Progressive acquisition of novel neural crest derivatives along the neural axis during vertebrate evolution

脊椎动物进化过程中沿神经轴逐步获得新型神经嵴衍生物

基本信息

批准号：
10617203
负责人：
Marianne Bronner
金额：
$ 57.13万
依托单位：
CALIFORNIA INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-05-15 至 2027-04-30
项目状态：
未结题

项目摘要

The neural crest is a uniquely vertebrate cell type that is thought to have played an important role in vertebrate evolution by forming peripheral ganglia and jaws, thus facilitating predation and expansion of the brain. We recently identified a “cranial-specific” neural crest transcriptional subcircuit in jawed vertebrates (gnathostomes) that imbues this neural crest population with the unique ability, absent from trunk neural crest, to form craniofacial cartilage that is critical for jaw formation. Here, we propose to examine whether homologous genes are expressed in the cranial premigratory neural crest of lamprey, a jawless basal vertebrate (agnathan). Our preliminary results suggest that many of these genes are “missing” from the lamprey's premigratory cranial neural crest, thus challenging the hypothesis that invention of neural crest in vertebrates gave rise to a “New Head”. Accordingly, we hypothesize that there was progressive expansion of neural crest derivatives during the course of vertebrate evolution. This likely occurred by addition of new enhancer elements into the premigratory neural crest that conferred novel developmental potential onto this cell population. As case in point, lamprey lack a vagal neural crest that in gnathostomes forms the enteric nervous system. To test this hypothesis, we will perform lineage analysis, analyze transcription factors and regulatory regions of selected genes across agnathan and gnathostomes. We will identify putative enhancers, dissect their regulatory inputs, and test the ability of these regions to drive reporter expression in lamprey as well as cross-species, in the zebrafish. The results promise to elucidate how new cell types arose during vertebrate evolution under the umbrella of the neural crest.

神经嵴是一种独特的脊椎动物细胞类型，被认为发挥了重要作用通过形成周围神经节和颌骨，从而促进捕食，从而在脊椎动物进化中发挥作用我们最近发现了一种“颅脑特异性”神经嵴转录。有颌脊椎动物（颌口动物）中的子电路使该神经嵴种群具有躯干神经嵴缺乏形成对下颌至关重要的颅面软骨的独特能力在这里，我们建议检查同源基因是否在其中表达。七鳃鳗的颅骨迁徙前神经嵴，一种无颚的基底脊椎动物（无颌类）。初步结果表明，七鳃鳗的许多基因“缺失” 迁徙前的颅神经嵴，从而挑战了神经嵴发明的假设因此，我们发现脊椎动物中存在“新头”。在脊椎动物进化过程中，神经嵴衍生物逐渐扩展。可能是通过在迁移前神经嵴中添加新的增强子元件而发生的赋予该细胞群新的发育潜力作为一个例子，七鳃鳗缺乏。颌体中形成肠神经系统的迷走神经嵴假设，我们将进行谱系分析，分析转录因子和调控我们将确定无颌类和颌类动物中选定基因的区域。增强剂，剖析其监管投入，并测试这些区域驱动报告者的能力在七鳃鳗以及跨物种、斑马鱼中的表达结果有望实现。阐明在神经网络的保护下，脊椎动物进化过程中新的细胞类型是如何产生的波峰。