Dermal Bone Growth in the Zebrafish

描述（由申请人提供）：本提案的长期目标是阐明真皮骨生长和发育的机制。由于哺乳动物颅面和颅顶骨形态复杂，研究真皮骨生长基因在哺乳动物中所起的作用是困难的。因此，本提案将利用斑马鱼鳍骨骼的特性来研究真皮骨的生长发育。斑马鱼鳍（鳍鳐）的骨骼部分的生长是通过远端添加的骨鳍鳐段来实现的。短鳍（软）突变产生的鳍鳍片段大约是野生型片段长度的一半。因此，本课题的首要目标是通过克隆软突变并鉴定其功能来揭示片段生长的分子基础。第二个目标是通过将信号分子shh、ptc1和bmp2的表达模式与一个已证实的生长标记（作为空间参考）和一个假定的联合标记（作为时间参考）进行比较，建立一个片段组装（生长）的时空模型。一旦这个模型建立起来，其他的鳍生长标志物可能会被添加到这个模型中。这些生长标记将在第三个目标中通过微阵列分析识别，表征为可靠的标记，然后添加到片段生长模型中。由于微阵列鉴定的基因代表了在片段生长过程中表达的基因，因此我们还将分析它们在五种不同片段长度突变体（包括软突变体）中的表达。最后，为了加强形态学分析，在第四个特定目标中，将通过柔化增强子筛选产生更多导致短鳍的新突变。通过完成这些目标，本提案将为理解人类畸形的生物学提供直接相关的新见解。

DESCRIPTION (provided by applicant): The long-term goals of this proposal are to elucidate the mechanisms of dermal bone growth and development. Studying the role of dermal bone growth genes in mammals is difficult due to the complex morphology of the craniofacial and cranial vault bones. Therefore, this proposal will utilize the properties of the zebrafish fin skeleton to examine the growth and development of dermal bone. Growth of the bony parts of the zebrafish fins (fin rays) is achieved by the distal addition of bony fin ray segments. The short fin (sof) mutation produces fin ray segments that are approximately half the length of wild-type segments. Therefore, the first aim of this proposal is to reveal the molecular basis of segment growth by cloning the sof mutation and characterizing its function. The second aim is to develop a spatial-temporal model for segment assembly (growth) by comparing the expression patterns of the signaling molecules shh, ptc1, and bmp2 with one proven growth marker (as a spatial reference) and with a presumptive joint marker (as a temporal reference). Once this is established, other fin growth markers may be added to this model. These growth markers will be identified by microarray analysis in the third aim, characterized as reliable markers, and then added to the model for segment growth. Since the genes identified by the microarray represent genes expressed during segment growth, their expression will also be analyzed in five different segment length mutants (including sof). Finally, to enhance the morphological analyses, a larger collection of new mutations causing short fins will be generated by a sof enhancer screen in the fourth specific aim. By completing these aims, this proposal will provide new insights of direct relevance for understanding the biology of human malformations.