PILOT STUDY--MOLECULAR MECHANISMS OF APOLIPOPROTEIN B BIOGENESIS

我们拟研究载脂蛋白B（apo B）在细胞内的作用过程 生物发生和脂蛋白颗粒形成。 载脂蛋白B， 在肝脏和肠道中合成，在胆固醇中起主要作用 运输 高胆固醇血症是动脉粥样硬化的主要危险因素 和冠心病。 血清水平升高的患者亚组 胆固醇在apo B结构上有缺陷，而许多其他胆固醇 含载脂蛋白B的代谢和清除中的未表征畸变 脂蛋白 对这些缺陷的分子理解将需要 关于正常脂蛋白颗粒 组装完成。 尽管在了解一般情况方面取得了重大进展 蛋白质生物合成的机制，脂蛋白的特定过程， 组装仍然在很大程度上未知。 我们将表达部分和全长 在两种膜补充的无细胞系统中克隆编码apo B的cDNA 和活细胞（非洲爪蟾卵母细胞）中。 载脂蛋白B生物合成的中间体， 通过脉冲追踪免疫沉淀鉴定，将与 载脂蛋白B跨内质网膜转运， 脂蛋白颗粒组装。 这些试点研究将启动一项计划， 目的在于解剖和重建载脂蛋白B的易位，装配， 细胞内运输和分泌。 通过这项工作将出现一个 载脂蛋白B生物发生中事件的分子描述和 与之相关的脂蛋白颗粒。 这种理解将 最终提供了对异常粒子可能作用的深入了解 在人类脂蛋白紊乱中的组装。

We propose to investigate the processes of apolipoprotein B (apo B) biogenesis and lipoprotein particle formation. Apolipoprotein B, synthesized in liver and intestine, plays a major role in cholesterol transport. Hypercholesterolemia is a major risk factor for atherosclerosis and coronary artery disease. A subset of patients with elevated serum cholesterol have defects in apo B structure, while many others have uncharacterized aberrations in metabolism and clearance of apo B containing lipoproteins. A molecular understanding of these defects will require detailed knowledge of the mechanism by which a normal lipoprotein particle is assembled. Despite major progress in understanding the general mechanisms of protein biogenesis, the specific process of lipoprotein assembly remains largely unknown. We will express partial and full-length cloned cDNAs encoding apo B in both membrane-supplemented cell-free systems and in living cells (Xenopus oocytes). Intermediates in apo B biogenesis, identified by pulse-chase immunoprecipitation, will be related to stages in apo B translocation across the endoplasmic reticulum membrane and lipoprotein particle assembly. These pilot studies will initiate a program aimed at dissection and reconstitution of apo B translocation, assembly, intracellular transport and secretion. Through this work will emerge a molecular description of events in the biogenesis of apo B and the lipoprotein particles with which it is associated. This understanding will ultimately provide insight into possible roles for aberrant particle assembly in lipoprotein disorders of humans.