RNAi-dependent H3K27 methylation is required for heterochromatin formation and DNA elimination in Tetrahymena

Yifan Liu, Sean D. Taverna, Tara L. Muratore, Jeffrey Shabanowitz, Donald F. Hunt, C. David Allis

Research output: Contribution to journalArticlepeer-review

178 Scopus citations


Methylated H3K27 is an important mark for Polycomb group (PcG) protein-mediated transcriptional gene silencing (TGS) in multicellular eukaryotes. Here a Drosophila E(z) homolog, EZL1, is characterized in the ciliated protozoan Tetrahymena thermophila and is shown to be responsible for H3K27 methylation associated with developmentally regulated heterochromatin formation and DNA elimination. Importantly, Ezl1p-catalyzed H3K27 methylation occurs in an RNA interference (RNAi)-dependent manner. H3K27 methylation also regulates H3K9 methylation in these processes. Furthermore, an "effector" of programmed DNA elimination, the chromodomain protein Pdd1p, is shown to bind both K27- and K9-methylated H3. These studies provide a framework for an RNAi-dependent, Polycomb group protein-mediated heterochromatin formation pathway in Tetrahymena and underscore the connection between the two highly conserved machineries in eukaryotes.

Original languageEnglish (US)
Pages (from-to)1530-1545
Number of pages16
JournalGenes and Development
Issue number12
StatePublished - Jun 15 2007
Externally publishedYes


  • DNA elimination
  • H3K27 methylation
  • Heterochromatin
  • Polycomb group proteins
  • RNA interference

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology


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