Figure 6

A lμm optical section of an El 5 mouse embryo cut in the sagittal plane at the level of the vomeronasal organ (VNO). A. PN-1 was localized using Texas Red fluorescence. Immunoreactive sensory cells (arrowheads) were found occassionally which supports the co-localization of this protein in vomeronasal nerve axon bundles (Figure 1). PN-1 is also concentrated in the basal laminae (arrow) and displays a meshwork pattern in the nerve. B. Trypsin was identified by FITC fluorescence. Trypsin staining forms a fine meshwork within the VNO. Note that sensory cell in A. (arrowhead) is not positive for trypsin. The staining pattern for trypsin suggests it also has an extracellular localization. There is no co-localization of PN-1 and trypsin proteins. Scale bar= 100 μm.