Proacrosin-acrosomal matrix binding interactions in ejaculated bovine spermatozoa.
Proacrosin-acrosomal matrix binding interactions in ejaculated bovine spermatozoa.
复制标题
射精牛精子中顶体素原-顶体基质结合相互作用。
DOI：
10.1095/biolreprod54.1.111
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发表时间：
1996
影响因子：
3.6
通讯作者：
Olson,GE
中科院分区：
文献类型：
--
作者：
NagDas,SK;Winfrey,VP;Olson,GE
哺乳动物精子顶体反应过程中水解酶释放的调控机制还不清楚。本研究表明，牛精子顶体基质的特定结构域的功能，以维持颗粒顶体酶原池和调节顶体酶原/顶体酶释放。在超声处理的精子悬浮液中，总顶体酶原活性的50-60%是可沉降的，并且可沉降的顶体酶原活性的量随时间保持不变。系列离心和再悬浮实验表明，颗粒顶体酶原部分导致从一个稳定的精子结构的顶体酶原的平衡结合。为了确定顶体的前顶体蛋白结合结构，在蔗糖密度梯度上分离纯化的精子头部部分。用Triton X-100提取精子头部，并在Percoll密度梯度上分离出均质顶体亚组分，即与顶体外膜（OMC）相关的基质复合物。然后使用离心测定来证明OMC以剂量依赖性方式特异性结合顶体蛋白原。这些数据表明，OMC代表了一个稳定的顶体结构组成部分，维持颗粒顶体酶原池。我们建议，OMC调节顶体反应过程中的顶体蛋白酶原的释放，并保持在精卵相互作用的网站顶体蛋白酶浓度升高。
The mechanisms regulating hydrolase release during the mammalian sperm acrosome reaction are poorly understood. The present study demonstrates that specific domains of the acrosomal matrix of bovine spermatozoa function to maintain a particulate proacrosin pool and to regulate proacrosin/acrosin release. In sonicated sperm suspensions, 50–60% of the total proacrosin activity was sedimentable, and the amount of sedimentable proacrosin activity remained unchanged over time. Serial centrifugation and resuspension experiments demonstrated that the particulate proacrosin fraction resulted from an equilibrium binding of proacrosin to a stable sperm structure. To identify the proacrosin-binding structure of the acrosome, a purified sperm head fraction was isolated on sucrose density gradients. The sperm heads were extracted with Triton X-100, and a homogeneous acrosomal subfraction, the matrix complex associated with the outer acrosomal membrane (OMC), was isolated on Percoll density gradients. A centrifugation assay was then used to demonstrate that the OMC specifically binds proacrosin in a dose-dependent manner. These data demonstrate that the OMC represents a stable structural component of the acrosome that maintains a particulate proacrosin pool. We propose that the OMC regulates proacrosin release during the acrosome reaction and maintains elevated acrosin concentrations at the site of sperm-egg interaction.