SummarySynaptotagmin 1 (Syt1) is an abundant and important presynaptic vesicle protein that binds Ca2+ for the regulation of synaptic vesicle exocytosis. Our previous study reported its localization and function on spindle assembly in mouse oocyte meiotic maturation. The present study was designed to investigate the function of Syt1 during mouse oocyte activation and subsequent cortical granule exocytosis (CGE) using confocal microscopy, morpholinol-based knockdown and time-lapse live cell imaging. By employing live cell imaging, we first studied the dynamic process of CGE and calculated the time interval between [Ca2+]i rise and CGE after oocyte activation. We further showed that Syt1 was co-localized to cortical granules (CGs) at the oocyte cortex. After oocyte activation with SrCl2, the Syt1 distribution pattern was altered significantly, similar to the changes seen for the CGs. Knockdown of Syt1 inhibited [Ca2+]i oscillations, disrupted the F-actin distribution pattern and delayed the time of cortical reaction. In summary, as a synaptic vesicle protein and calcium sensor for exocytosis, Syt1 acts as an essential regulator in mouse oocyte activation events including the generation of Ca2+ signals and CGE.

中文翻译：

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突触结合蛋白 1 在小鼠卵母细胞激活过程中调节皮质颗粒胞吐作用

摘要突触结合蛋白 1 (Syt1) 是一种丰富且重要的突触前囊泡蛋白，可结合 Ca2+用于调节突触小泡胞吐作用。我们之前的研究报告了其在小鼠卵母细胞减数分裂成熟中纺锤体组装的定位和功能。本研究旨在使用共聚焦显微镜、基于吗啉的敲低和延时活细胞成像研究 Syt1 在小鼠卵母细胞活化和随后的皮质颗粒胞吐 (CGE) 过程中的功能。通过活细胞成像，我们首先研究了 CGE 的动态过程，并计算了 [Ca2+]i 在卵母细胞激活后上升和 CGE。我们进一步表明 Syt1 共定位于卵母细胞皮质的皮质颗粒 (CGs)。用 SrCl 激活卵母细胞后2，Syt1 分布模式发生了显着变化，类似于 CG 的变化。Syt1 的敲低抑制 [Ca2+]i 振荡，扰乱了 F-肌动蛋白分布模式并延迟了皮层反应的时间。总之，作为胞吐作用的突触小泡蛋白和钙传感器，Syt1 在小鼠卵母细胞激活事件中充当重要的调节因子，包括 Ca 的产生2+信号和 CGE。