The protein Aly links pre-messenger-RNA splicing to nuclear export in metazoans.
In metazoans, most pre-messenger RNAs contain introns that are removed by splicing. The spliced mRNAs are then exported to the cytoplasm. Recent studies showed that splicing promotes efficient mRNA export, but the mechanism for coupling these two processes is not known. Here we show that Aly, the metazoan homologue of the yeast mRNA export factor Yralp (ref. 2), is recruited to messenger ribonucleoprotein (mRNP) complexes generated by splicing. In contrast, Aly does not associate with mRNPs assembled on identical mRNAs that already have no introns or with heterogenous nuclear RNP (hnRNP) complexes. Aly is recruited during spliceosome assembly, and then becomes tightly associated with the spliced mRNP. Aly shuttles between the nucleus and cytoplasm, and excess recombinant Aly increases both the rate and efficiency of mRNA export in vivo. Consistent with its splicing-dependent recruitment, Aly co-localizes with splicing factors in the nucleus. We conclude that splicing is required for efficient mRNA export as a result of coupling between the splicing and the mRNA export machineries.
Zhou
Z
Z
Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Luo
M J
MJ
Straesser
K
K
Katahira
J
J
Hurt
E
E
Reed
R
R
D000818:Animals; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
C105242:ALYREF protein, human; C122111:NXF1 protein, human; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; C486334:Refbp1 protein, mouse; D012261:Ribonucleoproteins; D014157:Transcription Factors; C026452:messenger ribonucleoprotein