RNA-directed DNA methylation in plants: Where to start?

RNA Biol. 2013 Oct;10(10):1593-6. doi: 10.4161/rna.26312.

Abstract

Plants use 24-nucleotide small interfering RNAs (24-nt siRNAs) and long non-coding RNAs (lncRNAs) to direct de novo DNA methylation and transcriptional gene silencing. This process is called RNA-directed DNA methylation (RdDM). An important question in the RdDM model is what explains the target specificity of RNA polymerase IV (Pol IV), the enzyme that initiates siRNA production. Two recent papers addressed this question by characterizing the DTF1/SHH1 protein, which contains a homeodomain in the N-terminus and a novel histone-binding domain SAWADEE in the C terminus. Here we review the main results of the two studies and discuss several possible mechanisms that could contribute to Pol IV and Pol V recruitment.

Keywords: DNA methylation; RdDM; histone modification; lncRNA; siRNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis Proteins / metabolism
  • DNA Methylation*
  • DNA-Directed RNA Polymerases / metabolism
  • Gene Expression Regulation, Plant*
  • RNA, Plant / metabolism
  • RNA, Small Interfering / metabolism

Substances

  • Arabidopsis Proteins
  • RNA, Plant
  • RNA, Small Interfering
  • RNA polymerase IV, Arabidopsis
  • RNA polymerase V, Arabidopsis
  • DNA-Directed RNA Polymerases