THERAPEUTIC POTENTIAL OF DYSTROPHIN MINI-GENES

杜氏肌营养不良症（Duchenne muscular dystrophy，DMD）是一种由dystrophin基因突变引起的X连锁隐性遗传病，是人类最常见的遗传病之一。不幸的是，没有治疗或治愈这种致命的疾病。DMD基因治疗的可行性研究取得了很大进展。然而，在基因治疗可以有效地应用于这种常见的遗传性疾病之前，仍然需要解决许多问题。主要问题之一是病毒载体携带全长肌营养不良蛋白cDNA（14 kb）的能力有限。本申请提出通过构建缺失构建体探索杆状结构域区域的功能作用来解决该问题，最终目标是鉴定具有治疗潜力的最小肌营养不良蛋白构建体。目的1将测试肌营养不良蛋白的Dp260同种型逆转转基因mdx（肌营养不良蛋白缺陷）小鼠中的营养不良表型的功能能力。Dp260cDNA由于N端截短而仅为7kb。目的2通过固相和共沉淀法研究Dp260亚型和杆状结构域的体外肌动蛋白结合能力。目的3将使用转基因mdx小鼠测试多种缺失的组合，以找到通过病毒载体递送的最小可能的功能性肌营养不良蛋白。这些研究将导致对肌营养不良蛋白功能的更深入了解，并将有助于推动DMD基因治疗的发展。

Duchenne muscular dystrophy (DMD), an X-linked recessive disease caused by mutations in the dystrophin gene, is one of the most common human genetic diseases. Unfortunately, there is no treatment or cure for this lethal disorder. Considerable progress has been made in demonstrating the feasibility of gene therapy for DMD. Nevertheless, numerous issues still need to be addressed before gene therapy can be effectively applied to this common genetic disease. One of the main issues is the limited ability of viral vectors to carry the full-length dystrophin cDNA (14 kb). This application proposes to address this concern by exploring the functional role of the rod domain region through construction of deletion constructs with the ultimate goal of identifying the smallest dystrophin construct that has therapeutic potential. Aim l will test the functional capacity of the Dp260 isoform of dystrophin to reverse the dystrophic phenotype in transgenic mdx (Dystrophin-deficient) mice. The Dp260 cDNA is only 7 kb due to an N- terminal truncation. Aim 2 will explore the actin binding capacity of the Dp260 isoform and rod domain in vitro through solid-phase and co- sedimentation assays. Aim 3 will test various combinations of multiple deletions using transgenic mdx mice in order to find the smallest possible functional dystrophin for delivery via viral vectors. These studies will lead to a greater understanding of the function of dystrophin and will help advance the development of gene therapy for DMD.