Figure 1
The CNG channel subunit CNG-3 is required for short-term adaptation responses in the primary sensory neuron pair AWC. (A) Gene structure of cng-3 on chromosome IV indicating the position of the deletion in jh113 12. 840 bp upstream of the start site for cng-3 was used to generate a transcriptional reporter for cng-3. (B) PCR fusion43 was used to fuse the promoter region of cng-3 to GFP. In the bottom panel, an overlay of the GFP and RFP expression patterns depicts the co-expression of GFP and RFP in the AWC neuron. (C) Chemotaxis assays were performed for wildtype and cng-3(jh113) animals to various concentrations of benzaldehyde. At each concentration, cng-3(jh113) mutant animals performed the same as wildtype animals (paired t-test). (D) The G-protein coupled receptor, STR-2, is asymmetrically expressed in only one of the two AWC neurons23, 24. The number of wildtype animals that expressed the transcriptional reporter, (p)str-2::RFP in only one of the AWC neurons was compared to that of cng-3(jh113) mutant animals, and no significant difference was observed (p > 0.7 using Chi-square test or Fisher’s exact test). 94% of wildtype animals (N = 98) exhibited asymmetrical expression of the reporter and 92% of cng-3(jh113) mutant animals (N = 88) exhibited asymmetrical expression of the str-2 transcriptional reporter. (E,F) Wildtype and cng-3(jh113) mutant animals were tested for an ability to adapt to the AWC sensed odor butanone (E) and benzaldehyde (F) after 60 mins odor exposure. In each case there was a significant difference in the chemotaxis index after odor exposure as compared to unexposed control animals (paired t-test, **p < 0.01). (G–H) Wildtype animals and cng-3(jh113) mutant animals were tested for an ability to adapt after 30 mins odor exposure to the AWC sensed odor butanone (G) and benzaldehyde (H). In each case there was a significant difference in the chemotaxis index after odor exposure as compared to unexposed control cases for wildtype animals (paired t-test, **p < 0.01), however, in the case of cng-3(jh113) mutant animals there was no significant change in the chemotaxis index after odor exposure as compared with unexposed animals (paired t-test).
