GLUCOSYLTRANSFERASE IN MAMMARY GLAND

乳腺中的葡萄糖基转移酶

• 批准号: 3303870
• 负责人: INDER K VIJAY
• 金额: $ 7.33万
• 依托单位: UNIV OF MARYLAND, COLLEGE PARK
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3303870
• 关键词: affinity chromatography; affinity labeling; antibody formation; dolichol; enzyme structure; glucose metabolism; glycoprotein biosynthesis; glycosyltransferase; hormone regulation /control mechanism; immunoprecipitation; laboratory rabbit; laboratory rat; lactation; mammary gland; molecular cloning; protein purification; transposon /insertion element; western blottings

The biosynthesis of N-linked glycoproteins involves a step wise, dolichol- linked assembly of a tetrasaccharide precursor, Glc3Man9GlcNAc2 and its en bloc transfer to the nascent peptide followed by co- and post-translational modifications of the oligosaccharyl moiety. The donor for the glycosyl residues in the precursor is Glc-P-Dol; its biosynthesis is catalyzed by UDP-Glc:Dol-P glucosyltransferase. It has been shown that glucosylation of the precursor signals its transfer to the acceptor polypeptides. One may hypothesize that the action of glucosyltransferase represents a key step for the overall regulation of N-glycosylation. The mammary gland possesses some unique features for studying the biosynthesis and regulation of glycoproteins. It is under intense hormonal modulation for its growth and development as it repeatedly cycles between dormancy -> gestation -> lactation -> regression -> dormancy throughout the reproductive life of the female. Further, the lactating gland synthesizes and secretes massive amounts of only a limited number of well characterized glycoproteins into milk. Previous studies from our laboratory have elucidated the outlines of the dolichol cycle and the stereochemical structures of the intermediates of the cycle in the mammary gland. The first enzyme, i.e., UDP-GlcNAc:Dol- P GlcNAc-1-P-transferase and processing-specific glucosidases I and II have been purified. The proposed program will purify, characterize and clone the glucosyltransferase. Innovative methodologies, based on the synthesis of novel analogs of the enzyme substrate will be incorporated in the purification protocol. The enzyme cDNA will be cloned in the expression vector lambdaZAP-II. IN studies outside the scope of this work, molecular probes for glucosyltransferase will be employed to investigate the gland. The recent pioneering studies on the expression of glycosylated and functional glycoproteins tPA, alpha-antitrypsin and blood clotting factor IX in the milk of transgenic animals illustrate the power of the mammary gland as a bioreactor of immense potential for biomedical and agrochemical purposes. Glycoproteins participate in a wide spectrum of biological functions and recognition phenomena. Pathological states including malignancy, atherosclerosis and many autosomal recessive disorders are accompanied with marked alterations in cellular glycoprotein metabolism. A glycoprotein-glycoprotein interaction between gp120 of HIV and CD4 receptor on the lymphocyte provides the entry port for the introduction of viral genetic material into the host leading to AIDS.

N连接糖蛋白的生物合成涉及阶梯方面的Dolichol- 四糖前体的链接组装Glc3Man9GlCNAC2及其EN 集体转移到新生的肽，然后转移到同时和翻译后 寡素charyl部分的修改。 糖基的供体 前体中的残基是GLC-P-DOL；它的生物合成是由 UDP-GLC：DOL-P-P葡萄糖基转移酶。 已经表明 前体信号将其转移到受体多肽中。 一个可能 假设葡萄糖基转移酶的作用代表了一个关键步骤 用于N-糖基化的总体调节。 乳腺拥有 研究生物合成和调节的一些独特功能 糖蛋白。 它的生长和 发育是在休眠 - >妊娠之间反复循环的发展 - > 哺乳 - >回归 - >整个生殖生活的休眠 女性。 此外，哺乳期合成并分泌大量 只有有限数量的良好特征糖蛋白到 牛奶。 我们实验室的先前研究阐明了 Dolichol循环和中间体的立体化学结构 乳腺周期的周期。 第一种酶，即udp-glcnac：dol- P GlcNAC-1-P-转移酶和加工特异性葡萄糖酶I和II具有 被纯化。 提议的程序将净化，表征和克隆 葡萄糖基转移酶。 创新方法，基于合成 酶底物的新型类似物将纳入 纯化协议。 酶cDNA将在表达中克隆 vector lambdazap-ii。 在这项工作范围之外的研究中，分子 葡萄糖基转移酶的探针将用于研究腺体。 最近关于糖基化和 功能性糖蛋白TPA，α-抗胰蛋白酶和血液凝血因子 ix在转基因动物的牛奶中说明了乳腺的力量 腺体作为生物医学和农业化学潜力的生物反应器 目的。 糖蛋白参与广泛的生物学 功能和识别现象。 病理状态包括 恶性，动脉粥样硬化和许多常染色体隐性疾病是 伴随着细胞糖蛋白代谢的明显改变。 一个 HIV和CD4受体GP120之间的糖蛋白 - 糖蛋白相互作用 在淋巴细胞上提供了引入病毒的入口端口 遗传物质进入宿主，导致艾滋病。