Campbell K H, Loi P, Cappai P, Wilmut I
AFRC Roslin Institute, Roslin, Midlothian, United Kingdom.
Biol Reprod. 1994 Jun;50(6):1385-93. doi: 10.1095/biolreprod50.6.1385.
The timing of pronuclear formation and the initiation and duration of the DNA synthetic period (S-phase) were determined during the first cell cycle of electrically activated ovine oocytes matured in vivo. Reconstructed embryos were produced by electro-fusion-mediated nuclear transfer of unsynchronized single blastomeres. These were derived from embryos produced in vivo at the 16-cell stage (Day 4) and transferred to enucleated metaphase II oocytes at the time of activation or to enucleated activated oocytes during early, mid, and late stages of the presumptive S-phase. The frequency of development to blastocyst was greatest in embryos reconstructed during the presumptive S-phase of enucleated activated oocytes than in embryos reconstructed at the time of activation (mean 55.4% vs. 21.3%). No significant differences were observed when embryos were reconstructed during early, mid, or late stages of the presumptive S-phase (61.3%, 45.7%, and 57.7%, respectively). The results indicate that the use of enucleated activated oocytes as cytoplasts for embryo reconstruction can increase the frequency of development to blastocyst of embryos reconstructed from unsynchronized donor blastomeres.
在体内成熟的电激活绵羊卵母细胞的第一个细胞周期中，确定了原核形成的时间以及DNA合成期（S期）的起始和持续时间。通过电融合介导的未同步化单个卵裂球的核移植产生重构胚胎。这些卵裂球来自于在16细胞阶段（第4天）体内产生的胚胎，并在激活时转移到去核的中期II卵母细胞中，或者在假定S期的早期、中期和晚期转移到去核的激活卵母细胞中。与在激活时重构的胚胎相比，在去核激活卵母细胞的假定S期重构的胚胎发育到囊胚的频率最高（平均分别为55.4%和21.3%）。当在假定S期的早期、中期或晚期重构胚胎时，未观察到显著差异（分别为61.3%、45.7%和57.7%）。结果表明，使用去核激活卵母细胞作为细胞质体进行胚胎重构，可以提高从未同步化供体卵裂球重构的胚胎发育到囊胚的频率。
