The expression of DCX-EMAP in fly mechanosensory organs and olfactory receptor cells. (A) The expression of DCX-EMAP (DCX-EMAP-gal4; uas-cd4-tdgfp) in the campaniform receptors at wing base (upper), larval lch5 (lower left), and the Johnson’s organ (lower right) of adult fly. The red arrowheads mark the campaniform receptors. Upper panel: scale bar, 100 µm; inset scale bar, 20 µm. Lower panel: scale bar, 25 µm. (B) Representative images showing the absence of the DCX-EMAP signal in DCX-EMAP^KO and the recovery of the signal in DCX-EMAP^rescue (DCX-EMAP-gal4/uas-gfp-DCX-EMAP; DCX-EMAP^KO) in the campaniform mechanoreceptors at the wing base. The immunofluorescence staining experiments were performed using the anti-DCX-EMAP antibody (Liang et al., 2014). The orange arrowheads indicate the campaniform receptors at the wing base. Scale bar, 5 µm. (C) The subcellular localization of GFP-DCX-EMAP in the olfactory receptors of DCX-EMAP^KI (lower) and DCX-EMAP^OE (upper, DCX-EMAP-gal4, uas-cd4-tdtom/uas-gfp-DCX-EMAP) strains. Note that the localization of DCX-EMAP in DCX-EMAP^KI was not visible, while that in DCX-EMAP^OE appeared to be fragmentary. Scale bar, 10 µm. Inset scale bar, 5 µm. (D) Olfactory tests on wild type (n = 730 flies from seven assays), Orco¹ (n = 286 flies from three assays), Orco² (n = 326 flies from three assays), DCX-EMAP^KO (n = 299 flies from three assays), and DCX-EMAP^rescue (DCX-EMAP-gal4/uas-gfp-DCX-EMAP; DCX-EMAP^KO, n = 366 flies from four assays). Two-sided unpaired Student’s test. ***, P < 0.001; n.s., no significance. Note that Orco, also known as Or83b, encodes broadly expressed chemoreceptors in almost all fly olfactory organs (Vosshall and Stocker, 2007). Orco¹ and Orco² are null mutants of Orco.