This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Buchberger, J. R.
Right arrow Articles by Moazed, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Buchberger, J. R.
Right arrow Articles by Moazed, D.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, November 2008, p. 6903-6918, Vol. 28, No. 22
0270-7306/08/$08.00+0     doi:10.1128/MCB.01210-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Sir3-Nucleosome Interactions in Spreading of Silent Chromatin in Saccharomyces cerevisiae{triangledown}

Johannes R. Buchberger,1,2 Megumi Onishi,1,2 Geng Li,1,2 Jan Seebacher,1 Adam D. Rudner,1,§ Steven P. Gygi,1 and Danesh Moazed1,2*

Howard Hughes Medical Institute,2 Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, Massachusetts 021151

Received 31 July 2008/ Returned for modification 22 August 2008/ Accepted 8 September 2008

Silent chromatin in Saccharomyces cerevisiae is established in a stepwise process involving the SIR complex, comprised of the histone deacetylase Sir2 and the structural components Sir3 and Sir4. The Sir3 protein, which is the primary histone-binding component of the SIR complex, forms oligomers in vitro and has been proposed to mediate the spreading of the SIR complex along the chromatin fiber. In order to analyze the role of Sir3 in the spreading of the SIR complex, we performed a targeted genetic screen for alleles of SIR3 that dominantly disrupt silencing. Most mutations mapped to a single surface in the conserved N-terminal BAH domain, while one, L738P, localized to the AAA ATPase-like domain within the C-terminal half of Sir3. The BAH point mutants, but not the L738P mutant, disrupted the interaction between Sir3 and nucleosomes. In contrast, Sir3-L738P bound the N-terminal tail of histone H4 more strongly than wild-type Sir3, indicating that misregulation of the Sir3 C-terminal histone-binding activity also disrupted spreading. Our results underscore the importance of proper interactions between Sir3 and the nucleosome in silent chromatin assembly. We propose a model for the spreading of the SIR complex along the chromatin fiber through the two distinct histone-binding domains in Sir3.

* Corresponding author. Mailing address: Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115. Phone: (617) 432-1258. Fax: (617) 432-1144. E-mail: danesh{at}hms.harvard.edu

{triangledown} Published ahead of print on 15 September 2008.

§ Present address: Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, 451 Smyth Rd., Ottawa, Ontario KlH 8M5, Canada.

Molecular and Cellular Biology, November 2008, p. 6903-6918, Vol. 28, No. 22
0270-7306/08/$08.00+0     doi:10.1128/MCB.01210-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Sampath, V., Yuan, P., Wang, I. X., Prugar, E., van Leeuwen, F., Sternglanz, R. (2009). Mutational Analysis of the Sir3 BAH Domain Reveals Multiple Points of Interaction with Nucleosomes. Mol. Cell. Biol. 29: 2532-2545 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»