Sequence-Independent Self-Assembly of Germ Granule mRNAs into Homotypic Clusters

Citation:

Trcek T, Douglas TE, Grosch M, Yin Y, Eagle WVI, Gavis ER, Shroff H, Rothenberg E, Lehmann R. Sequence-Independent Self-Assembly of Germ Granule mRNAs into Homotypic Clusters. Mol Cell 2020;

Date Published:

2020 May 20

ISSN:

1097-4164

Abstract:

mRNAs enriched in membraneless condensates provide functional compartmentalization within cells. The mechanisms that recruit transcripts to condensates are under intense study; however, how mRNAs organize once they reach a granule remains poorly understood. Here, we report on a self-sorting mechanism by which multiple mRNAs derived from the same gene assemble into discrete homotypic clusters. We demonstrate that in vivo mRNA localization to granules and self-assembly within granules are governed by different mRNA features: localization is encoded by specific RNA regions, whereas self-assembly involves the entire mRNA, does not involve sequence-specific, ordered intermolecular RNA:RNA interactions, and is thus RNA sequence independent. We propose that the ability of mRNAs to self-sort into homotypic assemblies is an inherent property of an messenger ribonucleoprotein (mRNP) that is augmented under conditions that increase RNA concentration, such as upon enrichment in RNA-protein granules, a process that appears conserved in diverse cellular contexts and organisms.

DOI:

10.1016/j.molcel.2020.05.008

Alternate Journal:

Mol. Cell