MATR3 is essential for oocyte growth and maturation quality through a dual molecular mechanism

The study examines the significance of Matrin-3 (MATR3), a protein abundantly found in growing oocytes, in the oocyte growth and maturation process. Researchers utilized mouse models with oocyte-specific knockout of MATR3 and human oocyte maturation arrest (OMA) samples to investigate its role.

MATR3 was found to be more abundant in growing oocytes compared to fully grown ones. It was also highly expressed in the nucleus of non-surrounded nucleolus (NSN) oocytes and moved out of the nucleus during the transition from NSN to surrounded nucleolus (SN) stage. In OMA patients, MATR3 was not found to localize inside the nucleus, and the oocytes were smaller than in females with normal maturation.

Deleting MATR3 in mouse growing oocytes led to restricted growth, global transcription disorders, failure in follicle development, blocked communication between growing oocytes and granulosa cells (due to reduced Gdf9 and Rdx expression), and infertility. Mechanistically, MATR3 regulated transcription by recruiting a protein called H3K9me2-demethylase 3B or binding to target gene promoters, including Rdx.

These findings underscore the crucial role of MATR3 in coordinating transcription and paracrine signaling during oogenesis. The research suggests that MATR3 could potentially serve as a diagnostic and therapeutic target for OMA.