The present study investigated the effect of treatment with nocodazole on the efficiency of cell cycle synchronization and development of mouse 4-cefl embryos. In addition, developmental ability of reconstituted embryos that received nuclei from 4-cell embryos synchronized with nocodazole at M phase was examined in vitro and in vivo. (1) When 4-cell blastorneres exposed to culture medium containing lg /ml nocodazole for 2, 4, 6 and 8 hrs, 40% (40/10l), 75% (l19/159), 85% (87/102) and 97% (155/160) of nuclei were synchronized at M phase, respectively. (2) Treated with nocodazole for 4 hrs, the proportion of 4-cell embryos developed to blastocysts (98%, 60/61) was not significanUy different from that of the control embryos (98%, 196/201). However, the developmental ability of 4-cell embryos treated for 8 (87%, P<0.05)and 12 hrs (76%, P

• 권오룡(동경농업대학)
• 하야우굉(동경농업대학)