Obscurin Depletion Impairs Organization of Skeletal Muscle in Developing Zebrafish Embryos
Figure 8
Obscurin depletion affects membrane-myofibril interactions. Skeletal muscle from 24 hpf zebrafish embryos were evaluated by transmission electron microscopy. (a) New myofibril assembly (arrowheads) occurs along the sarcolemma (arrows), preferentially at the intersection of three myocytes. Note the well-formed sarcoplasmic reticulum that encircles the new myofibrils. (b)–(e) In obscurin A morphant embryos, the sarcoplasmic reticulum is less well developed and less closely associated with the myofibril (b). Myofibril assembly still preferentially occurs at the sarcolemmal intersections ((c): arrowheads). However, frequent “internal myofibrils” form ((d): arrowheads) and distances between superficial myofibrils and the membrane increase ((e): arrowheads). Scale bars are 100 nm (a), (b) and 500 nm (c), (d).
