GENES RESPONSIBLE FOR PREDISPOSITION TO CARDIOVASCULAR DISEASE

该组件的目标是利用和扩展 基因分析对理解基因的贡献 对人类心血管病理有重大影响。在上一次 在授予期间，我们成功地将位置克隆策略应用于 分离强直性肌营养不良的基因，这是一种多系统疾病， 包括心脏传导缺陷和心脏骤停，作为其 主要特征。这个项目导致了对一个 以前未曾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，在 心脏。我们的实验计划旨在了解 在这种疾病中从基因到病理的途径。我们会 试图发展直接的检测方法来检测这些疾病的病理效应。 糖尿病细胞培养中三核苷酸重复序列的扩增 患者和心肌细胞(外周和心脏)来源于实验 被引入突变形式的DMPK基因的动物。我们 将利用转基因小鼠开发模型系统来了解 三核苷酸重复序列的基础及其影响因素 DMPK基因的扩增。我们将遵循成绩单的命运 包含扩展的三核苷酸重复序列以识别潜在的 基因作用的靶点。DMPK基因的基因靶向导致了 DMPK功能缺失小鼠品系的建立 出现迟发性多系统退行性疾病。我们会 鉴定DMPK基因敲除小鼠的心脏表型并尝试 将激酶功能丧失与心脏病理联系起来。我们将描述 DMPK基因的蛋白激酶功能，试图鉴定其 底物，并确定DMPK激酶功能失效是如何导致 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，完成之前的 发起合作研究，以确定 Romano-Ward长QT综合征的常染色体显性显性基因及其缺陷 施奈德角膜营养不良症的胆固醇代谢。我们将应用 在前一个授权期内开发的重复扩展技术 评估不稳定重复序列扩展在基因突变中的潜在作用 原发性肺心病等心血管疾病的遗传学研究 高血压。我们将完成一个高吞吐量的发展 基因分型策略，使准确定位和 中国人群心脏发育与高血压相关基因的筛选 那只老鼠。然后，我们计划利用这种方法来识别其他基因 在小鼠模型系统中对心血管病理学的意义 将这种方法扩展到利用同胞或其他人进行的人类研究 具有识别重要基因的适当能力的设计 人类的动脉粥样硬化、高血压和其他疾病 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.