Fig. 6. Effects of loss-of-function of Wnt signalling in vivo. Fluorescent images of transverse cryosections of day 8 chick wings that were infected with retroviruses expressing Sfrp2 (B,D) and Wnt11 (F,H) at stage 18-20, and the contralateral control wings (A,C,E,G), which have been visualized with antibody A4.1025, which recognizes slow and fast MyHCs (A,B,E,F, green), and antibody A4.840, which recognizes slow MyHC (C,D,G,H, red). (A-D) Sections through the whole wing. (E-H) High power pictures of the EMU and EDC muscles. The arrows in (A,B,G,H) compare equivalent muscles, showing the changes in muscle development. In (B), the muscles are absent (EMU, SUP) or are decreased in size (EMR, FCU). In H, the EMU muscle has more slow fibres. EDC, extensor digitorum communis; EIL, extensor indicis longus; EMR, extensor metacarpi radialis; EMU, extensor metacarpi ulnaris; FDP, flexor digitorum profundus; SUP, supinator. Scale bars: 200 µm in AD; 100 µm in E-L.