DEVELOPMENTAL REGULATION OF MAMMARY GLYCOPROTEINS

我们计划的最终目标是描绘分子基础 用于动物生长和发育过程中的基因表达。的关注点 本研究是关于蛋白质N-的激素调节的研究。 乳腺中的糖基化作用。天冬酰胺连接糖蛋白 由最大的一类糖蛋白组成，参与了无数种 这些现象是生物识别的基础。改建 糖蛋白新陈代谢与多种病理有关， 例如，恶性肿瘤、动脉粥样硬化、多种遗传性疾病以及 最初的宿主-寄生虫相互作用导致艾滋病。一场音乐会 17种糖基转移酶和两种糖苷酶，即葡萄糖苷酶 I和II是组装所有N-连接的最低要求 糖蛋白。其中，UDP-GlcNAc：Dolicol-P GlcNAc-1-P-转移酶 (GPT)和葡萄糖苷酶I在第一次承诺的关键位置 生物合成和初始反应进行加工的步骤， 分别在组装的多酶途径中。这些酶， 因此，控制碳水化合物的流量，就会显得 蛋白质N-的整体调控的优秀候选者 糖基化。拟议的调查将集中于审查 利用分子生物学对这些酶的激素调节 与HC11细胞的接触，这是一种来源于 小鼠乳腺。此外，还提出了生物化学实验。 这将挖掘我们开发的一种新方法的潜力 实验室绘制和描绘葡萄糖苷酶的活性部位 通过按顺序删除不同的域进行初步分析 还提出了葡萄糖苷酶I保持内质网的分子基础。 这些研究是我们正在进行的研究和工作的延伸 这是在前一个供资期间完成的。 乳腺为研究者研究提供了一个独特的模型。 糖蛋白在生物化学和生物化学中的生物合成和调节 分子生物学水平。这一组织受到强烈的 激素为其在整个生殖过程中的生长和分化 女性的生命。它有可能成为一种很好的生物反应器。 在转基因动物中收获大量生物医学上的 它的分泌物中含有重要的糖蛋白，即牛奶。初步 成功分泌α-抗胰蛋白酶、组织型纤溶酶原 激活剂和凝血因子似乎非常有前途。

The ultimate objective of our program is to delineate the molecular basis for gene expression during animal growth and development. The focus of the investigation is on the hormonal regulation of protein N- glycosylation in the mammary gland. Asparagine-linked glycoproteins comprise the largest class of glycoproteins and are involved in a myriad of phenomena that are fundamental to biological recognition. Alterations in glycoprotein metabolism are associated with a variety of pathologies, e.g., malignancy, atherosclerosis, numerous genetic disorders and the initial host-parasite interaction leading to AIDS. A concert of seventeen glycosyltransferases and two glycosidases, viz., glucosidase I and II are minimally required for the assembly of all N-linked glycoproteins. Among these, UDP-GlcNAc:Dolichol-P GlcNAc-1-P-transferase (GPT) and glucosidase I are critically positioned at the first committed step for the biosynthesis and the initial reaction for processing, respectively, in the multienzyme pathway of assembly. These enzymes, therefore, control the flux of carbohydrate and would appear to be excellent candidates for the overall regulation of protein N- glycosylation. The proposed investigation will focus on examining the hormonal modulation of these enzymes using molecular-biological approaches with HC11 cells, an epithelial cell line derived from the mouse mammary gland. Additionally, biochemical experiments are proposed that will exploit the potential of a novel methodology developed in our laboratory to map and delineate the active site of glucosidase I. A preliminary analysis by sequentially deleting various domains for the molecular basis for the ER-retention of glucosidase I is also proposed. these studies represent an extension of our ongoing studies and the work that has been accomplished in the previous funding period. The mammary gland offers a unique model to the investigator for studying glycoprotein biosynthesis and regulation at the biochemical and molecular-biological level. This tissue is intensely modulated by hormones for its growth and differentiation throughout the reproductive life of the female. It can potentially serve as an excellent bioreactor in transgenic animals to harvest large quantities of biomedically significant glycoproteins in its secretion, i.e., milk. Preliminary successes with the secretion of alpha-antitrypism, tissue plasminogen activator, and blood clotting factors appear very promising.