Fig. 5. Upregulation of laminin 2 and ß-dystroglycan in gxi mouse muscle. (A) Immunoblot with antibodies specific to laminin 2, ß-dystroglycan or sarcomeric actin in single (Itg7^–/– and gsg^–/–) and double-mutant (gxi) mice. Upregulation of laminin-2 may be effective through the integrin 7ß1 complex that is upregulated in gsg^–/– muscle. An increase of ß-dystroglycan is seen in Itg7^–/– mutant muscle and this upregulation may be significant as an intact sarcoglycan-dystroglycan complex is present. In contrast, upregulation of ß-dystroglycan is ineffective in gxi muscle where the major laminin binding complexes, integrin and sarcoglycan-dystroglycan, are disrupted. (B,C) Photomicrographs showing muscle membrane staining for laminin 2 (B) and ß-dystroglycan (C) in each genotype. Scattered fibers with reduced laminin 2 staining can be seen in gxi muscle (B, lower right panel^*). Bars in B and C, 50 µm.