Fig. 4.

Drp-1 has extreme effects on mitochondrial morphology and motility, but only subtle effects on touch sensitivity. Mitochondria were visualized through time-lapse fluorescent imaging of an MLS::GFP reporter to measure mitochondrial morphology in the soma and to track their movement in the PLM neuronal process of live worms. a) Representative binary images used to quantitate morphology in the genotypes indicated. Note that the mitochondria appear as blobs in the drp-1(tm1108) mutant, irrespective of the tau genotype and age. Scale bar: 5 µm. b, d) Quantitative analysis of mitochondrial density in the distal PLM cell bodies at day 3 and day 10 as a function of drp-1 and tau genotype. Control indicates data points from MLS::GFP reporter. Individual data points demarcate values from single PLM cells from separate animals (N = 30–75). c, e) Responsiveness to touch was plotted as a function of drp-1 and T231E at day 3 and 10. The data are from 3 independent biological replicates (N = 60–115). f, g) Representative confocal images of the PLM neurite from control and drp-1(tm1108) expressing MLS::GFP. Scale bar: 20 µm. Quantitative analysis of mitochondria (h, l) motility, (i, m) distribution, (j, n) run length, and (k, o) speed in distal PLM processes at day 3 or day 10 as a function of drp-1 or T231E, as indicated. Individual data points are from single PLM neurites from separate animals (N = 17–25). Data are the mean ± SD from 3 independent biological replicates. Statistical analysis for all datasets was by 1-way ANOVA with Tukey’s multiple comparison test, with ***P < 0.001, **P < 0.01, *P < 0.05 when comparing bracketed samples.