小鼠母源因子对早期胚胎发育的影响

Maternal Factors Affecting Development of Early Mouse Embryos

在脊椎动物发育过程中,卵母细胞要经历MⅡ期停滞、受精、早期胚胎发育的启动、胚胎基因组的转录激活、并指导完成个体的发育过程。同时,核移植过程中,分化的细胞核在去核的卵母细胞中能够重编程到胚胎早期的状态并能完成个体的发育过程。在这些发育过程中母源因子都发挥了极其重要的作用。在小鼠胚胎发育研究中发现,小鼠的基因组激活发生在2-细胞期,这一时期标志着合子的发育由卵母细胞控制向胚胎控制的过渡,期间发生一系列复杂的生化过程。体外培养的小鼠胚胎的发育阻断也易发生在2-细胞时期。因此对卵母细胞及早期胚胎母源因子的研究,将有利于了解早期体外培养胚胎和克隆胚胎发育失败的原因,为提高体外培养和克隆胚胎发育的成功率提供理论基础。

In vertebrates, oocytes undergo a series of maturation steps, arresting at metaphase Ⅱ, and can then be fertilized by a sperm. Fertilization initiates molecular events that lead to the activation of early embryonic development. Fertilized oocytes or activated reconstituted embryos then activate the zygotic genome, a crucial event that initiates early embryonic development. The functions of the maternal factors derived from oocytes are different at various mouse embryonic developmental stages. Mouse zygotic genome is activated at the two-cell stage which implies that embryonic development is transferred from the oocyte itself to the embryo. Sometimes mouse embryos are blocked at the two-cell stage, for which the mechanism is not clear. So exploring the functions of some maternal factors in the two-cell stage embryos may help us to understand the potential reasons for early embryonic development failure. Reprogramming a foreign and terminally differentiated somatic nucleus by transferring it to the enucleated oocyte cytoplasm triggers epigenetic changes that eventually lead to the birth of a viable animal. This indicates the oocyte cytoplasm plays a critical role in the development of reconstructed embryos.