Spontaneous activation of ovulated mouse eggs: Time-dependent effects on m-phase exit, cortical granule exocytosis, maternal messenger ribonucleic acid recruitment, and inositol 1,4,5-trisphosphate sensitivity
Spontaneous activation of ovulated mouse eggs: Time-dependent effects on m-phase exit, cortical granule exocytosis, maternal messenger ribonucleic acid recruitment, and inositol 1,4,5-trisphosphate sensitivity
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DOI：
10.1095/biolreprod57.4.743
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发表时间：
1997-10-01
影响因子：
3.6
通讯作者：
Ducibella, T
中科院分区：
文献类型：
--
作者：
Xu, Z;Abbott, A;Ducibella, T
随着排卵后时间的增加，哺乳动物卵子对体外激活激动剂变得更加敏感，或者可能在体内自发激活。我们已经测试了这样的假设：排卵后卵子经历时间依赖性的细胞周期和细胞质变化，导致部分激活状态，从而解释了它们的时间依赖性激活易感性。在hCG后13、16和22 h（排卵后1、4和10 h）定量小鼠卵子中关键活化标志物的体内变化。自发激活首次检测到在16小时，与组蛋白H1和有丝分裂原活化蛋白（MAP）激酶的活动减少20-25%，并与3%的鸡蛋经历后期发病和皮质颗粒的部分损失。到22 h，超过60%的卵进入后期，H1和MAP激酶活性下降40- 50%，透明质酸修饰程度增加，出现受精后正常合成的蛋白质。1，4，5-三磷酸肌醇注射后，原核形成率从13 h的10%显著增加到16 h和22 h的40%和90%。H1和MAP激酶活性的部分降低（低于受精后）为卵对激动剂的敏感性增加提供了可能的生化基础，随着时间的推移，这导致原核形成。此外，所有这些时间依赖性变化都警告不要使用hCG给药后> 16 h的小鼠卵子来研究正常受精的机制，并对动物和人类体外受精具有影响。
With increasing time after ovulation, mammalian eggs become more sensitive to agonists of activation in vitro or may undergo spontaneous activation in vivo. We have tested the hypothesis that postovulatory eggs undergo time-dependent cell cycle and cytoplasmic changes that result in a partially activated state, accounting for their time-dependent susceptibility to activate. In vivo changes in key activation markers in mouse eggs were quantified at 13, 16, and 22 h post-hCG (1, 4, and 10 h postovulation). Spontaneous activation was first detected at 16 h, with a 20-25% decrease in the activities of histone H1 and mitogen-activated protein (MAP) kinases and with 3% of eggs undergoing both anaphase onset and a partial loss of cortical granules. By 22 h, more than 60% of eggs were in anaphase, H1 and MAP kinase activities had decreased 40-50%, the extent of zona pellucida modification had increased, and proteins normally synthesized after fertilization had appeared. Pronuclear formation in response to inositol 1,4,5-trisphosphate injection increased dramatically from 10% at 13 h to about 40% and 90% at 16 h and 22 h, respectively. The partial decreases (less than those after fertilization) in H1 and MAP kinase activities provide a likely biochemical basis for the increased sensitivity of eggs to agonists, seen over time, that results in pronuclear formation. Also, all of these time-dependent changes caution against the use of mouse eggs > 16 h after hCG administration in studying the mechanism of normal fertilization and have implications for animal and human in vitro fertilization.