Fig. 5. Misexpression of Tbx3^VP16 causes a caudal shift in axial limb position. (A) MyoD expression marks the somites and Shh marks the ZPA. There is a two-somite level caudal shift (marked by bars) in the injected limb (right). (B) dHand expression at stage 17 following Tbx3^VP16 misexpression. dHand is restricted to the posterior limb mesenchyme in the control side (left, arrowhead shows rostral expression border), while in the injected side, dHand expression is displaced caudally (right, arrowhead). (C) Gli3 expression at stage 17 following Tbx3^VP16 misexpression. Gli3 is upregulated in the injected side (right) compared with the control side (left). The graded domain of Gli3 expression is displaced caudally (compare left and right arrowheads).