RNA granules are mesoscale assemblies that form in the absence of limiting membranes. RNA granules contain factors for RNA biogenesis and turnover and are often assumed to represent specialized compartments for RNA biochemistry. Recent evidence suggests that RNA granules assemble by phase separation of subsoluble ribonucleoprotein (RNP) complexes that partially demix from the cytoplasm or nucleoplasm. We explore the possibility that some RNA granules are nonessential condensation by-products that arise when RNP complexes exceed their solubility limit as a consequence of cellular activity, stress, or aging. We describe the use of evolutionary and mutational analyses and single-molecule techniques to distinguish functional RNA granules from “incidental condensates.”

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RNA 颗粒：功能区室还是偶然的凝聚物？

RNA 颗粒是在没有限制膜的情况下形成的中尺度组装体。RNA 颗粒含有 RNA 生物发生和周转的因子，通常被认为代表 RNA 生物化学的专门区室。最近的证据表明，RNA 颗粒是通过亚溶性核糖核蛋白 (RNP) 复合物的相分离来组装的，该复合物部分地从细胞质或核质中分离出来。我们探讨了一些 RNA 颗粒可能是非必需的缩合副产物，当 RNP 复合物由于细胞活动、压力或衰老而超过其溶解度极限时，就会产生这种副产物。我们描述了如何使用进化和突变分析以及单分子技术来区分功能性 RNA 颗粒和“偶然凝聚物”。