Zfp423 Mechanisms in Joubert Syndrome and Related Disorders

项目概要： 该项目重点研究发育过程中的细胞、遗传和分子机制 ZNF423 相关纤毛病的异常。纤毛病包括一系列统一的疾病 由初级纤毛缺陷引起。临床表现范围从单一器官的主要受累 （最常见的是后脑、肾脏、肝脏或眼睛）到更严重的表现，例如梅克尔综合征， 在多个器官中具有严重和多效性的发育表型。多个基因已被 被鉴定为纤毛病，其中绝大多数编码物理成分 初级纤毛。控制纤毛依赖性信号传导的调节基因和遗传修饰因子 控制纤毛缺陷的结果才刚刚开始与致病机制联系起来。这个 该项目重点研究ZNF423的作用和机制，ZNF423是一种组成型核转录因子 Joubert 综合征 (JBTS19) 和肾结核 (NPHP14) 患者的调节蛋白发生突变。 ZNF423 被认为包含多个转录复合物之间的整合节点， 对经典的发育信号做出反应。由于 ZNF423 表达也是发育动态的， 表型是细胞自主的程度，而不是细胞间相互作用的缺陷 信号，仍不清楚。目标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，从而实现自主性。因为 患者突变个体罕见，通常仅在一个等位基因上发现，并且在具有 的表现范围，目前尚不清楚哪部分患者可归因于 ZNF423，哪部分患者可归因于 ZNF423 ZNF423 突变确实具有致病性。目标 2 将在敏感且经过充分验证的环境中使用基因组编辑 小鼠模型来测试患者衍生突变的表型效应。目前尚不清楚具体是否 ZNF423 活性的靶标可能能够调节表型。目标 3 将确定是否 新发现的 ZNF423 抑制基因的活性降低，其表达在两种细胞中均增加 敲除细胞和突变动物，可以改善纤毛依赖性功能和突现 Zfp423 小鼠模型中的表型。

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.