Retinoid Signaling in Neural Patterning in Zebrafish

描述（申请人描述）：神经系统缺陷导致 控制神经发育的正常机制受到破坏。因此 了解遗传性神经系统疾病的基础需要一个 胚胎分子和遗传过程的知识，控制模式 神经前体的形成。这些包括组织相互作用， 建立神经管的主轴，其分化为 不同的神经元类型，以及它们之间的相互连接， 神经网络的这项建议利用遗传学和 胚胎学优势的斑马鱼作为一个模型。斑马鱼胚胎形成a 简单的神经系统，与人类大脑的区域同源， 脊髓是可识别的，许多基因模式这些地区， 在鱼类和人类之间是保守的。据认为， 神经系统的前-后模式的组成部分是视黄酸的 酸（RA），一种信号，指导神经元发育模式沿沿着 体轴外源性RA截断前部发育，并已被证明， 会导致人类严重的神经和颅面缺陷实验 他建议使用斑马鱼突变体来剖析这种信号的作用， 视黄醛脱氢酶（RALDH 2），一种在视网膜中合成RA的酶， 胚胎，以及特定拮抗剂或显性阴性形式的RA 受体（RARs）。目的1是表征基因表达的缺陷， RALDH 2突变体，并将其与RAR破坏的影响进行比较，以确定 RA及其可能的靶基因的需求程度， 神经系统目的二是分析斑马鱼初级的简单模式 神经元，结合活体神经发育的真实的时间成像 胚胎使用转基因方法，其中发育中的神经元表达 在RALDH 2突变体和RAR破坏的胚胎中， 信号装置.这将阐明RA沿着 身体轴及其在几乎每个人的行为和命运中的作用 系统中的神经元。转基因生物的光学透明度和可用性 斑马鱼使它特别适合这项研究。目标3侧重于一个特定的 需要RA的中胚层和发育中的神经细胞之间的组织相互作用 管，通过使用细胞移植在RALDH 2突变体，以获得生化 神经模式的基础

DESCRIPTION (Applicant's Description): Defects of the nervous system result from disruptions of the normal mechanisms that control neural development. Thus understanding the basis for inherited neurological disorders requires a knowledge of the embryonic molecular and genetic processes that control pattern formation in neural precursors. These include the tissue interactions that establish the primary axes of the neural tube, its differentiation into different neuronal types, and their interconnections to form a functional neural network. This proposal examines these issues using the genetics and embryological advantages of the zebrafish as a model. Zebrafish embryos form a simple nervous system, where homologies with regions of the human brain and spinal cord are recognizable and many of the genes that pattern these regions have been conserved between fish and humans. It is thought that a major component of anterior-posterior patterning of the nervous system is retinoic acid (RA), a signal that directs patterns of neuronal development along the body axis. Exogenous RA truncates anterior development and has been shown to cause severe neural and craniofacial defects in humans. Experiments are proposed to dissect the role of this signal using a zebrafish mutant in retinaldehyde dehydrogenase (RALDH2), an enzyme that synthesizes RA in the embryo, as well as specific antagonists or dominant negative forms of RA receptors (RARs). Aim 1 is to characterize defects in gene expression in the RALDH2 mutant and compare them with the effects of RAR disruption, to define the extent of the requirement for RA and its possible target genes in the nervous system. Aim 2 is to analyze the simple pattern of zebrafish primary neurons, combined with real time imaging of neural development in living embryos using a transgenic approach in which developing neurons express a fluorescent marker, both in RALDH2 mutants and in embryos with disrupted RAR signalling. This will elucidate the overall extent of the influence of RA along the body axis and its roles in the behaviors and fates of virtually every neuron in the system. The optical clarity and availability of transgenic zebrafish make it uniquely suited for this study. Aim 3 focuses on a particular tissue interaction that requires RA, between the mesoderm and developing neural tube, by using cell transplantation in RALDH2 mutants to get to the biochemical basis for neural patterning.