Letter | Published:

The protein Aly links pre-messenger-RNA splicing to nuclear export in metazoans

Naturevolume 407pages401405 (2000) | Download Citation



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 export1, 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 Yra1p (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.

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We are indebted to K. N. Clouse for discussions and comments on the manuscript. We thank R. Luhrmann for U5 antibodies, G. Dreyfuss for the hnRNP A1 and C antibodies, and A. Nunez-Roldan for the Aly antibody.

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Author notes

  1. Zhaolan Zhou, Ming-juan Luo, Katja Straesser, Jun Katahira and Ed Hurt: These authors contributed equally to this work.


  1. Department of Cell Biology, Harvard Medical School, Boston, 02115 , Massachusetts, USA

    • Zhaolan Zhou
    • , Ming-juan Luo
    •  & Robin Reed
  2. University of Heidelberg, Biochemie-Zentrum Heidelberg (BZH), Im Neuenheimer Feld 328, Heidelberg, D-69120 , Germany

    • Katja Straesser
    • , Jun Katahira
    •  & Ed Hurt


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