Zfp423 Mechanisms in Joubert Syndrome and Related Disorders

项目总结： 这个项目关注的是构成发育的细胞、遗传和分子机制。 ZNF423相关纤毛病变的异常。纤毛疾病包括一系列统一的疾患 由初级纤毛的缺陷引起。临床表现多样，从单个器官的原发受累到 (最常见的是后脑、肾脏、肝脏或眼睛)到更严重的症状，如梅克尔综合征， 在几个器官中具有严重和多向性的发育表型。有几个基因已经被 被确认为纤毛疾病，绝大多数编码物理成分 初级纤毛。控制纤毛依赖信号的调节基因和遗传修饰物 控制睫状体缺陷的结局才刚刚开始与致病机制有关。这 该项目重点研究ZNF423的作用和机制，ZNF423是一种结构性核转录 调节蛋白在Joubert综合征(JBTS19)和肾病综合征(NPHP14)患者中发生突变。 ZNF423被认为包括几个转录复合体中的一个整合节点，该复合体 对经典的发育信号做出反应。由于ZNF423的表达也是发育动态的， 表型在多大程度上是细胞自主的，而不是细胞间相互缺陷的 信号，目前仍不清楚。AIM 1将使用最近开发的遗传工具(MADM)来评估细胞 通过创建一个简单的平台来原位诱导和标记有丝分裂克隆来实现自主性。因为 患者的突变是个别罕见的，通常只在一个等位基因上发现，并在患有 目前尚不清楚多少患者可归因于ZNF423，哪些患者可归因于ZNF423 ZNF423突变是真正的致病基因。AIM 2将使用基因组编辑在一个敏感和经过充分验证的 小鼠模型，以测试患者衍生突变的表型效应。目前尚不清楚是否具体 ZNF423活性靶点可能能够调节表型。目标3将决定是否 新发现的ZNF423抑制基因活性降低，其在两者中的表达增加 基因敲除细胞和突变动物，可改善纤毛依赖功能和突发性 Zfp423小鼠模型的表型。

Project Summary: This project focuses on cellular, genetic, and molecular mechanisms that underlie developmental abnormalities in ZNF423-realted ciliopathy. The ciliopathies comprise a spectrum of disorders unified by defects in primary cilia. Clinical presentations range from primary involvement of a single organ (most often hindbrain, kidney, liver or eye) to more severe presentations, such as Meckel syndrome, with severe and pleiotropic developmental phenotypes in several organs. Several genes have been identified for ciliopathy disorders, with the overwhelming majority encoding physical components of primary cilia. Regulatory genes that control cilium-dependent signaling and genetic modifiers that control the outcome of ciliary defects are only beginning to be tied to pathogenic mechanisms. This project focuses on the role and mechanisms of ZNF423, a constitutively nuclear transcriptional regulatory protein mutated in Joubert syndrome (JBTS19) and nephronophthisis (NPHP14) patients. ZNF423 is thought to comprise an integrative node among several transcriptional complexes that respond to classical developmental signals. As ZNF423 expression is also developmentally dynamic, the extent to which phenotypes are cell autonomous, rather than defects in reciprocal intercellular signaling, remains unclear. Aim 1 will use recently developed genetic tools (MADM) to assess cell autonomy by creating a simple platform for inducing and marking mitotic clones in situ. Because patient mutations are individually rare, often found on only one allele, and found in subjects with a range of presentations, it remains unclear what fraction of patients is attributable to ZNF423 and which ZNF423 mutations are truly pathogenic. Aim 2 will use genome editing in a sensitive and well-validated mouse model to test phenotypic effect of patient-derived mutations. It remains unclear whether specific targets of ZNF423 activity might be able to modulate phenotype. Aim 3 will determine whether decreasing activity of newly identified ZNF423-repressed genes, whose expression is increased in both knockdown cell and mutant animals, can improve cilium-dependent functions and emergent phenotypes in the Zfp423 mouse model.