Figure 7.

Depletion of kinesin-6 increases the frequency of microtubule transport in axons. A, SCGs were transfected with EGFP–tubulin together with control or kinesin-6 siRNA just before plating. At 3 DIV, neurons were replated and axons were allowed to grow anew for 48 h. Laminin was included in these cultures because faster-growing axons were generally thinner and therefore better suited for the microtubule transport assay. Microtubule transport events were more frequent in neurons transfected with kinesin-6 siRNA. B, A bleached zone of ∼30 μm was made at a distance of 50–100 μm from the cell body using a laser, and the frequency of short fluorescent microtubules moving through the zone during a period of 6 min was noted. Scale bar, 5 μm. C, Frequency of anterograde and retrograde microtubule transport (transport events per minute) in kinesin-6 siRNA cultures was significantly higher than in control cultures. Data are represented as mean ± SEM number of events: anterograde transport, control siRNA = 1.05 ± 0.05; kinesin-6 siRNA = 0.61 ± 0.06 (n = 20, p < 0.001); retrograde transport, control siRNA = 0.47 ± 0.05; kinesin-6 siRNA = 0.57 ± 0.06 (n = 16, p < 0.01).