Figure 5.

R8-dependent phototaxis response was disrupted in bdl mutants. Flies were given UV vs green choice. Light PI was calculated as described in Materials and Methods. A, Canton-S wild-type and w¹¹¹⁸ flies could be attracted to both UV and green light sources. However, both bdl^EX1 and bdl^EX2 homozygous mutant flies were predominantly attracted toward UV light source. B, bdl was knocked down in flies carrying a pan-neuronal-specific driver C155-GAL4 and a UAS-bdl-RNAi transgene. Compared with control flies that carried C155-GAL4 or UAS-bdl-RNAi only, flies carrying both C155-GAL4 and UAS-bdl-RNAi showed a much greater preference for UV light. C, Eye-specific knockdown of bdl was performed by expressing UAS-bdl-RNAi under control of the eye-specific driver ey^3.5-GAL4. Reducing bdl in the eye significantly decreased the preference for green light. D, bdl was specifically knocked down in green-sensitive R8 photoreceptors (i.e., R8y) by expressing UAS-bdl-RNAi under control of the R8y-specific driver Rh6-GAL4. Knocking down bdl in green-sensitive R8 decreased the preference for green light. For each genotype, ∼5–10 trials were performed, and ∼50 flies were tested in each trial. One-way ANOVA followed by post hoc Tukey's test. *p < 0.05, **p < 0.01, ***p < 0.001. Error bars indicate SEM.