Volume 8, Issue 1, Pages 80-89 (July 2003) Expression of dystrophin driven by the 1.35-kb MCK promoter ameliorates muscular dystrophy in fast, but not in slow muscles of transgenic mdx mice  Patrick Dunant, Nancy Larochelle, Christian Thirion, Rolf Stucka, Daniel Ursu, Basil J Petrof, Eckhard Wolf, Hanns Lochmüller  Molecular Therapy  Volume 8, Issue 1, Pages 80-89 (July 2003) DOI: 10.1016/S1525-0016(03)00129-1 Copyright © 2003 The American Society of Gene Therapy Terms and Conditions

FIG. 1 Immunoblot analysis of full-length (427 kDa) and minidystrophin (220 kDa) in various muscles and other tissues of wild-type (wt; C57BL/6) and transgenic (tg) mice. Muscle samples show a prominent band (myosin at 200 kDa) on the posttransfer Coomassie gel (loading control). Dystrophin expression in transgenic mice is muscle-specific. It is strong in fast-twitch muscles but weak or absent in slow-twitch muscles, diaphragm, and heart. Molecular Therapy 2003 8, 80-89DOI: (10.1016/S1525-0016(03)00129-1) Copyright © 2003 The American Society of Gene Therapy Terms and Conditions

FIG. 2 Immunofluorescent localization of dystrophin in muscles from control and transgenic mice. TA (A, E, I, M, Q), EDL (B, F, J, N, R), M. soleus (C, G, K, O, S), and diaphragm (D, H, L, P, T). (A–P) Mice at the age of 7 months and (Q–T) mice at the age of 20 months are represented. Note the regularity of dystrophin expression in C57BL/6 mice (A–D), its absence in mdx mice (E–H), and the mosaic pattern in adult muscle from both transgenic lines, line 2 (I–L) and line 1 (N–P), at the age of 7 months, and line 2 at the age of 20 months (Q–T). Scale bar, 50 μm. Molecular Therapy 2003 8, 80-89DOI: (10.1016/S1525-0016(03)00129-1) Copyright © 2003 The American Society of Gene Therapy Terms and Conditions

FIG. 3 Correlation of dystrophin expression, central nucleation, and metabolic fiber type. Sections from 7-month-old C57BL/6 TA (A), mdx TA (B), transgenic TA (C), and transgenic EDL (D). Dystrophin immunostaining (red), nuclear bisbenzimide staining (blue), NADH-tetrazolium reductase (glycolytic fibers light, oxidative fibers dark). In transgenic muscles, dystrophin-positive fibers are large; central nuclei are nearly absent (C, D). In contrast, dystrophin-negative fibers are smaller, are mostly oxidative, and often have central nuclei (C, D). Note the central nucleus in the revertant (dystrophin-positive) fiber in the mdx muscle (B). Scale bar, 50 μm. Molecular Therapy 2003 8, 80-89DOI: (10.1016/S1525-0016(03)00129-1) Copyright © 2003 The American Society of Gene Therapy Terms and Conditions

FIG. 4 Mechanics of isolated EDL muscle. Evaluation of specific twitch force (A), specific tetanic force (B), and resistance to eccentric contractions (C) for female wild-type (black), transgenic (gray), and mdx (white) mice. Between 5 and 18 muscles were analyzed in every group. Data are presented as means ± SEM. Statistically relevant differences between transgenic and mdx mice are indicated (*P < 0.05; **P < 0.01). Differences between wild-type and mdx mice are highly significant for eccentric contraction (P < 0.001; not indicated). Molecular Therapy 2003 8, 80-89DOI: (10.1016/S1525-0016(03)00129-1) Copyright © 2003 The American Society of Gene Therapy Terms and Conditions