STUDIES OF PRODUCTION AND ANALYSIS OF CAVEOLIN-3 AND DYSTROPHIN DEFICIENT MOUSE LINE

包括dystrophin和Caveolin-3突变基因在内的大约30个基因被认为是肌营养不良症的原因，这些肌营养不良症表现为肌肉纤维的退化、坏死和再生。此前，我们通过基因打靶技术培育出了Caveolin-3缺陷小鼠。在这项研究中，我们建立了一种同时具有dystrophin和Caveolin-3基因缺陷的小鼠系，通过Dystrophin缺陷的MDX小鼠和Caveolin-3缺陷的小鼠的交叉出血。利用这条线，我们试图阐明这些蛋白在肌营养不良症的病理中的作用。我们发现MDX和这一系小鼠的肌肉表现出相似的组织学。然而，当分析基因表达时，我们在这条线上发现了有趣的结果。已知的促进肌肉再生的骨桥蛋白基因的表达在小窝蛋白-3缺陷的肌肉中显著降低。相反，在MDX肌肉中，它被极大地增强。利用双缺陷小鼠进一步阐明了小窝蛋白-3在骨桥蛋白基因表达中的作用。在MDX肌肉中，骨桥蛋白基因的表达水平比野生型高30-55倍，而在双缺陷小鼠中，骨桥蛋白基因的表达水平保持在5-14倍。因此，缺乏dystrophin和Caveolin-3会对骨桥蛋白基因的表达产生相反的影响，从而促进肌肉再生，尽管这两种蛋白的缺乏都会导致肌肉营养不良。

APPROXIMATELY 30GENES, INCLUDING DYSTROPHIN AND CAVEOLIN-3 MUTANT GENES, ARE KNOWN AS THE CAUSES OF MUSCULAR DYSTROPHIES THAT SHOW DEGENERATION, NECROSIS AND REGENERATION OF MUSCLE FIBERS. PREVIOUSLY, WE PRODUCED CAVEOLIN-3 DEFICIENT MICE BY GENE TARGETING TECHNIQUES. IN THIS STUDY, WE ESTABLISHED A MOUSE LINE HAVING DEFECTS IN BOTH DYSTROPHIN AND CAVEOLIN-3 GENES, BY CROSS-BLEEDING OF DYSTROPHIN DEFICIENT MDX MICE AND CAVEOLIN-3 DEFICIENT MICE. USING THIS LINE, WE TRIED TO CLARIFY THE ROLES OF THESE PROTEINS IN THE PATHOLOGY OF MUSCULAR DYSTROPHY. WE FOUND THAT MDX AND THIS LINE MOUSE MUSCLES SHOWED SIMILAR HISTOLOGY. HOWEVER, WE FOUND INTERESTING RESULTS IN THIS LINE, WHEN GENE EXPRESSION WAS ANALYZED. OSTEOPONTIN GENE EXPRESSION WHICH IS KNOWN TO INCREASE ON MUSCLE REGENERATION WAS GREATLY DECREASED IN CAVEOLIN-3 DEFICIENT MUSCLE. IN CONTRAST, IT WAS EXTREMELY ENHANCED IN MDX MUSCLE. PARTICIPATION OF CAVEOLIN-3 IN THE OSTEOPONTIN GENE EXPRESSION WAS FURTHER CLARIFIED BY USING THE DOUBLE DEFICIENT MICE. IN MDX MUSCLE, OSTEOPONTIN GENE EXPRESSION LEVEL INCREASED TO 30-55 TIMES HIGHER THAN THAT OF WILD TYPE MUSCLE, WHEREAS IT RETAINED AT 5-14 TIMES IN THE DOUBLE DEFICIENT MICE. THEREFORE, ABSENCE OF DYSTROPHIN AND CAVEOLIN-3 HAS THE INVERSE EFFECTS ON THE OSTEOPONTIN GENE EXPRESSION AND THUS FOR MUSCLE REGENERATION, ALTHOUGH THE ABSENCE OF EITHER PROTEIN RESULTS IN MUSCULAR DYSTROPHY.