Roles of the histone H2A-H2B dimers and the (H3-H4)(2) tetramer in nucleosome remodeling by the SWI-SNF complex.
SWI-SNF is an ATP-dependent chromatin remodeling complex required for expression of a number of yeast genes. Previous studies have suggested that SWI-SNF action may remove or rearrange the histone H2A-H2B dimers or induce a novel alteration in the histone octamer. Here, we have directly tested these and other models by quantifying the remodeling activity of SWI-SNF on arrays of (H3-H4)(2) tetramers, on nucleosomal arrays reconstituted with disulfide-linked histone H3, and on arrays reconstituted with histone H3 derivatives site-specifically modified at residue 110 with the fluorescent probe acetylethylenediamine-(1,5)-naphthol sulfonate. We find that SWI-SNF can remodel (H3-H4)(2) tetramers, although tetramers are poor substrates for SWI-SNF remodeling compared with nucleosomal arrays. SWI-SNF can also remodel nucleosomal arrays that harbor disulfide-linked (H3-H4)(2) tetramers, indicating that SWI-SNF action does not involve an obligatory disruption of the tetramer. Finally, we find that although the fluorescence emission intensity of acetylethylenediamine-(1,5)-naphthol sulfonate-modified histone H3 is sensitive to octamer structure, SWI-SNF action does not alter fluorescence emission intensity. These data suggest that perturbation of the histone octamer is not a requirement or a consequence of ATP-dependent nucleosome remodeling by SWI-SNF.
Boyer
L A
LA
Program in Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Shao
X
X
Ebright
R H
RH
Peterson
C L
CL
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002645:Chickens; D002843:Chromatin / Q000502:physiology*; D004247:DNA / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D019281:Dimerization; D004220:Disulfides / Q000378:metabolism; D005456:Fluorescent Dyes; D006657:Histones / Q000378:metabolism*; D009282:Naphthalenesulfonates; D009707:Nucleosomes / Q000378:metabolism*; D011487:Protein Conformation
D002843:Chromatin; D004220:Disulfides; D005456:Fluorescent Dyes; D006657:Histones; D009282:Naphthalenesulfonates; D009707:Nucleosomes; C048876:1,5-AEDANS; D004247:DNA; D015252:Deoxyribonucleases, Type II Site-Specific; C024400:GTYRAC-specific type II deoxyribonucleases; D000251:Adenosine Triphosphatases