Using Embryos to Understand the Chromatin State of Mesoderm Induction

描述（由申请人提供）：出生缺陷，包括神经管、眼睛和肢体的缺陷，是由胚胎发育过程中细胞特异性不正确引起的。形成这些特化组织所必需的主要胚胎学事件之一是中胚层的诱导。我们的目标是确定驱动中胚层形成的基因组和生化过程，其长期目标是能够产生更复杂的组织类型。 虽然介导中胚层诱导和许多其他胚胎学过程的信号通路已经很好地理解，但下游转录因子如何与染色质接口和通信仍然是一个谜。这种并置是正常细胞特化的核心，并且正在成为细胞重编程的关键要素。因此，我们认为， 对这一问题的深入研究对于理解开发过程中的错误非常重要，并将使再生医学能够建立更好的协议。随着基因组测序技术的出现，我们现在可以问一些基本问题，如信号通路如何与染色质相互作用，它们在产生开放的染色质结构中是允许的还是活跃的，以及这些信号如何在相邻细胞之间传递。 在这项授权中，我们使用非洲爪蟾和非洲爪蟾热带解决参与染色质状态及其接口与节点信号传导因子，smad 2/3，在体内中胚层诱导。这些物种中存在的丰富的胚胎学资源，对其命运图的深入了解，结合新的可用基因组工具，提供了一个利用新兴现代技术重新审视经典细胞命运和诱导相互作用机制的绝佳机会。这项研究的中心假设是染色质状态和smad 2/3之间的相互作用是中胚层诱导和模式化的基础。 公共卫生相关性：出生缺陷，包括神经管，眼睛和肢体的缺陷，是由胚胎发育过程中细胞特异性不正确引起的。许多这些疾病背后的分子信号已经被理解，但它们如何与基因组相互作用在很大程度上是未知的。在这项研究中，我们使用青蛙胚胎来研究相邻细胞之间的信号传导如何影响它们的基因组，无论是在染色质签名还是在转录因子占用方面。我们的中心假设是，染色质及其相关的转录状态的基础上的能力组织沟通正常胚胎发育。

DESCRIPTION (provided by applicant): Birth defects, including those of the neural tube, eye and limb, are caused by improper cellular specification during embryogenesis. One of the primary embryological events necessary for the formation of these specialized tissues is the induction of mesoderm. Our aim is to identify the genomic and biochemical processes that drive the formation of mesoderm with the long-term goal of being able to generate more complex tissue types. While the signaling pathways that mediate mesoderm induction and many other embryological processes are well understood, how downstream transcription factors interface and communicate with chromatin is still a mystery. This juxtaposition is central for normal cellular specification, and is emerging as a critical element of cellular reprogramming. Therefore, inroads into this problem are important for understanding errors during development and will enable the establishment of better protocols for regenerative medicine. With the advent of genomic sequencing technologies, we can now ask fundamental questions about how signaling pathways interface with chromatin, whether they are permissive or active players in generating open chromatin structures and how these signals are communicated between neighboring cells. In this grant, we use Xenopus laevis and Xenopus tropicalis to address the involvement of the chromatin state and its interface with the Nodal signaling factor, smad2/3, during in vivo mesoderm induction. The wealth of embryological resources present in these species, the deep knowledge of their fate maps, combined with newly available genomic tools, presents a prime opportunity to revisit mechanisms underlying classic cell fate and inductive interactions using emerging modern technologies. The central hypothesis of this grant is that the interplay between chromatin state and smad2/3 underlie mesoderm induction and patterning. PUBLIC HEALTH RELEVANCE: Birth defects, including those of the neural tube, eye and limb, are caused by improper cellular specification during embryogenesis. The molecular signals underlying many of these disorders are understood, but how they interact with the genome is largely unknown. In this grant, we use the frog embryo to examine how signaling between neighboring cells influences their genomes, both in terms of chromatin signatures and in transcription factor occupancy. Our central hypothesis is that chromatin and its associated transcriptional states underlie the competency of tissues to communicate for normal embryonic development.