Understanding the dynamics of RNA targeting to membraneless organelles is essential to disentangle their functions. Here, we investigate how P-bodies (PBs) evolve during cell cycle progression. PB purification at different cell cycle phases uncovers widespread changes in their RNA content. Importantly, these changes are partly uncoupled from cell cycle-dependent changes in RNA expression. Single molecule FISH shows various mRNA localization patterns in PBs peaking in G1, S, or G2, with multiple examples illustrating the timely capture of mRNAs in PBs when their encoded protein becomes dispensable. Cyclic mRNA localization in PBs does not directly reflect their non-polysomal pool. While mRNA localization in PBs is tightly linked to their GC content at all cell cycle phases, PB mRNAs are specifically longer in G1. Altogether, our study supports a model where PBs are more than a default location for excess untranslated mRNAs and suggests an RNA-mediated seeding mechanism for post-mitotic PB reassembly.

中文翻译：

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P 体中细胞周期依赖性 mRNA 定位

了解 RNA 靶向无膜细胞器的动力学对于解开它们的功能至关重要。在这里，我们研究 P 体 (PB) 在细胞周期进展过程中如何进化。不同细胞周期阶段的 PB 纯化揭示了其 RNA 含量的广泛变化。重要的是，这些变化部分与细胞周期依赖性 RNA 表达变化无关。单分子 FISH 显示了 PB 中各种 mRNA 定位模式，在 G1、S 或 G2 中达到峰值，多个例子说明当 PB 中的 mRNA 编码的蛋白质变得可有可无时，及时捕获 PB 中的 mRNA。 PB 中的环状 mRNA 定位并不直接反映其非多聚体库。虽然 PB 中 mRNA 的定位与所有细胞周期阶段的 GC 含量密切相关，但 PB mRNA 在 G1 期特别更长。总而言之，我们的研究支持一个模型，其中 PB 不仅仅是过量未翻译 mRNA 的默认位置，并提出了一种 RNA 介导的有丝分裂后 PB 重新组装的播种机制。