Figure 1. Segregation of ligand-specific ORs and IRs across female Ae. aegypti antennae.

(A) Three models of receptor expression in mosquito olfactory sensory neurons (OSNs): canonical expression of one receptor per neuron (left), within-family coexpression (middle), between-family coexpression (right). Orco and ‘Irco’ stand for conserved OR and IR family coreceptors. (B) Transgenic strategy used to express nuclear membrane-bound GFP in neurons. Confocal image of labeled nucleus. Scale bar, 1 μm. (C) Single nucleus RNAseq data collection schematic. (D) Annotated UMAP of 46,073 nuclei from female antennal neurons (n=52 major clusters). OSN cluster colors reflect on/off expression of orco, Ir8a, and Ir76b as shown. (E) Average expression of olfactory co-receptors in OSN clusters, computed as percent gene-specific maximum. Red dashed lines show cutoffs used to call expression in (D). (F) Triangle plot illustrating segregated expression of orco, Ir8a, and Ir76b. Position of each OSN cluster (circle) reflects relative expression of the 3 genes (where expression is first computed as percent max as in (E)). (G) Expression level of the most highly expressed ligand-specific OR (left) or IR (right) in each OSN cluster. Cluster 46 (purple) is the only cluster that expresses substantial levels of both an OR and an IR. Cluster 20 (dark grey) expresses neither ORs nor IRs (but instead an ammonium transporter, see Fig. 3). Dashed black line shows mean for mechanosensory neurons. Colors in (F–G) as in (D).