Mapping adiposity genes in mice

描述(申请人提供)：在小鼠中，许多基因组区域包含导致肥胖差异的变异(Reed 2003；2006；2007；2008)。这项研究计划的目标是找到小鼠9号染色体上的一个或多个基因，该基因解释了数量性状基因Adip5，该基因与性腺脂肪库的重量增加有关。尽管有几行证据表明，这里的某个基因或基因变体具有调节肥胖的能力，但导致这种影响的确切基因或DNA序列尚不清楚。QTL Adip5的特点使其成为位置克隆方法的实用靶标：它不受母体效应或上位性交互作用的特别影响，并且与一种不同的表型(性腺库重)有关。此外，实验计划被设计为识别ADIP5，如果该基因座是印记的(即，是否存在亲本起源效应)。在目前的Adip5可信区间内，有几个可信的候选基因(Bbs4、Cpy19a1、Crabp1、Cplx3、Il18、Lipc、Nedd4)，以及数十个未知功能的基因和非编码RNA。使用我们实验室为此目的开发的9号染色体替代株(css-9)，我们将这些小鼠与宿主株(C57BL/6ByJ；B6)回交，并进行基因组扫描，以减少ADIP5的可信区间(css-9X B6 n2基因组扫描；目标1)。基于遗传图谱信息提供的精细化可信区间，我们将在连续的育种周期中将该染色体解析为小区间，并创建微基因菌株(&lt；200kb)，其中一个将包含负责ADIP5(目标2)的基因。为了确定ADIP5的确切致病基因，我们将通过同源重组将一个或多个小鼠品系的129个DNA片段替换到B6背景中，并评估其对性腺库重的影响(特异性目标3)。这项工作的长期目标是开发一种方法，系统地识别导致小鼠肥胖正常变化的基因。与公共健康相关：与人类一样，小鼠在标准条件下以标准饮食喂养时，它们的天然脂肪含量也不同。通过杂交小鼠，我们可以检查肥胖小鼠之间共享的基因和等位基因的模式，以及它们与瘦小鼠不同的基因和等位基因的模式。通过在一个特定区域(老鼠9号染色体上)发现有影响的DNA变异，我们希望了解这种变异是如何导致人类肥胖的。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: Like people, mice vary in how naturally fat they are when fed a standard diet, under standard conditions. By interbreeding mice, we can examine the pattern of genes and alleles that fat mice share with each other and which they do not share with lean mice. By finding influential DNA variation in one specific region (on mouse chromosome 9), we hope to learn how this variation contributes to obesity in humans.