Positional cloning of obesity genes from congenic mice

描述（由申请人提供）：定位克隆-通过肥胖特征和基因在特定染色体区域的共同发生来鉴定肥胖基因，为发现新的肥胖基因和对肥胖机制的新见解提供了强有力的方法。与其他模型相比，小鼠首次被用于鉴定更多的人类肥胖基因。本研究的目的是利用定位克隆方法鉴定小鼠同源品系中的肥胖基因。基因小鼠菌株除了来自供体菌株的染色体区域外，与背景菌株完全相同。基因型和背景型之间的表型差异是由于供体菌株的等位基因具有不同于背景菌株的功能效应。参与该提案的两个实验室已经在小鼠2号染色体上与人类20号染色体同源的区域确定了几种具有统计显着的肥胖表型的小鼠同源菌株，其中几个肥胖数量性状位点已被定位。我们的一般假设是，先天性供体区域的一个或多个基因或转录本影响肥胖。我们具体的工作假设是，肥胖的基因/转录本可以被识别为大多数遗传。我们提出了七个具体目标。我们将:在初始基因中确定饮食、性别和年龄对肥胖的影响（目标1），通过饲养保留肥胖表型的更小供体区域的基因来确定含有肥胖基因的最小染色体位点（目标2），使用来自8个肥胖组织的RNA使用全基因组微阵列找到差异表达的供体区域基因（目标3），对选定的供体区域基因进行测序（目标4），确定差异表达基因的顺式或反式控制（目标5）。产生过表达10个候选基因的转基因小鼠（Aim 6），并鉴定可能影响肥胖的microrna或其他转录的非编码基因（Aim 7）。长期的结果是，我们将确定至少一个新的，强大的，合理的肥胖基因。

DESCRIPTION (provided by applicant): Positional cloning - the identification of obesity genes by co-incidence of mapped obesity traits and genes to a specific chromosomal region, provides a powerful method to discover novel obesity genes and to make novel insights into the mechanisms causing obesity. Mice have been used for the first identification of more human obesity genes than any other model. The goal of this proposal is to use positional cloning methods to identify obesity genes in mouse congenic strains. Congenic mouse strains are identical to a background strain except for a chromosomal region from a donor strain. Phenotype differences between congenic and background are due to alleles of the donor strain with functional effects different from the background strain. The two laboratories contributing to this proposal have identified several mouse congenic strains with statistically significant phenotypes for obesity on mouse chromosome 2 in a region homologous to human chromosome 20, where several obesity quantitative trait loci have been mapped. Our general hypothesis is that one or more genes or transcripts in the congenic donor regions influence obesity. Our specific working hypothesis is that genes/transcripts underlying obesity can be identified for most congenics. We propose seven Specific Aims. We will: determine diet, sex and age effects on obesity in the founding congenics (Aim 1), identify minimal chromosomal loci containing obesity genes by breeding congenics with ever smaller donor regions that retain obesity phenotypes (Aim 2), find differentially expressed donor region genes with whole genome microarrays using RNA from eight obesity tissues (Aim 3), sequence selected donor region genes (Aim 4), determine cis or trans control of mRNA levels for differentially expressed genes (Aim 5), produce transgenic mice overexpressing ten candidate genes prioritized by the results of Aims 3-5 (Aim 6) and identify microRNAs or other transcribed non-coding genes that may influence obesity (Aim 7). The long term outcome is that we will identify at least one novel and strong and plausible obesity gene.