Molecular Cell
Volume 41, Issue 1, 7 January 2011, Pages 56-66
Journal home page for Molecular Cell

Article
Asf1/HIRA Facilitate Global Histone Deacetylation and Associate with HP1 to Promote Nucleosome Occupancy at Heterochromatic Loci

https://doi.org/10.1016/j.molcel.2010.12.009Get rights and content
Under an Elsevier user license
open archive

Summary

Heterochromatin impacts various nuclear processes by providing a recruiting platform for diverse chromosomal proteins. In fission yeast, HP1 proteins Chp2 and Swi6, which bind to methylated histone H3 lysine 9, associate with SHREC (Snf2/HDAC repressor complex) and Clr6 histone deacetylases (HDACs) involved in heterochromatic silencing. However, heterochromatic silencing machinery is not fully defined. We describe a histone chaperone complex containing Asf1 and HIRA that spreads across silenced domains via its association with Swi6 to enforce transcriptional silencing. Asf1 functions in concert with a Clr6 HDAC complex to silence heterochromatic repeats, and it suppresses antisense transcription by promoting histone deacetylation. Furthermore, we demonstrate that Asf1 and SHREC facilitate nucleosome occupancy at heterochromatic regions but TFIIIC transcription factor binding sites within boundary elements are refractory to these factors. These analyses uncover a role for Asf1 in global histone deacetylation and suggest that HP1-associated histone chaperone promotes nucleosome occupancy to assemble repressive heterochromatin.

Highlights

S. pombe Asf1 binds histones and HIRA that localizes across heterochromatin domains ► Asf1/HIRA and Clr6 HDAC act in concert to enforce heterochromatic silencing ► Asf1 and SHREC promote nucleosome occupancy at heterochromatic loci ► Asf1 facilitates global histone deacetylation and suppresses spurious transcription

Cited by (0)

2

Present address: The Wistar Institute, Philadelphia, PA 19104, USA