Fig. 8. Composition of muscle BLs. (A-T) Cross-sections of quadriceps from P59 nmf417 and littermate controls were immunostained with antibodies against the indicated proteins and imaged with identical settings. Normal muscle fiber BL was rich in nidogen-1, collagen IV and perlecan, and contained low levels of laminin β2, but contained little or no laminin 1, 4 or 5. Laminins 4, 5 and β2 were concentrated in blood-vessel and perineurial BLs. Cell-surface proteins interacting with laminins were also examined, including β1 integrin, and β-sarcoglycan (βSG) and β-dystroglycan (βDG) were used as indicators of the DGC in muscle. There was little change in BL composition or cell-surface proteins in nmf417-mutant muscle. Notably, laminin 4 immunoreactivity increased on a subset of small-diameter fibers, but was absent from the majority of nmf417 myofibers. Scale bar: 60 µm.