Liquid-liquid phase separation is emerging as the universal mechanism by which membraneless cellular granules form. Despite many previous studies on condensation of intrinsically disordered proteins and low complexity domains, we lack understanding about the role of RNA, which is the essential component of all ribonucleoprotein (RNP) granules. RNA, as an anionic polymer, is inherently an excellent platform for achieving multivalency and can accommodate many RNA binding proteins. Recent findings have highlighted the diverse function of RNA in tuning phase-separation propensity up or down, altering viscoelastic properties and thereby driving immiscibility between different condensates. In addition to contributing to the biophysical properties of droplets, RNA is a functionally critical constituent that defines the identity of cellular condensates and controls the temporal and spatial distribution of specific RNP granules. In this review, we summarize what we have learned so far about such roles of RNA in the context of in vitro and in vivo studies.

中文翻译：

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RNA小滴。

液相-液相分离作为无膜细胞颗粒形成的普遍机制正在兴起。尽管以前有许多关于固有紊乱蛋白和低复杂性结构域缩合的研究，但我们对RNA的作用仍缺乏了解，RNA是所有核糖核蛋白（RNP）颗粒的必需成分。RNA作为一种阴离子聚合物，天生就是实现多价的绝佳平台，并且可以容纳许多RNA结合蛋白。最近的发现强调了RNA在上调或下调相分离倾向，改变粘弹性质从而驱动不同冷凝物之间不混溶方面的多种功能。除了有助于液滴的生物物理特性外，RNA是功能上至关重要的成分，可定义细胞凝缩液的身份并控制特定RNP颗粒的时间和空间分布。在这篇综述中，我们总结了到目前为止在体外和体内研究中关于RNA的这种作用的知识。