Mouse oocytes organize mRNA–protein assemblies and ER-associated translation hubs to drive meiosis
Year: 2026
Type: preprint
Abstract: Oocyte meiosis in animals is essential for producing fertilizable eggs. As transcription becomes largely quiescent, meiotic progression depends on temporally regulated translation of accumulated maternal mRNAs. However, the underlying mechanisms remain unclear. Here, we identified diverse and highly organized mRNA–protein assemblies in mouse oocytes that coordinate cytoplasmic mRNA regulation and enable spatiotemporal translation to drive oocyte meiosis. Twelve RNA-binding proteins (RBPs), including DDX4/VASA, HDLBP/Vigilin, and TDRD3, were assembled into widely distributed aggregates in germinal vesicle (GV)-stage oocytes. We depleted DDX4 and HDLBP using “Trim-Away” and found that these RBPs regulate the precise assembly of RNA granules and protein aggregates through distinct mechanisms, promoting temporal protein synthesis at cortical translation factories with the endoplasmic reticulum, termed CORTE. All 12 RBPs formed distinct mRNA–protein assemblies, whose size and distribution changed upon meiotic initiation. These findings reveal the molecular basis of spatiotemporal mRNA–protein–organelle networks underlying animal reproduction and development.
Institution: Hokkaido University
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
Awards: A study to understand oogenesis and early development through phase transition of molecules, G3501255619, Analysis of temporal and spatial control of mRNA translation that is mediated by subcellular structures and novel RNA processing, Analysis of the molecular mechanism regulating temporal and spatial mRNA translation that is mediated by novel RNA processing and phase transition
OpenAlex ID: W7221069188