Fig. 3: Vmn2r88 is a specific vomeronasal receptor for hemoglobin.
From: Hemoglobin in the blood acts as a chemosensory signal via the mouse vomeronasal system
a Dual-color ISH staining of a VNO section from a hemoglobin-stimulated C57BL/6 mouse labeled with the Egr1 cRNA probe (green) and V2Rf clade-specific cRNA probe (magenta). n = 3. Scale bar, 50 µm. b, c Bar graph representing the average cell number in VNO sections from C57BL/6 mice stimulated with hemoglobin. In Fig. 3b, probes to distinguish each V2R clade were used. In Fig. 3c, probes to narrow down candidate genes in V2Rf clade (named V2Rf1-V2Rf5) and to further distinguish each gene in V2Rf5 clade (Vmn2r88, 89 and 122) were used. Black, yellow, and gray parts represent only V2R-positive (b) or V2Rf-positive (c), V2R and Egr1 double-positive, and only Egr1-positive cells respectively. Hybridization temperatures are shown below the graphs. d Vmn2r88 and pS6 immunostaining of VNO sections from Vmn2r88+/+or Vmn2r88−/− male mice exposed to hemoglobin (Hb) or distilled water (control). Open arrowheads show pS6-positive cells; closed arrowheads show cells double-labeled for pS6 and Vmn2r88. In the mutant mice, corresponding pS6 and Vmn2r88 expression completely disappeared. n = 3 for Vmn2r88+/+-control, and Vmn2r88-/--Hb, and n = 5 for Vmn2r88+/+-Hb. Scale bar, 50 µm. e The number of pS6- (green), Vmn2r88- (magenta), and double-positive cells (yellow) per VNO section. In the group of Vmn2r88+/+-Hb 16 sections from each of 5 animals were quantified and 16 sections from each of 3 animals were counted in the other groups. Double-positive cells completely disappeared in the sections from Hb-stimulated Vmn2r88-/- mice.
