Role of Greatwall kinase in release of mouse oocytes from diplotene arrest |
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Authors: | Xiangyu Zhao Dahai Yu Chen Feng Xin Deng Didi Wu Minglin Jin Enhua Wang Xiuxia Wang Bingzhi Yu |
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Institution: | 1. Department of Biochemical and Molecular Biology, China Medical University, , Shenyang, Liaoning Province, China;2. Institute of Pathology and Pathophysiology, China Medical University, , Shenyang, Liaoning Province, China;3. Department of Obstetrics and Gynecology, Shengjing Hospital affiliated to China Medical University, , Shenyang, Liaoning Province, China |
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Abstract: | In eukaryotes, mitosis entry is induced by activation of maturation‐promoting factor (MPF), which is regulated by a network of kinases and phosphatases. It has been suggested that Greatwall (GWL) kinase was crucial for the M‐phase entry and could maintain cyclin B–Cdc2 activity through regulation of protein phosphatase 2A (PP2A), a counteracting phosphatase of MPF. Here, the role of GWL was assessed during release of mouse oocytes from prophase I arrest. GWL was crucial for meiotic maturation in mouse oocytes. As a positive regulator for meiosis resumption, GWL was continually expressed in germinal vesicle (GV) and MII stage oocytes and two‐cell stage embryos. Additionally, GWL localized to the nucleus and dispersed into cytoplasm during GV breakdown (GVBD). Furthermore, downregulation of GWL or overexpression of catalytically‐inactive GWL inhibited partial meiotic maturation. This prophase I arrest induced by GWL depletion could be rescued by the PP2A inhibition. However, both GWL‐depleted and rescued oocytes had severe spindle defects that hardly reached MII. In contrast, oocytes overexpressing wild‐type GWL resumed meiosis and progressed to MII stage. Thus, our data demonstrate that GWL acts in a pathway with PP2A which is essential for prophase I exit and metaphase I microtubule assembly in mouse oocytes. |
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Keywords: | Greatwall maturation‐promoting factor meiotic maturation oocyte protein phosphatase |
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