Identification of Novel Components of the Dystrophin Complex Using C. Elegans

描述（由申请人提供）：肌营养不良蛋白相关蛋白复合物是一种多聚体蛋白复合物，存在于许多不同的组织中，包括肌肉。肌营养不良蛋白相关蛋白复合物的遗传缺陷导致人类肌肉营养不良。肌营养不良蛋白相关蛋白复合物在质膜中起着几种不同的作用。然而，考虑到很大比例的肌肉萎缩症患者仍然需要分子诊断，有可能一些成分还没有被确定。此外，我们不知道肌营养不良蛋白复合物是如何准确地组装、加工和运输到质膜的。秀丽隐杆线虫是一种已建立的遗传模式生物，它具有肌营养不良蛋白相关蛋白复合物的大部分成分。在秀丽隐杆线虫中，肌营养不良蛋白相关蛋白复合物组分的突变导致一种独特的运动表型，这在任何其他类型的不协调或过度活跃的突变体中都没有观察到，并在某些条件下导致肌肉变性。我们之前设计了一个基因筛选，以确定与肌营养不良蛋白突变体具有相同运动表型的特异性突变体，并确定了几个编码肌营养不良蛋白复合物已知成分的基因。此外，我们还发现了一个编码乙酰胆碱/胆碱转运蛋白的新基因。在改良的基因筛选中，我们现在已经确定了至少两个新的基因。我们已经克隆了其中一个基因，并正在继续对该基因进行表征。我们建议扩大基因筛选，以完成并鉴定出与肌营养不良蛋白突变体表现出相同运动表型的突变体。我们将确定这些突变体是否代表已知基因或新的基因的肌营养不良蛋白相关复合体。我们将通过基因定位和转化拯救相结合的方法克隆新基因。这些新基因可能是肌营养不良蛋白复合物的未知成分，调节复合物的组装或运输，并介导细胞功能。我们将利用遗传、分子和细胞生物学技术表征这些新基因的分子功能。我们还将鉴定和研究功能性哺乳动物同源物。这些发现将提高我们对人类肌肉萎缩症发病机制的理解，并可能有助于制定新的治疗策略。

DESCRIPTION (provided by applicant): The dystrophin associated protein complex is a multimeric protein complex found in many different tissues, including muscle. Genetic defects in the dystrophin associated protein complex lead to muscular dystrophy in humans. The dystrophin associated protein complex plays several different roles in the plasma membrane. However, given that large percentages of patients with muscular dystrophy remain to be molecularly diagnosed, there is a possibility that some of the components may not have been identified yet. Furthermore, we do not know how the dystrophin complex is exactly assembled, processed and transported to the plasma membrane. The nematode C. elegans is an established genetic model organism, and possesses most of components of the dystrophin associated protein complex. In C. elegans, mutations in components of the dystrophin associated protein complex cause a unique locomotory phenotype that is not observed in any other class of uncoordinated or hyperactive mutants, and lead to muscle degeneration under certain conditions. We previously designed a genetic screen that identifies specifically mutants exhibiting the same locomotory phenotype as the dystrophin mutant, and identified several genes encoding known components of the dystrophin complex. Additionally, we identified a novel gene that encodes an acetylcholine/choline transporter. In a modified genetic screen we now have identified at least two additional novel genes. We have cloned one of the genes and are continuing to characterize the gene. We propose to expand the genetic screen to completion and identify mutants that exhibit the same locomotory phenotype as the dystrophin mutant. We will determine whether these mutants represent known genes or novel genes of the dystrophin associated complex. We will clone the novel genes by a combination of genetic mapping and transformation rescue. These novel genes may be unidentified components of the dystrophin complex, regulate assembly or trafficking of the complex, and mediate cellular functions. We will characterize the molecular functions of these novel genes using genetic, molecular and cell biology techniques. We will also identify and study the functional mammalian homologues. These findings will improve our understanding of the pathogenesis mechanism of muscular dystrophy in humans and may help to devise new therapeutic strategies.