HEART DEVELOPMENT AND GENETICS

心脏发育和遗传学

• 批准号: 2225674
• 负责人: MARK C FISHMAN
• 金额: $ 16.92万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1995-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2225674
• 关键词: alternatives to animals in research; angiogenesis; gene expression; gene mutation; heart; histogenesis; laboratory mouse; molecular pathology; troponin; zebrafish

This proposal is to continue our studies of cardiovascular development. The long-term goal of this work is to identify the genes responsible for fashioning of the cardiovascular system, genes that are critical both to its form and function. We seek to do so by genetic dissection, in other words by using mutations to define the important steps in development of the heart and ultimately to define the responsible genes at the molecular level. We have selected the zebrafish as the appropriate model system. This small fresh water teleost is easily raised, and produces hundreds of large eggs daily, with all development occurring externally in a transparent embryo. It is particularly amenable to genetic screens. Our focus is specifically upon the cardiovascular system. Within 3 days of fertilization we have found that the zebrafish heart forms and loops, becomes subdivided into chambers which are separated by valves, and begins to generate an effective circulation. By single cell injection we have begun to track the cardiac progenitor cells as they arise in the blastula, and to track their migration and fate within the nascent heart tube. In addition, we have identified mutations that affect the heart. For example, we are studying fish strains in which the homozygote lacks any heart beat. The specific aims of this proposal are: (1) To delineate the lineage of the heart, and determine the cell fate decisions which give rise to its various components. For example, preliminary results suggest that the progeny of separate precursor cells populate the endocardium as opposed to myocardium, and the atrium rather than the ventricle; (2) To generate monoclonal markers, in addition to the chamber-specific ones we have currently, in order to identify epitopes that provide patterning information, as well as ones that identify subpopulations of cardiac progenitor cells; (3) To continue the molecular analysis of zebrafish mutations that affect the heart, with special focus upon the silent heart mutation. Our preliminary evidence strongly suggests that the cell biology of this disorder resides at the coupling interface between electrical activity at the cell membrane and contraction (and that the deficit is one of "electromechanical dissociation"). Our preliminary evidence suggests that we may have identified the molecular defect, which we believe to be in troponin T, a component of the actomyosin regulatory complex. We seek to test this hypothesis specifically by molecular analysis. The genetics of cardiovascular disease is only poorly understood, even though many cardiac disorders have an important hereditary component. The zebrafish system provides a potential model system for molecular dissection of such disorders.

该提案是为了继续我们对心血管发育的研究。 这项工作的长期目标是确定负责的基因 心血管系统的形成，基因对心血管系统至关重要 它的形式和功能。 我们寻求通过基因解剖来做到这一点，在其他方面 通过使用突变来定义发展中的重要步骤 心脏并最终在分子水平上定义负责的基因 等级。 我们选择斑马鱼作为合适的模型系统。 这种小型淡水硬骨鱼很容易饲养，可产数百只 每天都有大鸡蛋，所有发育都在外部进行 透明胚胎。 它特别适合基因筛选。 我们的 重点特别关注心血管系统。 3天内 受精后我们发现斑马鱼的心脏形成并形成环状， 被细分为由阀门分隔的室，并且 开始产生有效的循环。 通过单细胞注射 我们已经开始追踪心脏祖细胞的产生 囊胚，并追踪它们在新生心脏内的迁移和命运 管子。 此外，我们还发现了影响心脏的突变。 例如，我们正在研究纯合子缺乏的鱼品系 任何心跳。 本提案的具体目标是： (1) 描绘心脏的谱系，并决定细胞的命运决定 从而产生其各种成分。 例如，初步 结果表明，单独的前体细胞的后代填充在 心内膜而不是心肌，心房而不是心房 心室; (2) 生成单克隆标记，除了 我们目前拥有室特异性的，以便识别表位 提供图案信息以及识别信息 心脏祖细胞亚群； (3)继续分子 分析影响心脏的斑马鱼突变，特别关注 静静的心突变。 我们的初步证据有力 表明这种疾病的细胞生物学在于耦合 细胞膜上的电活动与 收缩（并且赤字是“机电 解离”）。我们的初步证据表明我们可能有 确定了分子缺陷，我们认为该缺陷存在于肌钙蛋白 T 中， 肌动球蛋白调节复合物的一个组成部分。 我们试图测试这一点 具体通过分子分析进行的假设。 人们对心血管疾病的遗传学知之甚少，甚至 尽管许多心脏病都有重要的遗传因素。 斑马鱼系统为分子生物学提供了一个潜在的模型系统 对此类疾病的剖析。