Figure 6.

Notch1 is expressed by embryonic human OECs, while Jag1 is expressed by olfactory receptor neurons. Parasagittal sections of the human embryonic olfactory system. (A) At 7 weeks of development, Notch1 is expressed by the subventricular zone of the forebrain. (A¹) Same section as (A) showing Tubb3 immunostaining for axons. (B) Higher‐power view of boxed region in (A), showing expression of Notch1 on the olfactory nerve. (B¹) Same section as (B) immunostained for Tubb3‐positive axons and Elavl3/4‐positive neurons, with a false‐colour overlay of Notch1, shows that Notch1 is expressed by non‐neuronal cells on the olfactory nerve, presumably developing OECs. (C–D¹) At 8 weeks, Notch1 is expressed by non‐neuronal cells on the olfactory nerve, presumably developing OECs. (E–G³) At 8 weeks of development, Jag1 can be detected in Elavl3/4‐positive olfactory receptor neurons in the intermediate and basal layers of the olfactory epithelium (black/white arrowheads), which might be newly differentiated olfactory receptor neurons and/or precursors of the Jag1‐positive migratory neurons on the olfactory nerve (black/white arrows). Jag1 expression is also seen in non‐neuronal mesenchymal cells in the lamina propria (yellow arrows). BV, blood vessel; FB, forebrain; OB, olfactory bulb; OE, olfactory epithelium; ON, olfactory nerve. Scale bar: 100 μm.