近日，德国欧洲分子生物学实验室Duss Olivier团队报道了实时跟踪转录-翻译耦合。相关论文于2024年12月4日发表于国际顶尖学术期刊《自然》杂志上。

据悉，生物学的一个核心问题是大分子机器如何协同工作。在细菌中，转录和翻译发生在同一个细胞室中，并且可以在物理和功能上偶联。

尽管核糖体- RNA聚合酶（RNAP）复合物的高分辨率结构为耦合过程提供了初步的机制见解，但研究人员缺乏这些结构快照如何沿着动态反应轨迹放置的知识。

研究人员重建了一个完整和活跃的转录-翻译系统，并开展了多色单分子荧光显微镜实验，实时跟踪转录延伸、翻译延伸以及核糖体与RNAP之间的物理和功能耦合。他们的数据表明核糖体和RNAP之间的物理偶联，可以通过mRNA环在数百个核苷酸的干预mRNA中发生，这一过程由NthemG促进。

研究团队检测了mRNA环化过程中的主动转录延伸，并表明NusA暂停的RNAPs可以通过远程物理偶联被核糖体激活。相反，核糖体在与RNAP碰撞时减慢速度。因此，研究小组提供了另一种解释，说明核糖体如何有效地拯救RNAP免于频繁的路径化，而不需要与紧密尾随的核糖体碰撞。

总的来说，他们的动态数据在机制上突出了核糖体和RNAP这两个核心大分子，如何在物理和功能上合作以优化基因表达。

附：英文原文

Title: Tracking transcription–translation coupling in real time

Author: Qureshi, Nusrat Shahin, Duss, Olivier

Issue&Volume: 2024-12-04

Abstract: A central question in biology is how macromolecular machines function cooperatively. In bacteria, transcription and translation occur in the same cellular compartment, and can be physically and functionally coupled1,2,3,4. Although high-resolution structures of the ribosome–RNA polymerase (RNAP) complex have provided initial mechanistic insights into the coupling process5,6,7,8,9,10, we lack knowledge of how these structural snapshots are placed along a dynamic reaction trajectory. Here we reconstitute a complete and active transcription–translation system and develop multi-colour single-molecule fluorescence microscopy experiments to directly and simultaneously track transcription elongation, translation elongation and the physical and functional coupling between the ribosome and the RNAP in real time. Our data show that physical coupling between ribosome and RNAP can occur over hundreds of nucleotides of intervening mRNA by mRNA looping, a process facilitated by NusG. We detect active transcription elongation during mRNA looping and show that NusA-paused RNAPs can be activated by the ribosome by long-range physical coupling. Conversely, the ribosome slows down while colliding with the RNAP. We hereby provide an alternative explanation for how the ribosome can efficiently rescue RNAP from frequent pausing without requiring collisions by a closely trailing ribosome. Overall, our dynamic data mechanistically highlight an example of how two central macromolecular machineries, the ribosome and RNAP, can physically and functionally cooperate to optimize gene expression.

DOI: 10.1038/s41586-024-08308-w

Source: https://www.nature.com/articles/s41586-024-08308-w