Stable Remodeling of Tailless Nucleosomes by the Human SWI-SNF Complex
AbstractStable Remodeling of Tailless Nucleosomes by the Human SWI-SNF Complex † Jeffrey R. Guyon 1 , 2 , 3 , Geeta J. Narlikar 1 , 2 , Saïd Sif 1 , 2 , and Robert E. Kingston 1 , 2 , * Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114 1 ; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115 2 ; and Graduate Program, Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 3 ABSTRACT The histone N-terminal tails have been shown previously to be important for chromatin assembly, remodeling, and stability. We have tested the ability of human SWI-SNF (hSWI-SNF) to remodel nucleosomes whose tails have been cleaved through a limited trypsin digestion. We show that hSWI-SNF is able to remodel tailless mononucleosomes and nucleosomal arrays, although hSWI-SNF remodeling of tailless nucleosomes is less effective than remodeling of nucleosomes with tails. Analogous to previous observations with tailed nucleosomal templates, we show both (i) that hSWI-SNF-remodeled trypsinized mononucleosomes and arrays are stable for 30 min in the remodeled conformation after removal of ATP and (ii) that the remodeled tailless mononucleosome can be isolated on a nondenaturing acrylamide gel as a novel species. Thus, nucleosome remodeling by hSWI-SNF can occur via interactions with a tailless nucleosome core.