Studies on control mechanisms of cytoskeletal networks maintaining the morphology of mammalian eggs

1.细胞周期控制蛋白在哺乳动物卵角蛋白分布中的作用利用荧光成像技术研究了MPF、MAPK和Rho激酶对角蛋白在仓鼠卵细胞中分布的影响。结果表明，仓鼠卵的细胞质中含有角蛋白，在卵母细胞成熟过程中，角蛋白的分布从GV期的浓集型向M II期的纤维型动态变化。当MPF和MAP激酶被抑制时，角蛋白的分布没有发生变化。而抑制Rho激酶则无明显变化。提示角蛋白在哺乳动物卵子中的分布可能受MPF和MAP激酶的调控，而不受Rho激酶的调控。Rho激酶在猪卵母细胞成熟过程中的作用研究Rho激酶在猪卵母细胞成熟中的作用。本研究表明，抑制Rho激酶可抑制第一极体的生发泡(GV)分解和排出。然而，染色体的分离并未受到影响。此外，即使在成熟培养18小时后阻断Rho激酶，也会发生GV崩溃。提示Rho激酶可能在导致GV在培养18小时内破裂的调控机制中起作用。荧光观察表明，Rho激酶抑制剂使卵母细胞内的微丝密度显著降低，第一极体没有释放出来。用Rho激酶抑制剂孵育的卵母细胞-卵丘细胞复合体在成熟44h后不再出现卵丘细胞的扩张。除了微丝的构筑外，还可能影响到微管在卵丘细胞中的分布。

1. Functional roles of cell-cycle control kinase on the keratin distribution of the mammal eggs Influences of MPF, MAPK and Rho kinase on the distribution of keratin in the hamster eggs were investigated by the fluorescent-imaging. The present results clarified that hamster eggs included keratin in the cytoplasm, of which distribution changed dynamically from the concentrated pattern at the GV stage into the fibrous pattern at the M II stage during oocyte maturation. When MPF and MAP kinase were inhibited, the distributional change of the keratin had not happened. On the other hand, no remarkable changes was seen when Rho kinase was inhibited. It is suggested that the distribution of keratin in the mammal eggs may be controlled by MPF and MAP kinase, but not by Rho kinase.2. Functional role of Rho kinase in maturation process of the pig oocytes Functional role of Rho kinase during oocyte maturation was studied in the pig. The present study revealed that the germinal-vesicle (GV) breakdown and expulsion of the first polar body was restrained when Rho kinase was inhibited. However, the separation of the chromosome wasn't affected. In addition, the GV breakdown had occurred even if Rho kinase was blocked 18 hours after maturation incubation. It is suggested that Rho kinase may play a role in the control mechanism which causes GV breakdown by 18 hours of cultivation. Fluorescent observations revealed that the microfilament in the oocytes declined remarkably in density by Rho kinase inhibitor, thereby the first polar body was not released from the oocytes. The oocytes-cumulus cells complexes incubated with Rho kinase inhibitor didn't show the cumulus cell expansion after 44 hr of maturation. The possibility affecting the distribution of microtubules among the cumulus-cells was suggested in addition to the architecture of microfilaments.