Fig. 6

Behavior of Pax7^+ve cells in dystrophic muscle. A,B: Birefringence of muscle fibers in polarized light reveals large gaps in sapje^ta222a mutant larvae compared with wild-type at 5 days postfertilization (dpf). C: Pax7^+ve cells can be seen within the gaps of degrading myofibers in sapje^ta222a mutants at 2 dpf (arrows show a subset of Pax7^+ve cells localized within the lesion sites). D,E: Pax7^+ve cells continue to accumulate at 3 dpf and 4 dpf in sapje^ta222a mutants as fewer fully intact fibers remain (arrows show Pax7^+ve cells nestled in between detached myofibers, arrowheads xanthophores). F: Increase in numbers of Pax7^+ve nuclei at 3 dpf in damaged somites (yellow bar) of sapje^ta222a mutants compared with wild-type (blue bar). Counts in less severely damaged somites are slightly reduced (red bar). The Y-axis shows the number Pax7^+ve cells per somite. Numbers based on analysis of three somites in four to seven animals, error bars show standard error. Asterisks: P < 0.001. Counts include only weakly stained rounded Pax7^+ve cells and exclude intensely stained elongated Pax7^+ve xanthophores. G,H: Accumulation of Pax7^+ve cells in the myotome of 3 dpf larvae following morpholino mediated knock down of Integrin α7 expression. Scale bar = 50 μm.