Figure 1

Retrograde labeling of motor neurons with Golgi fragmentation following intramuscular injections of CTB. A-C) CTB (0.5% in 2.5 μl saline) is injected in the gastrocnemic muscle to retrogradely label motor neurons (A). B) Dot plot showing the number of CTB-positive motor neurons counted in each tenth section. Note reduced number of CTB-positive cells in 25 week old G1del mice compared to age matched non-transgenic mice (P < 0.05, unpaired Student's t-test). C) Maximal projection of confocal stack (optical section 22 μm) of CTB-labeled motor neuron illustrating small vacuoles in the distal dendrite (insert). D) Double-labeling confocal image of CTB and GM130 showing cross sections of 4 retrogradely labeled motor neurons. A large proportion of CTB localizes to the Golgi apparatus. The motor neuron below has fragmented Golgi. E) Bar graph showing the proportion of motor neurons with Golgi fragmentation in all large ventral horn neurons (GM130) and the CTB labeled population. F-I) Representative images of a CTB-labeled motor neuron with normal Golgi apparatus (F), fragmented Golgi (G), and fragmented Golgi with no or little CTB (H, I). J) Representative example of a proximal motor neuron dendrite with GM130-positve ribbons that stop at the branching point (arrow). K) Two motor neurons with Golgi fragmentation showing fragmented Golgi in the proximal dendrites up to the first branching point (arrows and insert). Bars: 20 μm (C, D), 10 μm (K), 5 μm (F, J).