CHARACTERIZATION OF TSC PROTEIN HAMARTIN AND TUBERIN

描述（由申请人提供）：多发性硬化症是多系统的 一种以广泛生长为特征的疾病， 许多组织和器官中的错构瘤，特别是在脑，眼， 皮肤、肾脏、心脏、肺和骨骼。受影响最严重的系统是 中枢神经系统与受影响个体的发生 癫痫发作（80 - 90%），精神发育迟滞（50 - 60%），自闭症（高达 50%）。TSC是一种常染色体显性遗传疾病， 大约三分之二的受影响患者是散发性的， 突变。遗传连锁研究表明， 疾病，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。TSC 1基因编码一种新的 蛋白质，包含单个跨膜结构域和一个大的 具有卷曲螺旋结构域的胞质尾区。TSC2基因编码一种新的 一种蛋白质，含有一个与GT3激活蛋白同源的区域 rap1GAP蛋白。我们已经进行了全面的突变分析， TSC 1和TSC 2基因，并指出TSC 1突变是显着的， 在散发患者中代表性不足。然而，第二次的发生 TSC病变，特别是脑病变中的体细胞突变尚不清楚。在 为了了解这是否是由于细胞多形性，或者如果 tuberin/hamartin的单倍不足足以促进肿瘤发生，我们 将对激光捕获的显微切割病变进行遗传分析。我们有 鉴定了一种与Myc相关的新蛋白质，命名为Pam， 蛋白质为块茎素。果蝇（hiw）和C. elegans （rpm-1）Pam的同源物显示突触过度生长。我们假设帕姆是 结核菌素-错构菌素复合物的基本成分，尤其是在中枢神经系统中 这些蛋白质可能在皮层神经元功能中起关键作用， 接受检查。与块茎素相互作用的Pam结构域显示90% 与苍蝇同源物HIW相似。可能的生理和遗传因素 将检测果蝇TSC 2产物Gigas和HIW之间的相互作用。 因此，这些研究旨在确定结核菌素-错构瘤蛋白在抗肿瘤治疗中的作用。 哺乳动物中枢神经系统将进一步加强果蝇模型系统， 基因操作是可能的。在此获得的信息将 阐明这些肿瘤抑制因子的生理功能， 帮助设计更好的治疗方法。

DESCRIPTION (provided by applicant): Tuberous sclerosis complex is 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. The most severely affected system is the central nervous system with the occurrence in affected individuals of seizures (80-90 percent), mental retardation (50-60 percent), and autism (up to 50 percent). TSC is inherited as an autosomal dominant disorder, but approximately two-thirds of affected patients are sporadic due to new germline mutations. 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 TSC1 gene encodes a novel protein, hamartin that contains a single transmembrane domain and a large cytoplasmic tail with a coiled-coil domain. The TSC2 gene encodes a novel protein tuberin that contains a region of homology to the GTPase activating protein rap1GAP. We have performed a comprehensive mutational analysis of the TSC1 and TSC2 genes and noted that TSC1 mutations are significantly underrepresented in sporadic patients. However, the occurrence of the second somatic mutation in TSC lesions, particularly brain lesions is not clear. In order to understand whether this is due to cellular pleomorphism, or if haploinsufficiency of tuberin/hamartin is enough to promote tumor genesis, we will perform genetic analysis on laser capture microdissected lesions. We have identified a novel protein associated with Myc named Pam as an interacting protein for tuberin. Mutations in both the Drosophila (hiw) and C. elegans (rpm-1) homologs of Pam show synaptic overgrowth. Our hypothesis that Pam is an essential component of the tuberin-hamartin complex, particularly in the CNS where these proteins may have a critical role in cortical neuron function will be examined. The domain of Pam that interacts with tuberin reveals 90 percent similarity with the fly homolog HIW. The possible physical and genetic interaction between the Drosophila TSC2 product Gigas and HIW will be examined. Thus the studies aimed at defining the role of tuberin-hamartin in the mammalian CNS will be further strengthened by the Drosophila model system where genetic manipulations are possible. The information obtained here will elucidate the physiological functions of these tumor suppressors, which will aid in designing better therapies.