Fig. 1. Generation of Dp116/mdx^4cv transgenic mice. (A) Design of the Dp116 expression construct with the domain structure of Dp116 compared with other dystrophin isoforms and mini-genes. NT, N-terminal domain; H, hinge; W, WW domain; CR, cysteine rich domain; CT, C-terminal domain; DgBD, dystroglycan-binding domain; HSA, human skeletal -actin promoter; in, hybrid HSA/SV40 vp1 intron; F, Flag epitope tag; pA, SV40 polyadenylation sequence. (B) Western analysis using a monoclonal antibody specific for the dystrophin C-terminal domain (Dys-2) shows expression of Dp116 in diaphragm (D) and quadriceps (Q) muscles from three independent lines of Dp116/mdx^4cv transgenic mice. Samples from control C57Bl/6 mice show full-length dystrophin in diaphragm and quadriceps, and Dp116 in peripheral nerve (N). (C) Immunofluorescence staining with antisera to the dystrophin N-terminal domain detects full-length dystrophin only in control C57Bl/6 muscles. Polyclonal antibodies to the dystrophin C-terminal domain or the Flag epitope demonstrate uniform expression of the Dp116 transgene in quadriceps and diaphragm muscles (line 2197).