(A) Schematic drawing of the DA9 neuron. Different regions of DA9 are boxed and labeled. The synaptic vesicle clusters (green) are indicated in the synaptic region. (B) Puncta formed by GFP::RAB-3 under the control of Pitr-1 appear in the tip region in unc-104(C184Y) and unc-104(L410F) animals (asterisks). Scale bar represents 50 μm. (C) GFP::RAB-3 signals appear in the dendritic region in unc-104(C184Y) and unc-104(L410F) animals. Line scan images of DA9 neurons. Ten DA9 neurons from independent animals were scanned and aligned. Scale bar represents 5 μm. Dashed boxes indicate the dendritic region. (D and E) Numbers of GFP::RAB-3 puncta in the tip region and the dendritic region. (F and G) Quantification of the length of the asynaptic region and the synaptic region. (H-L) The abnormal synaptic accumulation defect in unc-104(lf G1092E) could be suppressed by C184Y, L410F, or G421E mutation on UNC-104. (I) Quantification of the GFP::RAB-3 puncta in the asynaptic region and commissure region. (J) Quantification of the GFP::RAB-3 puncta in the dendritic region. (K and L) Quantification of the length of the asynaptic region and the synaptic region. *P<0.05, **P<0.01, ***P<0.001, one-way ANOVA with Tamhane’s T2 test. Mean ± SEM, N> = 19 worms for each genotype.