Protein phosphatase 2A regulatory subunit B55α functions in mouse oocyte maturation and early embryonic development

Protein phosphatase 2A regulatory subunit B55 alpha (PP2A-B55 alpha) has been studied in mitosis. However, its functions in mammalian meiosis and early embryonic development remain unknown. Here, we report that PP2A-B55 alpha is critical for mouse oocyte meiosis and preimplantation embryo development. Knockdown of PP2A-B55 alpha in oocytes led to abnormal asymmetric division, disordered spindle dynamics, defects in chromosome congression, an increase in aneuploidy, and induction of the DNA damage response. Moreover, knockdown of PP2A-B55 alpha in fertilized mouse zygotes impaired development to the blastocyst stage. The impairment of embryonic development might have been due to induction of sustained DNA damage in embryos, which caused apoptosis and inhibited cell proliferation and outgrowth potential at the blastocyst stage. Overall, these results provide a novel insight into the role of PP2A-B55 alpha as a novel meiotic and embryonic competence factor at the onset of life.