Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy.
Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy.
Cells. 2023 Feb 25;12(5):740. doi: 10.3390/cells12050740.
In starfish, the addition of the hormone 1-methyladenine (1-MA) to immature oocytes (germinal vesicle, GV-stage) arrested at the prophase of the first meiotic division induces meiosis resumption (maturation), which makes the mature eggs able to respond to the sperm with a normal fertilization response. The optimal fertilizability achieved during the maturation process results from the exquisite structural reorganization of the actin cytoskeleton in the cortex and cytoplasm induced by the maturing hormone. In this report, we have investigated the influence of acidic and alkaline seawater on the structure of the cortical F-actin network of immature oocytes of the starfish () and its dynamic changes upon insemination. The results have shown that the altered seawater pH strongly affected the sperm-induced Ca response and the polyspermy rate. When immature starfish oocytes were stimulated with 1-MA in acidic or alkaline seawater, the maturation process displayed a strong dependency on pH in terms of the dynamic structural changes of the cortical F-actin. The resulting alteration of the actin cytoskeleton, in turn, affected the pattern of Ca signals at fertilization and sperm penetration.
在海星中，添加激素 1-甲基腺嘌呤（1-MA）到处于第一次减数分裂前期的未成熟卵母细胞（生发泡期，GV 期）中会诱导减数分裂恢复（成熟），从而使成熟卵能够对精子做出正常的受精反应。在成熟过程中实现的最佳受精能力来自成熟激素诱导的皮质和细胞质中肌动蛋白细胞骨架的精细结构重排。在本报告中，我们研究了酸性和碱性海水对海星未成熟卵母细胞皮质 F-肌动蛋白网络结构及其受精时的动态变化的影响。结果表明，改变的海水 pH 值强烈影响精子诱导的 Ca 反应和多精受精率。当用 1-MA 在酸性或碱性海水中刺激未成熟的海星卵母细胞时，皮质 F-肌动蛋白的动态结构变化表明成熟过程对 pH 值具有很强的依赖性。肌动蛋白细胞骨架的这种改变反过来又影响了受精和精子穿透时的 Ca 信号模式。
