The RNA-binding protein FMRP facilitates the nuclear export of N6-methyladenosine-containing mRNAs

J Biol Chem. 2019 Dec 27;294(52):19889-19895. doi: 10.1074/jbc.AC119.010078. Epub 2019 Nov 21.

Abstract

N6-Methyladenosine (m6A) is the most abundant post-transcriptional mRNA modification in eukaryotes and exerts many of its effects on gene expression through reader proteins that bind specifically to m6A-containing transcripts. Fragile X mental retardation protein (FMRP), an RNA-binding protein, has previously been shown to affect the translation of target mRNAs and trafficking of mRNA granules. Loss of function of FMRP causes fragile X syndrome, the most common form of inherited intellectual disability in humans. Using HEK293T cells, siRNA-mediated gene knockdown, cytoplasmic and nuclear fractions, RNA-Seq, and LC-MS/MS analyses, we demonstrate here that FMRP binds directly to a collection of m6A sites on mRNAs. FMRP depletion increased mRNA m6A levels in the nucleus. Moreover, the abundance of FMRP targets in the cytoplasm relative to the nucleus was decreased in Fmr1-KO mice, an effect also observed in highly methylated genes. We conclude that FMRP may affect the nuclear export of m6A-modified RNA targets.

Keywords: FMRP; Fmr1 KO mice; N6-methyladenosine (m6A); RNA metabolism; RNA methylation; RNA-binding protein; fragile X mental retardation protein (FMRP); gene regulation; mouse; mouse brain; neurological disease; nuclear RNA; nuclear RNA export; post-transcriptional modification.

Publication types

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

MeSH terms

  • Active Transport, Cell Nucleus
  • Adenosine / analogs & derivatives*
  • Adenosine / metabolism
  • Animals
  • Binding Sites
  • Cell Nucleus / metabolism
  • Cerebral Cortex / metabolism
  • Fragile X Mental Retardation Protein / antagonists & inhibitors
  • Fragile X Mental Retardation Protein / genetics
  • Fragile X Mental Retardation Protein / metabolism*
  • Fragile X Syndrome / metabolism
  • Fragile X Syndrome / pathology
  • HEK293 Cells
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • RNA Interference
  • RNA Stability
  • RNA, Messenger / chemistry
  • RNA, Messenger / metabolism*
  • RNA, Small Interfering / metabolism

Substances

  • FMR1 protein, human
  • Fmr1 protein, mouse
  • RNA, Messenger
  • RNA, Small Interfering
  • Fragile X Mental Retardation Protein
  • N-methyladenosine
  • Adenosine