Molecular and Cell Biology of Neuromesodermal Progenitors

项目摘要： 我们的目标是了解神经中胚层祖细胞（NMPs）的正常生物学，以及使用NMPs， 在体内模拟细胞和分子机制。NMPs是位于尾芽中的基底祖细胞， 脊椎动物胚胎，在原肠胚形成后继续进行胚层决定以产生外胚层， 中胚层作为产生脊髓、骨骼肌和其他中胚层的细胞的主要来源， 作为一种衍生物，NMP是有助于脊椎动物身体计划形成的关键细胞类型。学习NMP 提高了我们对身体计划如何产生的理解，改进了体外组织的技术， 代，并提供了重要的见解信号通路机制。我发现斑马鱼的核基质蛋白 一个博士后研究员，我的实验室继续关注他们。我们最近的研究揭示了 对于转录因子Sox 2，通过与NMPs的相互作用维持NMPs处于未分化状态， 经典Wnt信号通路。这一点，结合过去的研究表明，Wnt信号效应器 bcat与Sox 2物理相互作用，表明Wnt信号转导可以调节基因表达和生物学活性。 直接通过Sox 2的活性。关于Wnt/ bcat通路的这个激动人心的分支知之甚少。我们将 在许多生物学水平上询问Sox 2和Wnt/ bcat相互作用的这一途径，重点是直接 Sox 2和bcat之间的物理相互作用，以及Sox 2/ bcat介导的全基因组分析， 转录调控我们假设Sox 2/ bcat信号通路代表了Wnt/ bcat信号通路的一个新分支。 与经典的TCF/LEF转录因子家族介导的信号传导不同的信号传导途径。我们最近还 开发了一种新的细胞周期蛋白依赖性激酶生物传感器转基因斑马鱼，并观察到NMPs和一些 它们的衍生物存在于受限的细胞周期阶段。NMP主要在G2阶段举行，而 中胚层脊索祖细胞仅限于G1期。细胞周期阶段广泛涉及 干细胞维持、细胞分化和细胞迁移和侵袭的各个方面。我们将 操纵NMPs及其衍生物中的细胞周期，以了解细胞周期阶段如何影响正常的细胞周期。 NMP开发。我们假设NMPs的G2期限制对于维持细胞的增殖是必要的。 未分化状态和接受基于G2依赖性受体活化的Wnt信号传导。我们也 假设脊索祖细胞的G1期是其形态发生行为所必需的， 收敛与扩展总之，我们的工作将不仅为NMP的开发， 脊椎动物身体计划的形成，而且细胞生物学和信号的基本原则。Wnt/ bcat信号传导和 Sox 2被发现在一起，并在许多正常和患病的细胞环境中发挥重要作用，包括 干细胞和癌症细胞周期是正常发育的一个基本方面， 疾病，如癌症。了解细胞周期阶段如何影响细胞命运和形态发生行为 将提供对正常和疾病状态的基本了解。

Project Summary: We aim to understand the normal biology of neuromesodermal progenitors (NMPs), as well as to use NMPs to model cellular and molecular mechanisms in vivo. NMPs are basal progenitor cells located in the tailbud of vertebrate embryos that continue to make a germ-layer decision after gastrulation to generate ectoderm and mesoderm. As a primary source of cells generating the spinal cord, skeletal muscle, and other mesodermal derivatives, NMPs are a key cell type contributing to the formation of the vertebrate body plan. Studying NMPs has advanced our understanding of how body plans are generated, improved techniques for in vitro tissue generation, and provided critical insights into signaling pathway mechanisms. I discovered zebrafish NMPs as a postdoctoral fellow and my lab continues to focus on them. Our recent work has uncovered important roles for the transcription factor Sox2 in maintaining NMPs in an undifferentiated state through interactions with the canonical Wnt signaling pathway. This, combined with the past research showing the Wnt signaling effector bcat physically interacts with Sox2, indicates Wnt signaling can modulate gene expression and biological activity directly via Sox2. Little is known about this exciting branch of the Wnt/ bcat pathway. We will interrogate this pathway of Sox2 and Wnt/ bcat interactions at a number of biological levels, focusing on direct physical interactions between Sox2 and bcat, as well as genome wide analysis of Sox2/ bcat mediated transcriptional regulation. We hypothesize that Sox2/ bcat signaling represents a new arm of the Wnt/ bcat pathway distinct from the canonical TCF/LEF transcription factor family mediated signaling. We also recently developed a new Cyclin Dependent Kinase biosensor transgenic zebrafish and observed that NMPs and some of their derivatives exist in restricted cell cycle phases. The NMPs are held primarily in the G2 phase, while mesodermal notochord progenitors are restricted to the G1 phase. Cell cycle phase is broadly implicated in various aspects of stem cell maintenance, cell differentiation, and cell migration and invasion. We will manipulate the cell cycle in NMPs and their derivatives to understand how the cell cycle phase impacts normal NMP development. We hypothesize that the G2 phase restriction of NMPs is essential for maintenance of the undifferentiated state and for receipt of Wnt signaling based on G2 dependent receptor activation. We also hypothesize that the G1 phase of notochord progenitors is essential for their morphogenetic behavior of convergence and extension. Together, our work will shed important light on not only NMP development and vertebrate body plan formation, but also basic principles of cell biology and signaling. Wnt/ bcat signaling and Sox2 are found together and play important roles in numerous normal and diseased cellular contexts, including stem cells and cancer. The cell cycle is a fundamental aspect of normal development and is dysregulated in diseases such as cancer. Understanding how cell cycle phase impacts cell fate and morphogenetic behaviors in vivo will provide essential insight into normal and disease states.