Fig 2: Infectious findings in the lungs and nasal cavity. (A) Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) gene detection with RT- quantitative polymerase chain reaction (*P < 0.05). (B) Immunohistochemistry staining of SARS-CoV-2 in the lung (shown in brown, arrow heads). (C, D) Representative images of the olfactory epithelium from control hamsters (C: hematoxylin and eosin stain, D: immunohistological staining of NQO1 and OCAM). The boxes in (C) indicate the regions of the olfactory epithelium shown in D; the dorsal nasal septum (DS) area, ventral nasal septum (VS) area, dorsal lateral turbinate (DLT) area, and lateral turbinate (LT) area. Only the DS area appears positive for NQO1. (E, F) Representative images of the olfactory epithelium from SARS-CoV-2 hamsters. (G) Immunohistochemistry staining of the olfactory epithelium in SARS-CoV-2 hamsters. The virus is mainly present in the lateral region of the nasal cavity. (H) Double stained images of SARS-CoV-2 and OMP in each region of the olfactory epithelium. No double positive cells for SARS-CoV-2 and OMP are present in the olfactory epithelium. The arrow heads show SARS-CoV-2 positive cells.

Fig 3: Cav2.1+ glomeruli and expression of neural adhesion molecules. (A,B) Confocal images of the dorsal-caudal MOB (sagittal plane) stained with Cav2.1 (red) and neural cell adhesion molecule Ncam2 (green). (A) The single Cav2.1+ glomerulus in the central-dorsal MOB exhibiting immunoreactivity for Ncam2 (arrow) represents a rare observation. Other Ncam2+ glomeruli in this area are devoid of Cav2.1 immunoreactivity (arrowheads). (B) Cav2.1+ glomeruli in the dorso-caudal MOB are Ncam2– (arrow) as depicted by the large glomerulus. (C,D) Double-labeling immunohistochemistry for Cav2.1 (red) and Taar (green) in the dorsal center (C) and dorso-caudal border (D) of the MOB. Cav2.1+ glomeruli are not labeled by the panTaar antibody used. Images are representatives of (N = 3) adult B6 mice, with N representing every second section per mouse. Scale bars: 100 μm.

Fig 4: The interactome of NCAM2; the mass spectrometry approach. (A) Schematic representation of the mass spectrometry approach. Brain lysates from P10–12 mice were enriched in membrane proteins and incubated with magnetic beads, which were previously conjugated with an antibody against NCAM2.1 or against both NCAM2 isoforms. The eluted proteins were processed for mass spectrometry analysis. A list of 103 proteins that interact with NCAM2 was obtained with a False Discovery Rate ≤ 0.01%, Table 1. (B) WB detection of NCAM2.1 and NCAM2 proteins in the cytosolic, membrane and insoluble fractions of the brain lysates used for the mass spectrometry assay. NCAM2.1 isoform is detected in both fractions, the membrane and the insoluble fraction while NCAM2.2 is specially enriched in the insoluble fraction. Tubulin was used as a loading control. (C) WB detection of NCAM2 from samples of magnetic beads elution.

Fig 5: NCAM2 interacts with MAP2, 14-3-3, NFs, CaMKII and Nogo. (A) WB detection of NCAM2.1 in different co-immunoprecipitation experiments with MAP2 (A), 14-3-3 (C), NEFs (E), CaMKII (F) or NEFs (G). Detection of MAP2 (B) or 14-3-3 (D) in different co-immunoprecipitation experiments with NCAM2.1 from P10–15 mouse cortex and hippocampal protein extracts. Immunoprecipitation using MAP2 (A), 14-3-3 (C), NEFs (E) or CaMKII (F) or Nogo (G) antibodies confirmed the presence of NCAM2.1 protein in the WBs after detection with NCAM2.1 or NCAM2 antibodies (G). Immunoprecipitation using NCAM2.1 antibodies confirmed the presence of MAP2 (B) and 14-3-3 (D).