Fig. 4

Fig. 4. itga3b mutant embryos display disorganized sarcomere structure. (A) α-actinin immunofluorescence shows striated Z-discs with reduced lengths in ventricles and atria of itga3b^+/- (b) and itga3b^−/− (c) mutants compared to sibling wild-types (WT, a) at 96 hpf. Enlarged images are indicated by the boxes in low magnification panels. Z-disc lengths (zl) and sarcomere lengths (sl) were measured from immunofluorescence images. Significantly decreased Z-disc length (d) but not sarcomere length (e) was observed in itga3b^+/- and itga3b^−/− mutants compared to sibling wild-types. Total number of embryos examined is indicated within each bar. Error bars indicate s.e.m. Quantitative data were analyzed by ANOVA with Tukey's multiple comparisons. Treatments that are not significantly different (α = 0.05) from each other are labeled with the same letter. Comparisons of Z-disc length between sib WT and itag3b^+/- or itga3b^−/− in ventricles or atria had p < 0.0001 (d). Scale bar, 25 μm. Scale bar for enlarged images, 5 μm. (B) Transmission electron microscopy shows thin myofibrils and indistinct Z-discs in ventricular sarcomere of itga3b^+/- and itga3b^−/− mutants compared to sibling wild-types at 96 hpf. Arrows indicate Z-disc. Scale bar, 200 nm.