Genetic and molecular anlaysis of neural development

描述（由申请人提供）：脊椎动物神经系统内细胞类型的多样性取决于发育早期发生的模式化事件。 神经组织的特化和模式化与其他胚层的发育密切相关。 中胚层和内胚层是诱导神经组织并在神经板内建立不对称性的信号的重要来源。 在这个建议中，我们试图利用有效的遗传和细胞的方法，在斑马鱼研究神经外胚层的图案。 斑马鱼非常适合这种分析。 斑马鱼胚胎是透明的，胚胎发育迅速。 这些属性促进了对正常和异常胚胎发育的详细观察。 斑马鱼产生大量的后代，除了促进表型表征，还增强了遗传分析。所提出的实验利用几个充分表征的斑马鱼突变来研究诱导和图案化神经组织的分子机制。 一般的方法是考虑产生前部和后部神经组织的所有信号。 将测试神经诱导和模式化的模型。 提出了一种遗传筛选，以确定新的基因座，破坏前神经规范。该筛选利用了产生单倍体斑马鱼胚胎的能力，以增加筛选的通量。 有两个组成部分的屏幕：基于形态学的方法，以确定增强突变（bozozok），破坏前神经模式和基于原位的努力，以检测phox2a转录因子的表达结构域的改变。 在试点筛选中发现的一个有希望的突变改变了前神经模式，并将进行详细研究。由于所有脊椎动物在神经系统的组织方面都具有基本的相似性，因此了解控制斑马鱼神经模式的遗传网络将为包括人类在内的其他物种的发展提供重要的见解。 几种破坏胚胎发育的斑马鱼突变具有与常见的人类先天性异常，前脑无裂畸形相似的前神经缺陷，并且具有相似的病因。 破译脊椎动物轴形成的机制也可能提供洞察其他人类发育障碍的原因。

DESCRIPTION (provided by applicant): The diversity of cell types within the vertebrate nervous system depends on patterning events that occur at early stages of development. The specification and patterning of neural tissue is closely coupled to the development of the other germ layers. The mesoderm and endoderm are important sources of signals that induce neural tissue and establish asymmetries within the neural plate. In this proposal, we seek to utilize the potent genetic and cellular methodologies available in the zebrafish to study patterning of the neural ectoderm. The zebrafish is well suited to this analysis. Zebrafish embryos are transparent and embryonic development occurs rapidly. These attributes foster detailed observation of normal and aberrant embryonic development. Zebrafish produce large numbers of offspring, which in addition to facilitating phenotypic characterization, enhances genetic analysis. The proposed experiments utilize several well characterized zebrafish mutations to investigate the molecular mechanisms that induce and pattern neural tissue. The general approach is to account for all the signals that generate anterior and posterior neural tissue. Models for both neural induction and patterning will be tested. A genetic screen is proposed to identify novel loci that disrupt anterior neural specification. The screen takes advantage of the ability to generate haploid zebrafish embryos in order to increases the throughput of the screen. There are two components to the screen: a morphology based approach to identify enhancers of a mutation (bozozok) which disrupts anterior neural patterning and an in situ based effort to detect alterations of the expression domains of the phox2a transcription factor. One promising mutation identified in a pilot screen alters anterior neural patterning and will be studied in detail. Because all vertebrates share fundamental similarities in the organization of their nervous systems, understanding the genetic networks that govern neural patterning in zebrafish will provide important insights into development of other species, including humans. Several zebrafish mutations have that disrupt embryonic development have anterior neural defects similar to a common human congenital abnormality, holoprosencephaly, and share similar etiologies. Deciphering the mechanisms of vertebrate axis formation may also provide insight into the causes other human developmental disorders.