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bioRxiv · 10.1101/2020.10.15.340570

Coordination of RNA and protein condensation by the P granule protein MEG-3

Schmidt, H.·Putnam, A.·Rasoloson, D.·Seydoux, G.
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Abstract

Germ granules are RNA-protein condensates in germ cells. The mechanisms that drive germ granule assembly are not fully understood. MEG-3 is an intrinsically-disordered protein required for germ (P) granule assembly in C. elegans. MEG-3 forms gel-like condensates on liquid condensates assembled by PGL proteins. 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). Using in vitro and in vivo experiments, we find the MEG-3 C-terminus is necessary and sufficient to build MEG-3/PGL co-condensates independent of RNA. The HMGL domain is required for high affinity MEG-3/PGL binding in vitro and for assembly of MEG-3/PGL co-condensates in vivo. The MEG-3 IDR binds RNA in vitro and is required but not sufficient to recruit RNA to P granules. Our findings suggest that P granule assembly depends in part on protein-protein interactions that drive condensation independent of RNA.

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Schmidt, H., Putnam, A., Rasoloson, D., Seydoux, G.. 2020-10-15. Coordination of RNA and protein condensation by the P granule protein MEG-3. https://doi.org/10.1101/2020.10.15.340570

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