HEL/UAP56 Binds Cotranscriptionally to the Balbiani Ring Pre-mRNA in an Intron-Independent Manner and Accompanies the BR mRNP to the Nuclear Pore
2002 (English)In: Current Biology, ISSN 0960-9822, Vol. 12, no 10, 859-62 p.Article in journal (Refereed) Published
The splicing factor UAP56/HEL/Sub2p is essential for mRNA export , ,  and . It has been proposed  and  that UAP56/HEL/Sub2p interacts with the pre-mRNA during splicing and recruits the export factor Aly/REF/Yra1 (reviewed in ) to the spliced mRNA. However, UAP56/HEL/Sub2p also participates in the transport of intronless mRNAs, and thus its role in export is not necessarily coupled to splicing ,  and . Here, we characterize the HEL protein of Chironomus tentans and we analyze in situ the interaction of HEL with a natural export substrate, the Balbiani ring pre-messenger ribonucleoprotein (BR pre-mRNP, reviewed in ). Using immunoelectron microscopy, we show that HEL binds to the BR pre-mRNP cotranscriptionally and that incorporation of HEL into the pre-mRNP is independent of the location of introns along the BR pre-mRNA. We also show that HEL accompanies the BR mRNP to the nuclear pore and is released from the BR mRNP during translocation to the cytoplasm. Aly/REF is also released from the BR mRNP during translocation but after dissociation of HEL. In summary, we have shown that binding of HEL to the BR pre-mRNA occurs independently of splicing, and we have established the point in the export pathway at which HEL and Aly/REF interact with the mRNP.
Place, publisher, year, edition, pages
Current Biology Limited , 2002. Vol. 12, no 10, 859-62 p.
IdentifiersURN: urn:nbn:se:su:diva-23275DOI: 10.1016/S0960-9822(02)00840-0OAI: oai:DiVA.org:su-23275DiVA: diva2:191083
Part of urn:nbn:se:su:diva-2182004-08-302004-08-302010-01-08Bibliographically approved