DIETARY REGULATION OF FATTY ACID SYNTHASE EXPRESSION

脂肪酸合酶表达的膳食调节

• 批准号: 3243784
• 负责人: STUART SMITH
• 金额: $ 21.56万
• 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/3243784
• 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.

新生脂肪生成途径在维持能量方面起着关键作用 哺乳动物的平衡 脂肪生成的速率在一个 组织特异性的方式，和响应依赖于 饮食中碳水化合物的类型（葡萄糖或果糖）。 的变化 脂肪生成率的变化伴随着两者浓度的变化 脂肪酸合成酶（FAS）及其mRNA在组织特异性 这表明FAS在转录水平上受到调控。 该提案的目的是表征启动子和增强子 FAS基因的区域，并决定这些区域中的调控元件如何 区域与反式作用因子相互作用， 营养状况 FAS基因转录速率的变化，以响应 碳水化合物喂养（葡萄糖和果糖）和禁食将被测量 在有反应和无反应的对照组织中。 转录 推定的启动子和增强子元件的活性将通过 测量它们驱动偶联报告基因表达的能力 体外 将评价肝细胞和脂肪细胞模型的 模拟体内观察到的FAS调节模式的能力， 感受态细胞将用于研究转染的 嵌合FAS/报告基因。 删除和突变将在 假定的FAS调节序列和对表达的影响， 报告基因测定。 激素作为介体的可能作用 将通过以下方法在体外评估饮食诱导的FAS转录变化： 监测它们对内源性FAS基因 和转染的FAS/报告基因。 候选调控序列 将使用蛋白质-DNA结合测定来绘制以这种方式鉴定的基因图谱， 确定特定序列是否与细胞核中存在的核蛋白结合， 从接受各种饮食方案的动物获得的组织， 其中FAS基因被表达或沉默。 最后，能力 鉴定的启动子和顺式调节元件介导死亡诱导的 FAS转录的调节将通过监测 FAS/报告基因嵌合体在转基因小鼠中的表达 营养状况的变化。 FAS和其他脂肪生成酶的表达改变， 能量平衡紊乱状态，如肥胖和恶病质。 肥胖 被认为易患糖尿病、高血压和冠状动脉 疾病 为了了解基因表达的改变是如何发生的， 肥胖，首先有必要了解如何表达的 脂肪生成酶的基因受到调节。