CRANIOFACIAL MORPHOGENESIS IN THE ZEBRAFISH

描述(申请人提供)：发育不正常时会出现颅面畸形。了解头部骨骼发育，包括控制发育的调控基因，对于我们理解人类遗传性疾病的问题至关重要。发育机制在动物中是广泛共享的。不同脊椎动物的颌骨来自相同的胚胎组织，并依赖于相同基因的正确功能。例如，编码细胞-细胞信号的Endothelin 1基因的突变会导致小鼠和斑马鱼的颌骨显著减少，这是本提案关注的一个有价值的动物模型，因为它具有良好的研究属性。提出了三个项目来检验关于骨骼和软骨形成机制的假说的预测。第一项研究是使用精确的细胞标记程序来了解胚胎面部骨骼形成细胞的排列，并通过在完整胚胎中进行延时记录来了解细胞在发育出形状不同的软骨时是如何重新排列的。另一个目标是，通过同样的方法，了解当关键的模式决定基因HOX基因和内毒素1基因不起作用时，细胞排列和重排是如何被破坏的。第二个研究是用分子方法检测细胞对内皮素-1信号的反应。这将通过了解在接收内皮素1信号的骨架形成细胞中哪些基因活动发生变化，以及这些变化的功能后果来实现。第三项研究是利用从诱变鱼类中提取的幼虫进行骨骼筛选，以发现颅面图案形成所需的新基因，并通过分析突变基因，了解这些基因是如何发挥作用的。

DESCRIPTION (provided by applicant): Craniofacial malformations arise when development does not work correctly. Learning about head skeletal development, including the regulatory genes that control development, is essential for our understanding of what goes wrong in human inherited disorders. Developmental mechanisms are broadly shared among animals. The jaws of diverse vertebrates come from the same embryonic tissues, and depend on correct function of the same genes. E.g., mutation of the Endothelin 1 gene, encoding a cell-cell signal, causes a prominent reduction of the jaw in mice and in zebrafish, a valuable animal model on which this proposal focuses because of favorable attributes for study. Three projects are proposed to test predictions of hypotheses about the mechanisms underlying formation of bones and cartilages. The first investigation is to use precise cell marking procedures to learn arrangements of embryonic facial skeleton-forming cells, and to learn by time-lapse recordings in intact embryos, how the cells rearrange as they develop cartilages that differ from one another in shape. A further goal is to learn, by the same methods, how the cell arrangements and rearrangements are disrupted when critical pattern-determining genes, Hox genes and the Endothelin 1 gene, do not function. The second investigation is to use molecular methods to examine the cellular responses to Endothelin 1 signaling. This will be accomplished by learning what gene activities change in skeleton-forming cells receiving an Endothelin 1 signal, and what are the functional consequences of these changes. The third investigation is use a skeletal screen with larvae derived from mutagenized fish to discover new genes required for craniofacial patterning, and, by analyzing the mutants, to learn how the genes function.