REGULATION OF THE POLYSPERMY BLOCK IN THE MOUSE EGG - MATURATION-DEPENDENT DIFFERENCES IN CORTICAL GRANULE EXOCYTOSIS AND ZONA-PELLUCIDA MODIFICATIONS INDUCED BY INOSITOL 1,4,5-TRISPHOSPHATE AND AN ACTIVATOR OF PROTEIN-KINASE-C
REGULATION OF THE POLYSPERMY BLOCK IN THE MOUSE EGG - MATURATION-DEPENDENT DIFFERENCES IN CORTICAL GRANULE EXOCYTOSIS AND ZONA-PELLUCIDA MODIFICATIONS INDUCED BY INOSITOL 1,4,5-TRISPHOSPHATE AND AN ACTIVATOR OF PROTEIN-KINASE-C
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DOI：
10.1095/biolreprod48.6.1251
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发表时间：
1993-06-01
影响因子：
3.6
通讯作者：
SCHULTZ, RM
中科院分区：
文献类型：
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作者：
DUCIBELLA, T;KURASAWA, S;SCHULTZ, RM
成熟囊泡（GV）完整的完全发育的小鼠卵母细胞不进行皮质颗粒（CG）胞吐反应A23187治疗，而中期II（MII）逮捕的鸡蛋。这种不同的反应可能反映了发展的能力，鸡蛋进行CG胞吐，这是负责生化修饰的糖蛋白ZP 2的透明质酸。因此，我们在这两个阶段中比较了12-O-十四酰基佛波醇13-乙酸酯（TPA）或肌醇1，4，5-三磷酸（IP 3）促进CG胞吐和/或ZP 2到ZP 2 t转化的能力;已知这些试剂刺激小鼠卵激活的早期事件。TPA（10 ng/ml）处理60和120 min分别导致GV完整卵母细胞CG损失25%和52%，MII卵分别损失38%和76%;受精导致CG损失约70- 80%。虽然在120分钟TPA处理后在卵母细胞和卵子中观察到类似程度的ZP 2至ZP 2f转化（约70-80%），但在60分钟处理后在卵母细胞中观察到更大程度的转化（卵母细胞为80%，卵子为50%）。微量注射IP 3（终浓度1 μ M）到MII卵导致ZP 2转换的程度与受精后观察到的相似，而几乎没有转换发生在GV-完整的卵母细胞类似注射。这些结果表明，蛋白激酶C的敏感性在减数分裂成熟之前发展，而对IP 3的反应性在成熟恢复后发展。我们建议，涉及IP 3介导的钙释放的监管机制是缺乏GV期卵母细胞。
Germinal vesicle (GV)-intact fully grown mouse oocytes do not undergo cortical granule (CG) exocytosis in response to A23187 treatment, whereas metaphase II (MII)-arrested eggs do. This differential response may reflect the development of the ability of the egg to undergo CG exocytosis, which is responsible for the biochemical modification of the glycoprotein ZP2 in the zona pellucida. Accordingly, we compared in these two stages the ability of 12-O-tetradecanoyl phorbol 13-acetate (TPA) or inositol 1,4,5-trisphosphate (IP3) to promote CG exocytosis and/or the ZP2 to ZP2t conversion; these agents are known to stimulate early events of mouse egg activation. TPA (10 ng/ml) treatment for 60 and 120 min resulted in a 25% and 52% CG loss in GV-intact oocytes and a 38% and 76% loss in MII eggs, respectively; fertilization resulted in a CG loss of approximately 70-80%. Although a similar extent of ZP2 to ZP2f conversion was observed in oocytes and eggs after a 120-min TPA treatment (approximately 70-80%), a greater extent of conversion was observed in oocytes after a 60-min treatment (80% for oocytes, 50% for eggs). Mi-croinjection of IP3 (final concentration 1 muM) into MII eggs resulted in an extent of ZP2 conversion similar to that observed following fertilization, whereas little conversion occurred in GV-intact oocytes similarly injected. These results indicate that a protein kinase C sensitivity develops prior to meiotic maturation, whereas responsiveness to IP3 develops after maturation has resumed. We propose that the regulatory mechanism involving an IP3-mediated calcium release is deficient in GV-stage oocytes.