Polycomb protein Ezh1 promotes RNA polymerase II elongation

Mol Cell. 2012 Jan 27;45(2):255-62. doi: 10.1016/j.molcel.2011.11.019. Epub 2011 Dec 22.


Polycomb group (PcG) proteins initiate the formation of repressed chromatin domains and regulate developmental gene expression. A mammalian PcG protein, enhancer of zeste homolog 2 (Ezh2), triggers transcriptional repression by catalyzing the addition of methyl groups onto lysine 27 of histone H3 (H3K27me2/3). This action facilitates the binding of other PcG proteins to chromatin for purposes of transcriptional silencing. Interestingly, there exists a paralog of Ezh2, termed Ezh1, whose primary function remains unclear. Here, we provide evidence for genome-wide association of Ezh1 complex with active epigenetic mark (H3K4me3), RNA polymerase II (Pol II), and mRNA production. Ezh1 depletion reduced global Pol II occupancy within gene bodies and resulted in delayed transcriptional activation during differentiation of skeletal muscle cells. Conversely, overexpression of wild-type Ezh1 led to premature gene activation and rescued Pol II occupancy defects in Ezh1-depleted cells. Collectively, these findings reveal a role for a PcG complex in promoting mRNA transcription.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Cell Differentiation
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Epigenesis, Genetic
  • Histone-Lysine N-Methyltransferase / antagonists & inhibitors
  • Histone-Lysine N-Methyltransferase / genetics
  • Histone-Lysine N-Methyltransferase / metabolism
  • Histone-Lysine N-Methyltransferase / physiology*
  • Histones / metabolism
  • Methylation
  • Mice
  • Muscle Development
  • Peptide Chain Elongation, Translational / physiology*
  • Polycomb Repressive Complex 2
  • RNA Interference
  • RNA Polymerase II / metabolism
  • RNA Polymerase II / physiology*
  • Repressor Proteins / metabolism
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*


  • DNA-Binding Proteins
  • Histones
  • Repressor Proteins
  • Suz12 protein, mouse
  • Transcription Factors
  • Ezh1 protein, mouse
  • Histone-Lysine N-Methyltransferase
  • Polycomb Repressive Complex 2
  • RNA Polymerase II