CDC25B is involved in the centrosomal microtubule nucleation in two‐cell stage mouse embryos

CDC25B has been demonstrated to activate the complex of CDK1/Cyclin B and trigger mitosis. We have recently demonstrated that p‐CDC25B‐Ser351 is located at the centrosomes of mouse oocytes and contributes to the release of mouse oocytes from prophase I arrest. But much less is known about CDC25B function at the centrosome in two‐cell stage mouse embryos. Here we investigate the effect of CDC25B regulating the microtubules nucleation. Microinjection of anti‐CDC25B antibody caused aberrant microtubule nucleation. In addition, embryos injected with anti‐CDC25B antibody showed the marked absence of microtubule repolymerization and Nek2 foci after nocodazole washout. CDC25B overexpression caused microtubule‐organizing center (MTOC) overduplication. Moreover, overexpression of CDC25B–?65 mutant resulted in the loss of CDC25B localization in the perinuclear region and made CDC25B less efficient in inducing mitosis. We additionally identified that CDC25B is responsible for the pericentrin localization to the MTOC. Our data suggest an important role of CDC25B for microtubule nucleation and organization. N‐terminal of CDC25B is required for regulating the microtubule dynamics and mitotic function.