The electrical block to polyspermy induced by an intracellular Ca2+ increase at fertilization of the clawed frogs, Xenopus laevis and Xenopus tropicalis.
The electrical block to polyspermy induced by an intracellular Ca2+ increase at fertilization of the clawed frogs, Xenopus laevis and Xenopus tropicalis.
复制标题
爪蛙、非洲爪蟾和热带爪蟾受精时细胞内 Ca2+ 增加诱导的多精受电阻断。
DOI：
10.1002/mrd.23115
复制
发表时间：
2019
影响因子：
2.5
通讯作者：
Iwao Y.
中科院分区：
文献类型：
--
作者：
Watabe M;Izaki K;Fujino S;Maruyama M;Kojima C;Hiraiwa A;Ueno S;Iwao Y.
为了保证单精子受精，多精子阻断是大多数动物正常二倍体发育所必需的。我们在这里已经证明了单精子在爪蛙，热带爪蟾，和inX。在第一个精子进入后，卵质膜上的多精细胞被快速电阻滞，这是由正向受精电位介导的。精子进入部位的细胞内Ca2+浓度（[Ca2+]i）以Ca2+波的形式在整个卵细胞浆中传播。在女王。在10%的Steinberg溶液中受精的热带植物卵，通过打开Ca2+激活的Cl -通道（CaCCs）产生+27 mV的正向受精电位。在+10 mV和0 mV的电压下，卵膜电位完全被抑制。tropicalisandX。光滑的。点。在0毫伏时，少量卵受精。在膜电位被限制在−10 mV以下的卵子中，记录到内向电流（受精电流）的大量增加，并允许多精子发生。在施肥电流增加的开始阶段，观察到一个小的初始步长电流（IS电流）。由于IS电流在[Ca2+]i少量增加后很快被激发，这可能是由CaCCs的开放介导的。本研究不仅描述了x染色体的快速和电性多精子。但也解释了[Ca2+]i增加的初始阶段在xenopus受精的卵子激活的早期阶段引起IS电流。
Polyspermy blocking, to ensure monospermic fertilization, is necessary for normal diploid development in most animals. We have demonstrated here that monospermy in the clawed frog,Xenopus tropicalis, as well as inX. laevis, is ensured by a fast, electrical block to polyspermy on the egg plasma membrane after the entry of the first sperm, which is mediated by the positive‐going fertilization potential. An intracellular Ca2+concentration ([Ca2+]i) at the sperm entry site was propagated as a Ca2+wave over the whole egg cytoplasm. In theX. tropicaliseggs fertilized in 10% Steinberg's solution, the positive‐going fertilization potential of +27 mV was generated by opening of Ca2+‐activated Cl−‐channels (CaCCs). The fertilization was completely inhibited when the egg's membrane potential was clamped at +10 mV and 0 mV inX. tropicalisandX. laevis, respectively. InX. tropicalis, a small number of eggs were fertilized at 0 mV. In the eggs whose membrane potential was clamped below −10 mV, a large increase in inward current, the fertilization current, was recorded and allowed polyspermy to occur. A small initial step‐like current (IS current) was observed at the beginning of the increase in the fertilization current. As the IS current was elicited soon after a small increase in [Ca2+]i, this is probably mediated by the opening of CaCCs. This study not only characterized the fast and electrical polyspermy inX. tropicalis, but also explained that the initial phase of [Ca2+]iincrease causes IS current during the early phase of egg activation ofXenopusfertilization.