Vesicular protein levels depend onunc-4 and unc-37 activity. Antibodies to RAB-3 (A), Synaptobrevin (B), and Synaptotagmin (C) were used to detect these vesicular proteins in the DA and VA motor neurons in wild-type and in unc-4- andunc-37-mutant animals. (Methods were as described for Fig. 2.) Vertical bars in the histograms indicate the percentage of DA and VA motor neurons showing intense antibody staining (white) plus the percentage of animals showing reduced or intermediate levels of staining (gray) (see Materials and Methods). At least 125 VA and DA neurons were scored for each strain and for each vesicular protein antibody. Allunc-4 and unc-37 mutants in these experiments are loss-of-function alleles.