Acrosin Accelerates the Dispersal of Sperm Acrosomal Proteins during Acrosome Reaction*
Acrosin Accelerates the Dispersal of Sperm Acrosomal Proteins during Acrosome Reaction*
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DOI：
10.1074/jbc.273.17.10470
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发表时间：
1998-04
期刊：
影响因子：
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通讯作者：
K. Yamagata;Keitaro Murayama;M. Okabe;K. Toshimori;T. Nakanishi;S. Kashiwabara;T. Baba
中科院分区：
文献类型：
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作者：
K. Yamagata;Keitaro Murayama;M. Okabe;K. Toshimori;T. Nakanishi;S. Kashiwabara;T. Baba
利用同源重组，我们先前已经产生了在顶体酶基因中携带破坏性突变（Acr −/−）的雄性小鼠。尽管缺乏顶体酶蛋白酶活性的Acr −/−小鼠精子仍能穿透卵透明膜并使卵受精，但突变体精子仅在受精后的早期阶段表现出穿透卵透明膜的延迟。为了进一步阐明顶体酶在受精中的作用，我们用Acr −/−突变小鼠研究了顶体酶参与精子顶体反应的情况。当在体外评估精子粘附（附着）和结合无卵丘卵的透明膜的能力时，在Acr +/+、Acr +/−和Acr −/−小鼠精子之间没有观察到显著差异。免疫细胞化学分析表明，尽管膜泡形成正常，但在钙离子载体和增溶透明质酸诱导的顶体反应期间，Acr −/−小鼠精子顶体中几种顶体蛋白的释放显著延迟。这些数据表明，Acr-/-小鼠中精子穿透透明带的延迟是由于顶体蛋白质分散速率的改变造成的，并提供了第一个证据表明顶体酶的主要作用是加速顶体的分散顶体反应期间的组分。
Using homologous recombination, we have previously produced male mice carrying a disruptive mutation (Acr −/−) in the acrosin gene. AlthoughAcr −/− mouse sperm lacking the acrosin protease activity still penetrated the zona pellucida and fertilized the egg, the mutant sperm exhibited a delay in penetration of the zona pellucida solely at the early stages after insemination. To further elucidate the role of acrosin in fertilization, we have examined the involvement of acrosin in the acrosome reaction of sperm using theAcr −/− mutant mice. When the ability of sperm to adhere (attach) and bind to the zona pellucida of cumulus-free eggs was assessed in vitro, no significant difference was observed among Acr +/+,Acr +/−, and Acr −/−mouse sperm. Immunocytochemical analysis demonstrated that the release of several acrosomal proteins from the acrosome ofAcr −/− mouse sperm was significantly delayed during the calcium ionophore- and solubilized zona pellucida-induced acrosome reaction, despite normal membrane vesiculation. These data indicate that the delayed sperm penetration of the zona pellucida in the Acr −/− mouse results from the altered rate of protein dispersal from the acrosome and provide the first evidence that the major role of acrosin is to accelerate the dispersal of acrosomal components during acrosome reaction.