Axon pathology of the touch neurons in the <i>gm379</i> mutant.

<p>(A-B) Touch neurons in live animals were visualized with <i>zdIs5(Pmec-4::GFP)</i>. Asterisks, ALM soma. Scale bar = 5 µm or 2 µm (insets). (A) ALM processes in the mutant appeared beaded at L2 and developed triangular-shaped swelling at L4 to adult. Anterior is to the left. (B) Mitochondria, labeled with <i>Pmec-7::mito::mCherry</i>, often accumulated at axon swellings. (C) Snapshots of PLM neurite during muscle contraction from a <i>gm379</i> mutant partially immobilized with microbeads. Arrows and asterisks are buckling and neurite swellings, respectively, that changed their morphology during muscle contraction. Muscles contracted between t = 2 second and t = 5 second. (D) ALM neurites of the <i>gm379</i> or the <i>unc-54; gm379</i> mutants. (E) Quantification (mean ± S.E.M.) of neurite swellings for single ALM or PLM neurons. Age of the animals was indicated as days in adulthood. *, <i>p</i>≤0.01, **, <i>p</i><0.0001, Mann-Whitney U test. (F) Longitudinal images of a single ALM neuron from L2 to middle adulthood. Arrows marked the same site over time. The animal died at day 10. Scale bar = 5 µm. Asterisks, ALM soma. (G) ALM neurites of the wild type, <i>gm379</i> and the <i>unc-54; gm379</i> mutants at day 16. Asterisks are ALM soma. Arrows mark neurite breaks and degeneration. (H) Quantification (mean ± S.E.M.) of neurodegeneration. *, <i>p</i><0.05, **, <i>p</i><0.0001, Fisher's exact test.