A novel requirement for DROSHA in maintenance of mammalian CG methylation

Nucleic Acids Res. 2017 Sep 19;45(16):9398-9412. doi: 10.1093/nar/gkx695.


In mammals, faithful inheritance of genomic methylation patterns ensures proper gene regulation and cell behaviour, impacting normal development and fertility. Following establishment, genomic methylation patterns are transmitted through S-phase by the maintenance methyltransferase Dnmt1. Using a protein interaction screen, we identify Microprocessor component DROSHA as a novel DNMT1-interactor. Drosha-deficient embryonic stem (ES) cells display genomic hypomethylation that is not accounted for by changes in the levels of DNMT proteins. DNMT1-mediated methyltransferase activity is also reduced in these cells. We identify two transcripts that are specifically upregulated in Drosha- but not Dicer-deficient ES cells. Regions within these transcripts predicted to form stem-loop structures are processed by Microprocessor and can inhibit DNMT1-mediated methylation in vitro. Our results highlight DROSHA as a novel regulator of mammalian DNA methylation and we propose that DROSHA-mediated processing of RNA is necessary to ensure full DNMT1 activity. This adds to the DROSHA repertoire of non-miRNA dependent functions as well as implicating RNA in regulating DNMT1 activity and correct levels of genomic methylation.

MeSH terms

  • Animals
  • CRISPR-Cas Systems
  • Cells, Cultured
  • Cytosine / metabolism
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methylation*
  • Embryonic Stem Cells / enzymology
  • HEK293 Cells
  • Humans
  • Mice
  • RNA, Messenger / chemistry
  • RNA, Messenger / metabolism
  • Ribonuclease III / genetics
  • Ribonuclease III / metabolism
  • Ribonuclease III / physiology*
  • Up-Regulation


  • RNA, Messenger
  • Cytosine
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • DNMT1 protein, human
  • Dnmt1 protein, mouse
  • Drosha protein, mouse
  • Ribonuclease III