Fig. 6. Myoferlin is highly upregulated after muscle injury. (A) Immunoblot of muscle extracts 5 days after cardiotoxin injection showing marked upregulation of myoferlin after injury. Dysferlin was not upregulated after cardiotoxin-induced injury in either myoferlin null or wild-type mice. (B) Myoferlin null muscle does not regain its normal architecture after cardiotoxin injection. At low magnification (scale bar: 100 µm), dystrophin staining (green) shows smaller, more irregular fibers in myoferlin null muscle than in wild-type muscle. Embryonic myosin heavy chain (red) indicates regenerating myofibers. Higher magnification images (scale bar: 50 µm) show an increase in the number of centrally placed nuclei, which is indicative of recent fusion, in wild type compared with in myoferlin null muscle. Nuclei are stained with DAPI (blue).