Regulation of Gene Expression by Dietary Fat

膳食脂肪对基因表达的调节

• 批准号: 6741479
• 负责人: LISA M SALATI
• 金额: $ 22.06万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6741479
• 关键词: dietary lipid; gene expression; genetic regulation; genetic transcription; genetically modified animals; glucose 6 phosphate dehydrogenase; immunoprecipitation; laboratory mouse; laboratory rat; liver cells; mass spectrometry; messenger RNA; nutrition related tag; phosphorylation; polymerase chain reaction; posttranscriptional RNA processing; precursor mRNA; protein binding; protein structure function; tissue /cell culture; transfection; unsaturated fats; unsaturated fatty acids; western blottings

DESCRIPTION (provided by applicant): For at least three decades, the American public has been encouraged to decrease their consumption of total dietary fat and to increase the ratio of polyunsaturated to saturated fatty acids in the diet. Yet the molecular details by which fatty acids act within cells is not well understood. The long-range goal is to understand how the addition of polyunsaturated fat in the diet regulates intracellular metabolism in the liver. The objective of this application is to define the steps by which polyunsaturated fatty acids inhibit posttranscriptional steps during gene expression using G6PD as our model gene. The central hypothesis of the application is that efficient splicing of the G6PD transcript requires the binding of a specific splicing co-activator protein to a splicing enhancer sequence in an exon of the pre-mRNA. The addition of polyunsaturated fat to the diet inhibits the activity of the splicing co-activator, decreasing pre-mRNA splicing and thereby targeting the transcript for degradation. The rationale is that this mechanism is not unique to G6PD but is shared by other genes involved in intermediary metabolism including those that are also regulated at transcriptional steps. This additional level of regulation would provide the cell with both redundant mechanisms to ensure regulated expression of these proteins and a more rapid response to changing environmental conditions. G6PD provides an ideal model to study this novel form of posttranscriptional regulation because the absence of transcriptional changes makes interpretation of the data much easier. Experiments to characterize the sequence of the exon splicing enhancer element are described in Specific Aims 1. Specific Aim 2 tests if a splicing co-activator protein binds the RNA element and if mutations in the element block binding of this protein. A long-term goal of this project has been to identify the mechanism by which dietary fat regulated gene expression. In Specific Aim 3, transgenic mice expressing G6PD RNA reporters will be used to test if the exon splicing enhancer is involved in dietary regulation of gene expression. Identification of the molecular pathway by which dietary fat alters intracellular metabolism is critical to understanding the molecular basis for diseases such as obesity, diabetes and atherosclerosis that are associated with over-consumption of fat, and can lead to improved strategies for treatment of these diseases via diet or drug intervention.

描述（由申请人提供）：至少三十年来，美国公众一直被鼓励减少膳食脂肪总量并增加饮食中多不饱和脂肪酸与饱和脂肪酸的比例。然而，脂肪酸在细胞内发挥作用的分子细节尚不清楚。长期目标是了解饮食中添加多不饱和脂肪如何调节肝脏的细胞内代谢。本申请的目的是使用 G6PD 作为我们的模型基因来定义多不饱和脂肪酸在基因表达过程中抑制转录后步骤的步骤。该申请的中心假设是G6PD转录物的有效剪接需要特定剪接共激活蛋白与前mRNA外显子中的剪接增强子序列结合。在饮食中添加多不饱和脂肪会抑制剪接共激活剂的活性，减少前 mRNA 剪接，从而靶向转录物进行降解。其基本原理是，这种机制并非 G6PD 所独有，而是参与中间代谢的其他基因所共有的，包括那些也在转录步骤中受到调节的基因。这种额外的调节水平将为细胞提供冗余机制，以确保这些蛋白质的调节表达以及对不断变化的环境条件做出更快速的反应。 G6PD 为研究这种新型转录后调控提供了一个理想的模型，因为不存在转录变化使得数据的解释变得更加容易。表征外显子剪接增强子元件序列的实验在具体目标 1 中描述。具体目标 2 测试剪接共激活蛋白是否与 RNA 元件结合，以及元件中的突变是否阻止该蛋白的结合。该项目的长期目标是确定膳食脂肪调节基因表达的机制。在具体目标 3 中，将使用表达 G6PD RNA 报告基因的转基因小鼠来测试外显子剪接增强子是否参与基因表达的饮食调节。确定膳食脂肪改变细胞内代谢的分子途径对于了解与过度消耗脂肪相关的肥胖、糖尿病和动脉粥样硬化等疾病的分子基础至关重要，并且可以通过以下方式改进治疗这些疾病的策略：饮食或药物干预。