Fig. 8. Fgf15 induces an expansion of Tcf4 expression in brain explants. (A) GFP activity in the right side of the brain explant shown in B after electroporation with pCIG-F15. The broken line in both panels indicates the ventral midline. Explants were cultured for 40 hours after electroporation and examined for Tcf4 expression. In the case of the control vector expressing only GFP (C), there was no significant difference in Tcf4 expression on the electroporated (right, indicated by arrow) and non-electroporated sides (left). By contrast, explants electroporated with the Fgf15-expressing vector (pCIG-F15) showed an expansion of the Tcf4 expression domain on the electroporated side (D, arrow). Rostral is towards the top in all panels.