Figure 4.

Quantification of slow and fast myofibers in the EOMs of adult obscurin mutants and sibling controls. Cross-sections of 10-month-old adult zebrafish EOMs immunolabeled with phalloidin to identify all myofibers (labeling of F-actin by phalloidin, green in A and C), S58 to identify all myofibers containing slow MyHC (red in B, D–F), F310 to identify all myofibers containing fast MyHC (red in G and H). The contours of the myofibers were labeled by the antibody against laminin (gray in A–H). Arrowheads indicate examples of positively-labeled myofibers with phalloidin, which labels F-actin (in A and C) and slow MyHC S58 (in B and D) in closely located masticatory myofibers (left) in the same section. Quantification of slow myofibers (S58 positive in E and F and quantified in I), fast myofibers (F310 positive in G and H and quantified in J), and the total number of myofibers (K) in obscna^−/−;obscnb^−/− and obscna^+/−;obscnb^+/−. (L, M) Cross-sections of obscna^+/−;obscnb^+/− and obscna^−/−;obscnb^−/− zebrafish EOMs immunolabeled with phalloidin, which labels F-actin, laminin, DAPI and TUNEL (arrowheads, red in L and M) to identify apoptotic myofibers. (N) The proportion of TUNEL-positive myofibers. Data in graphs are presented as mean ± SEM. *P < 0.05; **P < 0.01; ****P < 0.0001.