(A) Schematic of murine micro-dystrophin construct. A truncated MCK promoter/enhancer (563 bp) is used to drive muscle specific gene expression. Also labeled is a chimeric SV40 intron (97 bp) and synthetic polyadenylation site (53 bp). The 3,590 bp murine micro-dystrophin construction is depicted in detail. ABD is the complete actin binding domain, hinges 1, 2 and 4 are shown (green boxes), as are the flanking spectrin rod domains (SR blue boxes). The cysteine-rich dystroglycan binding domain is denoted by an orange box. AAV2 ITR are shown as arrowheads. (B) Immunofluorescence detection of micro-dystrophin expression in mdx mouse TA muscle. rAAV1, 6, or 8.micro-dystrophin (1011 vg) was delivered by intramuscular injection (IM Control) or ILP through the femoral artery of 3–4 week old mdx mice. Representative TA muscle sections (12 um) are shown from 4 week post-injected animals (8 and 12 weeks looked similar). Sections were immuno-stained with the N-terminal dystrophin antibody Manex1a. Scale Bar, 50 μm.