MOLECULAR GENETICS OF TUBEROUS SCLEROSIS 2

多发性硬化症（TSC）是一种多系统疾病， 在许多国家， 组织和器官，特别是大脑、眼睛、皮肤、肾脏， 心脏肺和骨骼 TSC是常染色体显性遗传 疾病，但很大一部分患者偶尔出现。 遗传连锁研究显示了这种疾病的基因座异质性， 在9号和16号染色体上具有至少两个TSC决定基因， 分别称为TSC 1和TSC 2。 16号染色体上的TSC2基因 最近通过定位克隆策略和基因内 在一些TSC病例中已经记录了该基因内的突变。的 TSC2基因产物命名为tuberin，编码1784个氨基酸的蛋白质， 显示了与GT3激活蛋白rap的一小段同源性， 1GAP。 这一建议旨在扩展我们以前的联系分析 TSC的分子遗传学和生物化学研究，以更好地了解 疾病表型。 TSC2基因的详细突变分析 将在TSC 2家族中进行，以精确定义 受影响个体的突变。 该分析将扩展到TSC 1 一旦在项目3中分离出TSC1家族中的基因， 突变 TSC 1和TSC 2基因的谱将在散发病例中定义。 将使用系统方法来扫描突变。 的 我们获得的信息将非常有用， 诊断TSC家庭，在理解遗传异质性， 这种混乱，最终将产生丰富的信息， 将块茎素与TSC 1的结构功能关系进行了关联， 蛋白 我们还建议产生结核菌素特异性抗体， 表达为融合蛋白的块茎蛋白的不同结构域， 确定其在正常和TSC2个体中的表达模式。 知识 这种蛋白质在组织培养细胞中的亚细胞定位 来源于正常和TSC 2病例，以及其响应于 各种细胞刺激将揭示TSC 2中的靶细胞。 的 假定的rap1 GAP活性的块茎蛋白将测试采用 细菌和杆状病毒构建体。 本文提出的研究应 为更好地了解块茎素的损失提供了基础， 导致这种多系统疾病。 从长远来看，这将导致 分离与块茎蛋白相互作用的蛋白质， 一旦确定了这一点，我们就能发现块茎蛋白和TSC 1蛋白之间的联系。

Tuberous sclerosis complex (TSC) is a multisystem disorder characterized by the widespread development of growths known as hamartomas in many tissues and organs, particularly within the brain, eyes, skin, kidneys, heart, lungs and skeleton. TSC is inherited as an autosomal dominant disorder, but a significant portion of patients appear sporadically. Genetic linkage studies have shown locus heterogeneity for the disease, with at least two TSC determining genes on chromosomes 9 and 16 which have been termed TSC1 and TSC2 respectively. The TSC2 gene on chromosome 16 has been recently isolated by positional cloning strategies and intragenic mutations within this gene have been documented in some TSC cases. The TSC2 gene product named tuberin encodes a 1784 amino acid protein that shows a small stretch of homology to the GTPase activating protein rap 1GAP. This proposal is aimed at extending our previous linkage analysis of TSC to molecular genetic and biochemical studies to better understand the disease phenotype. A detailed mutational analysis of the TSC2 gene will be performed in TSC2 families to precisely define the nature of mutations in affected individuals. This analysis will be extended to TSC1 gene in TSC1 families once this is isolated in Project 3. The mutation spectrum of both TSC1 and TSC2 genes will be defined in sporadic cases. A systematic approach will be used for scanning the mutations. The information that we gain will be very useful for providing a DNA based diagnostics in TSC families, in understanding the genetic heterogeneity in this disorder and finally will yield a wealth of information for correlating the structure function relationship of tuberin and the TSC1 protein. We also propose to generate tuberin specific antibodies to different domains of tuberin expressed as fusion proteins in order to define its expression pattern in normal and TSC2 individuals. A knowledge about the subcellular localization of this protein in tissue culture cells derived from normal and TSC2 cases, and its behavior in response to various cellular stimuli would reveal the target cells in TSC2. The putative rap1 GAP activity of tuberin will be tested employing the bacterial and baculoviral constructs. The studies proposed here should provide the basis for a better understanding of how loss of tuberin results in this multisystem disease. In the long term, this will lead to isolating the proteins with which tuberin interacts as well as unraveling the connection between tuberin and TSC1 protein once this is identified.