Development of the Zebrafish Enteric Nervous System

描述（由申请人提供）：我们的长期目标是了解脊椎动物肠神经系统（ENS）在胚胎发生过程中是如何被指定和定型的。了解ENS形成过程中涉及的细胞和分子过程将有助于了解神经系统等复杂结构在发育过程中是如何产生的。此外，我们的研究在理解ENS无法正确形成的儿科疾病（如先天性巨结肠病（HSCR））的机制和分子方面具有潜在的临床重要性。ENS来源于神经嵴，这是一种多能细胞群，从神经管沿着特定途径迁移，产生各种各样的神经和非神经组织。不同轴向群的神经嵴细胞有助于形成特定的结构和组织。在本提案中，我们将讨论胚胎发生过程中ENS前体的指定地点、时间和方式。我们的研究使用斑马鱼，因为模型系统的细胞生物学，分子和遗传优势，是唯一适合我们提出的实验。具体来说，我们的目标是回答以下问题：1)所有斑马鱼肠神经嵴前体都来自迷走神经嵴细胞的一个不同子集吗？我们将通过谱系分析确定斑马鱼ENS的起源。然后，我们将通过细胞消融和细胞移植来研究调节相互作用在确定迁移前神经嵴内ENS前体细胞命运中的作用；2)减少和灌肠两种突变影响肠前体发育的哪些步骤？我们已经确定了两种斑马鱼突变体，它们的肠道神经元数量显著减少。我们将对这些突变体进行特征描述，以确定这些突变在何处、何时以及如何导致其ENS表型；3)减量和灌肠突变体受哪些基因影响？我们将确定在减少和灌肠中受损的基因，并导致观察到的ENS表型。总之，提出的目标将有助于增加我们对产生ENS的机制和分子的理解，并可能为HSCR的潜在原因提供有价值的见解

DESCRIPTION (provided by applicant): Our long-term goal is to understand how the vertebrate enteric nervous system (ENS) is specified and patterned during embryogenesis. Understanding the cellular and molecular processes involved in ENS formation will provide insights into how a complex structure such as a nervous system arises during development. Furthermore, our studies are of potential clinical importance in understanding the mechanisms and molecules that underlie pediatric conditions where the ENS fails to form correctly, such as Hirschsprung's disease (HSCR). The ENS is derived from the neural crest, a multipotent population of cells that migrates from the neural tube along specific pathways to generate a wide variety of neural and non-neural tissues. Different axial populations of neural crest cells contribute to specific structures and tissues. In this proposal we will address where, when, and how ENS precursors are specified during embryogenesis. Our studies use the zebrafish due to the model system's cell biological, molecular and genetic strengths that are uniquely appropriate for our proposed experiments. Specifically, we aim to answer the following questions: 1) Do all zebrafish enteric neural crest precursors arise from a distinct subset of vagal neural crest cells? We will determine the origin of the zebrafish ENS by lineage analysis. We will then investigate by cell ablation and cell transplantation the role of regulative interactions in specifying ENS precursor cell fate within the premigratory neural crest; 2) Which steps in enteric precursor development are affected by two mutations, lessen and enema? We have identified two zebrafish mutants that have significant reductions in the number of enteric neurons. We will characterize these mutants to determine cell biologically where, when, and how these mutations cause their ENS phenotypes; 3) What genes are affected in the lessen and enema mutants? We will identify the genes that are lesioned in lessen and enema and result in the ENS phenotype observed. Together the proposed aims will help increase our understanding of the mechanisms and molecules involved in generating the ENS and may provide valuable insights into the underlying causes of HSCR