Regulation of Gene Expression by Dietary Fat

饮食中脂肪的数量和类型一直是公共卫生的主题 预防肥胖、糖尿病和动脉粥样硬化的建议。一个相当大的身体 已有大量文献表明，摄入大部分卡路里会导致肥胖 在胰岛素抵抗和II型糖尿病的发展中起重要作用。更少的是 已知饮食脂肪摄入量的非病理性波动如何改变细胞内 新陈代谢以及这些信号活动如何影响核内的事件。葡萄糖-6- 磷酸脱氢酶为研究这些核事件提供了一个独特的模型。 首先，它作为一种生脂酶的作用使其在血脂异常的病因学中具有重要意义。 其次，它参与了一个假定的碳水化合物信号分子的产生 参与糖酵解和产脂基因的转录调控。最后， 它在一个独特的转录后步骤被调节，允许探索新的 转录调控之外的调控机制。我们已经证明了 多不饱和脂肪酸降低G6PD前-mRNA的剪接率，而 该基因的转录活性不受调控。这个项目的总体目标是 了解这种受调控的剪接的分子机制。这样做的目的是 应用是确定参与这一调控的剪接调节蛋白 G6PD剪接以及多不饱和脂肪如何抑制其活性。中心假说 应用的目的是G6PD外显子12的剪接调节区包含 并列拼接、沉默和增强元素。HnRNP K和/或的结合 L以沉默的方式排除了剪接激活蛋白与增强子的结合。 多不饱和脂肪酸通过以下途径调节剪接调节蛋白的活性 翻译后修饰和/或核丰度。尽管无所不在地需要 调控剪接，对调控这一过程的细胞内信号知之甚少。 我们的实验首次将抑制剪接描述为一种 多不饱和脂肪抑制基因表达。因此，实验中的 目前的提案将提供有关剪接压力监管的新数据，并定义新的 营养物质调节基因表达的途径。

The amount and type of fat in the diet has been the subject of public health recommendations to prevent obesity, diabetes and atherosclerosis. A considerable body of literature has developed that suggests that eating the majority of calories as fat results in the development of insulin resistance and type II diabetes mellitus. Much less is known about how non-pathological fluctuations in dietary fat intake alter intracellular metabolism and how these signaling actions affect events in the nucleus. The glucose-6- phosphate dehydrogenase enzyme provides a unique model to study these nuclear events. First, its role as a lipogenic enzyme makes it important in the etiology of dyslipidemias. Second, it participates in the generation of a putative carbohydrate signaling molecule involved in the transcriptional regulation of both glycolytic and lipogenic genes. Finally, it is reglated at a unique posttranscriptional step permitting the exploration of new regulatory mechanisms beyond transcriptional regulation. We have demonstrated that polyunsaturated fatty acids decrease the rate of splicing of the G6PD pre-mRNA, while transcriptional activity of the gene is not regulated. The overall goal of this project is to understand the molecular mechanism for this regulated splicing. The objective of this application is to define the splicing regulatory proteins involved in this regulation of G6PD splicing and how polyunsaturated fats inhibit their activity. The central hypothesis of the application is that the splicing regulatory region of G6PD exon 12 contains juxtaposed splicing silencing and enhancing elements. The binding of hnRNP K and/or L to the silencer exclude the binding of splicing activators proteins to the enhancer. Polyunsaturated fatty acids regulate the activity of the splicing regulatory proteins by posttranslational modification and/or nuclear abundance. Despite the ubiquitous need for regulated splicing, little is known about the intracellular signals regulating this process. Our experiments are the first to describe inhibition of splicing as a mechanism for inhibition of gene expression by polyunsaturated fat. Thus, the experiments in the current proposal will provide new data on regulation of splicing pre se and define a new pathway by which nutrients regulate gene expression.