Tatone C, Van Eekelen C G, Colonna R
Dipartimento di Scienze e Technologie Biomediche e di Biometria, Università dell'Aquila, Italy.
Mol Reprod Dev. 1994 Jun;38(2):200-8. doi: 10.1002/mrd.1080380211.
The ability of parthenogenetically activated mouse eggs to establish a plasma membrane (PM) block to sperm penetration was studied. Zona-free eggs preloaded with Hoechst 33342 were activated by exposure to ethanol or OAG (1-oleoyl-2-acetyl-sn-glycerol) and inseminated after different periods. Eggs challenged with sperm at 30- or 60-min postactivation displayed a fertilization frequency significantly lower than that of control eggs. Conversely, when insemination was carried out at 120-min postactivation, the proportion of fertilized eggs was equivalent to that observed in the control group. Moreover, we report that when the eggs were induced to resume meiosis without any notable loss of CGs (egg exposure to OAG at 100 microM external Ca2+ or to heat shock), a normal ability to be penetrated was recorded at 30-min postactivation. Similar behaviour was exhibited by eggs that underwent a CG exocytosis close to that triggered by sperm in absence of nuclear activation (microinjection of inositol 1,4,5-trisphosphate into the egg at 1 microM cytosolic concentration). Present data support the conclusion that parthenogenetically activated mouse eggs are capable of a transitory PM block response that requires both CG exocytosis and meiosis resumption to occur.
研究了孤雌激活的小鼠卵建立对精子穿透的质膜（PM）阻断的能力。预先用Hoechst 33342加载的无透明带卵通过暴露于乙醇或OAG（1-油酰基-2-乙酰基-sn-甘油）进行激活，并在不同时间段后进行授精。在激活后30分钟或60分钟用精子挑战的卵显示出受精频率明显低于对照卵。相反，当在激活后120分钟进行授精时，受精卵的比例与对照组中观察到的相当。此外，我们报告说，当卵被诱导恢复减数分裂而没有任何明显的皮质颗粒（CGs）损失时（卵在100 microM外部Ca2+下暴露于OAG或热休克），在激活后30分钟记录到正常的被穿透能力。在没有核激活的情况下（以1 microM胞质浓度向卵内显微注射肌醇1,4,5-三磷酸），经历了接近精子触发的CG胞吐作用的卵也表现出类似的行为。目前的数据支持这样的结论：孤雌激活的小鼠卵能够产生短暂的PM阻断反应，这需要CG胞吐作用和减数分裂恢复都发生。
