GSE119977
RNA partitioning into stress granules is independent of G3BP
Stress granules (SGs) are stress induced RNA-protein assemblies formed from untranslating mRNPs.  Mammalian SGs are non-uniform and contain “cores”, which are stable in lysates and heterogenous in protein composition.  The interactions defining RNA recruitment into SGs, and whether the RNA composition varies between different cores remains unclear.  Herein, we determine the SG transcriptome through purification of both PABPC1 and G3BP SG cores during both arsenite and sorbitol stress.  We observe that similar RNAs are recruited to SGs independent of the protein used for core purification, suggesting individual RNA-binding proteins (RBPs) may play a limited role in defining the SG transcriptome. Analysis of the sorbitol-induced SG transcriptome reveals G3BP1/2 has little effect on RNAs recruited to SGs suggesting RNAs localize to SGs independent of individual RBPs.  Taken together, we suggest that partitioning of RNAs to SGs is independent of at least some proteins, consistent with SGs forming through intermolecular RNA-RNA interactions. Overall design: Stress granule core RNA was purified from U-2 OS cells via differential centrifugation and immunoprecipitation using a PABP antibody or GFP antibody (in the case of GFP-G3BP U-2OS cells).  In addition, we collected total cytoplasmic RNA (nuclei were spun out) from stressed and unstressed cells.  Stressed cells were either stressed with .5mM arsenite or .5M sorbitol.