gcy-28 and cng-1 regulate the interaction of two sensory signals in the same genetic pathway. A, Phenotypes of cng-1 mutants in the interaction assay. Error bars in A–D and F indicate SEM. *p < 0.01. B, Chemotaxis toward various concentrations of diacetyl of cng-1 was analyzed by the conventional chemotaxis assay. C, Avoidance of various concentrations of Cu²⁺ of cng-1 was analyzed by the quadrant assay. D, The genetic interaction between cng-1 and gcy-28 in the interaction assay (15 mm copper acetate was used as Cu²⁺ barrier). E, Confocal views of wild-type animals expressing GFP under the control of the cng-1 promoter at the adult stage. The expression of GFP was colocalized with monomeric red fluorescent protein expressed in AIA by ins-1 promoter (bottom, arrow). Scale bars, 10 μm. F, RNAi knockdown of cng-1 in AIA interneurons of wild-type animals; their behavior was analyzed in the interaction assay. Worms carrying the transgene (+Ex) and worms not carrying the transgene (−Ex) were compared. WT, Wild type.