The calcium signaling pathway that initiates embryonic development in fertilize amphibian eggs.

在受精时，细胞质钙离子(Ca^&lt；2+&gt；)的瞬时增加会在动物卵子中触发各种激活反应。在两栖动物中，这些反应包括退出减数分裂停滞和皮质重塑，观察到激活收缩。我们研究了钙调神经磷酸酶诱导减数分裂退出的底物和激活收缩的调节机制，使用了非洲爪哇卵的无细胞提取物和细胞皮质。结果表明，Erp1和Cdc20在激活时被去磷酸化，这两个基因都是导致Cyclin B破坏导致减数分裂退出所必需的。负责它们去磷酸化的磷酸酶(S)仍有待确定。我们还建立了从卵母细胞和卵子中分离细胞皮质并洗脱其皮质蛋白的方法。使用这些材料，我们发现苯丙素，一种肌动蛋白细胞骨架调节蛋白，在卵母细胞成熟过程中增加，并在激活时被去磷酸化。因此，本研究开发的皮质分离方法使细胞皮质的生化分析成为可能。

At fertilization, a transient increase of cytoplasmic calcium ions(Ca^<2+>) triggers various activation responses in animal eggs. In amphibian, these responses include exit from meiotic arrest and cortical remodeling observed as activation contraction. We have investigated substrates for calcineurin in inducing the meiotic exit and regulatory mechanisms for the activation contraction, using cell-free extracts and cell cortices isolated from Xenopus eggs. The results indicated that Erp1 and Cdc20, both of which are essential for cyclin B destruction which leads to the meiotic exit, are dephosphorylated upon activation. The phosphatase(s) responsible for their dephosphorylation remains to be identified. We have also established the method to isolate the cell cortex from oocytes and eggs and to elute their cortical proteins. Using these materials, we found that anillin, an actin cytoskeletal regulator protein, increases during oocytes maturation and is dephosphorylated upon activation. Thus, the cortical isolation method developed in this study has enabled the biochemical analyses of cell cortex.