Jun 13, 2018

SIR proteins create compact heterochromatin fibers

BioRxiv : the Preprint Server for Biology
Sarah SwygertCraig L Peterson

Abstract

Heterochromatin is a silenced chromatin region essential for maintaining genomic stability and driving developmental processes. The complicated structure and dynamics of heterochromatin have rendered it difficult to characterize. In budding yeast, heterochromatin assembly requires the SIR proteins -- Sir3, believed to be the primary structural component of SIR heterochromatin, and the Sir2/4 complex, responsible for the targeted recruitment of SIR proteins and the deacetylation of lysine 16 of histone H4. Previously, we found that Sir3 binds but does not compact nucleosomal arrays. Here we reconstitute chromatin fibers with the complete complement of SIR proteins and use sedimentation velocity, molecular modeling, and atomic force microscopy to characterize the stoichiometry and conformation of SIR chromatin fibers. In contrast to previous studies, our results demonstrate that SIR arrays are highly compact. Strikingly, the condensed structure of SIR heterochromatin fibers requires both the integrity of H4K16 and an interaction between Sir3 and Sir4. We propose a model in which two molecules of Sir3 bridge and stabilize two adjacent nucleosomes, while a single Sir2/4 heterodimer binds the intervening linker DNA, driving fiber co...Continue Reading

  • References
  • Citations

References

  • We're still populating references for this paper, please check back later.
  • References
  • Citations

Citations

  • This paper may not have been cited yet.

Mentioned in this Paper

TMBIM4
Study
Nucleosomes
Heterochromatin Assembly
Molecular Modeling
Genomic Stability
Yeasts
Histone H4
ABA3 protein, Arabidopsis
Nucleosome Location

About this Paper

Related Feeds

BioRxiv & MedRxiv Preprints

BioRxiv and MedRxiv are the preprint servers for biology and health sciences respectively, operated by Cold Spring Harbor Laboratory. Here are the latest preprint articles (which are not peer-reviewed) from BioRxiv and MedRxiv.

AFM in situ DNA

AFM in situ DNA describes in situ analysis (or study) of DNA using atomic force microscopy. Discover the latest research on AFM in situ DNA here.

Related Papers

Proceedings of the National Academy of Sciences of the United States of America
Sarah G SwygertCraig L Peterson
Proceedings of the National Academy of Sciences of the United States of America
Adam S Sperling, Michael Grunstein
© 2020 Meta ULC. All rights reserved