摘要
A typical ejaculate contains more than 100 million spermatozoa; however, only 1 spermatozoon participates in fertilization. There might be an ingenious molecular mechanism to ensure that a spermatozoon fertilizes an egg. Recent gene disruption experiments in mice have revealed that there are two key factors in the sperm–egg fusion process. CD9 on eggs and IZUMO1 on spermatozoa have emerged as indispensable factors. However, the molecular mechanism of sperm–egg fusion, that is, how and when sperm–egg fusion occurs, remains virtually unknown. We have recently reported the dynamics of redistribution of IZUMO1 during the acrosome reaction using red fluorescent protein-tagged IZUMO1 for live imaging of the moment of sperm–egg fusion. Consequentially, the result suggests that IZUMO1 diffused from the acrosomal membrane to the sperm surface in the equatorial segment, which is considered to initiate fusion with the oocyte; fusion takes place after the acrosome reaction. This was the first evidence for live imaging to monitor the fusion-related protein at sperm–egg fusion.
摘要译文
一个典型的射精含有100多万的精子;然而，只有1精子参与受精。有可能是一个巧妙的分子机制，以确保精子的受精鸡蛋。在小鼠中最近的基因破坏实验已经表明，存在两个关键因素精卵融合过程。CD9对鸡蛋和IZUMO1对精子已经成为不可缺少的因素。然而，精卵融合的分子机制，即如何以及何时精卵融合发生时，仍然几乎一无所知。我们最近报告了使用红色荧光蛋白标记的IZUMO1用于精卵融合的时刻实时成像顶体反应中IZUMO1再分配的动态。必然，结果表明，IZUMO1从顶体膜在赤道段，这被认为是引发融合的卵母细胞，精子表面扩散;顶体反应后的融合发生。这是第一个证据实时成像以监测在精卵融合的融合相关的蛋白质。
Naokazu Inoue (4). The Mechanism of Sperm–Egg Fusion in Mouse and the Involvement of IZUMO1. Sexual Reproduction in Animals and Plants [M].DE: Springer, 2014: 393-399