The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, 5290002, Israel.
Nat Commun. 2022 Oct 6;13(1):5881. doi: 10.1038/s41467-022-33572-7.
The changes occurring in mRNA organization during nucleo-cytoplasmic transport and export, are not well understood. Moreover, directionality of mRNA passage through the nuclear pore complex (NPC) has not been examined within individual NPCs. Here we find that an mRNP is compact during nucleoplasmic travels compared to a more open structure after transcription and at the nuclear periphery. Compaction levels of nuclear transcripts can be modulated by varying levels of SR proteins and by changing genome organization. Nuclear mRNPs are mostly rod-shaped with distant 5'/3'-ends, although for some, the ends are in proximity. The latter is more abundant in the cytoplasm and can be modified by translation inhibition. mRNAs and lncRNAs exiting the NPC exhibit predominant 5'-first export. In some cases, several adjacent NPCs are engaged in export of the same mRNA suggesting 'gene gating'. Altogether, we show that the mRNP is a flexible structure during travels, with 5'-directionality during export.
mRNA 在核质转运和输出过程中的结构变化尚不清楚。此外，mRNA 通过核孔复合物 (NPC) 的方向性尚未在单个 NPC 中进行检查。在这里，我们发现与转录后和核周相比，mRNP 在核质中旅行时更为紧凑。核转录本的压缩程度可以通过改变 SR 蛋白的水平和改变基因组组织来调节。核 mRNP 大多呈棒状，5'/3'-末端较远，尽管对于某些 mRNP，末端较近。后者在细胞质中更为丰富，并且可以通过翻译抑制来修饰。从 NPC 中输出的 mRNA 和 lncRNA 主要表现为 5'-端优先输出。在某些情况下，几个相邻的 NPC 参与同一 mRNA 的输出，表明“基因门控”。总的来说，我们表明 mRNP 在运输过程中是一种灵活的结构，在输出过程中具有 5'-方向性。
