Fig. 5. Function of Wnt11 in the epithelialization of somites. (A) Overexpression of Wnt11 RCAS by electroporation leads to small, epithelialized somites showing strong expression of Pax3 (arrowheads). (B) Fluorescence image of the embryo in A, showing the localization of the constructs electroporated. (C) Transverse section of the operated region in A, showing the upregulation of Pax3 expression (arrowhead) and the epithelialized morphology of the somite. (D) Overexpression of Wnt11 leads to small, epithelialized somites showing strong expression of Paraxis (arrowheads). (E) Fluorescence image of the embryo in D, showing the localization of the constructs electroporated. (F) Transverse section of the operated region of embryo in D, showing the upregulation of Paraxis expression (arrowhead). (G) Overexpression of Wnt11 leads to the complete loss of Pax1 expression (arrowheads). (H) Localization of the Wnt11 construct in the embryo shown in G. (I) Transverse section at the level of operation of the embryo in (G) showing loss of Pax-1 expression (arrowhead). The epithelial structure of the somite is maintained.