Fig. 2. Ectopic expression of Ato does not rescue the glomerular phenotype of ato¹/Df(3R)p¹³. (A,B) The SG18.1-Gal4 line was used to drive UAS-Ato and UAS-GFP in the SG18.1 UAS GFP/UAS-Ato; ato¹/Df(3R)p¹³ genotype. The adult lobe morphology is similar to ato¹/Df(3R)p¹³ (see Fig. 1D). Inter-antennal commissure is absent (?). Arrowheads mark the entry of sensory neurons. The left lobe in A is enlarged in B for clarity. Dotted line marks lobe boundary. (C,D) Third antennal segments from 22 hours APF pupae. Sensory neurons from the third segment and the arista (ar) have differentiated and leave the antenna in three distinct fascicles (1, 2, 3). (C) Staining with anti-Ato (red) shows no immunoreactivity in the third segment (III). Cells of the Johnston’s organ (arrows) in the second segment (II) express Ato (D). (E,F) RNA in situ hybridization on horizontal sections of the adult antenna with digoxygenin-labeled Or22b probe. Wild-type (E) and ato¹/Df(3R)p¹³ (F) antennae show the odorant receptor gene expression in a subset of large basiconica (arrows). The altered morphology of the ato^– antenna makes the location of the sensilla appear somewhat different, but we verified that the same number of expressing cells were present in wild-type and ato¹/Df(3R)p¹³ antennae. Scale bars: 25 µm in A,B; in D, 25 µm in C,D.