Positional cloning of obesity genes from congenic mice

描述(申请人提供)：位置克隆-通过定位肥胖特征和基因在特定染色体区域的共同出现来识别肥胖基因，为发现新的肥胖基因和对导致肥胖的机制提供了一种强有力的方法。与其他任何模型相比，小鼠已被用于首次鉴定更多的人类肥胖基因。这项提议的目标是使用定位克隆方法来识别小鼠同源品系中的肥胖基因。除了供体品系的染色体区域外，同基因小鼠品系与背景品系完全相同。同源菌株和背景菌株的表型差异是由于供体菌株的等位基因功能效应不同于背景菌株所致。为这一建议做出贡献的两个实验室已经在与人类20号染色体同源的区域发现了几个在小鼠2号染色体上具有统计学意义的肥胖表型的小鼠同源品系，在那里已经定位了几个肥胖数量性状基因座。我们的一般假设是，同源基因供体区域中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/转录本可以在大多数遗传基因中识别出来。我们提出了七个具体目标。我们将：确定饮食、性别和年龄对肥胖的影响(目标1)，通过培育保持肥胖表型的供体区域越来越小的同源基因来确定包含肥胖基因的最小染色体位点(目标2)，利用来自8个肥胖组织的RNA通过全基因组微阵列寻找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调控基因(目标5)，产生根据目标3-5(目标6)结果优先考虑的10个过表达候选基因的转基因小鼠，并鉴定microRNAs或其他可能影响肥胖的转录后非编码基因(目标7)。长期的结果是，我们将至少识别出一个新的、强大的、看似合理的肥胖基因。

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.