Fig. 8

Sema6A expression in the dorsal thalamus, prethalamus, developing basal ganglia and lateral olfactory tract in Plxna2; Plxna4 double mutant E13.5 brains. a–f Double immunohistochemistry for neurofilament (red) and Sema6A (green) on E13.5 coronal brain sections reveals the normal fasciculation and spatial navigation of Sema6A-positive caudally-projecting TCAs at dorsal thalamic and prethalamic level in Plxna2 ^−/− ; Plxna4 ^−/− (a–c) mouse brains, as compared to Plxna2 ^+/− ; Plxna4 ^+/− specimens (d–f). g, h Double immunohistochemistry for Islet1 (red) and Sema6A (green) on E13.5 coronal Plxna2 ^+/− ; Plxna4 ^+/− and Plxna2 ^−/− ; Plxna4 ^−/− brain sections demonstrates the preserved corridor region co-expression of the two proteins in the absence of PlxnA2/PlnxA4 function, as well as the normal presence of Sema6A in the globus pallidus and other subpallial areas. However, a Sema6A-positive axonal bundle, which normally elongates within the ventral vTel surface, can be observed to invade the subpallium in a ventro-dorsal direction in Plxna2 ^−/− ; Plxna4 ^−/− brains (arrow in h). i–j’ Double immunohistochemistry for TAG1 (red) and Sema6A (green) on E13.5 coronal wild-type and Plxna2 ^+/− ; Plxna4 ^−/− brain sections indicates that the Sema6A-positive axonal bundle invading the subpallium in mice lacking PlxnA2/PlxnA4 (arrowheads) co-expresses TAG1, and thus corresponds to the lateral olfactory tract. Moreover, immunohistochemical data confirms the normal expression of Sema6A in developing basal ganglia structures in Plxna2; Plxna4 null mutants. Co: corridor cells; GP: globus pallidus. Scale: a–g: 250 μm; i–j’: 200 μm