Candidate Gene Analysis for Macronutrient Selection QTL

大量营养素选择QTL的候选基因分析

• 批准号: 6937053
• 负责人: BRENDA K SMITH RICHARDS
• 金额: $ 28.11万
• 依托单位: LSU PENNINGTON BIOMEDICAL RESEARCH CTR
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6937053
• 关键词: chromosomes; dietary carbohydrates; dietary lipid; gene expression; genetic mapping; genetic models; genetic strain; laboratory mouse; linkage mapping; microarray technology; molecular genetics; nutrient intake activity; nutrition related tag; phenotype; polymerase chain reaction; quantitative trait loci; weight gain

DESCRIPTION (provided by applicant): This application is a direct continuation of our previous grant directed at the genetic mapping of QTL controlling macronutrient selection in the C67BL/6J and CAST/Ei mouse inbred strains which differ markedly in their self-selected intake of macronutrient diets. A genome-wide scan revealed significant linkage for traits representing self-selected fat and carbohydrate intake on chromosome 6, 8, 17, 18 and X. Loci on chromosome 17 and 18 were linked also to total energy intake when body weight was used as a covariate. These are the first QTL for food preference or total energy intake that have been mapped in the mouse. The overall goal of the current proposal is to identify candidate genes underlying Mnif1, a quantitative trait locus (QTL) for dietary fat intake located on chromosome 8, and Mnic1 on chromosome 17 for carbohydrate and kilocalorie intake. In Aim 1, we will isolate and narrow the Mnif1 and Mnic1 intervals to a size suitable for the positional candidate approach, by developing B6.CAST congenic and subcongenic lines. In Aim 2, gene expression microarrays will be used to identify candidate genes. The probes for the microarrays will consist of cDNA from tissues of the recipient strain (B6) and the interval-specific subcongenic strains (B6.CAST) developed in our laboratory, mRNA will be harvested from tissues important in the regulation of food intake phenotypes, i.e, hypothalamus, solitary tract nucleus/area postrema, liver, stomach, small intestine, pancreas, adipocyte, muscle. First, a genome-wide gene expression screen will be performed using a mouse oligonucleotide array (16,463 genes from UniGene) now ready and available from the PBRC Genomics Core. Thus we will characterize transcriptional differences that occur upstream or downstream from effects of genes within the QTL. These data will provide an entry point for modelling the process by which these feeding behaviors are controlled, and for identifying the most promising tissues to profile with the QTL-specific arrays. Next, custom arrays will be designed for the purpose of performing comprehensive analyses of the transcriptional activity of all mouse and human genes present in the subcongenic intervals for the QTL controlling fat intake on Chr 8 (Mnif1) and carbohydrate intake on Chr 17 (Mnic1). Knowledge of the biology of the feeding traits and analysis of differentially expressed genes within and outside of the QTL will help us reduce the number of candidates to a very few and select those that deserve further investigation for a functional role in determining the phenotype. Candidate gene identification will enhance our understanding of the regulation of food intake. Finding genes regulating macronutrient intake in mice will help us to understand the contribution of genetic versus environmental factors affecting food preferences in humans. This should lead to valuable insights into obesity and diabetes, and new approaches for modifying macronutrient selection that could be useful in controlling weight gain or promoting weight loss.

描述（由申请人提供）：该申请是我们之前资助的直接延续，该资助针对C67BL/6J和CAST/Ei小鼠自交品系中控制大量营养素选择的QTL遗传定位，这些自交品系在大量营养素饮食的自我选择摄入量方面存在显著差异。全基因组扫描显示，当体重作为一个辅助变量时，第6、8、17、18和x染色体上代表自我选择的脂肪和碳水化合物摄入量的性状与第17和18染色体上的位点也与总能量摄入有关。这是第一个在老鼠身上绘制的食物偏好或总能量摄入的QTL。目前研究的总体目标是确定mif1和Mnic1的候选基因，mif1是8号染色体上的一个决定膳食脂肪摄入量的数量性状位点（QTL）， Mnic1位于17号染色体上，决定碳水化合物和卡路里摄入量。在Aim 1中，我们将通过开发B6将mif1和Mnic1间隔隔离并缩小到适合位置候选方法的大小。CAST同源系和亚同源系。在第二阶段，基因表达微阵列将用于鉴定候选基因。微阵列探针将包括来自受体菌株（B6）和我们实验室开发的间隔特异性亚基因菌株（B6. cast）组织的cDNA， mRNA将从调节食物摄入表型的重要组织中收集，即下丘脑、孤立束核/区后脑、肝脏、胃、小肠、胰腺、脂肪细胞、肌肉。首先，将使用PBRC Genomics Core已经准备好的小鼠寡核苷酸阵列（来自UniGene的16,463个基因）进行全基因组基因表达筛选。因此，我们将描述发生在QTL内基因影响的上游或下游的转录差异。这些数据将为控制这些摄食行为的过程建模提供切入点，并为确定最有希望用qtl特定阵列进行分析的组织提供切入点。接下来，将设计定制阵列，对控制Chr 8 （mif1）上脂肪摄入和Chr 17 （Mnic1）上碳水化合物摄入的QTL在亚同源区间中存在的所有小鼠和人类基因的转录活性进行综合分析。对取食性状的生物学知识和对QTL内外差异表达基因的分析将帮助我们减少候选基因的数量，并选择那些值得进一步研究的基因，以确定表型的功能作用。候选基因的鉴定将增强我们对食物摄入调控的理解。找到调节小鼠大量营养素摄入的基因将有助于我们了解影响人类食物偏好的遗传因素和环境因素的作用。这将为肥胖和糖尿病的研究提供有价值的见解，并为控制体重增加或促进体重减轻而调整宏量营养素选择提供新方法。