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

Publication Year
2020

Type

Journal Article
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.

Journal
Mol Cell
Volume
78
Issue
5
Pages
941-950.e12
Date Published
2020 Jun 04
ISSN Number
1097-4164
Alternate Journal
Mol Cell
PMCID
PMC7325742
PMID
32464092