Export of mRNA from the nucleus to the cytoplasm is a critical process for all eukaryotic gene expression. As mRNA is synthesized, it is packaged with a myriad of RNA-binding proteins to form ribonucleoprotein particles (mRNPs). For each step in the processes of maturation and export, mRNPs must have the correct complement of proteins. Much of the mRNA export pathway revolves around the heterodimeric export receptor yeast Mex67•Mtr2/human NXF1•NXT1, which is recruited to signal the completion of nuclear mRNP assembly, mediates mRNP targeting/translocation through the nuclear pore complex (NPC), and is displaced at the cytoplasmic side of the NPC to release the mRNP into the cytoplasm. Directionality of the transport is governed by at least two DEAD-box ATPases, yeast Sub2/human UAP56 in the nucleus and yeast Dbp5/human DDX19 at the cytoplasmic side of the NPC, which respectively mediate the association and dissociation of Mex67•Mtr2/NXF1•NXT1 onto the mRNP. Here we review recent progress from structural studies of key constituents in different steps of nuclear mRNA export. These findings have laid the foundation for further studies to obtain a comprehensive mechanistic view of the mRNA export pathway.

中文翻译：

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核mRNA出口的机制：结构的角度。

mRNA从细胞核输出到细胞质是所有真核基因表达的关键过程。合成mRNA时，将其与无数的RNA结合蛋白包装在一起，形成核糖核蛋白颗粒（mRNPs）。对于成熟和输出过程中的每个步骤，mRNP必须具有正确的蛋白质补体。许多mRNA输出途径围绕异源二聚体出口受体酵母Mex67•Mtr2 /人NXF1•NXT1进行，该信号被征召来表示核mRNP组装的完成，介导mRNP靶向/通过核孔复合体（NPC）的转运。在NPC的细胞质侧转移，将mRNP释放到细胞质中。运输的方向性由至少两个DEAD-box ATPase决定，核中的酵母Sub2 / human UAP56和NPC胞质侧的酵母Dbp5 / human DDX19，分别介导Mex67•Mtr2 / NXF1•NXT1在mRNP上的缔合和解离。在这里，我们回顾了核mRNA出口不同步骤中关键成分的结构研究的最新进展。这些发现为进一步研究以获得mRNA输出途径的全面机理奠定了基础。