Regulation of Co-transcriptional Pre-mRNA Splicing by m 6 A through the Low-Complexity Protein hnRNPG

Mol Cell. 2019 Oct 3;76(1):70-81.e9. doi: 10.1016/j.molcel.2019.07.005. Epub 2019 Aug 21.

Abstract

N6-methyladenosine (m6A) modification occurs co-transcriptionally and impacts pre-mRNA processing; however, the mechanism of co-transcriptional m6A-dependent alternative splicing regulation is still poorly understood. Heterogeneous nuclear ribonucleoprotein G (hnRNPG) is an m6A reader protein that binds RNA through RRM and Arg-Gly-Gly (RGG) motifs. Here, we show that hnRNPG directly binds to the phosphorylated carboxy-terminal domain (CTD) of RNA polymerase II (RNAPII) using RGG motifs in its low-complexity region. Through interactions with the phosphorylated CTD and nascent RNA, hnRNPG associates co-transcriptionally with RNAPII and regulates alternative splicing transcriptome-wide. m6A near splice sites in nascent pre-mRNA modulates hnRNPG binding, which influences RNAPII occupancy patterns and promotes exon inclusion. Our results reveal an integrated mechanism of co-transcriptional m6A-mediated splicing regulation, in which an m6A reader protein uses RGG motifs to co-transcriptionally interact with both RNAPII and m6A-modified nascent pre-mRNA to modulate RNAPII occupancy and alternative splicing.

Keywords: CTD domain; RBMX; RGG; RNA polymerase II; co-transcription; hnRNPG; low complexity region; m6A; splicing.

Publication types

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

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / metabolism
  • Alternative Splicing*
  • Amino Acid Motifs
  • Binding Sites
  • Exons
  • HEK293 Cells
  • Heterogeneous-Nuclear Ribonucleoproteins / chemistry
  • Heterogeneous-Nuclear Ribonucleoproteins / genetics
  • Heterogeneous-Nuclear Ribonucleoproteins / metabolism*
  • Humans
  • Protein Binding
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism
  • RNA Precursors / biosynthesis*
  • RNA Precursors / genetics
  • RNA, Messenger / biosynthesis*
  • RNA, Messenger / genetics
  • Structure-Activity Relationship
  • Transcription, Genetic*

Substances

  • Heterogeneous-Nuclear Ribonucleoproteins
  • RBMX protein, human
  • RNA Precursors
  • RNA, Messenger
  • N-methyladenosine
  • RNA Polymerase II
  • Adenosine