Animal, Dairy and Veterinary Sciences Department, and Center for Integrated BioSystems, Utah State University, Logan, UT 84322-4815, USA.
Syst Biol Reprod Med. 2010 Oct;56(5):365-75. doi: 10.3109/19396360903398266.
At fertilization the sperm triggers a series of intracellular calcium oscillations that are pivotal to oocyte activation and development. Although the biological significance of the characteristic intracellular calcium (Ca(2+)(i)) oscillations is not fully understood, calcium ions are known to be involved in cortical granule release and in controlling cell cycle progression. Two different hypotheses attempt to explain how sperm initiate (Ca(2+)(i)) oscillations in mammalian oocytes. One hypothesis is that spermatozoa interact with a receptor located in the plasma membrane of the oocyte, which results in induction of pathways leading to activation. This receptor is coupled to a GTP-binding protein or to have tyrosine kinase activity and have the ability to induce activation of phospholipase C (PLC). In turn, PLC stimulates the hydrolysis of phosphatidyl inositol (4,5)-bisphosphate (PIP2) to produce diacylglycerol (DAG) and 1,4,5 inositol trisphosphate (IP3), a common Ca(2+) releasing compound. Most studies used to develop the mammalian model of oocyte activation have been performed in the mouse. There is a paucity of information from other mammalian models. The predominant mouse model of oocyte activation is that there is a soluble factor (PLC-zeta) delivered to the cytosol after fertilization that induces oocyte activation. However, as data in other mammals is collected, substantial evidence is beginning to support the existence of other more complex oocyte activation pathways in both murine and non-murine systems. Indeed, activation may involve redundant processes, each of which acting alone may be able to induce aspects of oocyte activation. Recent findings demonstrate the involvement of receptors that are known to associate in large, multimeric complexes. This fact leads one to speculate that the process of oocyte activation by the sperm cell is a highly complex and elaborate process that likely involves many more players than perhaps was initially expected.
在受精过程中，精子会引发一系列细胞内钙离子振荡，这对卵子激活和发育至关重要。虽然特征性的细胞内钙离子（Ca(2+)(i)）振荡的生物学意义尚未完全理解，但已知钙离子参与皮质颗粒的释放，并控制细胞周期的进展。有两个不同的假说试图解释精子如何在哺乳动物卵子中引发（Ca(2+)(i)）振荡。一种假说认为，精子与卵子质膜上的受体相互作用，导致激活途径的诱导。这种受体与 G 蛋白偶联或具有酪氨酸激酶活性，并具有诱导磷脂酶 C（PLC）激活的能力。反过来，PLC 刺激磷脂酰肌醇（4,5）-双磷酸（PIP2）的水解，产生二酰基甘油（DAG）和 1,4,5 肌醇三磷酸（IP3），这是一种常见的 Ca(2+)释放化合物。用于开发卵子激活哺乳动物模型的大多数研究都是在小鼠中进行的。来自其他哺乳动物模型的信息很少。卵子激活的主要小鼠模型是，受精后有一个可溶性因子（PLC-zeta）被递送到细胞质中，诱导卵子激活。然而，随着其他哺乳动物的数据被收集，大量证据开始支持在小鼠和非小鼠系统中存在其他更复杂的卵子激活途径。事实上，激活可能涉及冗余过程，每个过程单独作用都可能诱导卵子激活的某些方面。最近的发现表明，涉及与大的多聚复合物相关的受体的参与。这一事实使人推测，精子使卵子激活的过程是一个高度复杂和精细的过程，可能涉及比最初预期更多的参与者。
