Mechanism of mRNA transport in the nucleus
Mechanism of mRNA transport in the nucleus
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DOI：
10.1073/pnas.0505580102
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发表时间：
2005-11-22
影响因子：
11.1
通讯作者：
Tyagi, S
中科院分区：
文献类型：
--
作者：
Vargas, DY;Raj, A;Tyagi, S
信使核糖核酸 - 蛋白质（mRNP）复合物从转录位点运输到核孔的机制一直是许多研究的主题。我们利用分子信标追踪活细胞中的单个信使核糖核酸分子，对细胞核中mRNP复合物的扩散进行了表征。mRNP复合物以布朗扩散的方式自由移动，其速度确保它们在进入细胞质之前能在细胞核内扩散，即使转录位点位于核周边附近也是如此。mRNP复合物的扩散局限于核仁外的染色质间空间。当mRNP复合物进入致密染色质时，它们往往会停滞。尽管mRNP复合物的移动不需要消耗代谢能，但在它们停滞之后，需要三磷酸腺苷（ATP）才能恢复运动。这一发现为许多关于信使核糖核酸运输似乎是一个酶促过程的观察结果提供了一种解释。
The mechanism of transport of mRNA-protein (mRNP) complexes from transcription sites to nuclear pores has been the subject of many studies. Using molecular beacons to track single mRNA molecules in living cells, we have characterized the diffusion of mRNP complexes in the nucleus. The mRNP complexes move freely by Brownian diffusion at a rate that assures their dispersion throughout the nucleus before they exit into the cytoplasm, even when the transcription site is located near the nuclear periphery. The diffusion of mRNP complexes is restricted to the extranucleolar, interchromatin spaces. When mRNP complexes wander into dense chromatin, they tend to become stalled. Although the movement of mRNP complexes occurs without the expenditure of metabolic energy, ATP is required for the complexes to resume their motion after they become stalled. This finding provides an explanation for a number of observations in which mRNA transport appeared to be an enzymatically facilitated process.