Fig. 9.

Loss of Pnt results in Naa-to-Nab transformations in diverse sensillar subtypes. a A sensillum can contain up to four OSNs through differentiation of Naa (cyan), Nab (magenta), Nba (green), Nbb (yellow) terminal daughter cells originating from a single SOP lineage. b Representative images of RNA FISH for Or67d (magenta) in at1 sensilla in control and pnt RNAi antennae. In pnt RNAi antennae, Or67d-expressing OSNs are duplicated (arrow). A schematic of the proposed Naa-to-Nab fate transformation is shown on the right (color scheme as in (a)). Scale bar = 2 µm. The open circles in this and other schematics represent OSN precursors that have undergone apoptosis. c Representative images of RNA FISH for Or85a (magenta) and Or59b (green) in ab2 sensilla in control and pnt RNAi antennae. In pnt RNAi antennae, Or85a OSNs (Nab) are duplicated (arrow), while Or59b OSNs (Nba) are unaffected. d Representative images of RNA FISH for Or85b (magenta) and Or22a (green) in ab3 sensilla in control and pnt RNAi antennae. In pnt RNAi antennae, Or85b OSNs (Nab) are duplicated (arrow), while Or22a OSNs (Nba) are unaffected. e Representative images of RNA FISH for Or92a (magenta) and Or10a (cyan) in ab1 sensilla in control and pnt RNAi antennae. In pnt RNAi antennae, Or92a OSNs (Nab) are duplicated (arrow), while Or10a OSNs (Naa) are lost. f Top: theoretical ratios of OSN types in 2-, 3- and 4-neuron sensilla in control and pnt RNAi antennae, assuming Naa-to-Nab fate transformation (i.e. loss of Naa OSNs, and duplication of Nab OSNs). Bottom: experimentally determined OSN ratios in all sensilla in pnt RNAi antennae using as a proxy the normalized ratios of olfactory receptor mRNA expression from antennal transcriptomes (see Supplementary Fig. 6e). In ab10, Or49a is reported to be coexpressed with Or85f¹³, but transcript levels for this gene were below the cut-off applied during the analysis of these RNA-seq datasets