Figure 4.

Peripheral DAP complex members are localized to the sarcolemma in quadriceps muscle of wild-type (wt) and Δ71–78 mice. Immunofluorescent staining was performed using antibodies against α1-syntrophin (α1-syn), β1-syntrophin (β1-syn), α-dystrobrevin-2 (α-Db-2), α-dystrobrevin-1 (α-Db-1), and utrophin. α-dystrobrevin-2 is primarily found at the sarcolemma in wild-type muscles. mdx muscle sections have no α1-syntrophin or α-dystrobrevin-2 staining at the sarcolemma, but α-dystrobrevin-1 remains at the NMJ. Elevated levels of β1-syntrophin were observed in regenerating fibers of mdx mice. Utrophin sections were double labeled with α-bungarotoxin (α-BT) to identify NMJs. Utrophin was expressed at the sarcolemma and in capillaries surrounding muscle fibers. Scale bars, 50 μm.