Mitochondrial fission process 1 is required for bovine oocyte maturation through regulation of mitochondrial function and dynamics.

Oocyte maturation is a complex process that is regulated by a variety of factors. Mitochondria are a key factor affecting oocyte maturation in vitro. Mitochondrial fission process 1 (MTFP1) is located on the inner mitochondrial membrane and mediates the fission of this membrane. However, the role and mechanism of MTFP1 in bovine oocyte maturation are still unclear. Therefore, we performed siRNA-mediated MTFP1 knockdown during in vitro maturation of bovine oocytes and assessed its effects on oocyte maturation as well as mitochondrial function and dynamics. We found that MTFP1 is expressed at all stages of bovine oocyte maturation. Moreover, MTFP1 knockdown decreased oocyte maturation efficiency. These observations, combined with our transcriptome sequencing results, showed that MTFP1 knockdown caused mitochondrial dysfunction, impaired nuclear and cytoplasmic maturation, promoted mitochondrial fusion, induced mitophagy and decreased oocyte apoptosis. In summary, the inner mitochondrial membrane protein MTFP1 plays a crucial role in bovine oocyte maturation. The results provide a reference and theoretical basis for improving the quality of in vitro oocyte maturation and breeding efficiency in beef cattle.