Fig. 1

Genome editing generates zebrafish myog null alleles. a Schematic of myog gene exons (boxes) and protein showing the position of kg125, kg128 and fh265 mutant alleles. The tyrosine to stop mutations (Y37*) produce a truncated protein of 36 amino acids (aa) devoid of both basic (yellow) and helix–loop–helix (HLH, green) domains. The fh265 hypomorphic allele (Q167*) truncates downstream of bHLH. Beneath, DNA and protein alignment of wild-type (wt), 3 bp kg125 deletion (red) and 1 bp kg128 insertion (green) alleles with novel stop codons underlined causing an identical truncation. b In situ mRNA hybridisation (ISH) for myogenin on myog^kg128/+ and myog^kg125/+ incross lays reveal NMD of mutant myog mRNA at 20 somite stage (20 ss). Representative images n = 14 + 5 mutants, n = 39 + 22 sibs, respectively. Insets show magnification of boxed areas. c qPCR analysis on wt sibs and myog^kg125 embryos at 22 ss confirms NMD. Mean fold change ± SEM from four independent experiments on genotyped embryos from four separate lays analysed on separate days, paired t test statistic. Symbol shapes denote matched wt and mutant samples from each experiment. d Immunoreactivity of Myog is lost in myog^kg125 and myog^kg128 mutants at 20 ss, whereas F-actin is unaffected. Insets show nuclear staining in myog^kg125 and sib using Hoechst counterstain. Relative myotomal Myog immunofluorescence was assessed by nuclear intensity measurement. All images are lateral views anterior to left, dorsal to top. Representative images n = 10 + 7 mutants, n = 9 + 19 sibs, respectively. Bars = 50 µm