The role of Wnt signaling in craniofacial development

描述（由申请人提供）：本提案的目标是了解面部原基发育的分子机制。Wnt在颅面发育中是颅神经嵴的产生和迁移所必需的。基于报告基因的活性，Wnt还在形态发生、面部组织的图案化生长和上皮衍生结构的分化中发挥作用。携带Lef 1/TCF 4（经典Wnt信号的两个增强子）无效突变的胚胎表现出畸形的额鼻突出。在特定目的I中，将使用Wnt靶基因的原位杂交、确定细胞增殖和分化速率的细胞分析以及表征骨骼生成间充质破坏的组织学测定来确定这种畸形的基础。在特定目的II中，可溶性Wnt抑制剂的子宫内基因转移将用于在颅神经嵴迁移完成后产生经典途径的严格失活。以这种方式处理的胚胎将进行与无效胚胎相同的分析。总的来说，这些数据将阐明Wnt信号的功能在额鼻隆突的生长和形态发生过程中的作用。

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the molecular mechanisms governing development of facial primordia. Wnts are required in craniofacial development for the generation and migration of the cranial neural crest. Based on reporter gene activity, Wnts also play a role in morphogenesis, during the patterned outgrowth of the facial prominences and in the differentiation of epithelial-derived structures. Embryos carrying null mutations in Lef1/TCF4, two enhancers of canonical Wnt signaling, exhibit a dysmorphic frontonasal prominence. In Specific Aim I the basis for this malformation will be determined using in situ hybridization for Wnt target genes, cellular analyses to determine rates of cell proliferation and differentiation, and histologic assays to characterize the disruption in skeletogenic mesenchyme. In Specific Aim II in utero gene transfer of a soluble Wnt inhibitor will be utilized to produce a stringent inactivation of the canonical pathway after migration of the cranial neural crest is complete. Embryos treated in this manner will be subject to the same analysis as null embryos. Collectively these data will elucidate the functions of Wnt signaling functions during outgrowth and morphogenesis of the frontonasal prominence.