Poster abstracts
Poster number 37 submitted by Ian Price
A new phase in germ granule biology: using a novel two-component system to interrogate the mechanisms of germ granule formation and localization in C. elegans
Ian F. Price (OSBP), Wen Tang (Biological Chemistry and Pharmacology)
Abstract:
Ribonucleoprotein condensates (RNPCs) are liquid-like membraneless organelles which are assembled by weak, multivalent protein-protein and protein-RNA interactions. RNPCs such as nucleoli, stress granules, and P bodies are involved in RNA processing and metabolisms. In animals, germ cells—which give rise to sperm and egg—invariably contain RNPCs called germ granules. Germ granules promote diverse cellular processes required for successful reproduction, from silencing of mobile genomic elements to transmission of maternal RNAs and epigenetic information to offspring. One remarkable feature of germ granules is the absolute conservation of their localization: from worms to mammals, germ granules localize to the nuclear periphery of germ cells. The mechanism of germ granule localization remains elusive, though previous reports in flies, mice, and nematodes demonstrated that proteins containing LOTUS domains, and conserved Vasa RNA helicases are required for germ granule localization. We recently identified a LOTUS domain protein in Caenorhabditis elegans required for germ granule localization, called EGGD-1/MIP-1. Uniquely, EGGD-1 forms perinuclear granules when expressed as a transgene in somatic cells. We find that C. elegans Vasa protein, GLH-1, is recruited to perinuclear granules when co-expressed with EGGD-1, representing a minimal two-component model for germ granules. This model presents a significant opportunity to understand how EGGD-1 and GLH-1 function together to localize germ granules, because genetic redundancy often obscures the impact of mutations in native germ granules. Our ongoing work leverages this model of C. elegans germ granules to determine how EGGD-1 and GLH-1 promote the formation of perinuclear granules using mutational analysis and fluorescence microscopy. Considering the conservation of LOTUS domain proteins and Vasa helicases, our findings will likely provide broad insight to the mechanism of germ granule localization.
Keywords: germ granules, condensates, C elegans