Fig. 3.

Blebbistatin treatment does not rescue the loss of normal thin filaments in troponin-T-depleted sarcomeres. (A–G) Electron microscopy images of 48 hpf embryos, in tangential (A–D) and cross-sections (E–G). Control embryos (A,E) show normal sarcomeres with well-defined Z lines (white arrowheads) and M lines (black arrows) and regular hexagonal arrangement of thick filaments with intercalating thin filaments (circle in E). In blebbistatin-treated control embryos (B), Z lines are less sharp and M lines are not clearly defined. In tnnt-depleted muscles (C,F), sarcomeric components are disorganised (C) and bundles of thick filaments in cross-sections do not appear to be intercalating with thin filaments (F). Upon blebbistatin treatment, wider and regularly spaced Z lines can be observed in triple tnnt MO-injected embryos (D) and virtually no thin filaments are visible inside thick filaments bundles (circle in G). Scale bars: 1 μm (A–D); 150 nm (E–G).