Rapid isolation of diet-responsive obesity genes

描述（由申请人提供）：本申请是第二次竞争性更新（09-14年资助），重点是使用同源小鼠品系进行肥胖基因的位置克隆。同源菌株是在背景菌株的基因组中具有来自供体菌株的小染色体区域的小鼠菌株。基因株和背景株之间的表型差异是由于供体株的等位基因。因此，与脂肪量背景菌株不同的同源菌株定义了小的染色体区域，这些区域必须具有影响肥胖的基因，并且在供体菌株和背景菌株中具有功能不同的等位基因。在当前的拨款周期中，我们使用标记定向选择从同源菌株B6.C-H1中产生了11个亚同源菌株，每个菌株的供体染色体区域都减少了。这些亚同源菌株中的四个将成为本提案的创始菌株。三种菌株表现出显著的肥胖效应。第四种亚遗传菌株含有一个影响成年后代肥胖的母系效应基因。母体效应是指母体营养或基因型对后代肥胖的影响。本提案的核心目标是确定这四个亚同源菌株中包含的四个数量性状基因。从亚基因中分离基因使用位置克隆的工具——通过育种减少候选基因的数量，然后测试这些基因对表型的影响。我们提出了分离肥胖基因和母性效应基因的三个具体目标。在具体目标1中，我们将测试几种评估产妇影响的方法。在具体目标2中，我们将使用重组的育种和鉴定来缩小四个亚基因的目标区域。在具体目标3中，我们将通过测序和表达分析来测试亚基因与表型的基因。我们相信，这项研究提供了机会，以确定一个基因导致肥胖的母系效应，以及其他三个肥胖基因，通过使用表征良好的同源小鼠品系。

DESCRIPTION (provided by applicant): This application is for the second competitive renewal (funding for years 09-14) of a grant that has focused on positional cloning of obesity genes using congenic mouse strains. Congenic strains are mouse strains that have a small chromosomal region from a donor strain in the genome of a background strain. Phenotype differences between congenic and background strains are due to donor strain alleles. Thus, congenic strains that differ from background strains for fat mass define small chromosomal regions that must have a gene that influences obesity and that has functionally different alleles in the donor and background strains. In the current grant cycle we used marker directed selection to produce 11 subcongenic strains from the congenic strain B6.C-H1, each with reduced donor chromosomal regions. Four of these subcongenic strains will become the founding strains for this proposal. Three strains exhibit significant obesity effects. The fourth subcongenic strain contains a maternal effects gene that influences the obesity of adult progeny. Maternal effects refer to the observation that maternal nutrition or genotype can program obesity of progeny. The core goal of this proposal is to identify the four Quantitative Trait Genes that are included in these four subcongenic strains. Gene isolation from subcongenics uses the tools of positional cloning - minimizing the number of candidate genes by breeding and then testing these genes for their effects on the phenotype. We propose three specific aims to isolate the obesity genes and the maternal effects gene. In specific aim 1 we will test several methods to assess maternal effects. In specific aim 2, we will use breeding and identification of recombinants to narrow the target regions for the four subcongenics. In specific aim 3 we will test genes in subcongenics with phenotypes by sequencing and expression analysis. We believe that this study offers the opportunity to identify a gene causing maternal effects on obesity, as well as three other obesity genes, by using well characterized congenic mouse strains.