Rtf1-dependent transcriptional regulation of heart development

项目摘要 了解驱动多能祖细胞分化为 特定细胞类型与发育生物学密切相关，并在再生中具有重要意义 药过去的研究表明，动态心脏转录程序（CTPs）指导 在发育过程中的心脏发生和支持心脏结构和功能的稳态。而 关键的心脏特异性转录因子和心源性信号通路的贡献已经被 明确界定的分子机制，协调心源性基因的表达， 心肌细胞的特化和指导心肌细胞的成熟仍然难以捉摸。 我们最近使用斑马鱼和小鼠模型进行的研究表明，多功能蛋白Rtf 1是一种 转录调节因子，其协调负责心肌特化的心脏基因程序， 分化小鼠胚胎干细胞中rtf 1的敲低抑制心脏基因程序， 防止心脏分化。在体内，Rtf 1缺陷的斑马鱼和小鼠胚胎缺乏心肌 祖细胞，不能发育心脏。我们还发现，Rtf 1缺乏症， 心肌细胞损害心脏基因程序。总的来说，这些发现表明需要Rtf 1 在多个发育阶段的心肌细胞中的活性。深入了解Rtf 1如何调节动态CTP 来自我们的结构-功能分析，显示Rtf 1的Plus 3和HMD的不同要求 在两个时间上不同的心源性事件中，Plus 3结构域是激活 CTP和心肌特化，而HMD结构域影响组蛋白修饰并指导 心管形态发生这些令人兴奋的发现导致我们的总体假设，即Rtf 1控制 通过CTP激活在发育过程中心肌细胞中的动态转录程序， 表观遗传调节我们将采用一组新的转基因斑马鱼系来定义转录的 心肌祖细胞和定向心肌细胞中的Rtf 1网络。我们将研究Rtf 1是如何 Plus 3结构域协调心源性基因的表达，以驱动多能中胚层细胞 心肌结局（Aim 1）。我们还将询问Rtf 1的HMD结构域控制心脏的假设 通过影响新分化的植物的繁殖和/或成熟， 心肌细胞通过表观遗传调节（Aim 2）。成功完成拟议项目将 为心肌特化的转录调控提供了新的机制见解， 分化，并将为开发治疗心脏病的新治疗策略铺平道路 疾病

Project Summary Understanding the molecular mechanisms that drive a pluripotent progenitor cell to differentiate into a specific cell type is germane to Developmental Biology and has important significance in regenerative medicine. Past studies have illustrated that dynamic cardiac transcription programs (CTPs) guide cardiogenesis during development and support cardiac structure and function in homeostasis. While the contributions of key cardiac-specific transcription factors and cardiogenic signaling pathways have been clearly delineated, molecular mechanisms that coordinate the expression of cardiogenic genes to drive myocardial cell specification and direct the maturation of cardiomyocytes remain elusive. Our recent studies using both zebrafish and mouse models indicate that the multi-functional protein Rtf1 is a transcription regulator that orchestrates cardiac gene programs responsible for myocardial specification and differentiation. Knockdown of rtf1 in mouse embryonic stem cells inhibits the cardiac gene program and prevents cardiac differentiation. In vivo, Rtf1 deficient zebrafish and mouse embryos lack myocardial progenitor cells and cannot develop a heart. We also found that Rtf1 deficiency in committed cardiomyocytes impairs cardiac gene program. Collectively, these findings demonstrate a need for Rtf1 activity in myocardial cells at multiple developmental stages. Insights into how Rtf1 regulates dynamic CTPs come from our structure-function analysis showing differential requirements for Rtf1's Plus3 and HMD domains in two temporally distinct cardiogenic events; the Plus3 domain is required for the activation of the CTP and myocardial specification whereas the HMD domain influences histone modifications and directs heart tube morphogenesis. These exciting findings lead to our overarching hypothesis that Rtf1 controls dynamic transcriptional programs in myocardial cells during development by CTP activation and epigenetic modulation. We will employ a set of new transgenic zebrafish lines to define the transcriptional networks of Rtf1 in myocardial progenitors and committed cardiomyocytes. We will investigate how Rtf1's Plus3 domain coordinates the expression of cardiogenic genes to drive the multi-potent mesodermal cells to a myocardial fate (Aim1). We will also interrogate the hypothesis that the Rtf1's HMD domain controls heart tube morphogenesis by influencing the propagation and/or maturation of newly differentiated cardiomyocytes via epigenetic modulation (Aim 2). Successful completion of the proposed projects will provide new mechanistic insights into the transcriptional regulation of myocardial specification and differentiation and will pave the way for the development of novel therapeutic strategies to treat heart diseases.