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

描述(申请人提供)：营养不良相关蛋白复合体是一种多聚体蛋白质复合体，存在于许多不同的组织中，包括肌肉。营养不良蛋白相关蛋白复合体的遗传缺陷会导致人类肌肉营养不良。Dystrophin相关蛋白复合体在质膜上扮演着几种不同的角色。然而，考虑到很大比例的肌营养不良症患者仍有待分子诊断，存在一些成分可能尚未确定的可能性。此外，我们不知道dystrophin复合体是如何准确地组装、加工和运输到质膜上的。线虫是一种已建立的遗传模式生物，具有营养不良蛋白相关蛋白复合体的大部分成分。在线虫中，dystrophin相关蛋白复合体成分的突变会导致一种独特的运动表型，这在任何其他类型的非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退化。我们之前设计了一个遗传屏幕，专门识别表现出与dystrophin突变体相同的运动表型的突变体，并鉴定了几个编码dystrophin复合体已知成分的基因。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。在一个改进的基因筛查中，我们现在已经确定了至少两个额外的新基因。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。我们建议将遗传筛选扩大到完成，并确定表现出与dystrophin突变体相同的运动表型的突变体。我们将确定这些突变体是代表已知基因还是代表营养不良蛋白相关复合体的新基因。我们将通过遗传作图和转化拯救相结合的方法来克隆新基因。这些新基因可能是dystrophin复合体的未知成分，调节复合体的组装或运输，并调节细胞功能。我们将使用遗传、分子和细胞生物学技术来表征这些新基因的分子功能。我们还将鉴定和研究哺乳动物的功能性同源物。这些发现将加深我们对人类肌营养不良发病机制的理解，并可能有助于设计新的治疗策略。

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.