Cell cycle-dependent mRNA localization in P-bodies

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. Highlights ### Competing Interest Statement The authors have declared no competing interest.