. 1.

N-Myc binds unmethylated E-boxes in vitro. Nuclear extracts from SK-N-BE cells were incubated in the presence of a radiolabeled canonical E-box probe. Protein composition of the DNA/protein complex was determined by using a specific anti-N-Myc antibody (lane 2) or an anti-c-Jun antibody used as a negative control (lane 3). Competition analysis was performed by incubating the binding reaction with 10-, 25-, 50-, and 100-fold molar excess of unlabeled double-stranded oligonucleotides: wt E-box (lanes 4-7); mutated E-box (lanes 8-11); and wt-E-box methylated on the central cytosine of both strands (lanes 12-15).