Figure 6. The Brg1 chromatin remodeling factor does not catalyze chromatin assembly.
(A) Purified human Brg1 (hBrg1) has a specific activity for chromatin remodeling that is similar to that of wild-type yChd1. Restriction accessibility assays were performed with salt dialysis-reconstituted chromatin with Hae III restriction enzyme and the indicated concentrations of either yChd1 or hBrg1. Naked DNA was used as a reference. After digestion with Hae III, the nucleic acids were deproteinized, subjected to agarose gel electrophoresis, and then visualized by staining with ethidium bromide. (B) Brg1 does not assemble chromatin. Chromatin assembly reactions were performed with the indicated concentrations of yChd1 or hBrg1, and the extent of chromatin assembly was monitored by the DNA supercoiling assay.