p54nrb/NonO and PSF promote U snRNA nuclear export by accelerating its export complex assembly

Nucleic Acids Res. 2014 Apr;42(6):3998-4007. doi: 10.1093/nar/gkt1365. Epub 2014 Jan 10.


The assembly of spliceosomal U snRNPs in metazoans requires nuclear export of U snRNA precursors. Four factors, nuclear cap-binding complex (CBC), phosphorylated adaptor for RNA export (PHAX), the export receptor CRM1 and RanGTP, gather at the m(7)G-cap-proximal region and form the U snRNA export complex. Here we show that the multifunctional RNA-binding proteins p54nrb/NonO and PSF are U snRNA export stimulatory factors. These proteins, likely as a heterodimer, accelerate the recruitment of PHAX, and subsequently CRM1 and Ran onto the RNA substrates in vitro, which mediates efficient U snRNA export in vivo. Our results reveal a new layer of regulation for U snRNA export and, hence, spliceosomal U snRNP biogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism
  • DNA-Binding Proteins
  • HeLa Cells
  • Humans
  • Karyopherins / metabolism
  • Nuclear Matrix-Associated Proteins / metabolism*
  • Nucleocytoplasmic Transport Proteins / metabolism*
  • Octamer Transcription Factors / metabolism*
  • PTB-Associated Splicing Factor
  • Phosphoproteins / metabolism
  • RNA, Small Nuclear / metabolism*
  • RNA-Binding Proteins / metabolism*
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Xenopus
  • ran GTP-Binding Protein / metabolism


  • DNA-Binding Proteins
  • Karyopherins
  • NONO protein, human
  • Nuclear Matrix-Associated Proteins
  • Nucleocytoplasmic Transport Proteins
  • Octamer Transcription Factors
  • PHAX protein, human
  • PTB-Associated Splicing Factor
  • Phosphoproteins
  • RNA, Small Nuclear
  • RNA-Binding Proteins
  • Receptors, Cytoplasmic and Nuclear
  • exportin 1 protein
  • ran GTP-Binding Protein