Blocking neuropeptide processing or PI(3)P restores normal levels of the Venus cargo in unc-108 mutant axons. (A–G) Representative images of NLP-21–Venus in DA/DB motor neuron axons in animals with the indicated genetic backgrounds. Strains containing the same transgenic array are scaled identically for brightness after adjusting for differences in light source power. NLP-21–Venus is expressed from the integrated transgenic array ceIs56 in A–E and ceIs57 in F and G. (A and B) UNC-108 is required for normal levels and density of the Venus cargo in axons. (C) UNC-108 acts cell-autonomously in motor neurons during DCV cargo trafficking. This strain is identical to that in B except that it contains the ceEx282 transgene, which expresses the unc-108 cDNA in the same motor neurons as NLP-21–Venus. (D and E) Blocking peptide processing with an egl-3 (PC2 convertase) null mutation restores greater than wild-type levels of the neuropeptide tag in the axons of wild type and unc-108 null mutants. (F and G) Blocking PI(3)P function with excess 2XFYVE restores normal levels of the neuropeptide tag in the axons of wild type and unc-108 null mutants. (H) Quantification of Venus levels in the dorsal axons of unc-108 mutants. The graph shows the total integrated fluorescence per micrometer of dorsal axon length, expressed as arbitrary fluorescence units (a.f.u.). Data are means and SEMs from images acquired from 11 to 14 individual animals each. NLP-21–Venus was expressed from the ceIs56 integrated array for the first five bars and from the ceIs57 integrated array for the last two bars. P-values are from the Mann-Whitney test.