Mapping adiposity genes in mice

在小鼠中，许多基因组区域包含导致肥胖差异的变异 (Reed 2003年; 2006年; 2007年; 2008年）。这项研究计划的目标是找到基因或 小鼠9号染色体上的基因，它们负责数量性状基因座Adip 5， 与性腺脂肪库的重量增加有关。尽管几 一系列的证据表明，这里的一个基因或遗传变异有能力调节 肥胖症，导致这种影响的确切基因或DNA序列尚不清楚。的 QTL Adip 5具有使其成为位置克隆方法的实用靶标的特征： 它对母体效应或上位相互作用不是特别敏感， 与不同的表型（性腺贮库重量）相关。而且 设计实验方案以鉴定Adip 5是否基因座被印迹（即，如果有 原始效应）。在当前Adip 5置信区间内，有几个 可信的候选基因（Bbs 4、Cpy 19 a1、Crapp 1、Cplx 3、Il 18、Lipc、Nedd 4），以及 几十个基因和未知功能的非编码RNA。利用9号染色体 我们实验室为此目的开发的替代菌株（CSS-9），我们将 将这些小鼠与宿主品系（C57 BL/6 ByJ; B6）回交，并进行基因组扫描 降低Adip 5的置信区间（CSS-9 X B6 N2基因组扫描; Aim 1）。基于 根据遗传图谱信息提供的精确置信区间，我们将 通过连续的繁殖周期将该染色体解析成小间隔，并且 创建微同源菌株（<200 kb），其中一个将包含负责的基因 Adip 5（目标2）。为了确定负责Adip 5的确切基因，我们将从遗传学角度 将一个或多个小鼠品系用129个DNA的片段替换成B6 背景，并评估其对性腺贮库的影响 具体目标3（Specific Aim 3）这项工作的长期目标是制定一种方法， 系统地鉴定导致小鼠肥胖正常变异的基因。

In mice, many genomic regions contain variation that results in differences in adiposity (Reed 2003; 2006; 2007; 2008). The goal of this research program is to find the gene or genes on mouse chromosome 9 that account for the quantitative trait locus Adip5, which is associated with increased weight of the gonadal adipose depot. Although several lines of evidence suggest that a gene or genetic variant here has the ability to regulate adiposity, the exact gene or DNA sequence that causes this effect is not known. The QTL Adip5 has features that make it a practical target for a positional cloning approach: it is not particularly susceptible to maternal effects or epistatic interactions, and it is associated with a distinct phenotype (gonadal depot weight). Furthermore, the experimental plan is designed to identify Adip5 if the locus is imprinted (i.e., if there are parent-of-origin effects). Within the current Adip5 confidence interval, there are several credible candidate genes (Bbs4, Cpy19a1, Crabp1, Cplx3, Il18, Lipc, Nedd4), as well as dozens of genes and noncoding RNA of unknown function. Using a chromosome 9 substitution strain developed in our laboratory for this purpose (CSS-9), we will backcross these mice to the host strain (C57BL/6ByJ; B6) and conduct a genome scan to reduce the confidence interval of Adip5 (CSS-9 X B6 N2 genome scan; Aim 1). Based on the refined confidence interval provided by the genetic mapping information, we will parse this chromosome into small intervals through successive breeding cycles, and create microcongenic strains (<200 kb), one of which will contain the gene responsible for Adip5 (Aim 2). To identify the exact gene responsible for Adip5, we will genetically engineer one or more mouse strains with a segment of 129 DNA substituted into a B6 background by homologous recombination, and evaluate its effect on gonadal depot weight (Specific Aim 3). The long-range goal of this work is to develop an approach to systematically identify genes that contribute to normal variation in fatness among mice.