Figure 1. GR43a is expressed in the larval taste organs, as well as the brain and the gastrointestinal system.

(A) Diagram of larval taste organs, adapted from Stocker [19]: Structures associated with taste sensing and processing are shown in gray. The cell bodies of the taste neurons are arrayed in ganglia, extend dendrites into the taste organ and axons into the subesophageal ganglion. Olfactory structures are shown in blue. Note that only three brain structures - subesophageal ganglion, the antennal lobe and the mushroom bodies - are specifically indicated. The pharynx is shown in green. Abbreviations: AL, antennal lobe; BR, brain; MB, mushroom bodies; SOG, subesophageal ganglion; DO/TO/VO, dorsal/terminal/ventral organ; DPS/VPS/PPS, dorsal/ ventral/posterior pharyngeal sense organ.

(B) Overall view of Gr43a expression in larvae. Gr43a^GAL4 drives UAS-mCD8GFP expression in neurons located in chemosensory organs, the DPS/VPS and the PPS, and the proventricular ganglion. The live expression of mCD8GFP is at the left, the phase-contrast image at the center, the overlaid image is at the right.

(C and D) Expression analyses of Gr43a^GAL4 UAS-mCD8RFP (red) and Gr66a-GFP-IRES-GFP-IRES-GFP (green) in chemosensory organs (C) and their projections to the SOG (D). Gr43a is expressed only in the DPS/VPS neurons, but it is not expressed in the same neurons as Gr66a. Note that Gr66a is also expressed in neurons of the TO ganglion besides of the DPS/VPS neurons. Asterisk indicate DO and TO.

(E) Gr43a^GAL4 drives mCD8GFP expression in the CNS. The images on the right are enlargement view of the dorsal protocerebrum. Gr43a^GAL4 is expressed in one or two big neurons per hemisphere and in many Kenyon cells. Gr43a^GAL4 expressing neurons are also located in the VNC. Neuropil was counterstained with nc82.