细胞外钙诱导大鼠卵母细胞中Ca(2+)/钙调蛋白依赖性蛋白激酶II的激活并介导自发激活。
Extracellular calcium induces activation of Ca(2+)/calmodulin-dependent protein kinase II and mediates spontaneous activation in rat oocytes.
作者信息
Yoo Jae Gyu, Smith Lawrence C
机构信息
Centre de recherche en reproduction animale, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Canada J2S 7C6.
出版信息
Biochem Biophys Res Commun. 2007 Aug 10;359(4):854-9. doi: 10.1016/j.bbrc.2007.05.181. Epub 2007 Jun 4.
Ovulated rat oocytes are activated spontaneously soon after recovery from the oviducts. To investigate the kinetics and mechanism of rat oocyte spontaneous activation (OSA), we investigated the effect of aging in oviducts, hyaluronidase treatment, and extracellular and intracellular calcium, and examined the activity of CaMKII and the effect of its inhibitor on OSA. Oocyte aging in oviducts and hyaluronidase did not affect OSA. However, OSA was significantly decreased in calcium-free medium and in calcium-containing medium containing L-type calcium channel blocker and IP(3)R inhibitor. Moreover, significantly lower OSA was shown with an inhibitor of CaMKII. There was a significant increase of CaMKII activity at 30min after oocyte recovery and constitutively active CaMKII was located near the meiotic spindle in freshly recovered oocytes. Therefore, CaMKII is one of the upstream signals to activate rat oocytes spontaneously after recovery and rat oocytes respond very sensitively to extracellular calcium.
从输卵管中回收后不久，排出的大鼠卵母细胞会自发激活。为了研究大鼠卵母细胞自发激活（OSA）的动力学和机制，我们研究了输卵管内老化、透明质酸酶处理以及细胞外和细胞内钙的影响，并检测了CaMKII的活性及其抑制剂对OSA的作用。输卵管内卵母细胞老化和透明质酸酶处理不影响OSA。然而，在无钙培养基以及含有L型钙通道阻滞剂和IP(3)R抑制剂的含钙培养基中，OSA显著降低。此外，CaMKII抑制剂显示OSA显著降低。卵母细胞回收后30分钟时CaMKII活性显著增加，在刚回收的卵母细胞中，组成型活性CaMKII位于减数分裂纺锤体附近。因此，CaMKII是卵母细胞回收后自发激活大鼠卵母细胞的上游信号之一，并且大鼠卵母细胞对细胞外钙非常敏感。
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