Binding of a nuclear factor to the upstream region of the c-myc gene

We have studied the binding of proteins to a synthetic DNA fragment corresponding to a 21 base pair sequence in the upstream region of the human c-myc gene. This sequence has previously been reported to bind the c-myc protein, thus representing a putative site for autoregulation of the c-myc gene (Ariga et al., 1989). Our electrophoretic mobility shift assays indicated that this DNA fragment binds to a factor present in nuclear extracts from HeLa cells. However, analysis of extracts from other cells indicated that this binding does not correlate with the presence of the c-myc protein. No binding was observed using c-myc protein translated in vitro. Also, anti-c-myc antibodies could not inhibit binding of this factor. These experiments indicate, that nucleotides -2193 to -2173 from the P1 promoter of the c-myc gene are able to bind a nuclear factor, and that this factor most likely does not include the c-myc protein.