Swann K, Lai F A
Department of Anatomy and Developmental Biology, University College, London.
Bioessays. 1997 May;19(5):371-8. doi: 10.1002/bies.950190504.
At fertilization in mammals the sperm activates the egg by triggering a series of oscillations in the intracellular free Ca2+ concentration. The precise sequence of events that occur between sperm-egg contact and the increases in intracellular Ca2+ remains unknown. Here, we discuss recent evidence supporting the hypothesis that a cytosolic sperm protein enters the egg after gamete membrane fusion and triggers Ca2+ oscillations from within the egg cytoplasm. Biochemical studies suggest that there exists a novel sperm protein, named oscillin, that specifically comigrates with Ca2+ oscillation-inducing activity. Oscillin has been immunolocalised to the region of the sperm that first fuses with the egg. The concept of a specific protein that triggers Ca2+ oscillations may have wider physiological significance since sperm oscillin can induce Ca2+ oscillations in somatic cells, such as neurons and hepatocytes. Unravelling the novel signalling system involved in mammalian fertilization may help reveal some fundamental molecular mechanisms responsible for triggering cytoplasmic Ca2+ oscillations.
在哺乳动物受精过程中，精子通过引发细胞内游离钙离子浓度的一系列振荡来激活卵子。精子与卵子接触到细胞内钙离子浓度升高之间发生的精确事件顺序尚不清楚。在此，我们讨论了最近的证据，这些证据支持这样一种假说：一种胞质精子蛋白在配子膜融合后进入卵子，并从卵子细胞质内触发钙离子振荡。生化研究表明，存在一种名为振荡素的新型精子蛋白，它与钙离子振荡诱导活性特异性共迁移。振荡素已被免疫定位到精子最先与卵子融合的区域。触发钙离子振荡的特定蛋白这一概念可能具有更广泛的生理意义，因为精子振荡素可在体细胞（如神经元和肝细胞）中诱导钙离子振荡。揭示哺乳动物受精过程中涉及的新型信号系统可能有助于揭示一些引发细胞质钙离子振荡的基本分子机制。
