| Literature DB >> 23084401 |
Guramrit Singh1, Alper Kucukural1, Can Cenik1, John D Leszyk2, Scott A Shaffer2, Zhiping Weng3, Melissa J Moore4.
Abstract
In addition to sculpting eukaryotic transcripts by removing introns, pre-mRNA splicing greatly impacts protein composition of the emerging mRNP. The exon junction complex (EJC), deposited upstream of exon-exon junctions after splicing, is a major constituent of spliced mRNPs. Here, we report comprehensive analysis of the endogenous human EJC protein and RNA interactomes. We confirm that the major "canonical" EJC occupancy site in vivo lies 24 nucleotides upstream of exon junctions and that the majority of exon junctions carry an EJC. Unexpectedly, we find that endogenous EJCs multimerize with one another and with numerous SR proteins to form megadalton sized complexes in which SR proteins are super-stoichiometric to EJC core factors. This tight physical association may explain known functional parallels between EJCs and SR proteins. Further, their protection of long mRNA stretches from nuclease digestion suggests that endogenous EJCs and SR proteins cooperate to promote mRNA packaging and compaction.Entities:
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Year: 2012 PMID： 23084401 PMCID： PMC3522173 DOI： 10.1016/j.cell.2012.10.007
Source DB: PubMed Journal: Cell ISSN： 0092-8674 Impact factor: 41.582