Figure 2. In mature CNS axons, α9-GFP vesicles are retrogradely transported to the cell body. A, Day 10 cortical neuron transfected with α9-GFP was stained with Neufascin to identify the axon, where the vesicle movement was imaged. Transfected α9-GFPs are slightly missorted, with more integrin molecules found in the axons. Scale bar, 25 μm. B, Kymographs of α9-GFP vesicles traffic in axons at 10 DIV (left) and 3 DIV (middle) and in a dendrite at 10 DIV (right). In axons, less retrograde transportation was observed in younger cultures compared with 10 DIV cultures; in dendrites, vesicles were transported in both directions at 10 DIV. C, From 3 to 10 DIV (left), the overall percentage of retrogradely moving vesicles increases; a greater percentage of axons were observed to contain retrogradely moving vesicles and the number of vesicles increased as axons mature (middle; ***p < 0.001, Mann–Whitney test); in dendrites at 10 DIV, no significant difference was observed between number of anterogradely and retrogradely moving α9 vesicles (right). D, Kymographs and analysis of α9-GFP vesicle traffic in axons at 10 DIV at a region 100 μm into the axon (proximal) and toward the end of the axon (distal, 300–600 μm). E, α9β1 dimer was formed in neurons transfected with α9-GFP. F, Neuron cultures produce tenascin-C on the substrate. Scale bars, 50 μm.