Cell Surface Changes During the Egg-to-Embryo Transition

描述(申请人提供)：如果受精，所有的卵子都会经历卵子到胚胎的转变。在受精后的几分钟或几小时内，根据动物的不同，卵子会改变现有的分子机制，并将自己转变为具有巨大不同发育潜力的细胞。这种卵子到胚胎转变的第一个机械性改变建立了阻止多精受精的机制，随后是母体mRNA和细胞质蛋白的周转，信号转导能力的改变，以及细胞表面的变化，包括特定的膜蛋白和脂类的添加和去除。这种转变不依赖于新的转录活动，由于技术原因，最近对理解卵子到胚胎的转变的大多数研究都集中在信号转导机制和mRNAs的变化上。然而，海胆和海星提供了一个机会来研究特定发生在细胞表面的变化。虽然这一过程的细节在动物之间有所不同，就像许多生殖现象一样，但所有的卵子都经历了这种普遍的过渡。我们将利用海胆和海星，因为1)数以百万计的卵、卵和胚胎很容易获得；2)皮质颗粒的所有主要蛋白质都已经确定；3)卵和卵母细胞质膜可以通过多种方式进行实验操作；4)来自紫海胆的基因组序列和基因组资源是可用的。这项研究的结果将阐明这一重大发育转变在所有动物中的保守机制。此外，由于这里研究的变化发生在细胞表面，它们将帮助临床医生开发新的方法，以非侵入性地评估人类体外受精应用中的发展潜力。与公众健康相关：受精后，卵子立即迅速转变为具有许多新的生化、细胞和发育特征的胚胎。这种基本的变化被编程到卵子中，并独立于新的基因表达；也就是说，它们反映了现有分子机制的变化。我们的研究集中在卵子到胚胎转变过程中细胞表面发生的变化。这些是发生在胚胎中的一些最迅速和最保守的变化，可以从细胞外部检测到。因此，这项研究将有助于更好地了解所有动物受精和发育的重大转变，并识别指示成功发育的非侵入性早期标记。我们的结果将对人类生殖健康的临床试管受精预测具有特别重要的意义。

DESCRIPTION (provided by applicant): If fertilized, all eggs undergo an egg-to-embryo transition. Within minutes or hours of insemination, depending on the animal, the egg shuffles its existing molecular machinery and transforms itself into a cell with vastly different developmental potential. The first mechanistic alteration of this egg-to-embryo transition establishes the block to polyspermy, which is followed by and integrated with the turnover of maternal mRNA and cytoplasmic proteins, altered signal transduction capabilities, and changes at the cell surface including the addition and removal of specific membrane proteins and lipids. This transition is independent of new transcriptional activity, and for technical reasons, a majority of recent research towards understanding the egg-to-embryo transition has focused on signal transduction mechanisms and changes in mRNAs. The sea urchin and starfish, however, offer an opportunity to examine the changes that occur specifically at the cell surface. While the details of this process differ among animals, as with much of the reproductive phenomena, all eggs undergo this general transition. We will take advantage of the sea urchin and starfish because 1) millions of oocytes, eggs and embryos are readily obtained; 2) all the major proteins of the cortical granules have been defined; 3) the egg and oocyte plasma membrane can be manipulated experimentally in many ways; and 4) the genome sequence and genomic resources from the sea urchin Strongylocentrotus purpuratus are available. Results of this study will elucidate conserved mechanisms of this major developmental transition in all animals. Furthermore, because the changes examined here are at the cell surface, they will help clinicians develop new methods to non-invasively assess developmental potential in IVF applications for humans. PUBLIC HEALTH RELEVANCE: Immediately after fertilization, the egg rapidly transforms into an embryo with many new biochemical, cellular, and developmental features. This essential change is programmed into the egg and is independent of new gene expression; i.e., they reflect changes of the existing molecular machinery. Our research focuses on the changes that occur on the cell surface of the egg to embryo transition. These are some of the most rapid and conserved changes that occur in embryos and are detectable from the outside of the cell. Thus, this research will lead to a better understanding of a major transition in fertilization and development of all animals, and to the identification of non invasive, early markers indicative of successful development. Our results will have particular significance to clinical IVF predictions in human reproductive health.