Fig. 6

Location of the CREL in a heterotetrameric IR complex model. a, b Two hypothetical configurations of a heterotetramer of two IR8a subunits (dark/pale red) and two tuning IR subunits (dark/pale blue), in which the IR8a ATDs have a proximal (contacting) or b distal (non-contacting) positions. Top and side views are shown in slightly different orientations to facilitate visualisation of the IR8a CREL (green). The structure was built through coarse-grained homology modelling of D. melanogaster IR8a on the homotetrameric GluA2 structure [33]; the IR tuning subunits are represented simply by the same IR8a model from which the ATD is deleted. c Schematic of the principle of EYFP reconstitution through complex formation and/or close proximity of EYFP fragment:IR fusion proteins. d–i Endogenous EYFP fluorescence in antennal sections of animals expressing the indicated combinations of EYFP fragment fusions in Ir8a neurons. The higher magnification sacculus image in g (right) reveals the cilia localisation of fluorescent signals (arrowhead); here, the gain setting during imaging was increased, resulting in higher cuticular autofluorescence. Genotypes: d UAS-EYFP(1):Ir8a/+;Ir8a-Gal4/+, e UAS-EYFP(2):Ir84a/+;Ir8a-Gal4/+, f UAS-EYFP(1):Ir8a/UAS-EYFP(2):Ir84a;Ir8a-Gal4/+, g UAS-EYFP(1):Ir84a/UAS-EYFP(2):Ir8a;Ir8a-Gal4/+, h UAS-EYFP(1):Ir8a/UAS-EYFP(2):Ir8a;Ir8a-Gal4/+ and i UAS-EYFP(1):Ir84a/UAS-EYFP(2):Ir84a;Ir8a-Gal4/+. All scale bars: 20 μm. For each genotype, the phenotype was assessed in multiple sections of antennae from at least 20 animals from two independent genetic crosses