The molecular biology of the SIR proteins

Gene. 2001 Nov 14;279(1):1-16. doi: 10.1016/s0378-1119(01)00741-7.


Silent or heritably repressed genes constitute the major fraction of genetic information in higher eukaryotic cells. Budding yeast has very little consecutively repressed DNA, but what exists has served as a paradigm for the molecular analysis of heterochromatin. The major structural constituents of repressed chromatin in yeast are the four core histones and three large chromatin factors called Silent information regulators 2, 3 and 4. How these components assemble DNA into a state that is refractory to transcription remains a mystery. Nonetheless, there have been many recent insights into their molecular structures. This review examines the impact of these results on our understanding of silencing function in budding yeast.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Gene Expression Regulation, Fungal
  • Histone Deacetylases / genetics
  • Histone Deacetylases / metabolism
  • Saccharomycetales / genetics*
  • Silent Information Regulator Proteins, Saccharomyces cerevisiae*
  • Sirtuin 2
  • Sirtuins
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism
  • Transcription, Genetic


  • Fungal Proteins
  • SIR1 protein, S cerevisiae
  • SIR3 protein, S cerevisiae
  • SIR4 protein, S cerevisiae
  • Silent Information Regulator Proteins, Saccharomyces cerevisiae
  • Trans-Activators
  • SIR2 protein, S cerevisiae
  • Sirtuin 2
  • Sirtuins
  • Histone Deacetylases