美国怀特黑德生物医学研究所Ruth Lehmann团队近期取得重要工作进展，他们研究发现，核糖核蛋白（RNP）颗粒对翻译激活起到直接监管的作用。相关研究成果2024年7月4日在线发表于《自然—细胞生物学》杂志上。

据介绍，生物分子凝聚体在亚细胞水平上组织生物化学过程，并可以在细胞内提供时空调节。其中，核糖核蛋白（RNP）颗粒是翻译抑制mRNA的储存中心。RNP颗粒是否也能激活翻译以及如何实现这一点尚不清楚。

使用单分子成像，研究人员证明了果蝇胚胎中决定的生殖细胞是RNP颗粒是nanos mRNA活性翻译的场所。Nanos翻译优先发生在生殖颗粒表面，而3′UTR埋在颗粒内。Smaug是一种胞质RNA结合蛋白，它抑制nanos得翻译，当Smaug被支架蛋白Oskar封闭在生殖颗粒时，nanos翻译的抑制就会缓解。

总之，这一发现揭示了一个分子过程，RNP颗粒通过翻译抑制的区室化丧失来实现局部蛋白质合成的分子过程。

附：英文原文

Title: Direct observation of translational activation by a ribonucleoprotein granule

Author: Chen, Ruoyu, Stainier, William, Dufourt, Jeremy, Lagha, Mounia, Lehmann, Ruth

Issue&Volume: 2024-07-04

Abstract: Biomolecular condensates organize biochemical processes at the subcellular level and can provide spatiotemporal regulation within a cell. Among these, ribonucleoprotein (RNP) granules are storage hubs for translationally repressed mRNA. Whether RNP granules can also activate translation and how this could be achieved remains unclear. Here, using single-molecule imaging, we demonstrate that the germ cell-determining RNP granules in Drosophila embryos are sites for active translation of nanos mRNA. Nanos translation occurs preferentially at the germ granule surface with the 3′ UTR buried within the granule. Smaug, a cytosolic RNA-binding protein, represses nanos translation, which is relieved when Smaug is sequestered to the germ granule by the scaffold protein Oskar. Together, our findings uncover a molecular process by which RNP granules achieve localized protein synthesis through the compartmentalized loss of translational repression.

DOI: 10.1038/s41556-024-01452-5

Source: https://www.nature.com/articles/s41556-024-01452-5