Dystrophin maintains membrane integrity as a sarcolemmal protein. Dystrophin mutations lead to Duchenne muscular dystrophy, an X-linked recessive disorder. Since dystrophin is one of the largest genes consisting of 79 exons in the human genome, delivering a full-length dystrophin using virus vectors is challenging for gene therapy. Human artificial chromosome is a vector that can load megabase-sized genome without any interference from the host chromosome. Chimeric mice carrying a 2.4-Mb human dystrophin gene-loaded human artificial chromosome (DYS-HAC) was previously generated, and dystrophin expression from DYS-HAC was confirmed in skeletal muscles. Here we investigated whether human dystrophin expression from DYS-HAC rescues the muscle phenotypes seen in dystrophin-deficient mice. Human dystrophin was normally expressed in the sarcolemma of skeletal muscle and heart at expected molecular weights, and it ameliorated histological and functional alterations in dystrophin-deficient mice. These results indicate that the 2.4-Mb gene is enough for dystrophin to be correctly transcribed and translated, improving muscular dystrophy. Therefore, this technique using HAC gives insight into developing new treatments and novel humanized Duchenne muscular dystrophy mouse models with human dystrophin gene mutations.

抗肌萎缩蛋白作为一种肌膜蛋白维持膜的完整性。抗肌萎缩蛋白突变会导致杜氏肌营养不良症，这是一种 X 连锁隐性遗传病。由于抗肌萎缩蛋白是人类基因组中由 79 个外显子组成的最大基因之一，因此使用病毒载体递送全长抗肌萎缩蛋白对基因治疗具有挑战性。人类人工染色体是一种载体，可以加载兆碱基大小的基因组，不受宿主染色体的任何干扰。先前生成了携带 2.4-Mb 人类抗肌萎缩蛋白基因的人类人工染色体 (DYS-HAC) 的嵌合小鼠，并且在骨骼肌中证实了 DYS-HAC 的抗肌萎缩蛋白表达。在这里，我们调查了来自 DYS-HAC 的人抗肌萎缩蛋白表达是否挽救了抗肌萎缩蛋白缺陷小鼠中的肌肉表型。人抗肌萎缩蛋白通常以预期的分子量在骨骼肌和心脏的肌膜中表达，它改善了抗肌萎缩蛋白缺陷小鼠的组织学和功能改变。这些结果表明，2.4-Mb 基因足以让抗肌萎缩蛋白正确转录和翻译，从而改善肌营养不良症。因此，这种使用 HAC 的技术可以深入了解开发新的治疗方法和具有人类抗肌萎缩蛋白基因突变的新型人性化杜氏肌营养不良症小鼠模型。