Bałakier H, Masui Y
Dev Biol. 1986 Sep;117(1):102-8. doi: 10.1016/0012-1606(86)90352-0.
The cytoplasmic factor responsible for chromosome condensation was introduced into mouse zygotes at different times after fertilization by fusion of the zygotes with metaphase I oocytes. In 72% of heterokaryons obtained after fusion of early zygotes (14-18 hr post-human chorionic gonadotrophin (HCG) with oocytes, the male and female pronuclei of the zygote decondensed. At the same time, the oocyte chromosomes became enclosed in a nuclear envelope and decondensed to an interphase state. However, in the rest of the heterokaryons, the chromatin of the pronuclei condensed to metaphase chromosomes, thus resulting in three sets of chromosomes. Fusion of zygotes that had begun DNA synthesis (20-22 hr post-HCG) with oocytes induced chromosome condensation of the pronuclei in 76% of the cases. In some heterokaryons, however, the oocyte chromosome decondensed to an interphase state similar to the zygote pronuclei. Fusion between late zygotes (27-29 hr post-HCG) with oocytes resulted in chromosome condensation of the pronuclei in all heterokaryons. On the basis of these results, the formation of the pronuclei and their progression toward mitosis in the zygote may be explained by changing levels of a metaphase factor in the cell, or by a balance between interphase and metaphase factors.
通过将受精卵与中期I卵母细胞融合，在受精后的不同时间将负责染色体凝聚的细胞质因子引入小鼠受精卵中。在早期受精卵（人绒毛膜促性腺激素（HCG）注射后14 - 18小时）与卵母细胞融合后获得的异核体中，72%的受精卵雄原核和雌原核解聚。与此同时，卵母细胞染色体被核膜包裹并解聚至间期状态。然而，在其余的异核体中，原核染色质凝聚成中期染色体，从而产生三组染色体。已开始DNA合成的受精卵（HCG注射后20 - 22小时）与卵母细胞融合，在76%的情况下诱导原核染色体凝聚。然而，在一些异核体中，卵母细胞染色体解聚至与受精卵原核相似的间期状态。晚期受精卵（HCG注射后27 - 29小时）与卵母细胞融合，导致所有异核体中原核染色体凝聚。基于这些结果，受精卵中原核的形成及其向有丝分裂的进展可能是由细胞中期因子水平的变化，或间期因子与中期因子之间的平衡来解释的。
