Temporal Control of Mammalian Cortical Neurogenesis by M 6 A Methylation

Cell. 2017 Nov 2;171(4):877-889.e17. doi: 10.1016/j.cell.2017.09.003. Epub 2017 Sep 28.

Abstract

N6-methyladenosine (m6A), installed by the Mettl3/Mettl14 methyltransferase complex, is the most prevalent internal mRNA modification. Whether m6A regulates mammalian brain development is unknown. Here, we show that m6A depletion by Mettl14 knockout in embryonic mouse brains prolongs the cell cycle of radial glia cells and extends cortical neurogenesis into postnatal stages. m6A depletion by Mettl3 knockdown also leads to a prolonged cell cycle and maintenance of radial glia cells. m6A sequencing of embryonic mouse cortex reveals enrichment of mRNAs related to transcription factors, neurogenesis, the cell cycle, and neuronal differentiation, and m6A tagging promotes their decay. Further analysis uncovers previously unappreciated transcriptional prepatterning in cortical neural stem cells. m6A signaling also regulates human cortical neurogenesis in forebrain organoids. Comparison of m6A-mRNA landscapes between mouse and human cortical neurogenesis reveals enrichment of human-specific m6A tagging of transcripts related to brain-disorder risk genes. Our study identifies an epitranscriptomic mechanism in heightened transcriptional coordination during mammalian cortical neurogenesis.

Keywords: Mettl14; RNA methylation; autism; epitranscriptomics; human organoid; m(6)A; neurogenesis; radial glia cell; schizophrenia; transcriptional prepatterning.

MeSH terms

  • Animals
  • Cell Cycle
  • Gene Expression Regulation
  • Gene Expression Regulation, Developmental
  • Gene Knockdown Techniques
  • Humans
  • Methylation
  • Methyltransferases / genetics
  • Methyltransferases / metabolism
  • Mice
  • Mice, Knockout
  • Neural Stem Cells / metabolism
  • Neurogenesis*
  • Organoids / metabolism
  • Prosencephalon / cytology
  • Prosencephalon / embryology*
  • Prosencephalon / metabolism
  • RNA Processing, Post-Transcriptional*
  • RNA Stability
  • RNA, Messenger / metabolism*

Substances

  • RNA, Messenger
  • METTL14 protein, human
  • Methyltransferases
  • Mettl14 protein, mouse
  • Mettl3 protein, mouse