Protein-based condensation mechanisms drive the assembly of RNA-rich P granules

eLife

Helen Schmidt¹  Andrea Putnam¹  Geraldine Seydoux¹  Dominique Rasoloson¹ 

[1] HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States;

关键词: RNA granule;    intrinsically disordered protein;    phase separation;    germ plasm;    P granule;    C. elegans;   

DOI  :  10.7554/eLife.63698

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Germ granules are protein-RNA condensates that segregate with the embryonic germline. In Caenorhabditis elegans embryos, germ (P) granule assembly requires MEG-3, an intrinsically disordered protein that forms RNA-rich condensates on the surface of PGL condensates at the core of P granules. MEG-3 is related to the GCNA family and contains an N-terminal disordered region (IDR) and a predicted ordered C-terminus featuring an HMG-like motif (HMGL). We find that MEG-3 is a modular protein that uses its IDR to bind RNA and its C-terminus to drive condensation. The HMGL motif mediates binding to PGL-3 and is required for co-assembly of MEG-3 and PGL-3 condensates in vivo. Mutations in HMGL cause MEG-3 and PGL-3 to form separate condensates that no longer co-segregate to the germline or recruit RNA. Our findings highlight the importance of protein-based condensation mechanisms and condensate-condensate interactions in the assembly of RNA-rich germ granules.

【 授权许可】

CC BY