The Swi2/Snf2 Bromodomain Is Important for the Full Binding and Remodeling Activity of the SWI/SNF Complex on H3‐ and H4‐acetylated Nucleosomes

The SWI/SNF chromatin‐remodeling complex contains a bromodomain in its Swi2/Snf2 subunit that helps tether it to acetylated promoter nucleosomes. To study the importance of this bromodomain in the SWI/SNF complex, we have compared the nucleosome‐binding and the chromatin‐remodeling activities of the SWI/SNF to a mutant complex that lacks the Swi2/Snf2 bromodomain. Here we show that the SWI/SNF complex deleted of the Swi2/Snf2 bromodomain cannot bind to SAGA‐ or NuA4‐acetylated nucleosomes as well as the wild‐type complex. Moreover, we show that this reduced binding leads to partial remodeling of these acetylated nucleosome templates by the Δbromodomain SWI/SNF complex. These results demonstrate that the Swi2/Snf2 bromodomain is required for the full binding and functional activity of the SWI/SNF complex on H3‐ and H4‐acetylated nucleosomes.