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，在再生中具有重要意义 医药。过去的研究表明，动态心脏转录程序(CTP)引导 心脏发育过程中的心脏生成，并支持心脏结构和功能的动态平衡。而当 关键的心脏特异转录因子和致心信号通路的作用已被 明确描述的，分子机制，协调心脏基因的表达，以驱动 心肌细胞的特性和直接的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Rtf1是一种 转录调节器，协调心脏基因程序，负责心肌规范和 差异化。在小鼠胚胎干细胞中敲除rtf1抑制心脏基因程序和 防止心脏分化。在体内，Rtf1缺陷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Rtf1缺乏症 心肌细胞损害心脏基因程序。总而言之，这些发现证明了Rtf1的必要性 心肌细胞在多个发育阶段的活性。对Rtf1如何监管动态CTP的见解 来自我们的结构功能分析，显示了对RTF1的S Plus3和头盔显示器的不同要求 在两个时间上不同的心源性事件中的结构域；Plus3结构域是激活 CTP和心肌规范，而HMD结构域影响组蛋白修饰和导向 心管形态发生。这些令人兴奋的发现导致了我们的总体假设，即Rtf1控制 心肌细胞发育过程中CTP激活和转录的动态转录程序 表观遗传调节。我们将使用一组新的转基因斑马鱼品系来定义转录 Rtf1在心肌祖细胞和承诺心肌细胞中的网络。我们将调查RTF1的S是如何 Plus3结构域协调心源性基因的表达，以驱动多潜能中胚层细胞 心肌命运(Aim1)。我们还将询问Rtf1‘S HMD结构域控制心脏的假设 影响新分化植株繁殖和/或成熟的管形态发生 通过表观遗传调节的心肌细胞(目标2)。成功完成拟议的项目将 为心肌规范和转录调控提供了新的机制见解 并将为开发治疗心脏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.