In vivo dynamics of Swi6 in yeast

evidence for a stochastic model of heterochromatin

Thierry Cheutin, Stanislaw A Gorski, Karen M May, Prim B Singh, Tom Misteli

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

The mechanism for transcriptional silencing of pericentric heterochromatin is conserved from fission yeast to mammals. Silenced genome regions are marked by epigenetic methylation of histone H3, which serves as a binding site for structural heterochromatin proteins. In the fission yeast Schizosaccharomyces pombe, the major structural heterochromatin protein is Swi6. To gain insight into Swi6 function in vivo, we have studied its dynamics in the nucleus of living yeast. We demonstrate that, in contrast to mammalian cells, yeast heterochromatin domains undergo rapid, large-scale motions within the nucleus. Similar to the situation in mammalian cells, Swi6 does not permanently associate with these chromatin domains but binds only transiently to euchromatin and heterochromatin. Swi6 binding dynamics are dependent on growth status and on the silencing factors Clr4 and Rik1, but not Clr1, Clr2, or Clr3. By comparing the kinetics of mutant Swi6 proteins in swi6(-) and swi6(+) strains, we demonstrate that homotypic protein-protein interactions via the chromoshadow domain stabilize Swi6 binding to chromatin in vivo. Kinetic modeling allowed quantitative estimation of residence times and indicated the existence of at least two kinetically distinct populations of Swi6 in heterochromatin. The observed dynamics of Swi6 binding are consistent with a stochastic model of heterochromatin and indicate evolutionary conservation of heterochromatin protein binding properties from mammals to yeast.

Original languageEnglish
Pages (from-to)3157-67
Number of pages11
JournalMolecular and Cellular Biology
Volume24
Issue number8
Publication statusPublished - Apr 2004

Fingerprint

Heterochromatin
Yeasts
Schizosaccharomyces
Chromatin
Mammals
Proteins
Euchromatin
Mutant Proteins
Protein Binding
Epigenomics
Histones
Methylation
Binding Sites
Genome
Growth

Keywords

  • Animals
  • Chromosomal Proteins, Non-Histone
  • Evolution, Molecular
  • Fluorescence Recovery After Photobleaching
  • Gene Silencing
  • Heterochromatin
  • Models, Genetic
  • Nuclear Proteins
  • Nucleosomes
  • Protein Binding
  • Recombinant Fusion Proteins
  • Schizosaccharomyces
  • Schizosaccharomyces pombe Proteins
  • Journal Article
  • Research Support, Non-U.S. Gov't

Cite this

In vivo dynamics of Swi6 in yeast : evidence for a stochastic model of heterochromatin. / Cheutin, Thierry; Gorski, Stanislaw A; May, Karen M; Singh, Prim B; Misteli, Tom.

In: Molecular and Cellular Biology, Vol. 24, No. 8, 04.2004, p. 3157-67.

Research output: Contribution to journalArticle

Cheutin, T, Gorski, SA, May, KM, Singh, PB & Misteli, T 2004, 'In vivo dynamics of Swi6 in yeast: evidence for a stochastic model of heterochromatin', Molecular and Cellular Biology, vol. 24, no. 8, pp. 3157-67.
Cheutin, Thierry ; Gorski, Stanislaw A ; May, Karen M ; Singh, Prim B ; Misteli, Tom. / In vivo dynamics of Swi6 in yeast : evidence for a stochastic model of heterochromatin. In: Molecular and Cellular Biology. 2004 ; Vol. 24, No. 8. pp. 3157-67.
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