Dual ionic controls for the activation of protein synthesis at fertilization
Dual ionic controls for the activation of protein synthesis at fertilization
复制标题
DOI：
10.1038/287558a0
复制
发表时间：
1980-10
期刊：
影响因子：
64.8
通讯作者：
M. Winkler;R. Steinhardt;J. L. Grainger;L. Minning
中科院分区：
文献类型：
--
作者：
M. Winkler;R. Steinhardt;J. L. Grainger;L. Minning
受精时海胆卵的一般代谢活化依赖于细胞内钙储存的释放和随后细胞内Ca 2+的瞬时升高（参考文献1-3）。然而，这种升高本身并不导致大分子合成和发育的增加，而是启动导致细胞内pH长期升高的步骤（参考文献4-6）。在依赖于细胞内pH值升高的发育过程中，受精时蛋白质合成速率大大加快6。弱渗透碱如氨可用于模拟导致细胞内pH增加的过程，从而显示蛋白质合成速率的相应增加6 -9。相反，如果细胞内pH值被渗透性弱酸降低到未受精水平，则有可能证明蛋白质合成逐渐但完全关闭6。然而，氨激活的鸡蛋中的蛋白质合成速率落后于受精对照，即使氨激活可以导致细胞内pH值的增加大于受精鸡蛋中发生的6，8，10。这一结果表明，除胞内pH值外的其他因素可能在受精后调节蛋白质合成6，10。为了研究Ca 2+瞬变可能具有这样的作用的可能性，我们测量了在各种离子条件下激活的卵中的氨基酸掺入率，从而能够分别研究Ca 2+和pH变化的影响。我们的研究结果表明，如果intracellularpH值升高，细胞内Ca 2+的增加在受精时蛋白质合成的激活中发挥了额外的作用。
The general metabolic activation of the sea urchin egg at fertilization is dependent on a release of intracellular stores of calcium and the subsequent transient elevation of intracellular Ca2+(refs 1–3). However, this elevation does not by itself lead to increased macromolecular synthesis and development but initiates steps which result in a long-term elevation of intracellularpH (refs 4–6). Among the developmental processes dependent on the elevation of intracellularpH is the large acceleration in the rate of protein synthesis at fertilization6. Weak penetrating bases such as ammonia can be used to mimic the processes resulting in an increase in intracellularpH and so show the corresponding increases in protein synthesis rate6–9. Conversely, it is possible to demonstrate a gradual but complete shut down of protein synthesis if the intracellularpH is reduced to the unfertilized level with penetrating weak acids6. However, the rate of protein synthesis in ammonia-activated eggs lags behind that of fertilized controls even though ammonia activation can result in an intracellularpH increase greater than occurs in the fertilized egg6,8,10. This result has led to the suggestion that factors other than intracellularpH may be regulating protein synthesis following fertilization6,10. To investigate the possibility that the Ca2+transient may have such a role, we measured the rate of amino acid incorporation in eggs that were activated in various ionic conditions which enabled the effects of Ca2+andpH changes to be studied separately. Our results, reported here, show that if intracellularpH is elevated, increases in intracellular Ca2+play an additional part in the activation of protein synthesis at fertilization.