DNA replication origin and transcriptional enhancer in c‐myc gene share the c‐myc protein binding sequences.

We have previously reported that c‐myc protein, or protein(s) complexed with c‐myc protein, binds to the region upstream of the first exon of the c‐myc gene and that this region contains an origin of cellular DNA replication (ori) and also a transcriptional enhancer. Here we show by Southwestern blotting that c‐myc protein binds directly to a 7 bp sequence within the above region. Furthermore, we show that the c‐myc protein binding sequences are indispensable for both ori and enhancer functions, but that additional sequences are required for maximal ori and enhancer activities. Thus, c‐myc protein is a sequence specific factor which is apparently used both in initiation of DNA replication and in regulation of RNA transcription.