Figure 4.

Effect for a gradual change of flanking context on Egr-1 binding. (A) The identity of 8–11 nucleotides proximal to ZF3 or ZF1, for site -1 in a C1 DNA context, is gradually changed by their conversion to AT repeats. (B-E) Mutated DNA constructs of site -1 are subjected to multiple unzipping cycles in the presence of 500 nM Egr-1. (B and C) Difference between the breaking force measured for the unmodified C1 context, and constructs in which nucleotides proximal to ZF1 (b) or ZF3 (c) were mutated. (D and E) The corresponding binding probabilities, analyzed and presented as in Figure 1. The number of experiments for each case is shown in Supplementary Table S3, and the P-values in Supplementary Table S7.