2024 Gruber Science Fellowship Lecture: "In vivo observation of condensate-mediated translation in germ granules"

Biomolecular condensates organize biochemical processes within cells. In general, cytoplasmic ribonucleoprotein (RNP) granules have been characterized as storage depots for translationally repressed mRNA. Whether RNP granules can also activate translation had remained unclear. The embryonic, germ cell-determining RNP granules in Drosophila have been correlated genetically with the localization and activation of mRNAs required for germ cell specification and fate. We have used in vivo imaging of translation at the single-molecule level to show directly that germ granules are the sites of active translation for granule-localized mRNAs. I will discuss how changes in the 5’-3’organization of mRNA molecules within granules are linked to their translation status and how regulatory processes controlled by granule proteins achieve localized protein synthesis through the compartmentalized relief of translational repression.