Sun Ming-Hong, Hu Lin-Lin, Zhao Chao-Ying, Lu Xiang, Ren Yan-Ping, Wang Jun-Li, Cui Xiang-Shun, Sun Shao-Chen
Department of Animal Sciences, Chungbuk National University, Cheongju, 28644, South Korea.
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
Cell Div. 2021 Jun 10;16(1):3. doi: 10.1186/s13008-021-00071-y.
Ral family is a member of Ras-like GTPase superfamily, which includes RalA and RalB. RalA/B play important roles in many cell biological functions, including cytoskeleton dynamics, cell division, membrane transport, gene expression and signal transduction. However, whether RalA/B involve into the mammalian oocyte meiosis is still unclear. This study aimed to explore the roles of RalA/B during mouse oocyte maturation.
Our results showed that RalA/B expressed at all stages of oocyte maturation, and they were enriched at the spindle periphery area after meiosis resumption. The injection of RalA/B siRNAs into the oocytes significantly disturbed the polar body extrusion, indicating the essential roles of RalA/B for oocyte maturation. We observed that in the RalA/B knockdown oocytes the actin filament fluorescence intensity was significantly increased at the both cortex and cytoplasm, and the chromosomes were failed to locate near the cortex, indicating that RalA/B regulate actin dynamics for spindle migration in mouse oocytes. Moreover, we also found that the Golgi apparatus distribution at the spindle periphery was disturbed after RalA/B depletion.
In summary, our results indicated that RalA/B affect actin dynamics for chromosome positioning and Golgi apparatus distribution in mouse oocytes.
Ral家族是Ras样GTP酶超家族的成员，包括RalA和RalB。RalA/B在许多细胞生物学功能中发挥重要作用，包括细胞骨架动力学、细胞分裂、膜运输、基因表达和信号转导。然而，RalA/B是否参与哺乳动物卵母细胞减数分裂仍不清楚。本研究旨在探讨RalA/B在小鼠卵母细胞成熟过程中的作用。
我们的结果表明，RalA/B在卵母细胞成熟的各个阶段均有表达，减数分裂恢复后它们富集于纺锤体周边区域。向卵母细胞中注射RalA/B的小干扰RNA（siRNAs）显著干扰了极体排出，表明RalA/B对卵母细胞成熟至关重要。我们观察到，在敲低RalA/B的卵母细胞中，皮质和细胞质中的肌动蛋白丝荧光强度均显著增加，并且染色体未能定位在皮质附近，这表明RalA/B调节肌动蛋白动力学以促进小鼠卵母细胞中的纺锤体迁移。此外，我们还发现RalA/B缺失后纺锤体周边的高尔基体分布受到干扰。
总之，我们的结果表明，RalA/B影响小鼠卵母细胞中染色体定位和高尔基体分布的肌动蛋白动力学。
