select slightly different consensus sites in vitro (3,4,6). The major bands consistently selected by Dri in this assay are indicated by markers to the right of the Dri panel in Figure 3. In contrast to Dri, p270 (ARID1A) binds in a non-specific manner, binding to all fragments offered to it, showing selectivity only for longer fragments (>200 bp) at higher salt concentrations, presumably because longer fragments offer multiple binding sites. Despite the differences in sequence specificity, all three ARID proteins show similar affinities for DNA. These patterns have been documented previously (4,6,9,11), and are shown here for ease of comparison and as controls for the assay. The ARID1B protein has also been compared directly with p270, and found to bind without specificity (20).
