TAP binds to the constitutive transport element (CTE) through a novel RNA-binding motif that is sufficient to promote CTE-dependent RNA export from the nucleus
TAP binds to the constitutive transport element (CTE) through a novel RNA-binding motif that is sufficient to promote CTE-dependent RNA export from the nucleus
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DOI：
10.1093/emboj/18.7.1953
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发表时间：
1999-04-01
期刊：
影响因子：
11.4
通讯作者：
Izaurralde, E
中科院分区：
文献类型：
--
作者：
Braun, IC;Rohrbach, E;Izaurralde, E
猴D型逆转录病毒的组成型转运元件（CTE）通过招募TAP克服核滞留并使未剪接的病毒RNA能够从核输出，TAP是一种被认为是细胞mRNA输出所必需的宿主因子。在本报告中，我们表明TAP的前372个氨基酸残基（包含一段富含亮氨酸的重复序列）对于与CTE RNA结合并促进其输出到细胞质既是必需的也是充分的。此外，与全长蛋白一样，该结构域在与CTE RNA共同核注射时会迁移到细胞质。总之，这些结果表明CTE结合结构域包含核输出的信号。我们还描述了一种TAP的衍生物，其在CTE结合结构域内具有三个氨基酸的替换，并显著减少了mRNA从核的输出。这为TAP在这一过程中的作用提供了进一步的证据。因此，TAP的CTE结合结构域定义了一种新的RNA结合基序，它具有双重功能，既识别CTE RNA又与核转运机制的其他成分相互作用。
The constitutive transport element (CTE) of the simian type D retroviruses overcomes nuclear retention and allows nuclear export of unspliced viral RNAs by recruiting TAP, a host factor which is thought to be required for export of cellular mRNAs, In this report, we show that the first 372 amino acid residues of TAP, comprising a stretch of leucine-rich repeats, are both necessary and sufficient for binding to the CTE RNA and promoting its export to the cytoplasm, Moreover, like the full-length protein, this domain migrates to the cytoplasm upon nuclear co-injection with the CTE RNA. Together, these results indicate that the CTE-binding domain includes the signals for nuclear export. We also describe a derivative of TAP that bears a triple amino acid substitution within the CTE-binding domain and substantially reduces the export of mRNAs from the nucleus. This provides further evidence for a role for TAP in this process. Thus, the CTE-binding domain of TAP defines a novel RNA-binding motif which has dual functions, both recognizing the CTE RNA and interacting with other components of the nuclear transport machinery.