Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
EMBO J. 2022 May 2;41(9):e110137. doi: 10.15252/embj.2021110137. Epub 2022 Mar 31.
Numerous membrane-less organelles, composed of a combination of RNA and proteins, are observed in the nucleus and cytoplasm of eukaryotic cells. These RNP granules include stress granules (SGs), processing bodies (PBs), Cajal bodies, and nuclear speckles. An unresolved question is how frequently RNA molecules are required for the integrity of RNP granules in either the nucleus or cytosol. To address this issue, we degraded intracellular RNA in either the cytosol or the nucleus by the activation of RNase L and examined the impact of RNA loss on several RNP granules. We find the majority of RNP granules, including SGs, Cajal bodies, nuclear speckles, and the nucleolus, are altered by the degradation of their RNA components. In contrast, PBs and super-enhancer complexes were largely not affected by RNA degradation in their respective compartments. RNA degradation overall led to the apparent dissolution of some membrane-less organelles, whereas others reorganized into structures with altered morphology. These findings highlight a critical and widespread role of RNA in the organization of several RNP granules.
真核细胞的核仁和细胞质中观察到许多由 RNA 和蛋白质组成的无膜细胞器。这些 RNP 颗粒包括应激颗粒 (SGs)、处理体 (PBs)、Cajal 体和核斑。一个悬而未决的问题是，在核或胞质溶胶中，RNA 分子对于 RNP 颗粒的完整性需要多频繁。为了解决这个问题，我们通过激活 RNase L 在细胞质或核中降解细胞内 RNA，并检查 RNA 丢失对几种 RNP 颗粒的影响。我们发现，大多数 RNP 颗粒，包括 SGs、Cajal 体、核斑和核仁，其 RNA 成分的降解都会改变。相比之下，PBs 和超级增强复合物在其各自的隔室中基本上不受 RNA 降解的影响。总体而言，RNA 降解导致一些无膜细胞器明显溶解，而其他细胞器则重新组织成形态改变的结构。这些发现强调了 RNA 在几种 RNP 颗粒的组织中的关键和广泛作用。
