DIETARY REGULATION OF FATTY ACID SYNTHASE EXPRESSION

脂肪酸合酶表达的膳食调节

• 批准号: 2142434
• 负责人: STUART SMITH
• 金额: $ 20.85万
• 依托单位: CHILDREN'S HOSPITAL & RES CTR AT OAKLAND
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-15 至 1996-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2142434
• 关键词: DNA binding protein; adipocytes; dietary carbohydrates; fasting; fatty acid synthase; fusion gene; gene expression; genetic enhancer element; genetic promoter element; genetic regulatory element; genetically modified animals; hormone regulation /control mechanism; laboratory mouse; laboratory rat; liver cells; nuclear runoff assay; nutrition related tag; obesity; reporter genes; tissue /cell culture; transfection

The de novo lipogenic pathway plays a key role in the maintenance of energy balance in mammals. The rate of lipogenesis is modulated by die in a tissue-specific manner, and the hormone-dependency of the response depends on the type of carbohydrate (glucose or fructose) in the diet. The changes in lipogenic rate are accompanied by changes in the concentration of both the fatty acid synthase (FAS) enzyme and its mRNA in a tissue-specific manner, indicating that FAS is regulated at the level of transcription. The objective of the proposal is to characterize the promoter and enhancer regions of the FAS gene and determine how regulatory elements in these regions interact with trans-acting factors in mediating the response to nutritional status. Changes in the rate of transcription of the FAS gene, in response to carbohydrate-feeding (glucose and fructose), and fasting will be measured in both responsive and non-responsive control tissues. The transcriptional activity of putative promoter and enhancer elements will be assessed by measuring their ability to drive the expression of a coupled reporter gene in vitro. Hepatocyte and adipocyte cell models will be evaluated for their ability to mimic the pattern of FAS regulation observed in vivo and competent cells will be used to study the expression of transfected chimeric FAS/reporter genes. Deletions and mutations will be made in the putative FAS regulatory sequences and the effect on expression of the reporter gene measured. The possible roles of hormones as mediators of diet-induced changes in FAS transcription will be assessed in vitro by monitoring their effects on transcription of both the endogenous FAS gene and the transfected FAS/reporter gene. Candidate regulatory sequences identified in this way will be mapped using protein-DNA binding assays to determine whether specific sequences bind to nuclear proteins present in tissues, obtained from animals subjected to the various dietary regimens, in which the FAS gene is expressed or silent. Finally, the ability of identified promoter and cis-regulatory elements to mediate the die-induced regulation of FAS transcription will be tested in vivo by monitoring the expression of FAS/reporter gene chimeras in transgenic mice in response to changes in nutritional status. Altered expression of FAS and other lipogenic enzymes is observed in disordered states of energy balance such as obesity and cachexia. Obesity is recognized as predisposing to diabetes, hypertension and coronary artery disease. In order to understand how the altered gene expression occurs in obesity it will be necessary first to understand how expression of the genes for lipogenic enzymes is regulated.

从头脂肪生成途径在维持能量中起着关键作用 哺乳动物的平衡。 脂肪生成的速率是通过在 组织特异性方式和反应的激素依赖性取决于 饮食中的碳水化合物（葡萄糖或果糖）的类型。 更改 脂肪生成率伴随着两者的浓度的变化 脂肪酸合酶（FAS）酶及其在组织特异性中的mRNA 方式表明FAS在转录水平下受到调节。 该提案的目的是表征发起人和增强子 FAS基因的区域，并确定这些区域的调节元素如何 区域与跨性别因子相互作用，以介导对 营养状况。 FAS基因转录速率的变化，响应于 碳水化合物喂养（葡萄糖和果糖），将测量禁食 在反应性和无反应性控制组织中。 转录 推定启动子和增强子元素的活动将由 测量其驱动耦合报告基因表达的能力 体外。 将评估肝细胞和脂肪细胞细胞模型的 能够模仿体内观察到的FAS调节模式 主管细胞将用于研究转染的表达 嵌合FAS/报告基因。 删除和突变将在 假定的FAS调节序列以及对表达的影响 测量报告基因。 激素作为介体的可能作用 饮食引起的FAS转录变化将在体外评估 监视它们对两个内源性FAS基因转录的影响 和转染的FAS/报告基因。 候选调节序列 以这种方式识别将使用蛋白-DNA结合测定与 确定特定序列是否与存在的核蛋白结合 从受到各种饮食方案的动物获得的组织， 其中FAS基因表示或沉默。 最后，能力 确定的启动子和顺式调节元素，以介导模具诱导的 FAS转录的调节将在体内测试，通过监测 FAS/报告基因基因嵌合在转基因小鼠中的表达 营养状况的变化。 在 肥胖和恶病质等能量平衡状态无序状态。 肥胖 被认为易感糖尿病，高血压和冠状动脉 疾病。 为了了解改变的基因表达如何发生在 肥胖是首先必须了解如何表达 调节脂肪酶的基因。