Fig. 1

GPRC5C is expressed in dendritic knobs of OSNs. A Relative expression levels of GPCRs in cilia preparations of OSNs (black bars) and in next-generation sequencing results of FACS sorted OSNs (grey bars), shown are relative intensity or FPKM levels, each normalized to the most abundant GPCR in both data sets. Shown are non-olfactory GPCRs that have been identified with proteomic methods. B qPCR analysis of Gprc5c mRNA expression across different tissues in adult mice. CNS is brain excluding olfactory bulb (OB) (n = 3, individual data values Additional file 2). C Confocal images of adult OE cryosection upon FISH of DIG-labelled probes for GPRC5C (antisense and sense). Strong GPRC5C mRNA expression is detected in the neuronal cell layer (OSN). The apical sustentacular cell layer (SC) and basal cell layers (BC) do not express GPRC5C mRNA. Dotted lines demarcate the different cell layers. NC: Nasal cavity, LP: Lamina propria. Sense control showed no labelling. Scale bar: 20 µm. D En face preparation of the OE showing expression of GPRC5C in all dendritic knobs. Confocal images of adult OE coronal cryosection immunolabelled for E GPRC5C (green), acetylated-tubulin (AcTub) (white), OMP (red), and overlay along with DAPI (blue) showing localization in dendritic knobs of olfactory neuron F GPRC5C (green) and Phalloidin (red) showing GPRC5C + structures embedded in between sustentacular cell microvilli. G GPRC5C (green) and IP3R (red) showing that GPRC5C is not localized to the apical surface of microvillar cells. H Absence of GPRC5C (labelled in green) in ICAM-positive (white) HBCs, primary cilia are labelled with ARL13B (red), white line marks the basal lamina. I GPRC5C (green)-positive dendritic knobs, single-channel image for overlay shown in K. K ARL13B (red)-positive primary cilia are present on immature OSNs labelled with DCX (white), but not on GPRC5C (green) labelled dendritic knobs. Scale bars E–H 10 µm and I–K 1 µm