Figure 4.
Expression analysis of ephrin-B3 in wild-type mouse spinal cord sections reveals that ephrin-B3 is expressed in the midline. (A,B) Schematic lateral (A) and dorsal (B) views of E18.5 mouse brain indicating the location of the CST and the sections taken for panels C–E, with C at the site of the medullary decussation and those at D and E representative of more caudal sections through the spinal cord. (C–E) DIG in situ hybridizations (blue staining, black arrowheads) on coronal sections of the E18.5 medullary decussation and spinal cord. In C at the medullary decussation, which occurs ventrally (with stippled lines indicating approximate path of decussating fibers), ephrin-B3 is detected only in the dorsal portion of the midline and not in the ventral midline. In D and E, sections of the cervical and thoracic spinal cord are shown in which the ephrin-B3 expression extends over the ventral part of the midline. A higher magnification view of the dorsal funiculus (stippled box and inset) also reveals expression of ephrin-B3 in the midline of the dorsal funiculus. CC, central canal; DF, dorsal funiculus. Scale bars, 200 μm.