Mechanisms governing the differentiation and maintenance of atrial identity

项目摘要/摘要 所有器官的正常发育都需要适当的分化和维持细胞特性。 在心脏中，维持心肌细胞特性所必需的基因突变与 结构性先天性心脏病，这是新生儿最常见的畸形。尽管他们 然而，大多数先天性心脏病的病因仍然知之甚少。此外，还有许多 结构性先天性心脏病与心律失常有关。尽管外科技术的进步 已经成功地让患者活到成年，但手术不会修复心律失常 与结构缺陷有关。因此，了解基本的指导机制是至关重要的。 正常的脊椎动物心脏发育，以告知我们先天性心脏缺陷的病因及其 相关的心律失常。我们实验室的一个长期目标是了解保守的分子和遗传 脊椎动物早期发育过程中控制心腔大小的机制。Nr2f转录因子 对脊椎动物心脏发育有高度保守的要求。此外，Nr2f基因在中国的突变 人类与一系列先天性心脏缺陷有关，包括房间隔缺陷。这项建议 将通过研究Nr2f依赖来研究决定心房大小的基本机制 控制心房心肌细胞分化和维持心房心肌细胞特性的机制。 虽然在心房发育过程中对Nr2f因子的需求已经确立，但控制Nr2f的机制 心房肌细胞基因表达及Nr2f转录因子对心房肌细胞的调控作用 人们对发展仍然知之甚少。我们的工作表明斑马鱼Nr2f1a在功能上是等同的 Nr2f2在心房发育中的作用。我们的初步数据已经确定了一种保守的增强子，足以 促进Nr2f1a在斑马鱼心房肌细胞中的表达以及Nr2f1a具有先前未被识别的 要求同时维持心房肌细胞和抑制起搏器的获得 心肌细胞身份。在目标1中，我们将询问调节保守的nr2f1a顺式调控的信号。 促进心房肌细胞表达的增强子。在目标2中，我们将确定时间需求 以及nr2f1a突变体心房内心肌细胞的分化状态。在《目标3》中，我们将 阐明Nr2f依赖的基因调控网络抑制静脉起搏心肌细胞的特性 奥特里亚。我们的研究可能会为我们了解先天性心脏病的病因提供信息基础。 缺陷及其相关的心律失常，这最终可能导致新的治疗方法，可以预防或 改善人类先天性心脏缺陷和相关的心律失常。

Project Summary/Abstract Appropriate differentiation and maintenance of cellular identity are required for normal development of all organs. In the heart, mutations in genes that are necessary to maintain cardiomyocyte identity are associated with structural congenital heart defects, which are the most common malformations found in newborns. Despite their frequency, the etiology of most congenital heart defects remains poorly understood. Furthermore, numerous structural congenital heart defects are associated with arrythmias. Although advances in surgical techniques have been successful in allowing patients to survive to adulthood, the surgeries do not repair arrythmias associated with the structural defects. Thus, it is essential to understand fundamental mechanisms directing normal vertebrate heart development, in order to inform us of the etiology of congenital heart defects and their associated arrythmias. A long-term goal of our lab is to understand the conserved molecular and genetic mechanisms that direct cardiac chamber size during early vertebrate development. Nr2f transcriptions factors have highly conserved requirements in vertebrate heart development. Furthermore, mutations in Nr2f genes in humans are associated with a spectrum of congenital heart defects, including atrial septal defects. This proposal will investigate fundamental mechanisms determining atrial chamber size through investigating Nr2f-dependent mechanisms controlling atrial cardiomyocyte differentiation and the maintenance of atrial cardiomyocyte identity. While requirements for Nr2f factors are well-established in atrial development, the mechanisms controlling Nr2f gene expression in atrial cardiomyocytes and by which Nr2f transcription factors direct atrial cardiomyocyte development remain poorly understood. Our work has shown that zebrafish Nr2f1a is the functional equivalent of Nr2f2 in atrial development. Our preliminary data has identified a conserved enhancer that that is sufficient to promote Nr2f1a expression in atrial cardiomyocytes zebrafish and that Nr2f1a has a previously unrecognized requirement concurrently maintaining atrial cardiomyocyte and inhibiting the acquisition of pacemaker cardiomyocyte identity. In Aim 1, we will interrogate the signals that regulate the conserved nr2f1a cis-regulatory enhancer that promotes atrial cardiomyocyte expression. In Aim 2, we will determine the temporal requirements of nr2f1a and the differentiation state of cardiomyocytes within the atria of nr2f1a mutants. In Aim 3, we will elucidate the Nr2f-dependent gene regulatory networks that repress pacemaker cardiomyocyte identity in venous atria. Our studies may provide a foundation of information that may inform us of the etiology of congenital heart defects and their associated arrythmias, which ultimately may lead to novel therapies that can prevent or ameliorate congenital heart defects and associated arrythmias in humans.