GENES RESPONSIBLE FOR PREDISPOSITION TO CARDIOVASCULAR DISEASE

这一部分的目标是利用和扩展 基因分析，以了解基因， 对人类心血管病理学有显著影响。前一 在此期间，我们成功地将位置克隆策略应用于 分离肌强直性营养不良的基因，这是一种多系统疾病， 包括心脏传导缺陷和心脏骤停， 基本特征 该项目使人们了解到， 以前没有预料到的人类基因突变机制， 位于3'端的不稳定三核苷酸重复序列的扩增 DMPK基因的非翻译区，其以高水平表达， 心脏 我们的实验计划旨在了解 导致这种疾病从基因到病理的途径。 我们将 试图开发直接测定的病理影响， 源自DM的细胞培养物中的三核苷酸重复序列扩增 患者和心肌细胞（外周和心脏）来源于实验 已经引入DMPK基因突变形式的动物。 我们 将利用转基因小鼠开发模型系统，以了解 三核苷酸重复序列的基础和影响因素 DMPK基因的扩增。 我们将跟踪记录的命运， 含有扩展的三核苷酸重复序列，以确定潜在的 基因作用的靶点。 DMPK基因的基因靶向已经导致了 小鼠品系的开发，其中动物已经失去DMPK功能 发展成迟发性多系统退行性疾病 我们将 表征DMPK敲除小鼠的心脏表型，并尝试 将激酶功能丧失与心脏病理学联系起来。 我们将描述 DMPK基因的蛋白激酶功能，试图确定其 底物，并确定DMPK激酶功能的失败如何导致 下游细胞效应。 补充我们对DMPK基因的研究， 我们将继续我们的基因分离计划， 启动了合作研究， Romano-Ward长QT综合征的常染色体显性基因和 Schnyder角膜营养不良中的胆固醇代谢 我们将应用 在上一个授予期内开发的重复扩展技术， 评估不稳定重复序列扩增在 心血管疾病的遗传学，如原发性肺 高血压 我们将完成一个高吞吐量的发展 基因分型策略，以使准确的映射和 影响心脏发育和高血压的基因的鉴定 鼠标 然后我们计划利用这种方法来鉴定其他基因， 对小鼠模型系统中心血管病理学的意义，以及 将该方法扩展到利用同胞对或其它 具有适当功效的设计，以识别对 动脉粥样硬化、高血压以及人类的其它病症 心血管疾病

The objectives of this component are to utilize and extend the tools of genetic analysis to the understanding of genes which contribute significantly to human cardiovascular pathology. During the previous granting period, we successfully applied positional cloning strategies to isolate the gene for myotonic dystrophy, a multisystem disorder which includes cardiac conduction defects and sudden cardiac arrest as one of its cardinal features. This project has led to the understanding of a previously unanticipated mechanism for genetic mutation in man, the expansion of an unstable trinucleotide repeat sequence located ina the 3' untranslated region of the DMPK gene which is expressed at high levels in the heart. Our experimental plan is directed towards an understanding of the pathway which leads from gene to pathology in this disorder. We will attempt to develop direct assays for the pathological effects of trinucleotide repeat sequence expansion in cell cultures derived from DM patients and myocytes (peripheral and cardiac) derived from experimental animals into which mutant forms of the DMPK gene have been introduced. We will utilize transgenic mice to develop model systems to understand the basis for and factors which influence trinucleotide repeat sequence expansion in the DMPK gene. We will follow the fate of transcripts which contain expanded trinucleotide repeat sequences to identify potential targets of gene action. Gene targeting of the DMPK gene has led to the development of mouse strains in which animals which have lost DMPK function develop a late onset multisystem degenerative disorder. We will characterize the cardiac phenotype of the DMPK knockout mice and attempt to relate loss of kinase function to cardiac pathology. We will characterize the protein kinase functions of the DMPK gene, attempt to identify its substrate and determine how failure of the DMPK kinase to function leads to downstream cellular effects. Complementing our studies on the DMPK gene, we will continue our program of gene isolation, completing previously initiated collaborative studies directed towards the identification of the autosomal dominant genes for Romano-Ward long QT syndrome and the defect in cholesterol metabolism in Schnyder's corneal dystrophy. We will apply the repeat expansion technique developed during the previous granting period to assess the potential role of unstable repeat sequence expansion in the genetics of cardiovascular disorders such as primary pulmonary hypertension. We will complete the development of a high throughput genotyping strategy to make possible the accurate mapping and identification of genes affecting cardiac development and hypertension in the mouse. We then plan utilize this approach to identify others genes of significance to cardiovascular pathology in mouse model systems, as well as extending this methodology to human studies utilizing sib pair or other designs with appropriate power to identify genes significant to atherosclerosis, hypertension as well as other conditions in human cardiovascular disease.