Fig. 8.

The Golgi complex pattern at the NMJ is consistently perinuclear independently of fiber type. The NMJ of single fibers from different muscles was stained with different combinations of markers. To localize the NMJ along the fibers, we used either staining with Texas Red-labeled bungarotoxin (a) or the unique appearance of the clustered endplate nuclei (b) stained with Hoechst (blue channel). The insets show extrajunctional nuclei from the same fiber. a shows a single confocal image at the NMJ of a soleus fiber stained with bungarotoxin (red) and MG160 (green). Each myonucleus is surrounded by a belt of Golgi complex elements but, because the nuclei are not all in the same orientation, the staining is distinct around a few nuclei only (arrows). The arrowhead points to the Golgi complex of a nonmuscle nucleus. b shows the NMJ of a red gatrocnemius fiber stained for MG160 (red) and GLUT4 (green). Theinset shows an extrajunctional nucleus, the staining of which identifies the fiber as type IIB. The junctional nuclei, however, are surrounded by GLUT4 (green) and MG160 (red) staining. Nonmuscle nuclei (arrowheads) can be identified by the compact MG160 staining and the absence of GLUT4 staining. c shows the NMJ of a soleus fiber stained with α-bungarotoxin (red) and anti-tubulin (green). Notice that the tubulin staining is more intense in the immediate surrounding of the NMJ than further out. Scale bars, 10 μm.