Stress Granules and FUS condensates recruit functionally distinct sets of RNAs

Abstract

Cellular homeostasis relies on the organization of RNA and protein into membrane-less organelles. Stress granules (SGs) are well-known hubs for translational repression during cellular stress. Similar condensates formed by RNA-binding proteins such as FUS-- mutations in which cause amyotrophic lateral sclerosis (ALS)--remain poorly characterized relative to canonical SGs. Here, we develop Granule-seq, a microcapillary-based granule-resolved RNA sequencing approach, and demonstrate that SGs and FUS condensates are functionally distinct RNA compartments rather than variants of a unified granule class. Granules were individually aspirated, analyzed in small pooled sets, and validated through overlap with known SG components (794/2,759 genes, 28.8%, p View larger version (55K): org.highwire.dtl.DTLVardef@1378da9org.highwire.dtl.DTLVardef@35906borg.highwire.dtl.DTLVardef@9c7880org.highwire.dtl.DTLVardef@ab3b9d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic abstract.C_FLOATNO Granule-seq workflow and key findings.(Left) Individual cytoplasmic granules are isolated by microcapillary aspiration, pooled ([~]10 granules per replicate), and processed for RNA sequencing alongside total-cell input. (Middle) Venn diagram showing the overlap between FUS condensate-enriched (1,334 genes) and G3BP1 stress granule-enriched (2,759 genes) transcripts. FUS condensates preferentially recruit neuronal and synaptic transcripts; G3BP1 stress granules are enriched for stress-response and proteostasis transcripts. (Right) Two-step recruitment model: shared sequence features (long 3'UTR, GC-rich composition, stable RNA structure) provide permissiveness for granule entry (Step 1), while RBP interactome composition and functional context determine granule-type specificity (Step 2). C_FIG