Molecular Biology of the Oocyte

母体效应基因：在小鼠卵细胞减数分裂成熟过程中终止的转录，只有在双细胞胚胎的胚胎基因组被强力激活后才能恢复。卵母细胞和胚胎基因转录之间的间隙决定了储存的母体因子的作用。这些成分由母体效应基因编码，在卵子发生过程中积累，并为受精、胚胎基因组激活和胚胎发生裂解阶段提供必要的途径和细胞器。利用小鼠转基因，研究了个体或母体因子复合物在这些过程中的作用。

Maternal Effect Genes: Transcription that terminates during meiotic maturation of mouse eggs, resumes only after robust activation of the embryonic genome of the two-cell embryo. This interregnum between oocyte and embryonic gene transcription dictates a role for stored maternal factors. Encoded by maternal effect genes, these components accumulate during oogenesis and provide pathways and organelles essential for fertilization, activation of the embryonic genome and cleavage stage embryogenesis. Using mouse transgenesis, the role of individual or complexes of maternal factors is investigated in these processes. Fertilization: The taxon-specificity of sperm-egg recognition in mammals that results in fertilization is mediated primarily by the zona pellucida, an extracellular matrix surrounding ovulated eggs. Although a simple structure of 3-4 glycoproteins, the molecular basis of this sperm binding to the zona pellucida has been controversial. Current studies investigate: 1) molecular requirements to support taxon-specific sperm-egg recognition on the surface of the zona pellucida; 2) mechanism that result in acrosome exocytosis necessary for gamete fusion; and 3) the processes by which post-fertilization polyspermy is prevented. Early Development: Activation of the embryonic genome in mice begins late in the one-cell zygote and is fully underway by the two-cell cleavage stage. Initial cell lineages that presage the inner cell mass and extra-embryonic trophectoderm are established when eight blastomeres compact to form polarized morulae in pre-implantation mouse development. The role of maternal effect genes and organelles in these processes in mammals constitute a rapidly evolving area of inquiry. Current studies investigate: 1) novel maternal effect genes that affect early mouse development; 2) the role of maternal organelles in the maternal to zygotic transition; and 3) the role of degradation of maternal components in activation of the embryonic genome.