IMPACT OF GENETIC ALTERATIONS ON LIPOPROTEIN METABOLISM

这项计划的总体目标是开发新的动物 研究调节血浆中的代谢途径的模型 脂蛋白和胆固醇稳态。 这其中的主要焦点 建议将使用转基因动物（小鼠和兔子）， 过表达或不能表达涉及脂蛋白的特定基因， 胆固醇代谢，以了解其生理功能 这些蛋白质的功能及其故障的后果。 发展 这些动物模型应该提供新的见解的功能， 载脂蛋白（apo-）C-I、apo-C-II、apo-E、肝脂酶、apo-B、apo-B mRNA编辑因子和乙酰基低密度脂蛋白（LDL） 受体的 此外，使用动物进行的研究表明， 改变一个成分，应该会增强我们对 脂质、载脂蛋白和血浆酶之间的复杂相互作用 构成脂蛋白通路并调节血浆胆固醇 程度. 这些研究旨在阐明apo-C-I的作用， apo-C-Ⅲ和apo-E在乳糜微粒残体中的变异形式; 乙酰LDL受体在动脉粥样硬化中的作用; apo-B的肝形式（apo-B100）和apo-B的肠形式 （apo-B48）参与脂蛋白代谢。 此外，细胞生物学研究 将专注于含载脂蛋白B的脂蛋白合成， apo-B mRNA编辑的机制，以及apo-B基因表达的调控， 乙酰LDL受体 这些研究将采用多学科方法，包括 许多现代技术，从细胞生物学，免疫学，电子 显微学、病理学、遗传学、生物化学和动物生理学。 在 此外，本方案还有三大技术目标： 通过同源重组建立基因靶向， 对野生型基因进行定义的修饰;（2）开发转基因 兔子，这将提供一个更大的动物模型，其脂蛋白 生理学和动脉粥样硬化与人类相似;以及（3） 在转基因兔子中产生负显性突变， 允许消除特定的基因功能，而不诉诸 同源重组 转基因动物的产生，其中脂蛋白中的关键基因 代谢可以被选择性地删除或表达，这将有助于 增加对胆固醇代谢的分子基础的理解， 人类高脂血症的原因， 动脉粥样硬化 此外，基因缺陷的动物模型， 特异性脂蛋白紊乱将可用于测试治疗 干预措施。

The overall goal of this Program Project Grant is to develop new animal models in which to investigate metabolic pathways that regulate plasma lipoproteins and cholesterol homoeostasis. The major focus of this proposal will be to use transgenic animals (mice and rabbits) that overexpress or fail to express specific genes involved in lipoprotein and cholesterol metabolism in order to understand the physiological function of these proteins and the consequences of their malfunction. Development of these animal models should provide new insights into the function of apolipoprotein (apo-) C-I, apo-C-II, apo-E, hepatic lipase, apo-B, apo-B mRNA editing factor(s), and the acetyl low density lipoprotein (LDL) receptor. Moreover, studies using animals in which the function of a single component is altered should enhance our understanding of the complex interactions among lipids, apolipoproteins, and plasma enzymes that constitute lipoprotein pathways and regulate plasma cholesterol levels. The studies are designed to elucidate the role of apo-C-I, apo-C-III, and variant forms of apo-E in chylomicron remnant catabolism; the role of the acetyl LDL receptor in atherosclerosis; and the role of the hepatic form of apo-B (apo-B100) and the intestinal form of apo-B (apo-B48) in lipoprotein metabolism. In addition, cell biology studies will focus on the synthesis of apo-B-containing lipoproteins, the mechanisms of apo-B mRNA editing, and the regulation of expression of the acetyl LDL receptor. A multidisciplinary approach will be used for these studies, including many modern techniques from cell biology, immunology, electron microscopy, pathology, genetics, biochemistry, and animal physiology. In addition, this proposal has three major technical objectives: (1) to establish gene targeting by homologous recombination, which will permit the defined modification of wild-type genes; (2) to develop transgenic rabbits, which will provide a larger animal model whose lipoprotein physiology and atherosclerosis are similar to those of humans; and (3) to develop negative dominant mutations in transgenic rabbits, which will permit the elimination of specific gene function without resorting to homologous recombination. The generation of transgenic animals in which key genes in lipoprotein metabolism can be selectively deleted or expressed will contribute to an increased understanding of the molecular basis of cholesterol metabolism, the causes of hyperlipidemia in humans, and the pathogenesis of atherosclerosis. In addition, animal models with gene defects that cause specific lipoprotein disorders will be useful for testing therapeutic interventions.