CHOLESTEROL REGULATION OF HMG COA REDUCTASE & LDLR GENES

HMG COA 还原酶的胆固醇调节

• 批准号: 2399086
• 负责人: Timothy F Osborne
• 金额: $ 19.14万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2399086
• 关键词: DNA binding protein; HMG coA reductases; acetyl coA carboxylase; chimeric proteins; cholesterol; enzyme mechanism; genetic promoter element; genetic regulation; genetic regulatory element; homeostasis; lipid metabolism; low density lipoprotein receptor; recombinant proteins; tissue /cell culture; transcription factor; transfection

DESCRIPTION (Adapted from applicant's abstract): The goal of the proposed work is to understand how different genes that are regulated by intracellular cholesterol levels are controlled coordinately and independently. By identifying the important cis acting DNA controlling elements and proteins that regulated gene activity through the cis-elements, a more thorough understanding of how diverse genes are regulated will be obtained. The first specific aim in the experiments of the current proposal are aimed at characterizing the roles for the YY1 (Red25) and SREBP proteins in regulation of the gene encoding HMG CoA reductase which is the rate controlling enzyme of cholesterol biosynthesis. YY1 and SREBP bind to an overlapping site that is required for feedback regulation by cholesterol in the reductase promoter. The studies described will evaluate the role for YY1 and SREBP through expression analyses of wild type and mutant forms of each protein in cultured cells along with cell free methods. The experiments will determine how YY1 and SREBP function (together or antagonistically) and will identify the functional domains of YY1 involved. In addition, the cell free DNA binding and protein-protein interaction studies will help uncover a mechanism for how each of the two proteins influences the function of the other. In the second specific aim, the role for the SREBP protein in the stimulation of the promoter for the LDL receptor, the main protein involved in cholesterol uptake from outside the cell, will be evaluated. The exact experiments will determine which specific features of the SREBP molecule are required to stimulate the DNA binding of its dependent co-regulatory Sp1. Previous studies have shown that the stimulation of Sp1 binding by SREBP is an essential part of the activation process of the LDL receptor in response to cholesterol levels. In the third specific aim, the DNA binding specificity of the different SREBP proteins SREBP-1 and -2 will be evaluated to help determine how the two proteins may function differently inside the cell to maintain cholesterol homeostasis. These studies focus on the exact mechanism for how intracellular cholesterol metabolism is regulated to maintain an adequate supply for this essential nutrient. By understanding the mechanism for regulation of intracellular cholesterol metabolism at the molecular level the principal investigator will be able to use this information in the future to determine why individuals in the human population have trouble maintaining cholesterol balance even when they significantly alter its intake through dietary restriction.

描述（根据申请人的摘要改编）：提议的目标 工作是了解如何受到不同基因的调节 细胞内胆固醇水平是协调一致的，并且 独立。 通过识别重要的顺式作用DNA控制 通过顺式元素调节基因活性的元素和蛋白质， 对如何调节多种基因的更彻底的了解将是 获得。 当前提案实验的第一个特定目的是针对的 在表征YY1（RED25）和SREBP蛋白的作用时 调节编码HMG COA还原酶的基因，这是速率 控制胆固醇生物合成的酶。 YY1和SREBP与 胆固醇反馈规定所需的重叠站点 还原酶启动子。 描述的研究将评估 YY1和SREBP通过野生型和突变形式的表达分析 培养细胞中的每种蛋白质以及无细胞方法。 这 实验将确定YY1和SREBP的功能（一起或一起） 拮抗），并将确定涉及的YY1的功能域。 另外，无细胞的DNA结合和蛋白质 - 蛋白质相互作用 研究将有助于发现两种蛋白质中每种蛋白质中每种的机制 影响对方的功能。 在第二个特定目标中，SREBP蛋白在 刺激LDL受体的启动子，涉及的主要蛋白 在细胞外的胆固醇摄取中，将评估。 确切的 实验将确定SREBP分子的哪些特定特征是 刺激其依赖性共调节SP1的DNA结合所需。 先前的研究表明，SREBP对SP1结合的刺激为 LDL受体的激活过程的重要部分 胆固醇水平。 在第三个特定目的中，DNA的结合特异性不同 将评估SREBP蛋白SREBP -1和-2，以帮助确定如何 两种蛋白质在细胞内的作用可能有所不同以维持 胆固醇稳态。 这些研究着重于细胞内胆固醇的确切机制 代谢受到监管，以维持这一基本的足够供应 养分。 通过了解调节细胞内的机制 分子水平的胆固醇代谢主要研究者 将来能够使用这些信息来确定为什么 人口中的个体难以维持胆固醇 即使他们通过饮食显着改变其摄入量的平衡 限制。