Figure 2

PlexinC1 is expressed in migrating LHRH neurons. In situ hybridization for Sema7A and plexinC1 on consecutive horizontal (A-F), sagittal (G-K) and coronal (L-O) sections of the developing eye and nasal region. Rostral is to the top in A-F and to the left in G-K. Dorsal is to the top in L-O. (A, B) At E15, Sema7A and plexinC1 are expressed in the retinal ganglion cell layer (RGC). White line indicates the border of the RGC. (C, D) At E19, both Sema7A and plexinC1 are expressed in the inner plexiform layer (IPL) and RGC. (E, F) In addition, Sema7A and plexinC1 are expressed in the lens (arrow) and the lens epithelium (asterisk). (G-I) In the nasal region, plexinC1 is expressed in clusters of cells (arrows in G-I) located in close proximity to vomeronasal axon fascicles (asterisks in I). Panel I shows a higher magnification of the boxed area in panel H. (J, K) In situ hybridization for plexinC1 and immunohistochemistry for luteinizing hormone-releasing hormone (LHRH) on consecutive sections reveal that plexinC1 is expressed in migrating LHRH neurons. Arrow indicates a cell cluster that expresses plexinC1 and LHRH. (L, M) At E19, numerous plexinC1-positive LHRH neurons can be detected within and immediately outside the vomeronasal epithelium (VNE; arrows in M). (N, O) At P0, the majority of LHRH neurons have migrated to the forebrain and only few plexinC1-positive LHRH neurons remain in the VNE (arrows in O). (L-O) Note that both Sema7A and plexinC1 are expressed by vomeronasal neurons in the apical (a) and basal (b) VNE. 7A, Sema7A; C1, plexinC1; FB, forebrain; OB, olfactory bulb; OE, olfactory epithelium; vd, vomeronasal duct. Scale bar 320 μm (A, B), 85 μm (C, D), 95 μm (E, F), 90 μm (G), 675 (H), 25 μm (I), 80 μm (J, K), 150 μm (L, M), and 275 μm (N, O).