Figure 2

Differential distribution of nidogens at the neuromuscular junction (NMJ). (A) Schematic representation of the three cellular components of the NMJ (motor nerve terminal (NT), peri-synaptic Schwann cell process (SC), and skeletal muscle fibers (M)) and the basal laminas (BLs) that coat them (dashed lines). Dashed lines: red, synaptic BL; blue, extrasynaptic BL; green, Schwann cell BL. (B-C") Young adult NMJ cross-sections costained with α-bungarotoxin (BTX) and either anti-nidogen-1 (B) or anti-nidogen-2 (C). Nidogen-1 is present in synaptic, extrasynaptic (arrows in B', B") and Schwann cell BLs (arrowheads in B', B"). Nidogen-2 is absent extrasynaptically, but is enriched in synaptic and Schwann cell BLs (arrowheads in C', C"). (D-D") Confocal, en face image of an NMJ double-stained with BTX and anti-nidogen-2. Regions of co-localization demonstrate nidogen-2-rich synaptic BL. Tube-like structures overlaying synaptic sites (arrowheads) represent Schwann cell BL. Nidogen-2-positive structures near synaptic sites are capillaries (asterisks). (E-E") Nidogen-2 localized to acetylcholine receptor-rich (BTX-stained) sites in C2C12 myotubes. Scale bars are 5 μm in (B, C) and 20 μm in (D, E).