Role of the conserved Sir3-BAH domain in nucleosome binding and silent chromatin assembly

Megumi Onishi; Gunn-Guang Liou; Johannes R Buchberger; Thomas Walz; Danesh Moazed

doi:10.1016/j.molcel.2007.12.004

Role of the conserved Sir3-BAH domain in nucleosome binding and silent chromatin assembly

Mol Cell. 2007 Dec 28;28(6):1015-28. doi: 10.1016/j.molcel.2007.12.004.

Authors

Megumi Onishi¹, Gunn-Guang Liou, Johannes R Buchberger, Thomas Walz, Danesh Moazed

Affiliation

¹ Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.

PMID: 18158899
DOI: 10.1016/j.molcel.2007.12.004

Abstract

Silent chromatin domains in Saccharomyces cerevisiae represent examples of epigenetically heritable chromatin. The formation of these domains involves the recruitment of the SIR complex, composed of Sir2, Sir3, and Sir4, followed by iterative cycles of NAD-dependent histone deacetylation and spreading of SIR complexes over adjacent chromatin domains. We show here that the conserved bromo-adjacent homology (BAH) domain of Sir3 is a nucleosome- and histone-tail-binding domain and that its binding to nucleosomes is regulated by residues in the N terminus of histone H4 and the globular domain of histone H3 on the exposed surface of the nucleosome. Furthermore, using a partially purified system containing nucleosomes, the three Sir proteins, and NAD, we observe the formation of SIR-nucleosome filaments with a diameter of less than 20 nm. Together, these observations suggest that the SIR complex associates with an extended chromatin fiber through interactions with two different regions in the nucleosome.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Acetyltransferases / genetics
Acetyltransferases / metabolism
Binding Sites / genetics
Binding Sites / physiology
Chromatin Assembly and Disassembly*
Chromatin Immunoprecipitation
Gene Silencing
Histones / chemistry
Histones / genetics
Histones / metabolism
Microscopy, Electron
Models, Molecular
Mutation
Nucleosomes / metabolism*
Nucleosomes / ultrastructure
Protein Binding
Protein Processing, Post-Translational
Protein Structure, Tertiary
Saccharomyces cerevisiae Proteins / genetics
Saccharomyces cerevisiae Proteins / metabolism*
Silent Information Regulator Proteins, Saccharomyces cerevisiae / chemistry
Silent Information Regulator Proteins, Saccharomyces cerevisiae / genetics
Silent Information Regulator Proteins, Saccharomyces cerevisiae / metabolism*
Surface Plasmon Resonance

Substances

Histones
Nucleosomes
SIR3 protein, S cerevisiae
Saccharomyces cerevisiae Proteins
Silent Information Regulator Proteins, Saccharomyces cerevisiae
Acetyltransferases