Fig 6.

Fast and unidirectional movement of AAV2 particles is dependent on intact microtubules. (A) Representative trajectories for AAV2 in DMSO- or nocodazole-treated cells as shown in Movies S6 and S7 in the supplemental material. Bars represent 5 μm. (B) Three simulated MSD plots for various types of particle motion. The mean square displacement (MSD) is plotted against time interval ΔT (t). Normal diffusion is usually described by a linear plot given by the formula MSD = 4Dt (D is the diffusion coefficient). Directed motion is usually described by a quadratic curve given by the formula MSD = 4Dt + v²t² (v is the mean velocity of the motion). An asymptotic behavior with MSD∝t^α (α<1) indicates confined diffusion. (C) Proportions of viral particles with directed motion or diffusion from MSD analysis. (D) Maximal instantaneous speed (panel a) and displacement length (panel b) of each AAV2 track. For panels C and D, trajectories were generated only for these viral particles continuously tracked over 20 frames, and about 40 to 60 trajectories were analyzed for each group.