Stress granules are mRNA-protein assemblies formed from nontranslating mRNAs. Stress granules are important in the stress response and may contribute to some degenerative diseases. Here, we describe the stress granule transcriptome of yeast and mammalian cells through RNA-sequencing (RNA-seq) analysis of purified stress granule cores and single-molecule fluorescence in situ hybridization (smFISH) validation. While essentially every mRNA, and some noncoding RNAs (ncRNAs), can be targeted to stress granules, the targeting efficiency varies from <1% to >95%. mRNA accumulation in stress granules correlates with longer coding and UTR regions and poor translatability. Quantifying the RNA-seq analysis by smFISH reveals that only 10% of bulk mRNA molecules accumulate in mammalian stress granules and that only 185 genes have more than 50% of their mRNA molecules in stress granules. These results suggest that stress granules may not represent a specific biological program of messenger ribonucleoprotein (mRNP) assembly, but instead form by condensation of nontranslating mRNPs in proportion to their length and lack of association with ribosomes.

应力颗粒是由非翻译 mRNA 形成的 mRNA 蛋白组装体。应激颗粒在应激反应中很重要，可能导致一些退行性疾病。在这里，我们通过纯化应激颗粒核心的 RNA 测序 (RNA-seq) 分析和单分子荧光原位杂交 (smFISH) 验证来描述酵母和哺乳动物细胞的应激颗粒转录组。虽然基本上每个 mRNA 和一些非编码 RNA (ncRNA) 都可以靶向应激颗粒，但靶向效率从 <1% 到 >95% 不等。应激颗粒中的 mRNA 积累与较长的编码和 UTR 区域以及较差的可翻译性相关。通过 smFISH 对 RNA-seq 分析进行量化表明，只有 10% 的大量 mRNA 分子在哺乳动物应激颗粒中积累，并且只有 185 个基因的 mRNA 分子在应激颗粒中的占比超过 50%。这些结果表明，应力颗粒可能并不代表信使核糖核蛋白 (mRNP) 组装的特定生物学程序，而是通过非翻译 mRNP 与其长度成比例的缩合形成，并且与核糖体缺乏关联。