Cyclin B3 is required for metaphase to anaphase transition in oocyte meiosis I

In this study, we explored the role of cyclin B3 in female meiosis by generating Ccnb3 mutant mice via CRISPR/Cas9. Ccnb3 mutant oocytes characteristically arrested at metaphase I (MetI) with normal spindle assembly and lacked enough anaphase-promoting complex/cyclosome (APC/C) activity, which is spindle assembly checkpoint (SAC) independent, to initiate anaphase I (AnaI). Securin siRNA or CDK1 inhibitor supplements rescued the MetI arrest. Furthermore, CCNB3 directly interacts with CDK1 to exert kinase function. Besides, the MetI arrest oocytes had normal development after intracytoplasmic sperm injection (ICSI) or parthenogenetic activation (PA), along with releasing the sister chromatids, which implies that Ccnb3 exclusively functioned in meiosis I, rather than meiosis II. Our study sheds light on the specific cell cycle control of cyclins in meiosis.

Source: Journal of Cell Biology - May 5, 2019 Category: Cytology Authors: Li, Y., Wang, L., Zhang, L., He, Z., Feng, G., Sun, H., Wang, J., Li, Z., Liu, C., Han, J., Mao, J., Li, P., Yuan, X., Jiang, L., Zhang, Y., Zhou, Q., Li, W. Tags: Cell Cycle and Division, Development Articles Source Type: research