Role of the novel regulator lbh in neural crest and craniofacial development

项目摘要/摘要 颅面畸形是人类最常见的先天缺陷之一， 影响1/700的出生率。虽然这些缺陷背后的许多基因是 已知的，许多其他人的身份和功能是未知的。首要目标是 这一建议的目的是评估一种基本上没有特征的基因--肢芽的作用 和心脏同源基因(LBH)，在斑马鱼头面部发育期间。这个基因 可能介导电荷综合征，一种神经脊细胞(NCC)的疾病 包括头面部缺陷，如小颌畸形。此外，我们还有 将该基因与文昌鱼的颌骨进化联系起来，这是一种进化模型 它在头面部形态上表现出广泛的多样性，其中许多模仿人类 面部畸形。综合起来，这些数据导致了LBH是一种 NCC和颅面发育的新型调节剂，将进行测试 通过以下实验目标。目标1：鉴于信息的匮乏 关于LBH，我们将首先描述其表达模式和细胞特异性 在斑马鱼面部发育过程中使用整体和分段的LBH 原位杂交，并与已知的头面部标记进行比较。目标2：我们 将评估调节LBH表达的效果(吗啡基因敲除或 信使核糖核酸过度表达)。初步实验 表明LBH消耗会导致NCC的减少和相应的 头面部骨骼有缺陷。具体地说，我们将确定细胞 这种缺陷的机制是由于诱导失败，迁移失败， NCC存活率降低或过早分化 原位杂交、报告斑马鱼品系和细胞分析。目标3：我们 将用生物学的方法分析LBH的功能保守和进化 不同下颌长度的柔鱼LBH的相关等位基因。 总体而言，这些研究将阐明LBH在头面部发育中的作用， 疾病和进化。

Project Summary/Abstract Craniofacial malformations are among the most common human birth defects, affecting 1/700 births. While many of the genes that underlie these defects are known, the identity and functions of many others are not. The overarching goal of this proposal is evaluate the role of a largely uncharacterized gene, limb bud and heart homolog (lbh), during zebrafish craniofacial development. This gene may mediate CHARGE syndrome, a disease of neural crest cells (NCCs) that includes craniofacial defects such as micrognathia. Additionally, we have associated this gene with the evolution of jaws in cichlids, an evolutionary model that exhibits extensive diversity in craniofacial form, many of which mimic human facial malformations. Combined, these data led to the hypothesis that lbh is a novel regulator of NCC and craniofacial development, which will be tested through the following experimental aims. Aim 1: Given the paucity of information about lbh, we will first characterize the expression pattern and cellular specificity of lbh throughout zebrafish facial development using whole-mount and sectioned in situ hybridization and comparison with known craniofacial markers. Aim 2: We will evaluate the effects of modulating lbh expression (morpholino knockdown or mRNA overexpression) on the craniofacial skeleton. Preliminary experiments indicate that depletion of Lbh results in reduction of NCCs and commensurate defects in the craniofacial skeleton. Specifically, we will determine if the cellular mechanism of this defect is due to a failure of induction, failure of migration, decreased survival, or premature differentiation of NCCs using a combination of in situ hybridization, reporter zebrafish strains, and cellular assays. Aim 3: We will analyze the functional conservation and evolution of lbh using biologically relevant alleles of lbh isolated from cichlids with differing mandible lengths. Overall, these studies will illuminate the role of lbh in craniofacial development, disease, and evolution.