BIOCHEMICAL AND GENETIC ANALYSES OF AN EMBRYONIC ANTIGEN

这项提案的目标是分离和表征一种哺乳动物 胚胎细胞表面糖蛋白（ESGp），其表达和生化 结构似乎是发育调节的。 来自两个细胞的ESGp 通过桑椹胚阶段，小鼠胚胎作为单个离散的 电泳条带的分子量为90 kDa。 在胚泡 然而，在第一阶段，分子作为一个宽的、不均匀的带迁移 范围为90至110 kDa。 使用畸胎瘤细胞类似物， 表明这条带实际上是三个不同分子的复合物， MW 90、95和110 kDa，每种分子量都是由 囊胚的不同细胞类型：胚胎外胚层（EE）和 内脏（VE）和壁内胚层（PE）。 调查 各种小鼠组织和细胞系仅揭示了这三种形式的 糖蛋白 所有未分化的细胞和精子都表达90 kDa的 胚胎外胚层的“胚胎”形式特征， 细胞和成体组织表达110 kDa的“成体”形式， 壁内胚层;只有胚胎内脏内胚层细胞已被证明 以表达95 kDa形式。 为了理解的意义 这些小鼠胚胎发育中的分子差异，我建议 分离胚胎和成体ESGps并分析其蛋白质， 碳水化合物部分。 将针对分离的 糖蛋白，并用于检查功能和分布的糖蛋白， 胚胎、组织和细胞系中的ESGp。 抗体也将被用于 筛选cDNA文库中的ESGp阳性克隆。 该cDNA将 测序和ESGp序列将在它们之间进行比较， 与所有其他已知序列可能的同源性。 这些研究将 这无疑增强了我们目前对生物化学和 遗传相互作用调节哺乳动物早期发育。

The goals of this proposal are to isolate and characterize a mammalian embryonic cell surface glycoprotein (ESGp) whose expression and biochemical structure appear to be developmentally regulated. ESGp from two cell through morula stage mouse embryos migrates as a single discrete electrophoretic band at a molecular weight of 90 kDa. At the blastocyst stage, however, the molecule migrates as a broad, heterogeneous band ranging from 90 to 110 kDa. Using teratocarcinoma cell analogues, I have shown that this band is actually a composite of three distinct molecules of MW 90, 95, and 110 kDa each of which is synthesized uniquely by the different cell types of the blastocyst: the embryonic ectoderm (EE) and visceral (VE) and parietal endoderms (PE), respectively. A survey of various mouse tissues and cell lines reveal only these three forms of glycoprotein. All undifferentiated cells and sperm express the 90 kDa "embryonic" form characteristic of embryonic ectoderm, which differentiated cells and adult tissues express the 110 kDa "adult" form characteristic of parietal endoderm; only embryonic visceral endoderm cells have been shown to express the 95 kDa form. In order to understand the significance of these molecular differences in mouse embryonic development, I propose to isolate the embryonic and adult ESGps and to analyze their protein and carbohydrate moieties. Antisera will be raised against the isolated glycoproteins and used to examine both the function and distribution of the ESGp in embryos, tissues and cell lines. The antibodies will also be used to screen cDNA libraries for ESGp positive clones. This cDNA will be sequenced and the ESGp sequences will be compared amongst themselves and with all other known sequences for possible homology. These studies will certainly enhance our current understanding of both the biochemical and genetic interactions regulating early mammalian development.