FIGURE 4:
Vezatin is dispensable for neuromuscular synapse formation. (A) AChRs were isolated from muscle lysates of veztF/+ control and veztF/−; hsa::cre mice with biotin-conjugated α-BGT, and Western blots were probed with antibodies to vezatin or the AChR β subunit. AChR-associated vezatin levels were reduced nearly 10-fold in veztF/−; hsa::cre mice. (B–D) Toluidine blue–stained cross-sections of diaphragm muscles showed a normal number and size of myofibers in E17.5 veztF/−; hsa::cre mice with normal cross-sectional area. Scale bar = 50 μm. (E) Whole mounts of diaphragm muscles from E17.5 veztF/+ and veztF/−; hsa::cre mice were stained with Alexa 594–conjugated α-BGT, and antibodies to neurofilament and synapsin to visualize AChRs (red) and axons and nerve terminals (green). Scale bar = 250 μm. (F) The number of synapses, synaptic area, synaptic AChR density, and total synaptic AChRs were normal in the absence of vezatin. (G) The distribution of synapses was modestly wider in the absence of vezatin. Error bars indicate SEM, n = 3 mice, and p values were calculated using an unpaired t test (****, p < 0.00005).