FIG. 6.

DNase I footprinting of DNAs containing mutated binding sites. Twenty femtomoles of 265-bp end-labeled DNA fragments containing binding sites mutated as shown at the top were incubated in the absence (−) or presence (+) of 400 ng of large T antigen (LT) in Tris-HCl buffer, pH 7, and then incubated with DNase I, as described in Materials and Methods. The DNAs were analyzed on 12% polyacrylamide–8 M urea gels. Regions protected against DNase I digestion are indicated by brackets. WT, wild type.