Fig. 7. SHH-independent dorsoventral neural patterning. E11.5 neural tube sections were assayed for expression of Pax3 (A-D), Pax6 (E-H), Dbx1 (I-L), Isl2 (M-P), Nkx2.2 (Q-T) and Foxa2 (U-X) in wild-type (A,E,I,M,Q,U), Shh^-/- (B,F,J,N,R,V), Fkbp8^-/- (C,G,K,O,S,W) and Shh^-/-;Fkbp8^-/- (D,H,L,P,T,X) embryos. Dorsal and lateral cell fates (marked by Pax3 and Pax6, respectively) are excluded from the ventral neural tube of wild-type and Fkbp8^-/- embryos but were expressed across the ventral midline of Shh^-/- mutants. Ventral repression of these cell fates was restored in the Shh^-/-;Fkbp8^-/- double mutant. Note the specification in Shh^-/-;Fkbp8^-/- mutants of lateral and ventral cell types such as Dbx1⁺ V0 interneuron progenitors, Isl2⁺ motoneurons (arrows in M,O,P), Nkx2.2⁺ V3 interneuron progenitors, and Foxa2⁺ floorplate. These cell types are absent in E11.5 Shh^-/- mutants. In addition to motoneurons, dorsal root ganglia (DRG, arrowheads in M-O) also express Isl2. DRG, derived from the dorsally specified neural crest, are observed in wild-type and Shh^-/- mutant embryos but are displaced dorsally or missing altogether in Fkbp8^-/- and Shh^-/-;Fkbp8^-/- mutants, consistent with disruption of dorsal fates in these embryos. Scale bars: 65 µm.