A new view of mRNA export: separating the wheat from the chaff.
Current models for the export of messenger RNA share the notion that the highly abundant class of nuclear RNA-binding proteins--the hnRNP proteins--have a key role in exporting RNA. But recent studies have led to a new understanding of several non-hnRNP proteins, including SR proteins and the conserved mRNA export factor ALY, which are recruited to the mRNA during pre-mRNA splicing. These studies, together with older work on hnRNP particles and assembly of the spliceosome, lead us to a new view of mRNA export. In our model, the non-hnRNP factors form a splicing-dependent mRNP complex that specifically targets mature mRNA for export, while hnRNP proteins retain introns in the nucleus. A machinery that is conserved between yeast and higher eukaryotes functions to export the mRNA.
Reed
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R
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA. rreed@hms.harvard.edu
Magni
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D000818:Animals; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D005091:Exons; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D007438:Introns; D008954:Models, Biological; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins