Fig. 5. Misexpression of 5ß1 integrins induces fusion of joints and differentiation of pre-hypertrophic cells. Chick legs of HH stage 27 were electroporated with full-length cDNA 5ß1 integrins in the region of the autopod and incubated for 5 days (B,D,F,H,J), as controls, contralateral legs were used (A,C,E,G,I). Chick legs were fixed in paraformaldehyde and photographed to observe phenotype induced by misexpression of human 5ß1 integrin (A,B). Serial section of the legs shown in A and B were prepared for paraffin inclusion and used for histology (C,D), immunofluorescence for human 5ß1 integrin (E,F), IHH (G,H) and in-situ hybridization for Wnt14 (I,J). (K-N) Forelimbs of E14.5 mouse embryos cultured for 4 days in the presence of 1 µg/ml BMP7 were injected at the wrist with 10 µg of an anti-5 integrin mAb. Cultures were added with nothing (K,L), or sonic hedgehog 400 ng/ml (M,N). Histological sections were stained with Safranin O and Fast Green (K,M), or processed for in-situ hybridization for Wnt14 (L,N).