The Role of Primary Cilia in Murine Craniofacial Development

项目摘要 初级纤毛是普遍存在的细胞器，其接收和传递来自细胞的分子信号。 细胞的分子环境Kif3a是一种鞭毛内转运蛋白， 初级纤毛的延伸和功能。颅神经嵴细胞中Kif3a的条件性缺失 导致严重的面中部扩张和舌头的丧失（无舌症）。这些表型， 沿着我们的初步数据表明，Kif3a的缺失会导致异常的Sonic hedgehog (Shh)活动我们的目标是确定神经嵴细胞中Kif3a的缺失如何影响Shh 颅面复合体中的信号。在我们的第一个目标，我们将测试的假设，损失的 Kif3a阻止发育中的神经嵴细胞中Gli3阻遏物的形成 中脸我们将研究Kif3a在Gli3加工中所起的作用，并测试是否重新引入Gli3。 阻遏物可以拯救面中部表型。在我们的第二个目标中，我们测试了Kif3a的丢失是否在 神经嵴细胞破坏神经外胚层和面部神经系统中Shh依赖的信号传导中心 外胚层是中面部发育和生长所必需的。这一目标考验着 假设Kif3a突变体中的面中部表型是由继发的非细胞 自主机制在我们的第三个目标中，我们测试了Kif3a的缺失阻止了 在发育中的舌头和下颌中形成Gli激活剂。活化剂丢失 随后导致Shh函数的丢失。我们将比较 Kif3a条件性敲除和另一种Shh依赖性失言语症模型之间的失言语症。 最后，我们将确定中胚层来源的舌肌前体细胞的命运 Kif3a突变体总之，这些研究将提供必要的洞察机制， 初级纤毛在发育中的颅面复合体中处理Shh信号的功能。我们 期望我们的研究能对颅面纤毛病变的病因学提供新的见解。

Project Summary Primary cilia are ubiquitous organelles that receive and transduce molecular signals from the cell's molecular environment. Kif3a is an intraflagellar transport protein necessary for the extension and function of primary cilia. Conditional loss of Kif3a in cranial neural crest cells results in severe midfacial expansion and the loss of a tongue (aglossia). These phenotypes, along with our preliminary data, suggest that loss of Kif3a causes aberrant Sonic hedgehog (Shh) activity. Our objective is to determine how loss of Kif3a in neural crest cells affects Shh signaling within the craniofacial complex. In our first aim we will test the hypothesis that loss of Kif3a prevents the formation of the Gli3 repressor in neural crest cells of the developing midface. We will examine the role Kif3a plays in Gli3 processing and test if reintroduction of Gli3 repressor can rescue the midfacial phenotype. In our second aim we test if loss of Kif3a in neural crest cells disrupts Shh dependent signaling centers in neuroectoderm and facial ectoderm that are necessary for development and growth of the midface. This aim tests the hypothesis that the midfacial phenotype in Kif3a mutants is caused by a secondary, non-cell autonomous mechanism. In our third aim we test the hypothesis that loss of Kif3a prevents formation of Gli activator in the developing tongue and lower jaw. Loss of the activator subsequently leads to a loss-of-Shh function. We will compare the molecular mechanism of aglossia between Kif3a conditional knock-outs and another, Shh-dependent aglossia model. Finally, we will determine the fate of mesodermally derived muscle precursor cells of the tongue in Kif3a mutants. Taken together, these studies will lend essential insight into the mechanism of primary cilia function in processing a Shh signal within the developing craniofacial complex. We expect our studies will provide novel insight into the etiology of craniofacial ciliopathies.