RNA export mediated by Tap involves NXT1-dependent interactions with the nuclear pore complex
RNA export mediated by Tap involves NXT1-dependent interactions with the nuclear pore complex
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DOI：
10.1074/jbc.m106558200
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发表时间：
2001-11-30
影响因子：
4.8
通讯作者：
Paschal, BM
中科院分区：
文献类型：
--
作者：
Lévesque, L;Guzik, B;Paschal, BM
核糖核蛋白复合物的核输出需要顺式作用信号和受体的识别，介导通过核孔复合物的易位。易位可能涉及核糖核蛋白复合物和核孔复合物内的核孔蛋白之间的一系列物理相互作用。 Here, we have characterized the function of NXT1 in the context of the Tap-dependent RNA export pathway. Tap 与源自梅森-辉瑞猴病毒的 RNA 转录本的核输出有关，这些转录本含有组成型转运元件。我们证明NXT1在体外刺激Tap-RNA复合物与核孔蛋白的结合，并且我们提供的突变分析表明这些相互作用对于体内含内含子的病毒mRNA的核输出是必要的。 Tap 包含用于与核孔蛋白和 NXT1 结合的单独结构域，这两者对其输出功能至关重要。 RNA 输出由 Tap 和 NXT1 的异二聚体介导，NXT1 在该途径中的功能是调节 Tap-RNA 复合物与核孔复合物内核孔蛋白的亲和力。我们提出，Tap-RNA 复合物与核孔蛋白 p62 的 NXT1 依赖性结合（我们使用重组蛋白在体外重建了核孔蛋白 p62）代表了易位反应的一步。
Nuclear export of ribonucleoprotein complexes requires cis-acting signals and recognition by receptors that mediate translocation through the nuclear pore complex. Translocation is likely to involve a series of physical interactions between the ribonucleoprotein complex and nucleoporins within the nuclear pore complex. Here, we have characterized the function of NXT1 in the context of the Tap-dependent RNA export pathway. Tap has been implicated in the nuclear export of RNA transcripts derived from Mason-Pfizer monkey virus that contain the constitutive transport element. We demonstrate that NXT1 stimulates binding of a Tap-RNA complex to nucleoporins in vitro, and we provide mutational analysis that shows these interactions are necessary for nuclear export of an intron-containing viral mRNA in vivo. Tap contains separate domains for binding to nucleoporins and NXT1, both of which are critical for its export function. RNA export is mediated by a heterodimer of Tap and NXT1, and the function of NXT1 on this pathway is to regulate the affinity of the Tap-RNA complex for nucleoporins within the nuclear pore complex. We propose that NXT1-dependent binding of the Tap-RNA complex to the nucleoporin p62, which we have reconstituted in vitro using recombinant proteins, represents a single step of the translocation reaction.