Liquid-liquid phase separation (LLPS) is a mechanism of intracellular organization that underlies the assembly of a variety of RNP granules. Fundamental biophysical principles governing LLPS during granule assembly have been revealed by simple in vitro systems, but these systems have limitations when studying the biology of complex, multicomponent RNP granules. Visualization of RNP granules in cells has validated key principles revealed by simple in vitro systems, but this approach presents difficulties for interrogating biophysical features of RNP granules and provides limited ability to manipulate protein, nucleic acid, or small molecule concentrations. Here, we introduce a system that builds upon recent insights into the mechanisms underlying RNP granule assembly and permits high-fidelity reconstitution of stress granules and the granular component of nucleoli in mammalian cellular lysate. This system fills the gap between simple in vitro systems and live cells and allows for a variety of studies of membraneless organelles, including the development of therapeutics that modify properties of specific condensates.

中文翻译：

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哺乳动物细胞裂解液中应激颗粒和核仁的高保真重建。

液-液相分离（LLPS）是细胞内组织的机制，是多种RNP颗粒组装的基础。简单的体外系统已经揭示了在颗粒组装过程中支配LLPS的基本生物物理原理，但是当研究复杂的多组分RNP颗粒的生物学特性时，这些系统存在局限性。细胞中RNP颗粒的可视化已验证了简单的体外系统揭示的关键原理，但是这种方法在询问RNP颗粒的生物物理特征方面存在困难，并且操纵蛋白质，核酸或小分子浓度的能力有限。这里，我们介绍了一个系统，该系统基于对RNP颗粒组装的基本机制的最新见解，并允许对应激颗粒和哺乳动物细胞裂解物中核仁的颗粒成分进行高保真重构。该系统填补了简单的体外系统和活细胞之间的空白，并允许对无膜细胞器进行多种研究，包括开发可改变特定冷凝物特性的治疗剂。