Gene Interaction in Development and Disease

描述(申请人提供)：在之前的资助期间，我们发现了两种蛋白质在神经疾病中的致病作用。通过定位克隆小鼠周围神经节和中枢神经系统神经变性的苍白震颤突变，我们证明这种疾病是由磷脂酰肌醇5磷酸酶FIG4的零突变引起的。我们在一种严重的Charcot Marie Tooth病患者中发现了人类FIG4的突变，这是一种周围神经病变。我们还发现，功能相关蛋白VAC14的突变与苍白震颤小鼠的表型相似。为了进一步评估这一途径在神经系统疾病中的作用，我们将描述人类FIG4突变的小鼠模型，并使用条件突变剖析神经元和雪旺细胞的致病作用。我们将评估VAC14在Charcot Marie Tooth病中的作用，并将这两个基因的分析扩展到相关的神经疾病。为了确定这一调控途径的其他成分，我们将克隆C57BL/6J株中加速FIG4缺失小鼠临床进展的修饰基因，并研究与该途径中第三种酶-磷酸肌醇激酶突变相关的体内表型。我们将评估FIG4与最近在酵母2杂交筛选中发现的蛋白质的相互作用。这项工作将扩大我们对FIG4和VAC14突变发病机制的理解，并更好地确定它们在人类神经疾病中的作用。公共卫生相关性：在过去的资助期间，我们发现一种脂质信号分子是神经元生存所必需的。我们发现，一种新的哺乳动物基因的突变改变了这种细胞信号的浓度，并导致小鼠患上严重的神经疾病。我们还成功地将这些信息转化到临床领域，识别了患者突变并开发了4J型Charcot Marie Tooth疾病的分子诊断。我们建议将这项工作扩展到相关的基因和疾病，并建立更好的人类疾病的动物模型，以了解致病机制，并为测试治疗干预提供准确的模型。

DESCRIPTION (provided by applicant): During the previous funding period we discovered the pathogenic role of two proteins in neurological disease. By positional cloning the mouse neurological mutant pale tremor, with neurodegeneration in peripheral ganglia and CNS, we demonstrated that this disorder is caused by a null mutation of FIG4, a phosphatidyl inositol 5 phosphatase. We identified mutations of human FIG4 in patients with a severe form of Charcot Marie Tooth disease, a peripheral neuropathy. We also found that mutation of the functionally related protein VAC14 mimics the phenotype of the pale tremor mouse. To further evaluate the role of this pathway in neurological disease, we will characterize mouse models of human mutations in FIG4 and dissect the pathogenic contributions of neurons and Schwann cells using conditional mutants. We will evaluate the contribution of VAC14 to Charcot Marie Tooth disease, and extend the analysis of both genes to related neurological disorders. In order to identify additional components of this regulatory pathway, we will clone the modifier locus in strain C57BL/6J that exacerbates clinical progression in FIG4 null mice and investigate the in vivo phenotypes associated with mutation of the third enzyme in this pathway, a phosphoinositide kinase. We will evaluate the interaction of FIG4 with proteins recently identified in a yeast 2 hybrid screen. This work will extend our understanding of the mechanisms of pathogenesis of mutations in FIG4 and VAC14 and better define their contribution to human neurological disease. PUBLIC HEALTH RELEVANCE: During the past funding period, we discovered that a lipid signaling molecule in required for survival of neurons. We found that mutations in a novel mammalian gene change the concentration of this cellular signal and result in severe neurological disease in the mouse. We were also successful in translating this information into the clinical realm by identifying patient mutations and developing molecular diagnosis for Charcot Marie Tooth disorder type 4J. We propose to extend this work to related genes and disorders, and to generate better animal models of the human disease in order to understand the pathogenic mechanism and provide an accurate model for testing therapeutic intervention.