Defect in KIF5A/KLC1-driven transport of SFPQ leads to axon degeneration in DRG sensory neurons. (A) Examples of TUJ1 immunostaining. Magnified view depicts individual axon morphology, and corresponding binarized images show axons of DRG neurons grown in compartmented cultures expressing control or shSFPQ rescued with empty vector (-), WT SFPQ, or SFPQ^Y527A. Red boxes outline regions shown for the higher magnification view of axons. Asterisks indicate interruptions in TUJ1 continuity. Scale bar: 100 µm and 10 µm (magnified image). (B) Quantification of axonal degeneration from A, which is calculated by using the ratio of the region of fragmented axons to total axon area (degeneration index [Sasaki et al., 2009]). Control (n = 26 captured images) or shSFPQ rescued with empty vector (n = 20), WT SFPQ (n = 29), or SFPQ^Y527A (n = 22). *P = 0.0112; **P = 0.0019; ***P = 0.0002; ****P < 0.0001 by one-way ANOVA; data from 3 independent experiments; data represent mean ± SEM. (C) DRG neurons were infected with control or shRNA against SFPQ and rescued with empty, GFP-tagged WT, or SFPQ^Y527A. Protein lysates were blotted against GFP, endogenous SFPQ, and actin as loading control.