Patterning of the Primitive Heart Tube in Zebrafish

描述（由申请人提供）：胚胎心脏的形成和/或功能异常通常会导致胚胎死亡或在以后的生活中出现严重的健康问题。在细胞和分子水平上理解早期心脏发育的基本机制不仅具有科学挑战性，而且具有临床意义。我们选择斑马鱼作为我们的模式生物来研究早期心脏模式，因为它适合于遗传，胚胎学和分子操作。此外，所有脊椎动物物种的胚胎心脏经历类似的形态发生过程，并受到保守的遗传回路的调节。从一种模式生物获得的信息可能适用于其他脊椎动物，包括人类。在这个项目中，我们采取三个独立的方法来研究原始心管形态发生的细胞和分子机制。我们最近对斑马鱼心脏和心智突变的研究揭示了Na，K-ATP酶a1 B1在原始心管伸长中的意想不到的作用。我们将研究Na，K-ATP酶a1 B1功能丧失对心肌细胞结构的影响。我们还将在细胞和遗传水平上研究Na，K-ATP酶a1 B1和其他对斑马鱼原始心管形态发生至关重要的基因之间的相互作用（目的1）。此外，我们将研究Na，K-ATP酶a1 B1调节斑马鱼和培养细胞中原始心管伸长的分子机制，作为理解原始心管形成中涉及的遗传网络的第一步（具体目标2）。最后，从一个正在进行的斑马鱼基因筛选中，我们发现了一个影响原始心管模式的新突变。我们将描述这种突变体的表型，并确定导致这种突变体表型的分子病变（目的3）。本研究结合细胞、分子和遗传学的研究方法，将对原始心管形态发生的机制提供新的、深入的认识。

DESCRIPTION (provided by applicant): Abnormalities in the formation and/or function of the embryonic heart often lead to embryonic lethality or severe health problems later in life. Understanding the fundamental mechanisms underlying early heart development at the cellular and molecular level is not only scientifically challenging but is also clinically relevant. We choose the zebrafish as our model organism to study early cardiac patterning because it is amenable to genetic, embryological and molecular manipulation. Furthermore, the embryonic hearts of all vertebrate species undergo similar morphogenic processes and are regulated by conserved genetic circuits. Information obtained from one model organism may apply to other vertebrates, including humans. In this project, we take three independent approaches to study the cellular and molecular mechanisms governing primitive heart tube morphogenesis. Our recent study on the zebrafish heart and mind mutation uncovered an unexpected role of Na,K-ATPase a1B1 in the elongation of the primitive heart tube. We will investigate the impact of loss of function of Na,K-ATPase a1 B1 on the cellular architecture of cardiomyocytes. We will also investigate the interaction of Na,K-ATPase a1 B1 other genes critical for the morphogenesis of the primitive heart tube in zebrafish at the cellular and genetic level (Aim 1). Furthermore we will investigate the molecular mechanism by which the Na,K-ATPase a1 B1 regulates the elongation of the primitive heart tube in the zebrafish and in cultured cells, as the first step toward understanding genetic networks involved in the primitive heart tube formation (Specific Aim 2). Finally, from an ongoing zebrafish genetic screen, we identified a new mutation affecting the patterning of the primitive heart tube. We will characterize the phenotypes of this mutant and identify the molecular lesion causing this mutant phenotype (Aim 3). The combination of cellular, molecular and genetic studies proposed in this project will provide new and in-depth insight into mechanisms of primitive heart tube morphogenesis.