The Eyeless/Pax6 ortholog <i>vab-3</i> controls the identity of neurons in the anterior ganglion.

Fig 5A: In a vab-3(ot1243) mutant allele, many neurons in the anterior ganglion lose their NeuroPAL coloring (from otIs669) and expression of the eat-4 reporter allele (syb4257). Notably, there are much less blue neurons (URY/URA/URB but URX seem present), and the bright green OLQ and turquoise OLL are never seen. Representative images of wild type and mutant worms are shown with 10 μm scale bars. Graphs compare expression in wild type and mutant worms with the number of neurons (for n = 10 WT worms / 7 vab-3 mutant) examined listed at the bottom of the bar. P-values were calculated by Fisher’s exact test. Similar results were observed with a larger deletion allele, ot1269 (S7 Fig). Fig 5B: In vab-3 mutant worms (ot1239, ot1238, all carrying the same lesion, introduced into respective reporter background; S7 Fig), the OLL and URYmarkers nlp-66(syb4403), eat-4prom8 (otIs521) are affected. Markers are more frequently lost in the ventral URY than the dorsal URY. vab-3 mutants also ectopically express nlp-66 in hypodermal cells. Representative images of wild type and mutant worms are shown with 10 μm scale bars. Graphs compare expression in wild type and mutant worms with the number of animals examined listed at the bottom of the bar. P-values were calculated by Fisher’s exact test. Fig. 5C: In vab-3 mutant worms (ot1240, ot1269; S7 Fig), URA and URB identities are affected as seen with the markers sri-1 (otIs879) (URB, OLL) and a promoter fragment of unc-17/VAchT (prom9; otEx7705) [105] expressed in IL2/URA/URB. Representative images of wild type and mutant worms are shown with 10 μm scale bars. Graphs compare expression in wild type and mutant worms with the number of animals (sri-1) or neurons (unc-17prom9) examined listed at the bottom of the bar. vab-3 does not affect expression of an unc-17 reporter allele in the IL2 neurons, and we can therefore infer that the remaining positive cells labeled with unc-17prom9, are the IL2 neurons and the lost expression is in URA/URB. P-values were calculated by Fisher’s exact test. Fig 5D: Markers of OLQ neuron identity (ocr-4 kyEx581, ttll-9 otIs850 and des-2 otEx7697) are fully lost in the vab-3(ot1237) mutant animals. Representative images of wild type and mutant worms are shown with 10 μm scale bars. Graphs compare expression in wild type and mutant worms with the number of animals examined listed at the bottom of the bar. P-values were calculated by Fisher’s exact test.