Maintenance, germ-layer induction, and patterning of neuromesodermal progenitors

在脊椎动物身体的建立过程中，头部首先形成，身体的其余部分形成 逐渐远离头部。一群神经中胚层祖细胞(NMPs) 位于胚胎最后端的位置为这种后部生长过程提供了动力。NMPS 原肠发育结束后保持胚层可塑性，促进脊椎生长 脐带、体节和血管。NMP是身体形成所需的关键细胞， 然而，由于它们在胚胎发育中的时间作用较晚，而且它们利用了许多 同样的基因和信号是原肠形成所必需的，但它们极难 学习。我的实验室已经开发出使用斑马鱼胚胎在体内操纵NMP的方法， 使用细胞移植和临时基因操作的组合。这些方法 使我们能够确定斑马鱼NMP的存在，并定义了一些基本的分子 有助于在中胚层和外胚层之间决定胚层的特性。这项建议 在我们过去研究的基础上，将研究NMP维持和分子控制 图案化。在目标1中，我们将使用新的sox2和sox3突变斑马鱼品系的细胞移植。 和热激可诱导的Sox2和Wnt信号转导系来确定Sox2和Wnt如何 信号协作通过调节一类新的WNT/βCAT靶基因来维持NMP。 在目标2中，我们将确定骨形态发生蛋白(BMP)途径如何作为一种形态发生因子 将中胚层胚层分为不同的细胞类型。这一目标将使用新的方法来 精确调节个体信号通路激活的强度和持续时间 移植的细胞。我们的研究结果将有助于破译 脊椎动物的身体形成，并将提供有关干细胞使用的基本信息 用于再生医学。

During the establishment of the vertebrate body, the head forms first and the rest of the body grows progressively away from the head. A population of neuromesodermal progenitor cells (NMPs) located at the posterior-most end of the embryo fuels this process of posterior growth. NMPs maintain germ-layer plasticity after the end of gastrulation, and contribute to the growing spinal cord, somites, and blood vessels. NMPs are critical cells required for the formation of the body, yet due to their late temporal role in embryogenesis and the fact that they utilize many of the same genes and signals that are essential for gastrulation, they have been extremely difficult to study. My laboratory has developed methods using the zebrafish embryo to manipulate NMPs in vivo, using a combination of cell transplantation and temporal genetic manipulations. These methods allowed us to determine the existence of zebrafish NMPs and to define some of the basic molecular properties that facilitate their germ-layer decision between mesoderm and ectoderm. This proposal builds on our past studies and will examine the molecular control of NMP maintenance and patterning. In Aim 1 we will use cell transplantation of new sox2 and sox3 mutant zebrafish lines and heat-shock inducible sox2 and Wnt signaling transgenic lines to determine how Sox2 and Wnt signaling collaborate to maintain NMPs through regulation of a new class of Wnt/βcat target genes. In Aim 2, we will determine how the Bone Morphogenetic Protein (BMP) pathway acts as a morphogen to pattern the mesodermal germ layer into distinct cell types. This aim will use new methods to precisely regulate the intensity and duration of signaling pathway activation in individual transplanted cells. The results of our study will help decipher some of the basic underpinnings of vertebrate body formation, and will provide essential information regarding the use of stem cells for regenerative medicine.