METABOLIC HEPATIC FLUX OF ISOPRENOIDS

类异戊二烯的代谢肝通量

• 批准号: 2519338
• 负责人: ISHAIAHU SHECHTER
• 金额: $ 32万
• 依托单位: HENRY M. JACKSON FDN FOR THE ADV MIL/MED
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-06-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2519338
• 关键词: cholesterol; enzyme activity; enzyme mechanism; farnesyl compound; genetic promoter element; genetically modified animals; isoprenoid; laboratory mouse; liver metabolism; molecular cloning; squalene; steroid biosynthesis; transcription factor; transferase

DESCRIPTION (Adapted from applicant's Abstract): The main objective of this proposal is to study the first specific enzyme in the cholesterol biosynthetic pathway, squalene synthase, in order to understand the mechanisms of its regulation. This objective is now obtainable since in the first three years of the project the investigators have obtained the cDNA clones of both the rat hepatic and the human hepatic enzymes as well as genomic clones of the 5' flanking sequences of the human gene. Based on work completed in the current grant period we now apply for a 5-year renewal in which the investigators propose to investigate the underlying mechanisms involved in the sterol-mediated transcriptional regulation of this gene. The investigators have identified a 69 bp promoter sequence which is responsible for this regulation and propose to investigate and elucidate the structure of the cis-acting elements which are involved in this regulation. It is further proposed to investigate the cellular trans-acting protein factors that are involved in the regulation of this gene and to compare them, and the regulatory mechanism to the regulation of other highly regulated enzymes in the cholesterol biosynthetic pathway. This will be achieved by the isolation and cloning of these protein factors and a detailed study of their interaction with the gene encoding squalene synthase. Based on results obtained in the current grant period the investigators propose to investigate the significance of the existence of different size-classes isoforms of squalene synthase mRNA in the regulation of this hepatic enzyme activity under varying cholesterogenic conditions. Finally, the investigators propose to verify the regulation of the human squalene synthase gene by its expression in transgenic mice. We also propose to study the implication of over production of this enzyme, in transgenic mice, on the overall metabolism of sterol and non sterol isoprenoids. The successful completion of these studies outlined in the grant application should enhance the understanding of the molecular basis of hepatic cholesterol production.

描述（改编自申请人的摘要）：此的主要目的 建议是研究胆固醇中的第一个特定酶 生物合成途径，小矛烯合酶，以了解 其调节机制。 现在可以实现此目标，因为在 该项目的前三年调查人员获得了cDNA 大鼠肝和人类肝酶的克隆以及 人类基因的5侧侧序序列的基因组克隆。 基于 在当前赠款期间完成的工作，我们现在申请5年续期 研究人员建议研究基本机制 参与该基因的固醇介导的转录调节。 研究人员已经确定了一个69 bp的启动子序列 负责此调节，并建议调查和阐明 该调节中涉及的顺式作用元件的结构。 进一步提出了研究细胞反式作用蛋白 调节该基因并比较的因素 它们以及其他高度调节的调节机制 胆固醇生物合成途径中的调节酶。 这将是 通过分离和克隆这些蛋白质因子和A 详细研究它们与编码矛质基因的相互作用 合酶。 根据当前赠款期间获得的结果 调查人员建议研究存在的重要性 在调节中，不同尺寸的小孢子合酶mRNA同工型 在不同的胆固醇条件下，这种肝酶活性。 最后，调查人员建议验证人类的调节 小鳞基因通过其在转基因小鼠中的表达。 我们也是 建议研究该酶过度生产的意义， 转基因小鼠，固醇和非固醇的总代谢 类异型。 这些研究的成功完成了 授予应用应增强对分子基础的理解 肝胆固醇生产。