Redistribution and increase in cortical inositol 1,4,5-trisphosphate receptors after meiotic maturation of the mouse oocyte
Redistribution and increase in cortical inositol 1,4,5-trisphosphate receptors after meiotic maturation of the mouse oocyte
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DOI：
10.1006/dbio.1996.0322
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发表时间：
1996-12-15
影响因子：
2.7
通讯作者：
Kline, D
中科院分区：
文献类型：
--
作者：
Mehlmann, LM;Mikoshiba, K;Kline, D
小鼠卵母细胞在成熟过程中对1，4，5-三磷酸肌醇（IP 3）产生敏感性。我们最近报道，卵母细胞成熟过程中内质网（ER）组织的变化可能有助于这种增强的敏感性（Mehlmann et al.，1995年，德夫。170，607-615）。在这里，我们研究了成熟后可用的IP 3受体的数量是否增加，以及是否存在与成熟过程中发生的ER重新分布类似的IP 3受体重新分布。卵母细胞和卵子中IP 3受体的Western印迹分析表明，卵母细胞成熟后IP 3受体的免疫反应质量增加了1.8倍。显微注射功能阻断单克隆抗体18 A10以浓度依赖性方式抑制卵和卵母细胞中IP 3诱导的Ca 2+释放。更多的抗体需要抑制钙释放到相同程度的卵母细胞相比，当两者都注射了相同浓度的IP 3，这表明鸡蛋含有更多的功能IP 3受体。IP 3受体的免疫定位显示，受体存在于大集群，1-2 μ m的直径，在皮质的成熟卵除了在一个环形带的皮质邻近减数分裂纺锤体。相比之下，受体簇位于未成熟卵母细胞的整个皮质周围，并且要小得多（
Mouse oocytes develop sensitivity to inositol 1, 4, 5-trisphosphate (IP3) during oocyte maturation. We recently reported that a change in the organization of the endoplasmic reticulum (ER) during oocyte maturation may contribute to this enhanced sensitivity (Mehlmann et al., 1995, Dev. Biol. 170, 607-615). Here, we investigated whether there is an increase in the number of available IP3 receptors after maturation and whether there is a redistribution of IP3 receptors similar to the redistribution of the ER that occurs during maturation. Western blot analysis of the IP3 receptor in oocytes and eggs demonstrated a 1.8-fold increase in immunoreactive mass of the IP3 receptor following oocyte maturation. Microinjection of the function-blocking monoclonal antibody 18A10 inhibited IP3-induced Ca2+ release in a concentration-dependent manner in both eggs and oocytes. More antibody was required to inhibit Ca2+ release to the same extent in eggs compared to oocytes when both were injected with the same concentration of IP3, suggesting that eggs contain a greater number of functional IP3 receptors. Immunolocalization of the IP3 receptor revealed that receptors were present in large clusters, 1-2 mu m in diameter, in the cortex of the mature egg except in a ring-shaped band of cortex adjacent to the meiotic spindle. In contrast, receptor clusters were located around the entire cortex of the immature oocyte and were much smaller (