Molecular Biology of the Oocyte

卵泡发生：哺乳动物的卵巢卵泡发生是一个复杂的过程，涉及生殖细胞和体细胞之间的相互作用。转录因子、细胞粘附分子和生长因子的精心协调表达是成功所必需的。我们已经鉴定了一种生殖细胞特异性的碱性螺旋-环-螺旋转录因子FIGLA（Factor In the GermLine，Alpha）。FIGLA首先在胚胎第13.5天（E13.5）检测到，并在成年雌性小鼠中持续存在。最初研究作为雌性基因的激活剂，它也抑制雄性生殖系基因，以防止卵子发生过程中的不适当表达。目前的研究已经确定了FIGLA的潜在卵母细胞特异性靶点，这些靶点对于：1）卵泡发生; 2）受精;和3）植入前发育很重要。 受精：哺乳动物精卵识别的特异性主要由透明膜介导。然而，尽管进行了广泛的调查，没有统一的模型，精子与精子基质的相互作用，导致哺乳动物受精的分子基础。目前的研究调查：1）细胞外透明壳形成的分子生物学; 2）透明壳基质支持分类群特异性精卵识别的分子要求; 3）受精后多精受精被阻止的机制。 早期发育：小鼠胚胎基因组的激活开始于单细胞受精卵的晚期，并在双细胞分裂阶段完全进行。在着床前小鼠发育中，当八个卵裂球紧密形成极化桑椹胚时，就建立了预示内细胞团和胚外滋养外胚层的初始细胞谱系。在更简单的模式生物中，有令人信服的证据表明，成功的胚胎发生需要来自卵的持续基因产物。然而，在小鼠中，这种影响只是最近才有记录，并构成了一个迅速发展的研究领域。目前的研究调查：1）影响小鼠早期发育的新的母体效应基因; 2）最近描述的母体编码的皮层下复合体的组分;和3）复合体的丢失影响卵裂阶段胚胎发生的机制。

Folliculogenesis: Ovarian folliculogenesis in mammals is a complex process involving interactions between germ and somatic cells. Carefully orchestrated expression of transcription factors, cell adhesion molecules and growth factors are required for success. We have identified a germ-cell specific, basic helix-loop-helix transcription factor, FIGLA (Factor In the GermLine, Alpha). FIGLA is first detected at embryonic day 13.5 (E13.5) and persists in adult female mice. Initially investigated as an activator of female genes, it also represses male germline genes to prevent inappropriate expression during oogenesis. Current studies have identified potential oocyte-specific targets of FIGLA important for: 1) folliculogenesis; 2) fertilization; and 3) pre-implantation development. Fertilization: The specificity of sperm-egg recognition in mammals is mediated primarily by the zona pellucida. However, despite extensive investigation, there is no unifying model for the molecular basis of sperm interactions with the zona matrix that result in mammalian fertilization. Current studies investigate: 1) the molecular biology of the formation of the extracellular zona pellucida; 2) the molecular requirements of the zona pellucida matrix to support taxon-specific sperm-egg recognition; and 3) the mechanism 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. In simpler model organisms, there is compelling evidence that persistent gene products from the egg are required for successful embryogenesis. However, in mice such effects have been documented only more recently and constitute a rapidly evolving area of investigation. Current studies investigate: 1) novel maternal effect genes that affect early mouse development; 2) components of a recently described maternally encoded subcortical complex; and 3) mechanisms by which the loss of the complex affects cleavage stage embryogenesis.