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Figure 1. Expression of dystrobrevins, nNOS, and syntrophins in wild-type and bgn null skeletal muscle sections and microsomal membrane fractions. Quadriceps femoris sections from 5-wk-old wild-type and bgn null (bgn -/o) animals were stained using the indicated antibodies. The experiment was repeated six times, using animals from 6 litters. A) The levels of dystrophin are indistinguishable in wild-type and bgn null muscle. In contrast, there is a selective reduction of 
-dystrobrevin-1 (-DB-1), -dystrobrevin-2 (-DB-2), -syntrophin (-Syn), ß1-syntrophin (ß1-Syn), and nNOS at the sarcolemma of bgn null muscle. B) Higher magnification images of wild-type and bgn null quadriceps femoris sections stained using the indicated antibodies. The intracellular levels of -syntrophin are increased in the biglycan null compared with wild-type muscle. The intracellular levels of dystrophin (DYS) remain unchanged. Scale bar = 20 µm. C) A comparison of expression of the dystrobrevins, syntrophins, and nNOS in KCl-washed microsomal membranes from wild-type and bgn null muscle. 10 µg of membrane proteins from 5-wk-old quadriceps femoris muscles from wild-type and bgn null animals was separated by SDS-PAGE and immunoblotted with antibodies against -dystrobrevin-1 (-DB-1), -dystrobrevin-2 (-DB-2), -syntrophin (-Syn), ß1-syntrophin (ß1-Syn), and ß2-syntrophin (ß2-Syn). The expression levels of -DB-1 and -DB-2 are decreased in bgn null microsomes, while the levels of -Syn, ß1-Syn, and ß2-Syn are increased. Proteins (10 µg) from non-KCl-washed microsomal membranes isolated from 5-wk-old quadriceps femoris muscles from wild-type and bgn null animals were separated via SDS-PAGE and immunoblotted using antibodies against nNOS and ß-actin (as a loading control). Note the selective decrease in nNOS expression in bgn null muscle membranes.
