Fig. 6

Odorant exposure in the absence of new Orco production accelerates dendritic Orco depletion. a Experimental scheme. We maintained UAS-mCherry::Orco ^WT /tub-GAL80 ^ts , Or22a-GAL4 (II); tub-GAL80 ^ts , Orco ¹ (III) flies at 29 °C until 3 days post-eclosion. Then, after transferring them to 18 °C to block additional Orco expression, we divided the flies into two groups: those maintained on normal food and those maintained on food plus a perforated microcentrifuge tube containing 10 % ethyl butyrate. b–e Orco protein localization in ab3A dendrites visualized via its mCherry tag. b Orco ON control antennae prior to the transfer to 18 °C show clear ab3A soma and outer dendritic localization of Orco. c Orco OFF control antennae from flies maintained continuously at 18 °C show no Orco expression, indicating three copies of tub-GAL80 ^ts suffice to block Orco expression completely at the restrictive temperature. d When new Orco production is blocked, existing Orco seems to move gradually from the ab3A soma to the outer dendrites. Three days after the transfer to 18 °C, the ab3A soma shows slightly less Orco and the outer dendrites slightly more (left). By day 9, the ab3A soma is empty while the outer dendrites show only slightly lower levels of Orco (right). e When new Orco production is similarly blocked in the presence of the ab3A ligand ethyl butyrate, the level of outer dendritic Orco is reduced even after only 3 days. This is accompanied by enhanced signal in ab3A soma (left). By day 9, the ab3A outer dendrites are nearly depleted of Orco, but residual Orco is still readily visible in the OSN soma. For b–e, the color of each image is inverted to improve outer dendrite visibility. All scale bars, 10 μm. PE post-eclosion