Department of Biological Sciences, Ochanomizu University, Tokyo, Japan.
Mol Reprod Dev. 2011 Oct-Nov;78(10-11):808-13. doi: 10.1002/mrd.21378. Epub 2011 Sep 1.
In many animals, fully grown oocytes are arrested at prophase of meiosis I. Before or after ovulation/spawning, a secondary arrest occurs at metaphase of meiosis I or II (MI or II, respectively). MI arrest in the ovary is released after spawning, and is followed by fertilization, whereas MI and MII arrest after ovulation are released by fertilization. Insemination of isolated oocytes from the ovaries at an inappropriate time increases the rate of polyspermy, indicating that ovaries provide the proper environment for acquisition of the polyspermy blocks and the development of competence to be fertilized normally. Due to MI arrest in the ovaries or MI/MII arrest after ovulation/spawning, the fertilizable period can be elongated. Thus, MI and MII arrest may play a role in maintaining the cell-cycle phases to enable normal fertilization. Here, the evolution of fertilization timing is discussed.
在许多动物中，完全成熟的卵母细胞在减数分裂 I 的前期被阻滞。在排卵/产卵之前或之后，第二次阻滞发生在减数分裂 I 或 II 的中期（分别为 MI 或 II）。卵巢中的 MI 阻滞在产卵后被释放，并随后进行受精，而排卵后的 MI 和 MII 阻滞则通过受精被释放。在不合适的时间对卵巢中的分离卵母细胞进行授精会增加多精入卵的比率，表明卵巢为获得多精入卵阻滞和正常受精的能力提供了适当的环境。由于卵巢中的 MI 阻滞或排卵/产卵后的 MI/MII 阻滞，可使受精期延长。因此，MI 和 MII 阻滞可能在维持细胞周期阶段以实现正常受精方面发挥作用。在这里，讨论了受精时间的演变。
