Fig. 2

Behavior of retrograde comets in wild type axons. (A,B) Wild type neurons expressing EB3-GFP. Small subsets of comets travel retrogradely in peripheral (A) and central (B) axons. Scale bars are 10 μm. (A',B') Time-lapse sequences of representative retrograde comets in yellow boxes. Time is shown in min:sec. (A”,B”) Kymographs of regions outlined by white boxes in (A,B). Retrograde comets can be visualized as positively sloped lines (red) in the kymographs. Scale bars are 5 μm (y) and 1 min (x). (C) The distance retrograde comets travel does not significantly differ from anterograde comets in peripheral or central axons, (mean peripheral anterograde distance = 9.03 μm, n = 81 axon segments, mean peripheral retrograde distance = 7.77 μm, n = axon segments, p = 0.33 student's t-test; mean central anterograde distance = 9.43 μm, n = 44 axon segments, mean central retrograde distance = 8.31 μm, n = 20 axon segments, p = 0.47 student's t-test). (D) Retrograde comet velocities do not differ from anterograde comets. Anterograde comet velocity data is the same as in Figure 1, shown here again for comparison, ****p < 0.0001, student's t-test (mean peripheral retrograde velocity = 5.19 μm/min, n = 18 axon segments; mean central retrograde velocity = 6.91 μm/min, n = 20 axon segments). (E) Retrograde comets traveled similar distances in proximal and distal axon regions (mean peripheral proximal distance = 9.89 μm, n = 7 axon segments, mean peripheral distal distance = 6.42 μm, n = 11 axon segments, p = 0.26 student's t-test; mean central proximal distance = 7.24 μm, n = 12 axon segments, mean central distal distance = 9.90 μm, n = 8 axon segments, p = 0.29 student's t-test).