Evidence that phospholipase C from the sperm is not responsible for initiating Ca(2+) release at fertilization in mouse eggs.
Evidence that phospholipase C from the sperm is not responsible for initiating Ca(2+) release at fertilization in mouse eggs.
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DOI：
10.1006/dbio.2001.0329
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发表时间：
2001-08
影响因子：
2.7
通讯作者：
L. Mehlmann;A. Chattopadhyay;G. Carpenter;L. Jaffe
中科院分区：
文献类型：
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作者：
L. Mehlmann;A. Chattopadhyay;G. Carpenter;L. Jaffe
哺乳动物卵子受精时，胞内Ca（2+）的释放是由三磷酸肌醇（IP 3）介导的，但精子启动IP 3产生的机制尚不清楚。我们测试了这样一个假设，即磷脂酶C（PLC）的活性引入到小鼠卵子作为精卵融合的结果是负责引起Ca（2+）的释放。我们证明，将纯化的重组PLC γ 1蛋白显微注射到小鼠卵子中会引起Ca（2+）振荡，就像在受精时看到的那样。然而，当注射到卵子中时，引起Ca（2+）释放所需的最小量的纯化PLC γ 1蛋白中的PLC活性大约是单个精子中所含PLC活性的500-900倍。这表明单个小鼠精子不包含足够的PLC活性来负责引起受精时的Ca（2+）释放。我们还研究了磷脂酰肌醇3-激酶（PI 3 K）是否在这一过程中发挥作用，并发现PI 3 K介导的信号传导的几种抑制剂对受精时的Ca（2+）释放没有影响。
Release of Ca(2+) from intracellular stores at fertilization of mammalian eggs is mediated by inositol 1,4,5-trisphosphate (IP3), but the mechanism by which the sperm initiates IP3 production is not yet understood. We tested the hypothesis that phospholipase C (PLC) activity introduced into the mouse egg as a consequence of sperm-egg fusion is responsible for causing Ca(2+) release. We demonstrated that microinjecting purified, recombinant PLCgamma1 protein into mouse eggs caused Ca(2+) oscillations like those seen at fertilization. However, the PLC activity in the minimum amount of purified PLCgamma1 protein needed to elicit Ca(2+) release when injected into eggs was approximately 500-900 times the PLC activity contained in a single sperm. This indicates that a single mouse sperm does not contain enough PLC activity to be responsible for causing Ca(2+) release at fertilization. We also examined whether phosphatidylinositol 3-kinase (PI3K) could have a role in this process, and found that several inhibitors of PI3K-mediated signaling had no effect on Ca(2+) release at fertilization.