Transcriptional control of gene expression by microRNAs

Cell. 2010 Jan 8;140(1):111-22. doi: 10.1016/j.cell.2009.12.023.


MicroRNAs (miRNAs) control gene expression in animals and plants. Like another class of small RNAs, siRNAs, they affect gene expression posttranscriptionally. While siRNAs in addition act in transcriptional gene silencing, a role of miRNAs in transcriptional regulation has been less clear. We show here that in moss Physcomitrella patens mutants without a DICER-LIKE1b gene, maturation of miRNAs is normal but cleavage of target RNAs is abolished and levels of these transcripts are drastically reduced. These mutants accumulate miRNA:target-RNA duplexes and show hypermethylation of the genes encoding target RNAs, leading to gene silencing. This pathway occurs also in the wild-type upon hormone treatment. We propose that initiation of epigenetic silencing by DNA methylation depends on the ratio of the miRNA and its target RNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Bryopsida / genetics*
  • Bryopsida / metabolism*
  • DNA Methylation
  • Gene Expression Regulation*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Molecular Sequence Data
  • Plant Proteins / metabolism
  • RNA, Plant / genetics
  • RNA, Plant / metabolism*
  • RNA, Small Interfering
  • Transcription, Genetic


  • MicroRNAs
  • Plant Proteins
  • RNA, Plant
  • RNA, Small Interfering