FIG. 3.

Direct intramuscular injection of tyrosine modified AAV-6 leads to robust and persistent micro-dystrophin expression in DMD dog limb muscle. (A) Representative immunostaining photomicrographs of normal and untreated DMD dog limb muscles. Dystrophin expression in normal dog muscle was revealed by an antibody that recognizes dystrophin spectrin-like repeat R16 (R16 antibody) and an antibody that recognizes the C-terminal domain. Dystrophin expression was not detected in DMD dog muscle. (B) Representative dystrophin immunostaining at 7, 11, and 15 weeks after intramuscular injection of the AAV micro-dystrophin vector. Top panel, immunostaining with the R16 specific antibody; bottom panel, immunostaining with the C-terminal specific antibody. Asterisk, an endogenous revertant myofiber stained positive by both the R16 and C-terminal antibodies. Insert, the long exposure image of the boxed region in the same photomicrograph. (C) A representative cross-sectional image of the extensor carpi radialis muscle stained with the R16 specific antibody at 22 weeks after intramuscular AAV injection. Dotted area marks the tendon.