Dishevelled-Mediated Control of Wnt/PCP Pathways

描述（由申请人提供）：保守良好的规范和非规范Wnt通路对哺乳动物发育的各个方面都很重要，包括中枢神经系统的发育。一个悬而未决的问题仍然存在：调节发育的各种Wnt途径是如何在体内整合的？dvl是解决这个问题的杰出候选者，因为这些保守蛋白在所有真核生物中都是典型和非典型Wnt通路所必需的。我们已经在三个Dvl基因中发现了部分独特但主要是冗余的功能。单突变体在社会行为和圆锥状心脏发育方面表现出一些独特的缺陷，而双Dvl突变体表现出严重的神经管缺陷（颅裂）和严重的耳蜗缺陷。为了进一步支持冗余性，Dvl1/2/3三重突变体不能进行原肠胚形成，也不能形成中胚层。我们计划剖析Dvl调节正常发育的体内途径，并在Dvl突变体中被破坏以产生这些表型。我们在小鼠体内制造了每个Dvl基因的条件等位基因，以及能够区分典型Wnt和非典型Wnt/PCP通路功能的体内等位基因。我们使用这些等位基因提供了明确的证据，表明Dvl1显示的颅裂表型；Dvl2双突变体是由Wnt/PCP通路的趋同延伸运动中断引起的。我们将使用这些工具来全面分析从原肠胚形成和神经发育过程中神经褶皱的第一次发育到整个神经发生和神经元迁移过程中，典型Wnt和非典型Wnt/PCP通路在神经元发育过程中的作用。根据我们发表的和初步的数据，我们预测dvl和它们调节的通路在大脑发育的所有阶段都是至关重要的。我们将使用以下具体目标：1)确定体内原肠形成过程中典型Wnt和非典型Wnt/PCP通路的作用；2)表征神经发育过程中负责神经管闭合的Dvl依赖通路；3)利用双Dvl突变体确定Dvl以及典型Wnt和非典型Wnt/PCP通路在前脑/中脑-后脑发育中的作用；4)利用三重Dvl突变体确定Dvl以及典型Wnt和非典型Wnt/PCP通路在前脑/中脑-后脑发育过程中的作用。

DESCRIPTION (provided by applicant): The well-conserved canonical and non-canonical Wnt pathways are important for all aspects of mammalian development, including the development of the central nervous system. An outstanding question remains: how are the various Wnt pathways that regulate development integrated in vivo? Dvls are outstanding candidates to address this question, since these conserved proteins are required in all eukaryotes for both canonical and non-canonical Wnt pathways. We have uncovered partially unique but predominantly redundant functions among the three Dvl genes. Single mutants display some unique defects in social behavior and conotruncal heart development, while double Dvl mutants display severe neural tube defects (craniorachischisis) and severe cochlear defects. In further support of redundancy, Dvl1/2/3 triple mutants are unable to undergo gastrulation and do not form mesoderm. We plan to dissect the in vivo pathways that Dvls regulate normal development and are disrupted in the Dvl mutants to produce these phenotypes. We produced in vivo conditional alleles in mice for each of the Dvl genes as well as in vivo alleles that can distinguish either canonical Wnt of non-canonical Wnt/PCP pathway function. We used these alleles to provide definitive evidence that the craniorachischisis phenotype displayed by Dvl1;Dvl2 double mutants resulted from disruption of convergent extension movements via the Wnt/PCP pathway. We will use these tools to provide a comprehensive analysis of the role of the canonical Wnt and non-canonical Wnt/PCP pathways during neuronal development from the first development of neural folds during gastrulation and neurulation throughout neurogenesis and neuronal migration. Based on our published and preliminary data, we predict that Dvls and the pathways they regulate are critical at all stages of brain development. We will use the following specific aims: 1) Determine the role of canonical Wnt and non-canonical Wnt/PCP pathways during gastrulation in vivo; 2) Characterize the Dvl dependent pathways responsible for neural tube closure during neurulation; 3) Determine the role of Dvls and the canonical Wnt and non-canonical Wnt/PCP pathways during forebrain/midbrain-hindbrain development using double Dvl mutants; and 4) Determine the role of Dvls and the canonical Wnt and non-canonical Wnt/PCP pathways during forebrain/midbrain-hindbrain development using triple Dvl mutants.