Development of the Zebrafish Enteric Nervous System

我们的长期目标是了解脊椎动物肠道神经系统(ENS)在胚胎发育过程中是如何指定和形成模式的。了解ENS形成过程中涉及的细胞和分子过程将有助于深入了解复杂结构，如神经系统在发育过程中是如何产生的。此外，我们的研究对于理解儿科疾病的机制和分子具有潜在的临床重要性，这些疾病是无法正确形成ENS的，例如先天性巨结肠(HSCR)。 ENS来源于神经脊，它是一个多潜能的细胞群体，沿着特定的路径从神经管迁移，产生各种各样的神经和非神经组织。不同轴向的神经脊细胞群对特定的结构和组织有贡献。在这项提案中，我们将解决在胚胎发育过程中，ENS前体在哪里、何时以及如何被指定。我们的研究使用斑马鱼，因为模型系统的细胞生物学、分子和遗传强度特别适合我们建议的实验。具体地说，我们的目标是回答以下问题：1)斑马鱼肠道神经脊前体细胞是否起源于迷走神经脊细胞的一个不同的子集？我们将通过谱系分析来确定斑马鱼的起源。然后，我们将通过细胞移植来研究调控相互作用在指定迁移前神经脊内的ENS前体细胞命运中的作用；2)在斑马鱼ENS突变体灌肠中，什么基因受到影响？我们已经确定了几个斑马鱼突变体，它们的肠道神经元数量显著减少。一 这些突变体中的一种是灌肠，另一种是减少。我们最近确定LELEEN在TRAP100中有一个突变。我们现在将确定在灌肠过程中导致突变表型的基因；3)ENS前体发育的哪些步骤在减少和灌肠过程中受到影响？我们将对这些突变进行表征，以确定这些突变在哪里、何时以及如何导致其表型的细胞生物学。这些拟议的目标将有助于我们加深对产生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。

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 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 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 transplantation the role of regulative interactions in specifying ENS precursor cell fate within the premigratory neural crest; 2) What gene is affected in the zebrafish ENS mutant, enema? We have identified several zebrafish mutants that have significant reductions in the number of enteric neurons. One of these mutants is enema another is lessen. We recently determined that lessen has a mutation in TRAP100. We will now identify the gene that is lesioned in enema that results in the mutant phenotype; 3) Which steps in ENS precursor development are affected in lessen and enema? We will characterize these mutants to determine cell biologically where, when, and how these mutations cause their phenotypes.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.