Cheng Yong, Fan Heng-Yu, Wen Duan-Cheng, Tong Chao, Zhu Zi-Yu, Lei Lei, Sun Qing-Yuan, Chen Da-Yuan
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Mol Reprod Dev. 2003 Jul;65(3):278-82. doi: 10.1002/mrd.10285.
The relationship between nucleus and cytoplasm can be well revealed by nuclear transplantation. Here, we have investigated the behavior changes of the reconstructed oocytes after transferring the karyoplasts from mouse GV, MI, and MII oocytes into the cytoplasts at the different developmental stages. When the GV cytoplast was used as recipient and MI or MII karyoplast was used as donor (MI-GV pair and MII-GV pair), the reconstructed pairs extruded a polar body after electrofusion and culture. Both the cytoplasm and the polar body had a metaphase spindle in the MI-GV pair, while only a clutch of condensed chromatin was observed in the cytoplasm and polar body of the MII-GV pair. When the MI cytoplast was used as recipient and GV or MII karyoplast was used as donor (GV-MI pair and MII-MI pair), the reconstructed pairs also extruded a polar body. Each had one spindle and a group of metaphase chromosomes in the cytoplasm and polar body, respectively. When the MII cytoplast was used as recipient and GV or MI karyoplast was used as donor (GV-MII pair and MI-MII pair), the reconstructed pairs were activated, became parthenogenetic embryos and even developed to hatching blastocysts after electrofusion. The result from immunoblotting showed that MAP kinase activity was high in the MI and MII cytoplasts, while not detected in GV cytoplast. The results demonstrate that the cytoplasmic environment determines the behavior of asynchronous donors.
核移植能够很好地揭示细胞核与细胞质之间的关系。在此，我们研究了将小鼠GV期、MI期和MII期卵母细胞的核体转移到不同发育阶段的胞质体后，重构卵母细胞的行为变化。当以GV期胞质体作为受体，MI期或MII期核体作为供体时（MI-GV组和MII-GV组），重构组在电融合和培养后排出了极体。在MI-GV组的细胞质和极体中均有一个中期纺锤体，而在MII-GV组的细胞质和极体中仅观察到一团凝聚的染色质。当以MI期胞质体作为受体，GV期或MII期核体作为供体时（GV-MI组和MII-MI组），重构组也排出了极体。在细胞质和极体中分别有一个纺锤体和一组中期染色体。当以MII期胞质体作为受体，GV期或MI期核体作为供体时（GV-MII组和MI-MII组），重构组被激活，成为孤雌胚胎，甚至在电融合后发育至孵化囊胚。免疫印迹结果显示，MAP激酶活性在MI期和MII期胞质体中较高，而在GV期胞质体中未检测到。结果表明，细胞质环境决定了不同步供体的行为。
