The exon-exon junction complex provides a binding platform for factors involved in mRNA export and nonsense-mediated mRNA decay
The exon-exon junction complex provides a binding platform for factors involved in mRNA export and nonsense-mediated mRNA decay
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DOI：
10.1093/emboj/20.17.4987
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发表时间：
2001-09-03
期刊：
影响因子：
11.4
通讯作者：
Moore, MJ
中科院分区：
文献类型：
--
作者：
Le Hir, H;Gatfield, D;Moore, MJ
我们最近报道，剪接体改变信使核糖核蛋白颗粒（mRNP）的组成，沉积几个蛋白质20-24核苷酸上游的mRNA外显子外显子连接。当在体外组装时，这种所谓的“外显子-外显子连接复合物”（EJC）包含至少五种蛋白质：SRm 160、DEK、RNPS 1、Y14和REF。为了更好地研究其功能属性，我们现在描述一种在体外和体内产生剪接mRNA的方法，所述剪接mRNA携带或不携带EJC。非洲爪蟾卵母细胞中这些mRNA的分析表明，这种复合物是负责增强剪接mRNA的核质出口的物种。它通过为mRNA输出因子REF和TAP/p15提供强结合位点来实现。此外，通过作为Upf 2和Upf 3因子的锚定点，EJC提供了剪接和无义介导的mRNA衰变之间的直接联系。最后，我们表明，组成的EJC是动态的，在体内，是受显着的演变后，mRNA出口到细胞质。
We recently reported that spliceosomes alter messenger ribonucleoprotein particle (mRNP) composition by depositing several proteins 20-24 nucleotides upstream of mRNA exon-exon junctions. When assembled in vitro, this so-called 'exon-exon junction complex' (EJC) contains at least five proteins: SRm160, DEK, RNPS1, Y14 and REF. To better investigate its functional attributes, we now describe a method for generating spliced mRNAs both in vitro and in vivo that either do or do not carry the EJC. Analysis of these mRNAs in Xenopus laevis oocytes revealed that this complex is the species responsible for enhancing nucleocytoplasmic export of spliced mRNAs. It does so by providing a strong binding site for the mRNA export factors REF and TAP/p15. Moreover, by serving as an anchoring point for the factors Upf2 and Upf3, the EJC provides a direct link between splicing and nonsense-mediated mRNA decay. Finally, we show that the composition of the EJC is dynamic in vivo and is subject to significant evolution upon mRNA export to the cytoplasm.