Description
Heterochromatin is a repressive chromatin compartment essential for maintaining genomic integrity. A hallmark of heterochromatin is the presence of specialized nonhistone proteins that alter chromatin structure to inhibit transcription and recombination. It is generally assumed that heterochromatin is highly condensed. However, surprisingly little is known about the structure of heterochromatin or its dynamics in solution. In budding yeast, formation of heterochromatin at telomeres and the homothallic silent mating type loci require the Sir3 protein. Here, we use a combination of sedimentation velocity, atomic force microscopy and nucleosomal array capture to characterize the stoichiometry and conformation of Sir3 nucleosomal arrays. The results indicate that Sir3 interacts with nucleosomal arrays with a stoichiometry of two Sir3 monomers per nucleosome. We also find that Sir3 fibres are less compact than canonical magnesium-induced 30 nm fibres. We suggest that heterochromatin proteins promote silencing by ‘coating’ nucleosomal arrays, stabilizing interactions between nucleosomal histones and DNA.
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Title
- Solution-state conformation and stoichiometry of yeast Sir3 heterochromatin fibres
Contributors
Agent
- Swygert, Sarah G. (Author)
- Manning, Benjamin J. (Author)
- Senapati, Subhadip (Author)
- Kaur, Parminder (Author)
- Lindsay, Stuart (Author)
- Demeler, Borries (Author)
- Peterson, Craig L. (Author)
- Biodesign Institute (Contributor)
- Single Molecule Biophysics (Contributor)
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2014-08-01
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Identifier
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Digital object identifier: 10.1038/ncomms5751
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Identifier TypeInternational standard serial numberIdentifier Value0032-0633
Note
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The final version of this article, as published, can be viewed online at: http://dx.doi.org/10.1038/ncomms5751
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Swygert, Sarah G., Manning, Benjamin J., Senapati, Subhadip, Kaur, Parminder, Lindsay, Stuart, Demeler, Borries, & Peterson, Craig L. (2014). Solution-state conformation and stoichiometry of yeast Sir3 heterochromatin fibres. NATURE COMMUNICATIONS, 5: 4751. http://dx.doi.org/10.1038/ncomms5751