Figure 1.

Both Ir25a and Ir76b are required co-receptors for amine-sensing receptors in ac2 and ac4 sensilla. (A) Left, diagram of an ac2 sensillum, showing receptor expression in each ORN. ORNs that respond to the tested amines are in black. Middle, representative traces of responses to 1,4-diaminobutane and pyrrolidine in ac2 sensilla in WT, Ir8a¹, Ir25a², and Ir76b¹ fly lines. Right, box plots overlaid with individual data points (n = 10 WT, 13 Ir8a¹, 7 Ir25a², and 11 Ir76b¹ sensilla). Genotypes that are significantly different are indicated with different letters. (B) Similar to (A), but for ac4 sensilla tested with phenethylamine, pyrrolidine, and ammonia (phenethylamine: n = 7 WT, 6 Ir8a¹, 7 Ir25a², and 7 Ir76b¹ sensilla; pyrrolidine: n = 7 WT, 7 Ir8a¹, 6 Ir25a², and 7 Ir76b¹ sensilla; ammonia: n = 7 WT, 6 Ir8a¹, 6 Ir25a², and 7 Ir76b¹ sensilla). ORN, olfactory receptor neuron.