Inductive and morphogenetic processes shaping the zebrafish embryonic axes

 描述（由申请人提供）：脊椎动物体如何从单细胞发育是我研究的首要问题。尽管取得了很大进展，但胚胎发生的许多基本机制仍然知之甚少。我特别感兴趣的是，建立胚胎身体计划的诱导和形态发生过程如何在空间和时间上协调，以确保正常发育。斑马鱼受精卵中前后和背腹胚胎轴的特化涉及促进背侧Wnt/β-连环蛋白活性的因子的微管依赖性运输，其图案化胚层并协调原肠胚形成运动。我们发现Ccl19.1趋化因子通过Ccr 7 G蛋白偶联受体（GPCR）信号传导通过下调β-连环蛋白限制轴的形成。利用斑马鱼ccl19.1和ccr 7基因的突变，我们将描绘出它们调节钙信号和限制轴形成的途径。我们最近发现，Dachsous（Dchs）钙粘蛋白调节细胞骨架在受精卵和轴的形成。而Dchs是众所周知的相互作用与脂肪钙粘蛋白和Fjx 1激酶，我们将表征脂肪/Fjx 1依赖和独立的作用Dchs。我们将确定与Dchs相互作用的蛋白质，以确定其与细胞骨架和其他效应物的功能联系。 在原肠胚形成过程中，会聚和伸展（C&E）运动使胚层前后伸长，背腹变窄。Wnt/Planar Cell Polarity（Wnt/PCP）信号转导是脊椎动物中驱动C&E的极化细胞行为的保守调节因子。我们的研究表明，Wnt/PCP信号在原肠胚形成过程中起着细胞罗盘的作用，协调个体细胞的极性和行为与前后胚胎极性，部分原因是PCP组分在前后细胞膜上的不对称分布。为了了解PCP组件的平面不对称性如何出现在动态间充质细胞中，我们将测试的假设，即粘附GPCR，Gpr 125，一个新的PCP组件，促进形成后富集膜PCP复合物。我们将确定Dchs是否在原肠胚形成过程中与Fat和Fjx 1一起作用以抑制微管并调节Wnt/PCP信号依赖性细胞极性。最后，我们将测试Dchs/Fat/Fjx 1系统是否提供了一种将Wnt/PCP信号与全球胚胎模式联系起来的机制。 为了揭示参与轴形成和原肠胚形成的其他趋化因子GPCR，我们将通过表征功能丧失的单一和复合突变体表型来询问胚胎发生过程中表达的21种趋化因子GPCR的子集的功能。由于Wnt、Dchs/Fat和GPCR通路的组分突变会导致流产、出生缺陷和疾病;我们的研究可以促进对它们的理解、诊断和促进疗法的开发。

 DESCRIPTION (provided by applicant): How does a vertebrate animal body develop from a single cell is an overarching question of my research. Despite much progress, many basic mechanisms underlying embryogenesis remain poorly understood. I am particularly interested how the inductive and morphogenetic processes that establish the embryonic body plan are coordinated in space and time to ensure normal development. Specification of anteroposterior and dorsoventral embryonic axis in the zebrafish zygote involves microtubule dependent transport of factors promoting dorsal Wnt/β-catenin activity, which patterns germ layers and coordinates gastrulation movements. We showed that Ccl19.1 chemokine signaling through Ccr7 G protein-coupled receptor (GPCR) limits axis formation by downregulating β-catenin. Using mutations in ccl19.1 and ccr7 zebrafish genes we will delineate the pathways through which they regulate calcium signaling and limit axis formation. We recently discovered that Dachsous (Dchs) cadherins regulate cytoskeleton in the zygote and during axis formation. Whereas Dchs is commonly known to interact with Fat cadherin and Fjx1 kinase, we will characterize Fat/Fjx1-dependent and independent roles of Dchs. We will identify proteins interacting with Dchs to define its functional links to cytoskeleton and other effectors. During gastrulation, convergence and extension (C&E) movements elongate the germ layers anteroposteriorly and narrow them dorsoventrally. Wnt/Planar Cell Polarity (Wnt/PCP) signaling is a conserved regulator of polarized cell behaviors driving C&E in vertebrates. Our studies posit that Wnt/PCP signaling works during gastrulation as a cellular compass coordinating polarity and behaviors of individual cells with anteroposterior embryonic polarity, in part by asymmetric distribution of PCP components at anterior and posterior cell membranes. To understand how the planar asymmetries of PCP components arise in dynamic mesenchymal cells, we will test the hypothesis that adhesion GPCR, Gpr125, a new PCP component, promotes formation of the posteriorly enriched membrane PCP complexes. We will determine whether Dchs works with Fat and Fjx1 during gastrulation to polarize microtubules and regulate Wnt/PCP signaling-dependent cell polarity. Finally, we will test whether the Dchs/Fat/Fjx1 system provides a mechanism to link Wnt/PCP signaling to global embryo patterning. To uncover additional chemokine GPCRs involved in axis formation and gastrulation, we will interrogate functions of the subset of 21 chemokine GPCRs expressed during embryogenesis by characterizing loss-of-function single and compound mutant phenotypes. As mutations in the components of the Wnt, Dchs/Fat and GPCR pathways cause miscarriages, birth defects and diseases; our studies can advance their understanding, diagnosis and facilitate development of therapies.