A study of an egg-activating molecule in the sperm cytoplasm

精子细胞质中卵子激活分子的研究

• 批准号: 12680717
• 负责人: IWAO Yasuhiro
• 金额: $ 2.3万
• 依托单位: Yamaguchi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12680717/
• 关键词: Fertilization; Amphibians; Mammals; Ca; cell division; 哺乳類; カルシウム; イモリ; 細胞分裂; Ca; 両生類; 細胞周期再開

In our study, we have found the following major results. Unfertilized eggs of the newt, Cynops pyrrhogaster, are arrested at the second meiotic metaphase. A transient increase of [Ca^<2+>]_i, which is triggered by fertilizing sperm and propagates over the egg cortex as Ca^<2+> wave, is a primary signal to cause egg activation. The injection of an extract of Cynops sperm (SE) into the unfertilized eggs induced the wave-like [Ca^<2+>]_i increase, and then the eggs underwent activation and resumption of meiosis. In the SE-injected eggs, not only degradation of cyclin B1, but also DNA replication was confirmed. When SE had been boiled or treated with Proteinase K before injection, the activity to cause egg activation was lost. Preinjection of Ca^<2+>-chelator BAPTA before SE-injection inhibited egg activation. These results indicate that a heat-labile and proteinous factor in sperm cytoplasm induces a transient increase of [Ca^<2+>]_i indispensable for egg activation. Injection of IP_3 into unfertilized eggs caused [Ca^<2+>]_i increase and egg activation, but injection of cADP-ribose did not. In addition, preinjection of heparin, an inhibitor of IP_3 receptors, prevented egg activation by fertilizing sperm or by SE-injection. These results indicate that not only fertilization, but also SE-injection induces [Ca^<2+>]_i increase through the IP_3 receptors, rather titan rianodine receptors.

在我们的研究中，我们发现了以下主要结果。蝾螈（Cynops pyrrhogaster）的未受精卵在第二个减数分裂中期被捕获。[Ca^<2+>]_i的短暂增加由受精精子触发，并以Ca^<2+>波的形式在卵子皮层传播，是导致卵子激活的主要信号。将Cynops精子提取物（SE）注射到未受精卵中，诱导波浪状的[Ca^<2+>]_i升高，随后卵被激活并恢复减数分裂。在se注射的卵中，不仅细胞周期蛋白B1降解，而且DNA复制得到证实。注射前将SE煮沸或用蛋白酶K处理，使其失去激活鸡蛋的活性。在se注射前预注射Ca^<2+>-螯合剂BAPTA抑制卵子活化。这些结果表明，精子细胞质中的一种热不稳定蛋白因子诱导了卵子激活所必需的[Ca^<2+>]_i的短暂增加。未受精卵注射IP_3可引起[Ca^<2+>]_i升高，激活卵子，而注射cadp -核糖则无此作用。此外，预注射肝素（一种IP_3受体抑制剂）可阻止受精精子或se注射激活卵子。结果表明，除受精外，硒注射通过IP_3受体诱导[Ca^<2+>]_i升高，而不是通过titan rianodine受体。

项目成果

Iwao,Y: "Mechanisms of egg activation and polyspermy block in amphibians and comparative aspects with fertilization in other vertebrates."Zoological Science. 17. 1-11 (2000)

Iwao，Y：“两栖动物卵子激活和多精受精阻断的机制以及与其他脊椎动物受精的比较。”动物学。

Iwao Y: "Fertilization of Amphibians Chapter 4, pp.147-149. In "Fertilization in Protozoa and Metazoan Animals, Cellular and Molecular Aspects" Tarin, J.J. and Cano,A.(Eds.)"Springer-Verlag Heidelberg. 318 (2000)

Iwao Y：“两栖动物的受精，第 4 章，第 147-149 页。见“原生动物和后生动物的受精，细胞和分子方面”Tarin, J.J. 和 Cano,A.（编辑）”Springer-Verlag Heidelberg。

Ueda Y., Yoshizaki N., Iwao Y.: "Acrosome Reaction in Sperm of the Frog, Xenopus laevis: Its Detection and Induction by Oviductal Pars Recta Secretion"Dvelopmental Biology. 243. 55-64 (2002)

Ueda Y.、Yoshizaki N.、Iwao Y.：“非洲爪蟾精子中的顶体反应：其通过输卵管直肠分泌物的检测和诱导”发育生物学。

Iwao Y: "Fertilization of Amphibians Chapter 4. In "Fertilization in Protozoa and Metazoan Animals, Cellular and Molecular Aspects" Tarin, J.J. and Cano, A. (Eds.)"Springer-Verlag Heidelberg. 318(147-191) (2000)

Iwao Y：“两栖动物的受精”第 4 章。在“原生动物和后生动物的受精，细胞和分子方面”Tarin, J.J. 和 Cano, A.（编辑）“Springer-Verlag Heidelberg。

Iwao Y., Tarin, J.J. and, Cano, A. (Eds.) Chapter 4 (Yasuhiro Iwao): "Fertilizatioh of mphibians, Fertilization in Protozoa and Metazoan Animals, Cellular and Molecular Aspects"Springer-Verlag. 147-191 (2000)

岩尾 Y.，塔林，J.J.