Genetic Dissection of Cardiogenesis

心脏发生的基因剖析

• 批准号: 6813995
• 负责人: ERIC N Olson
• 金额: $ 50.14万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6813995
• 关键词: Drosophilidae; cardiogenesis; cell differentiation; chromatin immunoprecipitation; congenital heart disorder; developmental genetics; embryogenesis; gel mobility shift assay; gene deletion mutation; gene expression; genetic regulatory element; genetic screening; genetically modified animals; green fluorescent proteins; laboratory mouse; microarray technology; molecular cloning; protein structure; southern blotting; transcription factor; yeast two hybrid system

DESCRIPTION (provided by applicant): Heart formation involves a complex series of events that are initiated when mesodermal precursor cells adopt a cardiac cell fate. Subsequent migration, patterning, growth and differentiation of cardiac myocytes give rise to the embryonic myocardium, which undergoes looping morphogenesis, septation and interconnection with the vascular system to ultimately yield the multi-chambered heart. The complexity of heart formation and the large number of genes involved in this process are reflected in the high frequency of congenital heart defects in humans, which can be ascribed to abnormalities in specific steps in the cardiac developmental pathway. Our laboratory has discovered two distinct families of basic helix-loop-helix (bHLH) transcription factors, referred to as HANDs and HRTs, with central roles in cardiac growth and development. HAND1 and HAND2 are expressed in distinct patterns in the developing heart, as well as in the neural crest and limb buds, and knockout mice lacking these genes show severe abnormalities in growth and patterning of the corresponding embryonic structures. There are three members of the HRT family (HRT1, 2, 3), which also exhibit highly specific and dynamic expression patterns during cardiovascular development. The HRT genes are regulated by Notch signaling, and HRT2 has been shown to be required for cardiac and arterial development. The overall objective of this project is to use HANDs and HRTs as entry points into the developmental circuits that control the formation and function of the cardiovascular system and to further define the mechanisms of action of these transcription factors. As a complement to our primary focus on mammalian cardiovascular development, we will use the Drosophila HAND gene as an entry point into the pathways that control heart formation. Toward that end, we have generated a strain of transgenic fruit flies that expresses green fluorescent protein (GFP) under control of cardiac-specific regulatory elements from the Drosophila HAND gene. These flies have enabled us to undertake an unbiased search for genes that regulate multiple steps in cardiac development, including cardiac cell specification, differentiation, patterning, growth, morphogenesis, and contractility. The cloning of these mutant genes and the ultimate elucidation of their functions should provide new insights into the fundamental developmental circuitry of cardiac development and provide candidate genes for further exploration in mammalian heart development and congenital heart disease.

描述（由申请人提供）：心脏形成涉及一系列复杂的事件，这些事件是在中胚层前体细胞采取心脏细胞命运时启动的。心肌细胞随后的迁移、形成、生长和分化产生胚胎心肌，胚胎心肌经历循环形态发生、分隔以及与血管系统的互连，最终形成多腔心脏。心脏形成的复杂性和参与这一过程的大量基因反映在人类先天性心脏缺陷的高发率上，这可以归因于心脏发育途径中特定步骤的异常。我们的实验室发现了两个不同的碱性螺旋-环-螺旋 (bHLH) 转录因子家族，称为 HAND 和 HRT，在心脏生长和发育中发挥着核心作用。 HAND1和HAND2在发育中的心脏、神经嵴和肢芽中以不同的模式表达，缺乏这些基因的敲除小鼠在相应胚胎结构的生长和模式方面表现出严重的异常。 HRT 家族共有三个成员（HRT1、2、3），它们在心血管发育过程中也表现出高度特异性和动态的表达模式。 HRT 基因受 Notch 信号传导调节，并且 HRT2 已被证明是心脏和动脉发育所必需的。该项目的总体目标是使用 HAND 和 HRT 作为控制心血管系统形成和功能的发育回路的切入点，并进一步定义这些转录因子的作用机制。作为对哺乳动物心血管发育的主要关注的补充，我们将使用果蝇 HAND 基因作为控制心脏形成途径的切入点。为此，我们培育了一种转基因果蝇品系，它在果蝇 HAND 基因的心脏特异性调控元件的控制下表达绿色荧光蛋白 (GFP)。这些果蝇使我们能够公正地寻找调节心脏发育多个步骤的基因，包括心肌细胞规格、分化、模式形成、生长、形态发生和收缩性。这些突变基因的克隆及其功能的最终阐明将为心脏发育的基本发育回路提供新的见解，并为进一步探索哺乳动物心脏发育和先天性心脏病提供候选基因。