PRECOCIOUS LOSS OF CORTICAL GRANULES DURING MOUSE OOCYTE MEIOTIC MATURATION AND CORRELATION WITH AN EGG-INDUCED MODIFICATION OF THE ZONA PELLUCIDA
PRECOCIOUS LOSS OF CORTICAL GRANULES DURING MOUSE OOCYTE MEIOTIC MATURATION AND CORRELATION WITH AN EGG-INDUCED MODIFICATION OF THE ZONA PELLUCIDA
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DOI：
10.1016/0012-1606(90)90006-5
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发表时间：
1990-01-01
影响因子：
2.7
通讯作者：
SCHULTZ, RM
中科院分区：
文献类型：
--
作者：
DUCIBELLA, T;KURASAWA, S;SCHULTZ, RM
受精导致皮质颗粒胞吐作用，这被认为与构成多精受精的透明卵块的透明卵的修饰有关。先前的报道表明，在小鼠卵母细胞体内成熟过程中，透镜凝集素染色颗粒（可能是皮质颗粒）的数量减少，并在中期II停滞，以及在中期II纺锤体区域形成无皮质颗粒区（T. Ducibella、E.安德森，D. F. Albertini、J. Aalberg和S. Rangarajan，1988，Dev. 130，184-197）。我们扩展这些观察报告在这里，germinocyte囊泡完整的卵母细胞在体外成熟中期II的存在或不存在血清开发皮质颗粒的自由域和皮质颗粒的数量减少相比，germinocyte囊泡完整的卵母细胞，这些变化是类似的卵母细胞在体内成熟。皮质颗粒数量的减少需要胚芽囊泡破裂，因为它被双丁酰cAMP阻止，其在体外抑制胚芽囊泡破裂。卵母细胞对钙离子载体A23187做出反应并减少皮质颗粒数量的能力也与减数分裂成熟有关，并在成熟开始后7至12小时之间发展。与成熟相关的皮质颗粒数量减少可能代表皮质颗粒胞吐作用，因为当卵母细胞在无血清培养基中体外成熟时，这种减少伴随着无皮质颗粒结构域的形成和ZP 2向ZP 2f的转化;这种透明质酸修饰发生在受精后，被认为是由于皮质颗粒胞吐作用。与此相反，皮质颗粒的损失和发展的皮质颗粒无域的卵母细胞在体外成熟的血清的存在下，并不伴随着ZP 2的修改。血清对ZP 2修饰的抑制作用可能在体内提供了一种生理机制，以防止可能导致多精受精过早阻断的透明卵的早熟修饰，从而抑制受精。
Fertilization results in cortical granule exocytosis, which is thought to be involved in modifications of the zona pellucida that constitute the zona pellucida block to polyspermy. A previous report demonstrated that a decrease in the number of Lens culinaris agglutinin-staining granules, which are likely to be cortical granules, occurred during in vivo mouse oocyte maturation with arrest at metaphase II, as well as the formation of cortical granule-free domain in the area of the metaphase II spindle (T. Ducibella, E. Anderson, D. F. Albertini, J. Aalberg, and S. Rangarajan, 1988, Dev. Biol. 130, 184-197). We extend these observations by reporting here that germinal vesicle-intact oocytes matured in vitro to metaphase II in either the absence or the presence of serum develop a cortical granule-free domain and have reduced numbers of cortical granules when compared to germinal vesicle-intact oocytes; these changes are similar to those of oocytes matured in vivo. The reduction in the number of cortical granules requires germinal vesicle breakdown, since it is prevented by dibutyryl cAMP, which inhibits germinal vesicle breakdown in vitro. The ability of oocytes to respond to the calcium ionophore A23187 with a reduction in the number of cortical granules is also associated with meiotic maturation and develops between 7 and 12 hr after initiation of maturation. The maturation-associated reduction in the number of cortical granules is likely to represent cortical granule exocytosis, since this reduction is accompanied by the formation of a cortical granule-free domain and a conversion of ZP2 to ZP2f when the oocytes are matured in vitro in serum-free medium; this zona pellucida modification occurs following fertilization and is thought to be due to cortical granule exocytosis. In contrast, the loss of cortical granules and development of the cortical granule-free domain of oocytes matured in vitro in the presence of serum is not accompanied by the modification of ZP2. The inhibitory effect of serum on the ZP2 modification may afford in vivo a physiological mechanism to prevent a precocious modification of the zona pellucida that could result in a premature block to polyspermy and hence inhibit fertilization.