Injection of mmp11 MOs increases Fn at the 48 hpf MTJ in laminin gamma1 mutants and improves slow-twitch fiber morphology. A–D Anterior left, dorsal top, side-mounted, 3D projections of embryos stained for slow-twitch fibers with F59 antibody (blue) and Fn antibody (red). A 32 hpf laminin gamma1 mutant. B 32 hpf laminin gamma1 mutant; mmp11 morphant. C 48 hpf laminin gamma1 mutant. D 48 hpf laminin gamma1 mutant; mmp11 morphant. Note that in 48 hpf laminin gamma1 mutants, Fn is not clearly concentrated at MTJs (C, n = 14 embryos). In contrast, Fn robustly concentrates at MTJs in laminin gamma1 mutants injected with mmp11 morpholinos at 48 hpf (D, n = 8 embryos). E–H Anterior left, dorsal top, side-mounted, 3D projections of embryos stained with anti-F59 antibody. Small inset boxes are brightfield, whole mount, live images. E laminin gamma1 mutant at 24 (inset) or 32 hpf. F laminin gamma1 mutant injected with mmp11 MOs at 24 (inset) or 32 hpf. Note that overall body shape and slow-twitch muscle fibers are similar in both mutants and mutant morphants at 24 and 32 hpf. G laminin gamma1 mutant at 72 hpf. H laminin gamma1 mutant injected with mmp11 MOs at 72 hpf. Slow-twitch muscle fiber detachment can be clearly seen in laminin gamma1 mutant embryos at 72 hpf. However, laminin gamma1 mutants injected with mmp11 MOs have less fiber detachment at this time point
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