GENETIC MODIFIERS OF TGF BETA 1 ACTION IN VIVO

转化生长因子β 1（TGF β 1）基因的失活导致血管生成和造血缺陷，从而导致产前死亡。这种表型的遗传多样性取决于遗传背景。一个主要的遗传修饰因子tgfmod 1，在控制TGF β 1-/-胚胎致死率的遗传中贡献了超过50%。该项目的总体目标是识别tgfmod 1。将采取遗传和定位克隆相结合的方法。tgfmod 1的鉴定将为我们理解胚胎血管生成和体内造血以及TGF β 1对这些过程的调节做出重大贡献。此外，它将测试克隆胚胎致死表型的遗传修饰剂的一般方法，其中许多已在纯合基因敲除小鼠的产生过程中发现。TGF β 1与许多人类疾病有关，包括遗传性出血性毛细血管扩张症（HHT）、癌症、病理性血管生成、动脉粥样硬化、炎症、骨质疏松症、纤维化、伤口愈合和肾小球肾炎。然而，这些疾病表型的严重程度，包括单基因疾病，HHT，是非常可变的，这表明存在修改基因性状。因此，鉴定可以改变由TGF β的错误调节引起的疾病的发病率和严重程度的基因对普通医学具有价值。tgfmod 1将被明确定位到约0.5cM，使用我们的互惠同类小鼠小组，以及一个经过验证的功能性遗传测试交叉。将生成跨越该关键图谱区域的BAC重叠群，并且将使用比较基因组测序以及大量选择的DNA序列分析软件工具来鉴定BAC重叠群内的每个基因。候选基因将根据其精细图谱位置和基因表达模式进行选择。候选基因内的功能多态性将通过各种分子多态性检测技术、DNA测序以及RNA和蛋白质分析来搜索。将通过几种小鼠品系中的基因型/表型相关性和功能分析（包括转基因）确认tgfmod 1的身份。

Inactivation of the transforming growth factor beta1 (TGFbeta1) gene causes defects in angiogenesis and haematopoiesis that lead to prenatal death. The penetrance of this phenotype depends on genetic background. A major genetic modifier, tgfmod1, contributes over 50% of the genetic in control of the penetrance of TGFbeta1-/-embryo lethality. The overall goal of this project is to identify tgfmod1. A combined genetic and positional cloning approach will be taken. The identification of tgfmod1 will make a significant contribution to our understanding of embryonic angiogenesis and hematopoiesis in vivo, as well as that of TGFbeta1 regulation of these processes. Moreover, it will test the general approach of cloning genetic modifiers of embryo-lethal phenotypes, many of which have been found during generation of homozygous gene knock out mice. TGFbeta1 is implicated in many human diseases, including hereditary haemorrhagic telangiectasia (HHT), cancer, pathological angiogenesis, atherosclerosis, inflammation, osteoporosis, fibrosis, wound healing and glomerulonephritis. However, the severity of these disease phenotypes, including the single gene disorder, HHT, is very variable, suggesting the existence of modifying gene traits. Identification of genes that can modify the incidence and severity of diseases caused by mis-regulation of TGFbeta is therefore of value to general medicine. tgfmod1 will be definitively mapped to approximately 0.5cM, using our panel of reciprocal congenic mice, together with a proven functional genetic test cross. A BAC contig will be generated that spans this critical map region, and comparative genomic sequencing, together with a large selection of DNA sequence analysis software tools, will be used to identify every gene within the BAC contig. Candidate genes will be selected on the basis of their fine map location and gene expression pattern. Functional polymorphisms within candidate genes will be searched for by various molecular polymorphism detection techniques, DNA sequencing and RNA and protein analysis. Identity of tgfmod1 will be confirmed by genotype/phenotype correlation in several mouse strains, and by functional analysis, including transgenesis.