Accumulation of autophagosomes and motor neuron degeneration in the <i>dnc-1</i><i>(</i><i>RNAi</i><i>)</i> worms.

<p>(<i>A, B</i>) Representative kymographs of Lgg1::DsRed in the ventral nerve cord from the <i>control(RNAi</i> (<i>A</i>) and <i>dnc-1(RNAi)</i> (<i>B</i>) worms derived from time-lapse images. Vertical lines represent stationary/docked Lgg1 puncta, while the oblique lines (labeled with arrowheads) represent the tracks of moving Lgg1 puncta. The slope of this track is an indicator of velocity. (<i>C</i>) The number of Lgg1 puncta within a single kymograph image. (<i>D, E</i>) Quantitative analyses of the mobility of puncta. The number of puncta that moved more than 2 μm was counted (<i>D</i>). The ratio of moving puncta was calculated by dividing the number of moving puncta by the total number of puncta (<i>E</i>). (<i>F</i>) The mean velocities of Lgg1 puncta. A total of 20 time-lapse images were analyzed for each strain in <i>C–F</i>. (<i>G</i>) The number of Lgg1 puncta was increased in the <i>dnc-1(RNAi)</i> worms compared with the <i>control(RNAi)</i> worms (n = 15 for each group). (<i>H, I</i>) Accumulation of autophagosomes in the <i>dnc-1(RNAi)</i> worms was correlated with the severity of axonal defasciculation (<i>H</i>) and locomotor function (<i>I</i>) (n = 20 for each analysis). (<i>J–L</i>) Ultrastructural images of ventral motor neurons from the <i>dnc-1(RNAi)</i> worms. Aberrant membranous vesicles including degenerated mitochondria were observed in the cytoplasm (<i>J</i>) and axons (<i>K</i>) (arrows). Autophagosome-like, double membrane vesicles (asterisk in <i>L</i>) were also found in the axons of the <i>dnc-1(RNAi)</i> worms (<i>L</i>). Scale bar = 500 nm (A–C) or 10 μm (D). Statistical analyses were performed using Student's t test (*p<0.05 and **p<0.0001) and Pearson's correlation coefficient in <i>H</i> and <i>I</i>. The error bars are S.E.M.</p>