Heart Development and Genetics

描述（由申请人提供）：这项工作是我们的延续 利用斑马鱼遗传学和胚胎学来了解最早的 形成心血管系统的胚胎步骤。我们在这里的重点是 特别是在第一动脉组装的分子途径上， 胚胎中的静脉这一过程被称为血管发生， 明白我们使用我们在一个基因组中发现的两个突变作为这项工作的关键。 斑马鱼基因筛选交通堵塞是一种影响主动脉的突变我们 定位克隆了gridlock基因它在主动脉中表达，但在 静脉，是一个新的成员的HES家族的转录因子。的 第二种突变，cloche，是一种阻止两种血液形成的突变。 和船只，似乎作为一个基本要素的产生， 一种难以捉摸的成血管细胞，一种被认为可以产生最早的血液 胚胎中的血管 具体目标1：我们将使用激光激活染料撑开来确定起源 以及产生第一动脉和静脉的成血管细胞的迁移轨迹， 在野生型和血管发生缺陷的突变体中均如此。具体目标2：在 在其他系统中，已知HES基因在驱动细胞命运决定中起作用， 并且是细胞表面受体Notch的下游效应物。我们 我认为GRI在一条途径中起作用， 动脉前或静脉前，甚至在功能血管生成之前，以及 作为涉及细胞表面Notch受体的途径的一部分。我们 我将通过检查细胞和分子效应来检验这一假设 增加或减少Grl和Notch级联的分子组分。 具体目标三：完成钟形物的定位克隆，开始 研究其作用机制。 这项工作定义了正常血管形成的关键途径。这些基因 作为先天性血管疾病的候选基因， 主动脉缩窄审查这些问题也很重要， 成人血管损伤、修复和 抵押

DESCRIPTION (provided by applicant): This work represents a continuation of our program using zebrafish genetics and embryology to understand the earliest embryonic steps in fashioning the cardiovascular system. We focus here in particular upon the molecular pathways for assembly of the first artery and vein in the embryo. This process, termed vasculogenesis, is not well understood. We use as linchpins for this work two mutations we discovered in a zebrafish genetic screen. gridlock is a mutation affecting the aorta. We positionally cloned the gridlock gene. It is expressed in the aorta but not the vein, and is a novel member of the HES family of transcription factors. The second mutation, cloche , is a mutation that prevents formation of both blood and vessels, appearing to act as an essential element in generation of the elusive hemangioblast, a cell proposed to give rise both to the earliest blood and vessels in the embryo. Specific Aim 1: We will use laser-activated dye uncaging to define the origin and migratory track of angioblasts giving rise to the first artery and vein, both in wild-type and mutants defective in vasculogenesis. Specific Aim 2: In other systems, HES genes are known to function in driving cell fate decisions, and are the downstream effectors of the cell surface receptor, Notch. We propose that gri acts in a pathway which drives angioblasts to become pre-arterial or pre-venous even prior to generation of functioning vessels, and to do so as part of a pathway involving the cell surface Notch receptor. We will test this hypothesis by examination of the cellular and molecular effects of increasing or reducing grl and molecular components of the Notch cascade. Specific Aim 3: We will complete the positional cloning of cloche, and begin to examine its mechanism of action. This work defines pathways critical to normal vessel formation. These genes will be of importance as candidate genes for congenital vascular disorders such as aortic coarctation. It will also be of importance to examine these developmental pathways in the context of adult vessel injury, repair, and collateralization.