KIF2A regulates the spindle assembly and the metaphase I-anaphase I transition in mouse oocyte

Ming-Huang Chen,Fei-Ping Li,Yan-Hong Lin,Yu Liu,Lin Xu,Rui Liu,Xiao-Xue Wang,Hai-Long Wang,Xian-Pei Fu,Shu-Wen He,Bai-Hui Xu,Ya-Long Wang,Xiang-Jun Yang,Fei Zhang,Bao-Qiong Liao

doi:10.1038/srep39337

Abstract

KIF2A, a member of the kinesin-13 family, has been reported to play a role in spindle assembly in mitosis. However, its function in mammalian meiosis remains unknown. In this research, we examined the expression, localization and function of KIF2A during mouse oocyte meiosis. KIF2A was expressed in some key stages in mouse oocyte meiosis. Immunofluorescent staining showed that KIF2A distributed in the germinal vesicle at the germinal vesicle stage and as the spindle assembling after meiosis resumption, KIF2A gradually accumulated to the entire spindle. The treatment of oocytes with taxol and nocodazole demonstrated that KIF2A was co-localized with α-tubulin. Depletion of KIF2A by specific short interfering (si) RNA injection resulted in abnormal spindle assembly, failure of spindle migration, misaligned chromosomes and asymmetric cell division. Meanwhile, SKA1 expression level was decreased and the TACC3 localization was disrupted. Moreover, depletion of KIF2A disrupted the actin cap formation, arrested oocytes at metaphase I with spindle assembly checkpoint protein BubR1 activated and finally reduced the rate of the first polar body extrusion. Our data indicate that KIF2A regulates the spindle assembly, asymmetric cytokinesis and the metaphase I-anaphase I transition in mouse oocyte.

Highlights

In mammalian oocytes, meiosis is a crucial event for the success of keeping genomic stability
Oocytes were cultured for 0 h, 2 h, 6.5 h, 8.5 h, 10 h and 12 h, corresponding to most oocytes had reached germinal vesicle (GV), germinal vesicle breakdown (GVBD), pro-metaphase I (Pro-MI), metaphase I (MI), anaphase-telophase I (ATI) and metaphase II (MII), respectively
KIF2A immunofluorescent staining was used to investigate the subcellular localization of KIF2A at different stages of meiotic maturation in mouse oocytes

Summary

Introduction

Meiosis is a crucial event for the success of keeping genomic stability. In contrast to the mitosis, the division in mammalian oocytes maturation is highly asymmetric giving rise to a large and highly polarized oocyte and a tiny polar body. This process plays a critical role in female meiosis to ensure that most of the maternal components can be retained within the oocyte for the early embryo development[2]. The kinesin-13 proteins, one branch of KIFs, are the important regulators in microtubule dynamics during mitosis[18]. Our results demonstrate that KIF2A regulates the spindle assembly, asymmetric cytokinesis and metaphase I-anaphase I transition in mouse oocyte

Methods

Results

Conclusion