Picard A, Harricane M C, Labbe J C, Doree M
CNRS, L.P. 8402 and INSERM U.249, Université Montpellier I, France.
Dev Biol. 1988 Jul;128(1):121-8. doi: 10.1016/0012-1606(88)90273-4.
We show that certain events of the cell cycle can still occur in starfish oocytes or fertilized eggs from which the germinal vesicle (the prominent nucleus of prophase-arrested oocytes) has been removed before the induction of meiotic maturation. Two meiotic asters develop following hormonal induction of meiotic maturation in these enucleated oocytes. The asters then divide to form a transient tetrapolar figure. When enucleated oocytes are fertilized, the sperm centrosome duplicates at the times corresponding to each cleavage in control nucleated embryos. Periodic changes in the organization of the asters and in the morphology of the cell surface also occur in synchrony with controls. Decondensation of the sperm nucleus, spindle formation, and cleavage do not occur when enucleated oocytes are fertilized. Ultimately the number of asters increases to approximately 520 (about 2(9] before the pseudo-embryo arrests and cytolyzes. Fertilized eggs from which both pronuclei but not the sperm aster have been removed undergo nine cleavages and then cease cell division. The cessation of division may be related to the events that cause the midblastula transition after seven cleavages in normal nucleated embryos.
我们发现，在诱导减数分裂成熟之前已去除生发泡（处于前期阻滞的卵母细胞的显著细胞核）的海星卵母细胞或受精卵中，细胞周期的某些事件仍可发生。在这些去核卵母细胞中，激素诱导减数分裂成熟后会形成两个减数分裂星体。然后星体分裂形成一个短暂的四极形态。当去核卵母细胞受精时，精子中心体在与对照有核胚胎每次卵裂相对应的时间进行复制。星体组织和细胞表面形态的周期性变化也与对照同步发生。去核卵母细胞受精时，精子核不会解聚、纺锤体不会形成且不会发生卵裂。最终，星体数量增加到约520个（约2^9），然后假胚胎停止发育并发生细胞溶解。去除了两个原核但未去除精子星体的受精卵进行九次卵裂，然后停止细胞分裂。这种分裂的停止可能与正常有核胚胎在七次卵裂后导致中囊胚转换的事件有关。
