The Functional and Molecular Determinants of Stress-Induced Mrna Condensation

Stress-induced condensation of mRNA and protein into massive, heterogeneous clumps is widely conserved across eukarya, but the physiological mechanism of mRNA condensation and recruitment to the stress granules they mature into is unclear. The release of ribosome-free mRNA following stress-induced polysome collapse is thought to be the trigger of stress granule formation. Yet, coalescence of proteins into stress granules can be blocked without affecting protein condensation, raising the question: is the same true of mRNAs? Can we separate mRNA condensation from stress granule formation? Here, we show blocking translation initiation triggers specific mRNA condensation.