Fig. 3

Expression of Osi8 in the antenna. A Schematic of the protein domain structure of Osi8. B Histogram of expression levels of Osi family members in antennae of control (w¹¹¹⁸) and amos mutant (amos³) animals, determined by bulk RNA-seq. Mean values ±SD of fragments per kilobase of transcript per million mapped reads (FPKM) are plotted; n = 3 biological replicates. Note that Osi10 values represent the combined counts of Osi10a and Osi10b. C Histogram of Osi8 expression levels in the indicated D. melanogaster tissues determined by bulk RNA-seq; mean FPKM values ±SD are plotted (n = 2–3 biological replicates; data are from the Fly Atlas 2.0 [88]). D tSNE plot of whole head single-cell transcriptomes (Fly Cell Atlas 10× stringent dataset [29]) highlighting the selective detection of Osi8 within a subset of sv-positive cells (most of which are likely to be antennal support cells (Fig. 2A)). E Histogram of expression levels of the Aedes aegypti Osi8 ortholog (AAEL004275) in the indicated tissues determined by bulk RNA-seq; mean values ±SD of transcripts per kilobase million mapped reads (TPM) are plotted (n = 3–8 biological replicates; data are from [89]). F Osi8 RNA FISH on a whole-mount antenna of a control (w¹¹¹⁸) animal; the bright-field channel is overlaid on the lower image to reveal cuticle morphology. Morphologically distinct proximal and distal populations of Osi8 RNA-expressing cells are indicated (see “Results”). Scale bar, 20 μm. G Top: schematic of the neuronal composition of the antennal trichoid (at) and antennal intermediate (ai) sensillar classes. Bottom: Osi8 RNA FISH and GFP immunofluorescence in whole-mount antennae of animals in which the distributions of the different sensillar classes are revealed with a representative Or neuron transgenic reporter. In the left-hand image, the arrowheads indicate Osi8-expressing cells that are found in close proximity to Or67d neurons (see “Results”). Genotypes (left-to-right): UAS-mCD8:GFP/+;Or67d^Gal4#1/+, Or88a-mCD8:GFP, Or83c-mCD8:GFP, Or2a-mCD8:GFP. Scale bar, 20 μm. H Top: schematic of an olfactory sensillum, illustrating the main cell types and other anatomical features. Bottom: Osi8 RNA FISH and GFP immunofluorescence on antennal cryosections of animals in which the tormogen (UAS-mCD8:GFP;ASE5-Gal4) or thecogen (nompA-Gal4;UAS-mCD8:GFP) support cells are labeled. Scale bars, 20 μm. I Immunofluorescence for GFP on antennal cryosections of Osi8-Gal4/+;UAS-SS:EGFP:Osi8/+ animals; the bright-field channel is overlaid on the right-hand image to reveal cuticle morphology. The open arrowheads point to prominent intracellular puncta of GFP signal. The filled arrowheads point to GFP signal within the lumen of the proximal region of trichoid sensillar hairs, which may represent extracellular vacuoles (see “Results”). Scale bar, 20 μm