EXPRESSION OF DYSTROPHIN AND ITS ASSOCIATED PROTEINS FOLLWING MYOBLAST TRANSPLANTATION INTO MDX MICE.

Dystropin是Duchenne肌营养不良症(DMD)的主要致病蛋白，存在于正常肌膜的胞浆表面。在DMD和MDX(相当于DMD的小鼠)肌肉中观察到它的缺失，并被认为是肌肉纤维退化的原因。将具有正常营养不良基因的成肌细胞注射到MDX小鼠肌肉中，构建成肌膜下肌营养不良蛋白内衣。我们将正常的小鼠肌肉细胞系C2肌肉母细胞注射到MDX裸鼠的肌肉中。C2成肌细胞移植后出现大量抗肌营养不良蛋白阳性纤维。我们用抗dystrophin相关蛋白抗体检测了dystrophin阳性纤维。我们报道了抗肌营养不良蛋白相关蛋白在生物化学上分为3类，即抗肌营养不良蛋白多糖复合体和合体营养素复合体。我们还克隆了一个新的肌聚糖(γ-肌甘聚糖)基因，发现人的γ-肌聚糖基因被定位到染色体13q12上，并在3个家系和4例散发性SCARMD患者中发现了改变其阅读框架的缺失。我们证明了腺病毒介导的LacZ基因在成年C57BL/10ScSN小鼠骨骼肌中的高效转导和表达。在鸡b-肌动蛋白启动子和巨细胞病毒增强子的控制下，注射LacZ基因后，胫前肌中62%的肌纤维呈b-半乳糖苷酶阳性。转导基因在IIA型和IIX型纤维中优先表达，这两种纤维的氧化酶含量高于IIB型纤维。

Dystropin is a responsible protein of Duchenne muscular dystrophy (DMD) and is present at the protoplasmic surface of normal sarcolemma. Its absencd is observed in DMD and mdx (mouse equivalent to DMD) muscles and is considered to be the cause of muscle fiber degeneration. To construct the subsarcolemmal dystrophin-undercoat in mdx muscle, myoblasts with normal dystrophy gene are injected into mdx mouse muscle. We injected C2 myblasts, a normal mouse muscle cell line, into the muscles of mdx nude mouse. A large number of dystrophin-positive fibers appeared after C2 myoblast transplantation. We examined dystrophin-positive fibers with antidystrophin associated proteins antibodies. We reported that dystrophin-associated proteins are biochemically classified into 3 groups, namely, dystroglycan complex and syntrophin complex. We also cloned a new sarcoglycan (gamma-sarcoglydan) cDNA and showed that the human gamma-sarcoglycan gene was mappetd to chromosome 13q12 and delations that alter its reading frame were identified in three families and one of four sporadic cases of SCARMD.We showed the efficient transduction and expression of lacZ gene in the skeletal muscle of adult C57BL/10ScSn mice after adenovirus-mediated gene transfer. Sixty-two percent of the myofibers in the tibialis anterior (TA) muscle were b-galactosidase-positive after injection of the lacZ gene under the control of the chicken b-actin promoter and the cytomegalovirus enhancer. The transduced gene was preferentially expressed in type IIA and IIX fibers which were richer in oxidative enzymes than type IIB fibers.