Psrc1 Ensures Proper Spindle Assembly and Chromosome Segregation During Mouse Oocyte Maturation

The proper assembly and migration of the spindle and the correct segregation of the chromosomes play a crucial role in oocyte quality. In somatic cells, Psrc1 regulates spindle dynamics and mitotic progression; however, its functions in oocyte meiosis have not been fully elucidated. This study aims to elucidate the functions of Psrc1 in mouse oocyte meiosis. To understand PSRC1's function, immunofluorescence staining was used to examine its location in the oocyte and to analyze phenotype after protein knockdown. Western blotting was used to examine the PSRC1 protein abundance. The treatment of oocytes with Taxol and nocodazole demonstrated that PSRC1 co-localizes with spindle microtubules. Psrc1 was knocked down by siRNA injection, and myc-Psrc1 mRNA was overexpressed via plasmid construction. In the current study, we demonstrated for the first time that PSRC1 is located at the poles of the spindle at all stages of mouse oocyte development. Knockdown of Psrc1 leads to abnormal spindle morphology, continuous activation of the spindle assembly checkpoint (SAC) protein, abnormal kinetochore-microtubule (K-M) attachments, and an increased aneuploidy rate. Surprisingly, either knockdown or overexpression of Psrc1 also causes abnormal spindle assembly and increases the rate of large polar bodies. To summarize, Psrc1 is essential for spindle assembly and chromosome segregation during mouse oocyte maturation.