Figure 2

(A) Schematic of trunk muscle processing for qPCR analysis (left), sib (blue), myog^-/- (red). Expression of pax3a and pax3b mRNAs is unchanged in myog^-/- muscle (right). Symbol shapes denote paired sib and myog^-/- samples, n = 6 fish/genotype, paired t-test. (B) Representative images of adult pax7a:GFP;myog^+/- (sib) and pax7a:GFP;myog^-/- (left). Scale bar = 1 cm. Quantification showing reduced length, weight, body mass index and standard weight in myog^-/- compared to co-reared sibs (right), n = 7, unpaired t-test. (C) Schematic of pax7a:GFP adult trunk muscle processing for MuSC analysis (left). Fraction of GFP^+ve cells (bona fide MuSCs) per myofibre-associated nucleus is significantly increased in myog^-/- muscle (right). n = 3 fish/genotype, unpaired t-test. (D) Quantification of absolute number of (non-MuSC, GFP^-ve) myonuclei per adult myofibre. n = 3 fish/genotype, n = 20–30 myofibres/fish, unpaired t-test. (E,F) Quantification of absolute myofibre volume and myonuclear SADS (Surface Area Domain Size). n = 3 fish/genotype, n = 20–30 myofibres/fish, unpaired t-test. (G) Fraction of myofibres (%) with indicated number of GFP^+ve cells (MuSCs), n = 3 fish/genotype, n = 20–30 myofibres/fish,p-value indicates probability of rejecting null hypothesis of no difference between myog^-/- and sib in χ² test. (H) Schematic of GFP^+ve cell distance to nearest myofibre-end measurement (left). Note that while average half-length (in magenta) of sib myofibre (blue diagram) is 500 µm, myog^-/- myofibre average half-length is 250 µm (red diagram). To compare absolute distance to myofibre-end, each myofibre was segmented into 50 µm segments and the fraction of GFP^+ve cells (%) within each distance segment from nearest myofibre-end plotted, n = 3 fish/genotype, n = 20–30 MuSCs/fish, p-value indicates probability of rejecting null hypothesis of no difference between myog^-/- and sib in χ² test. Note that in sibs almost no GFP^+ve MuSCs were located in the central 50% of their myofibre. All graphs report mean ± SEM.