Figure 4.

(A) Footprinting of the DNA fragment including SRE-like sequence at −646 bp. (B) Footprinting of the DNA fragment including the SRE-like sequence at −395 bp. Both probes had been end-labeled as described and were incubated in the presence of 5 or 30 μg of nuclear extract (lanes 2 and 3) or without nuclear extract (lanes 1 and 4). Following digestion with DNase I, G+A Maxam–Gilbert sequencing reactions were carried out on the same end-labeled fragments to serve as size markers. The protected regions are shown as FP-1 (corresponding to SRE-like sequence 1) and FP-2 (corresponding to SRE-like sequence 2).