Figure 4: Effects resulting from ectopic expression of Gr8a, Gr66a and Gr98b in sugar and low-salt responsive GRNs.
From: The full repertoire of Drosophila gustatory receptors for detecting an aversive compound
(a) Schematic depicting ectopic expression of Gr8a, Gr66a and Gr98b in sweet-sensing GRNs (above) and representative traces (below) evoked by 30 mM L-canavanine from L3 sensilla expressing Gr8a, Gr66a and Gr98b in sweet-sensing GRNs. (b) Dose-dependent L-canavanine responses in the indicated sweet-sensing GRNs. Shown are the responses of the indicated sensilla from control flies without a GAL4 (UAS–Gr8a,UAS–Gr66a,UAS–Gr98b; dashed lines) or flies expressing the three Grs under the control of the Gr64f–GAL4 (solid lines). n=6–21. Data are mean±s.e.m. (c) Response frequencies evoked by 30 mM L-canavanine after ectopic expression of Gr8a, Gr66a and Gr98b in the indicated sweet-sensing GRNs using the Gr64f–GAL4. Genotypes: (1) green circles: 2 × (UAS–Gr66a,UAS–Gr98b);Gr64f–GAL4/+, (2) blue circles: 2 × (UAS–Gr8a,UAS–Gr98b);Gr64f–GAL4/+, (3) ochre circles: 2 × (UAS–Gr8a, UAS–Gr66a);Gr64f–GAL4/+ and (4) purple circles: 2 × (UAS–Gr8a, UAS–Gr66a,UAS–Gr98b);Gr64f–GAL4/+. n=4–21 for each genotype. Shown are the medians and quartiles. *P<0.05, **P<0.01 (Kruskal–Wallis test with Mann–Whitney U post hoc-test). (d) Response frequencies evoked by 30 mM L-canavanine after ectopic expression of Gr8a, Gr66a and Gr98b in the indicated low salt-sensing GRNs using the Ir76b–GAL4. Genotypes: (1) blue circles: Ir76b–GAL4/+, and (2) purple circles: UAS–Gr8a,UAS–Gr66a,UAS–Gr98b/+;Ir76b–GAL4/+. n=8–14. Median and quartile are shown. *P<0.05, **P<0.01 (Mann–Whitney U-test). (e) Response frequencies from the indicated sensilla in flies ectopically expressing Gr8a, Gr66a and Gr98b in sugar-responsive GRNs. We tested 1 mM of each of the indicated chemicals (BER, berberine; DEN, denatonium; LOB, lobeline; PAP, papaverine; STR, strychnine), except for caffeine (CAF; 5 mM). n=6–9. Median and quartile are shown.
