DIETARY REGULATION OF FATTY ACID SYNTHASE EXPRESSION

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。脂肪生成的速度受体内脂肪的调节。 组织特异性的方式，反应的激素依赖性取决于 根据饮食中碳水化合物的类型(葡萄糖或果糖)。这些变化 在成脂率中伴随着两者浓度的变化 组织特异性脂肪酸合成酶及其mRNA的研究 这表明Fas在转录水平上受到调控。 该提案的目的是描述启动子和增强子的特征 Fas基因的区域并确定这些区域中的调控元件 区域与反式作用因子相互作用，调节对 营养状况。 Fas基因转录速率的变化，以响应 将测量碳水化合物摄入量(葡萄糖和果糖)和空腹时间 在反应性和非反应性对照组织中。转录本 可能的启动子和增强子元件的活性将通过以下方式进行评估 测量它们驱动偶联报告基因表达的能力 在试管中。肝细胞和脂肪细胞模型将被评估其 能够模拟体内观察到的Fas调控模式和 将使用感受态细胞来研究转基因细胞的表达。 嵌合Fas/报告基因。删除和突变将在 推测的Fas调控序列及其对基因表达的影响 记者基因测量。激素作为血管紧张素转换酶的介体的可能作用 饮食诱导的Fas转录变化将通过以下方法在体外进行评估 监测它们对内源性Fas基因转录的影响 和Fas/报告基因的表达。候选调控序列 以这种方式识别的将使用蛋白质-DNA结合分析来映射到 确定特定序列是否与存在于 组织，从接受不同饮食方案的动物身上获得， Fas基因在其中表达或沉默。最后，有能力 确定了介导芯片诱导的启动子和顺式调控元件 Fas转录的调节将在体内通过监测 Fas/Report基因嵌合体在转基因小鼠中的表达 营养状况的变化。 观察到Fas和其他造脂酶的表达变化 能量平衡失调的状态，如肥胖和恶病质。肥胖 被公认为易患糖尿病、高血压和冠状动脉 疾病。为了了解改变的基因表达是如何发生在 肥胖症首先有必要了解 产脂酶的基因是受调控的。

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.