Tap and NXT promote translation of unspliced mRNA
Tap and NXT promote translation of unspliced mRNA
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DOI：
10.1101/gad.1155703
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发表时间：
2003-12-15
影响因子：
10.5
通讯作者：
Hammarskjöld, ML
中科院分区：
文献类型：
--
作者：
Jin, L;Guzik, BW;Hammarskjöld, ML
已经提出Tap在一般mRNA输出中起作用，并且还在具有包含MPMV CTE（组成型转运元件）的保留内含子的RNA的表达中起作用。Tap与NXT/p15形成功能性异源二聚体。我们以前已经证明，未剪接的内含子含有CTE RNA被有效地输出到哺乳动物细胞的细胞质。在这里，我们表明，Tap和NXT蛋白一起发挥作用，以增强从出口CTE RNA的蛋白质的翻译。脉冲追踪实验表明，Tap/NXT显着增加蛋白质合成的速率。蔗糖梯度分析表明，Tap和NXT有效地将未剪接的RNA转移到多核糖体组分中。此外，在多聚核糖体中检测到Tap，而不是NXT。两者合计，我们的研究结果表明，Tap和NXT在RNA输出到细胞质后的翻译调节中起作用。他们进一步表明，Tap/NXT可能在细胞质RNP复合物的重塑中发挥作用，提供了输出途径和细胞质命运之间的联系。
Tap has been proposed to play a role in general mRNA export and also functions in expression of RNA with retained introns that contain the MPMV CTE (constitutive transport element). Tap forms a functional heterodimer with NXT/p15. We have previously demonstrated that unspliced intron-containing CTE RNA is efficiently exported to the cytoplasm in mammalian cells. Here we show that Tap and NXT proteins function together to enhance translation of proteins from the exported CTE RNA. Pulse chase experiments show that Tap/NXT significantly increases the rate of protein synthesis. Sucrose gradient analysis demonstrates that Tap and NXT efficiently shift the unspliced RNA into polyribosomal fractions. Furthermore, Tap, but not NXT is detected in polyribosomes. Taken together, our results indicate that Tap and NXT serve a role in translational regulation of RNA after export to the cytoplasm. They further suggest that Tap/NXT may play a role in remodeling of cytoplasmic RNP complexes, providing a link between export pathways and cytoplasmic fate.