Figure 3.
TBCE accumulation at the Golgi apparatus of spinal motor neurons. A, Western blot analysis shows that a polyclonal antibody directed against murine TBCE detects a band of ∼59 kDa in adult spinal cord protein extracts and in COS cells overexpressing TBCE. B, Immunolabeling for TBCE in an adult cervical spinal cord cross section. C, TBCE immunostaining in retrogradely labeled phrenic motor neurons on a frontal section of adult cervical spinal cord. D, Immunolabeling for TBCE and neurofilament medium chain (NF) in a ventral root shows that TBCE is barely detectable in axons. E, Triple labeling for TBCE (in red), S-100 (in blue), and the axon (in green) in the sciatic nerve of a Thy1–YFP line 16 mouse shows TBCE expression in the cell body of a Schwann cell. F, G, Immunolabeling for TBCE and the cis-Golgi markers GM130 (F) or p115 (G) demonstrates that TBCE decorates cis-Golgi membranes in motor neurons of adult spinal cord. H, I, Immunolabeling for TBCE and Vti1a (H), a trans-Golgi marker, or Vti1b (I), a marker of post-Golgi compartments. Insets show magnified areas depicted by arrows. Scale bars: B–D, 100 μm; E, 5 μm; F–I, 20 μm. J, Western blot analysis showing distribution of TBCE, p115, and GM130 in postnuclear, cytosolic, and crude membrane fractions of spinal cord.