Current Genetics

, Volume 65, Issue 2, pp 495–505 | Cite as

Proteomic profiling of yeast heterochromatin connects direct physical and genetic interactions

  • Alexis Zukowski
  • Juliana Phillips
  • Soyeon Park
  • Ronghu Wu
  • Steven P. Gygi
  • Aaron M. JohnsonEmail author
Original Paper


Heterochromatin domains are stably repressed chromatin structures composed of a core assembly of silencing proteins that condense adjacent nucleosomes. The minimal heterochromatin structure can serve as a platform for recruitment of complementary regulatory factors. We find that a reconstituted budding yeast heterochromatin domain can act as a platform to recruit multiple factors that play a role in regulating heterochromatin function. We uncover the direct interaction between the SIR heterochromatin complex and a chromosomal boundary protein that restricts the spread of heterochromatin. We find that the SIR complex relieves a mechanism of auto-inhibition within the boundary protein Yta7, allowing the Yta7 bromodomain to engage chromatin. Our results suggest that budding yeast shares with other eukaryotes the ability to establish complex heterochromatin domains that coordinate multiple mechanisms of silencing regulation through physical interactions.


Heterochromatin SIR complex Proteasome Yta7 



We thank Danesh Moazed for initial support on this project. Thanks to Cassie Smith for preliminary test purifications of Yta7. This work was supported by NIH Grants T32GM008730 (A. Z.); R35GM119575 and K99/R00GM094291 (A. M. J.); NIH HG3456 and GM67945 (S. G.).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

294_2018_889_MOESM1_ESM.xlsx (38 kb)
Supplementary material 1 (XLSX 37 KB)
294_2018_889_MOESM2_ESM.pdf (75 kb)
Supplementary material 2 (PDF 74 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Biochemistry and Molecular GeneticsUniversity of Colorado School of MedicineAuroraUSA
  2. 2.Molecular Biology ProgramUniversity of Colorado, DenverAuroraUSA
  3. 3.Department of Molecular, Cellular, and Developmental BiologyUniversity of Colorado, BoulderBoulderUSA
  4. 4.Department of Chemistry and BiochemistryGeorgia Institute of TechnologyAtlantaUSA
  5. 5.Department of Cell BiologyHarvard Medical SchoolBostonUSA

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