Extended Data Figure 2: RAB-3 is ectopically localized in lin-14, unc-55, and oig-1 mutants.

a: Presynaptic marker RAB-3 ectopically localizes to the dorsal nerve cord (DNC; marked in red) in lin-14 mutant animals. RAB-3::GFP puncta (from otEx5663, unc-30p::GFP::RAB-3) localize mostly to the ventral nerve cord (VNC; marked in red) in wild-type L1 animals (left). Ectopic RAB-3::GFP puncta localize mostly to the dorsal nerve cord in 95% of lin-14 L1 animals (right, scored in progeny from lin-14 null animals carrying a lin-14 rescue array ²³. Ventral and dorsal nerve cords are indicated by red dotted lines. L1 animals were obtained by hypochlorite-treating gravid adult animals and letting embryos hatch and arrest in M9 for 16-18 hours. n>20 for each strain scored.

b: RAB-3 ectopically localizes to the dorsal nerve cord in unc-55 L4 mutant animals. RAB-3::GFP puncta localizes to both the ventral (VNC) and dorsal (DNC) nerve cord in 100% of wild-type L4 animals (left). RAB-3::GFP puncta localize mostly to the dorsal nerve cord in 100% of unc-55 L4 animals (right). Ventral and dorsal nerve cords are indicated by red dotted lines. Signals between the nerve cords are autofluorescence from the gut. n>20 for each strain scored.

c: RAB-3 ectopically localizes to the dosal nerve cord in oig-1 mutants. RAB-3 normally localizes to the ventral nerve cord (VNC, marked in red) in wild-type L1 animals (top left). Ectopic RAB-3::GFP puncta localize to the dorsal nerve cord in 55% of oig-1 L1 animals (top right, compared to 20% of wild-type animals). L1 animals were obtained by hypochlorite-treating gravid adult animals and letting embryos hatch and arrest in M9 for 16-18 hours. n>20 for each strain scored. In wild-type L4 animals, more RAB-3::GFP puncta are localized in the VNC than in the DNC of the animal (bottom, black dots). Conversely, in oig-1 mutants, more RAB-3::GFP puncta are localized in the DNC than in the VNC (bottom, red dots). **p<0.01, n=20 for each strain.