hSWI/SNF disrupts interactions between the H2A N-terminal tail and nucleosomal DNA.
We have employed a site-specific core histone-DNA cross-linking approach to investigate the mechanism of hSWI/SNF remodeling of a nucleosome. Remodeling results in the complete loss of canonical contacts between the N-terminal tail of H2A and DNA while new interactions are detected between this domain and DNA near the center of the original nucleosome. The data are consistent with a model in which remodeling results in the unraveling of a region of DNA from the edge of the nucleosome, leading to a repositioning of the H2A/H2B dimer to a noncanonical position near the center of the remodeled complex. Additionally, we find that prior cross-linking of the H2A N-terminal region to nucleosomal DNA does not restrict hSWI/SNF remodeling of the remainder of the nucleosome. Thus, disruption of both H2A-DNA interactions near the edge of the nucleosome is not an obligatory step in remodeling of the remainder of the complex.
Lee
K M
KM
Department of Biochemistry and Biophysics, University of Rochester Medical Center, New York 14642, USA.
Sif
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Kingston
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Hayes
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D000818:Animals; D001386:Azides / Q000737:chemistry; D002645:Chickens; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004265:DNA Helicases; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins; D009707:Nucleosomes / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019920:Photoaffinity Labels / Q000737:chemistry; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014982:Xenopus laevis
D001386:Azides; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; D010446:Peptide Fragments; D019920:Photoaffinity Labels; C499336:SMARCA1 protein, human; C084011:SMARCA2 protein, human; D014157:Transcription Factors; D004247:DNA; C084108:SMARCA4 protein, human; D004265:DNA Helicases; C011171:4-azidophenacyl bromide