The
mdx mouse has X-chromosome linked myopathy due to dystrophin deficiency, and is therefore used as a model of human Duchenne muscular dystrophy. As the
mdx mouse bears a point mutation resulting in a stop colon in the middle of the dystrophin gene, most of its muscle fibers are not stained in immunohistochemistry with anti-dystrophin antisera. However, a clear immunostaining occurs on the cell membrane in a small number of fibers. We characterized these rare positive fibers in the present study with five different antibodies raised against various regions of dystrophin. They were stained with four of them inluding those raised against the N- and C-terminals of dystrophin. However, they were not stained with antibody Dy4/6D3 raised against the middle region of dystrophin close to the site corresponding to the
mdx mutation. The staining could not be explained by the expression of the dystrophin related protein, an autosomal homologue of dystrophin. We tentatively concluded that the positive staining is due to truncated dystrophin lacking the region corresponding to the
mdx mutation.
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