Figure 3
A candidate PKG site in CNG-3 is important for tuning odor sensitivity. (A) Cartoon structure of CNG-3 highlighting the position of the candidate PKG site at Serine 20 (S20) which was mutated to an Aspartic acid (S20D) to generate a phosphomimetic allele of CNG-3 and was mutated to an Alanine (S20A) to generate a phosphorylation defective allele of CNG-3. (B) Alignment of CNG-3 orthologues from C. elegans, C remanei, and C. briggsae reveal that this candidate PKG site is conserved. (C) Wildtype animals exhibited a significant change in chemotaxis index after 30 mins odor exposure as compared with unexposed animals (ANOVA with Tukey’s HSD, **p < 0.01). Transgenic animals expressing CNG-3(S20D) also exhibited a significant change in chemotaxis index after 30 mins odor exposure when compared with unexposed animals (ANOVA with Tukey’s HSD, *p < 0.05). (D) The chemotaxis response of two independent transgenic lines that express the phosphorylation defective version of CNG-3 (i.e. S20A) was examined and compared to wildtype responses. Wildtype animals exhibited a significant change in chemotaxis index after 30 mins odor exposure as compared with unexposed animals (ANOVA with Tukey’s HSD, *p < 0.01), and similarly the transgenic lines (line 1, 2nd set of bars and line 2, 3rd set of bars) expressing CNG-3(S20A) exhibited a significant change in chemotaxis index after 30 mins odor exposure when compared with unexposed animals (ANOVA with Tukey’s HSD, *p < 0.05). (E,F) Wildtype animals and animals expressing the normal wildtype version of CNG-3[WT], a phosphomimetic version of CNG-3(S20D) or the phosphorylation defective version of CNG-3(S20A) were tested for their ability to sense butanone (E) and benzaldehyde (F) at various concentrations. In each case the animals expressing CNG-3(S20D) exhibited a greater sensitivity to each odor at more dilute concentrations as compared with wildtype animals or animals expressing the phosphorylation defective version of CNG-3(S20A). (ANOVA with Tukey’s HSD, *p < 0.05). For all graphs, error bars represent S.E.M.
