The role of Wnt signaling in craniofacial development

描述(申请人提供)：这项建议的目标是了解控制面部原基发育的分子机制。WNTs是颅面发育所必需的，也是颅面神经隆起形成和迁移所必需的。基于报告基因的活性，WNTS还在形态发生、面部隆起的图案化生长和上皮源性结构的分化中发挥作用。携带Lef1/TCF4零突变的胚胎表现出畸形的额鼻突起，Lef1/TCF4是规范Wnt信号的两个增强子。具体而言，将使用Wnt靶基因的原位杂交、细胞分析来确定细胞增殖和分化率，以及组织学分析来表征骨源性间充质的破坏，以确定这种畸形的基础。在特定的目的II，子宫内基因转移的可溶性Wnt抑制剂将被用来产生一个严格的失活的典型途径后，颅神经脊的迁移完成。以这种方式处理的胚胎将接受与零胚胎相同的分析。总而言之，这些数据将阐明Wnt信号功能在额鼻隆起的生长和形态发生中的作用。

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.