RNAguided Epigenetic Control of Gene Expression

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RNA-guided Epigenetic Control of Gene Expression
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RNA-guided Epigenetic Control of Gene Expression

• As little as 10 of the genome is coding DNA. The
  rest of the genome is non-coding and is comprised
  of a diverse family of repeating sequences (e.g.
  cen, mat, IES). These DNA repeats are foci for
  the generation and accumulation of short
  heterochromatic RNA (shRNAs). shRNAs are
  important for the regulation of heterochromatin
  initiation and formation. Double stranded shRNAs
  undergo RNAi-like processing involving dicer
  (dcr), RdRp (RNA dependent RNA polymerase),
  argonaute (ago) and Twi1 (piwi-related gene of
  the argonaute family). The processed shRNA is
  thought to interact with Chromo domain containing
  proteins (e.g. Chp1, Pdd1). The resultant complex
  is the molecular link between DNA target sequence
  (through pairing with the shRNA), HP1
  (Heterchromatin Protein 1), histone H3
  methylation and DNA methylation. (Black genomic
  region. Purple DNA repeats. Green a gene or
  transcription unit (green). Blue Promoter-driven
  mRNA. Dashed blue intergenic transcription.)
• Adapted from Jenuwein T. Science 2972215, 2002.