The Effect of Small Ubiquitin-Related Modifier Modification of Aurora B on Meiosis in Mice Oocytes

Abstract

Background: Aurora B is one of the spindle assembly checkpoint proteins. It plays a crucial role in the regulation of mammalian female mitosis and meiosis. In this study, we examined the mechanism of small ubiquitin-related modifier modification (SUMOylation) of Aurora B on the chromosome arrangement of mice oocytes. Methods: Oocytes were randomly divided into three groups: Control group, AuroraB_K207R group, and the small ubiquitin-related modifier (SUMO) inhibitor group. The number of oocytes that developed at 2.5, 8, and 14 h were counted. Metaphase II (MII) oocytes in each group were selected for observing the arrangement of chromosomes and spindles. Meanwhile, MII oocytes in the control and AuroraB_K207R groups were collected for use in the Smart-seq2 protocol. Results: Messenger ribonucleic acid (mRNA) was obtained from the AuroraB_K207R group via the transcription of a linearized pMD 18T-T7-AuroraB_K207R plasmid. The proportion of metaphase I (MI) oocytes after 8 h in the SUMO inhibitor group was significantly lower than in the AuroraB_K207R and control groups (p < 0.05). The MII oocytes in the AuroraB_K207R and SUMO inhibitor groups decreased significantly compared with the control group after 14 h (p < 0.05). Furthermore, the rate of abnormal chromosome arrangement in the AuroraB_K207R and SUMO inhibitor groups increased significantly compared with the control group (p < 0.05). Using Smart-seq2, a total of 3288 differentially expressed genes were identified;2874 of these genes involving Aurora B were upregulated and 414 genes were downregulated in the AuroraB_K207R group. Conclusions: Small ubiquitin-related modifier modifications may directly affect the regulatory function of Aurora B on chromosome arrangement in mice oocyte meiosis, leading to oocyte maturation disorder. Therefore, the SUMOylation of Aurora B plays an important role in chromosome arrangement in mice oocyte meiosis.