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: 6612765
• 负责人: BRENDA K SMITH RICHARDS
• 金额: $ 32.08万
• 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/6612765
• 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）：本申请是我们之前拨款的直接延续，该拨款旨在控制 C67BL/6J 和 CAST/Ei 小鼠近交系中控制大量营养素选择的 QTL 的遗传图谱，这些小鼠近交系在自我选择的大量营养素饮食摄入方面存在显着差异。全基因组扫描显示，6、8、17、18 和 X 染色体上代表自选脂肪和碳水化合物摄入量的性状存在显着关联。当体重用作协变量时，17 号和 18 号染色体上的基因座也与总能量摄入量相关。这些是在小鼠体内绘制的第一个关于食物偏好或总能量摄入的 QTL。当前提案的总体目标是确定 Mnif1 的候选基因，Mnif1 是位于 8 号染色体上的膳食脂肪摄入量的数量性状位点 (QTL)，以及位于 17 号染色体上的碳水化合物和千卡摄入量的 Mnic1 的候选基因。在目标 1 中，我们将通过开发 B6.CAST 同源和亚同源系，分离并缩小 Mnif1 和 Mnic1 间隔至适合位置候选方法的大小。在目标 2 中，基因表达微阵列将用于鉴定候选基因。微阵列探针将由来自我们实验室开发的受体菌株（B6）和间隔特异性亚同类菌株（B6.CAST）组织的 cDNA 组成，将从对食物摄入表型调节重要的组织中收获 mRNA，即下丘脑、孤束核/后区、肝脏、胃、小肠、胰腺、 脂肪细胞、肌肉。首先，将使用现已准备好并可从 PBRC Genomics Core 获得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，我们将表征 QTL 内基因效应上游或下游发生的转录差异。这些数据将为控制这些摄食行为的过程提供一个切入点，并为识别最有希望用 QTL 特异性阵列进行分析的组织提供切入点。接下来，将设计定制阵列，以对控制 Chr 8 (Mnif1) 脂肪摄入和 Chr 17 (Mnic1) 碳水化合物摄入的 QTL 亚同类区间中存在的所有小鼠和人类基因的转录活性进行全面分析。了解摄食性状的生物学知识以及对 QTL 内外差异表达基因的分析将有助于我们将候选基因的数量减少到极少，并选择那些值得进一步研究的基因，以在确定表型中发挥功能作用。候选基因的鉴定将增强我们对食物摄入调节的理解。在小鼠中寻找调节大量营养素摄入的基因将有助于我们了解遗传因素与环境因素对人类食物偏好的影响。这应该会带来对肥胖和糖尿病的有价值的见解，以及改变常量营养素选择的新方法，这可能有助于控制体重增加或促进减肥。