Figure 7

Anti-Hedgehog antibody delays slow MyHC and reduces muscle differentiation in chick wing bud. Implants of anti-Hh (5E1; A,B,E,F) or control anti-MyHC (N2.261; I,J) hybridoma cells were placed into HH21-24 chick wing buds and analysed two days later at HH27-30 for pan MyHC (A4.1025; A,C,E,G,I) or slow MyHC (Na8; B,D,F,H,J), in parallel with contralateral limb controls (C,D,G,H). A-D. A less mature wing shows failure of slow MyHC expression (arrows) with little effect on overall muscle differentiation. E-H. A more mature wing showing reduced muscle differentiation, but slow MyHC is present in the residual muscle mass. I,J. Control implants have no effect on timing, extent or type of muscle differentiation. Slow fibres are less abundant in some regions, as in unmanipulated wings (red arrows, G-J). In this example, the Cellagen block containing hybridoma cells detected by the secondary reagents is located within the forewing region (arrowheads) but does not disrupt muscle pattern. Dorsal up, posterior to left. Contralateral images have been reversed to aid comparison.