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>Interaction of force transmission and sarcomere assembly at the muscle-tendon junctions of carp (Cyprinus carpio): ultrastructure and distribution of titin (connectin) and α-actinin
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Interaction of force transmission and sarcomere assembly at the muscle-tendon junctions of carp (Cyprinus carpio): ultrastructure and distribution of titin (connectin) and α-actinin
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机译：Interaction of force transmission and sarcomere assembly at the muscle-tendon junctions of carp (Cyprinus carpio): ultrastructure and distribution of titin (connectin) and α-actinin
At muscle-tendon junctions of red and of white axial muscle fibres of carp, new sarcomeres are found adjacent to existing sarcomeres along the bundles of actin filaments that connect the myofibrils with the junctional sarcolemma. As the filament bundles that transmit force to the junction originate proximal to new sarcomeres, they probably relieve these new sarcomeres from premature loading. In red fibres, these filament bundles are long (up to 20 μm) and dense, permitting light-microscopical immunohistochemistry (double reactions: anti-titin or anti-α-actinin and phalloidin). New sarcomeres have clear I bands; their A band lengths are similar to those of older sarcomeres and the thick filaments lie in register. T tubules are found at the distal side of new sarcomeres but terminal Z lines are absent. The late addition of α-actinin suggests that α-actinin mainly has a stabilizing role in sarcomere formation. The presence of titin in the terminal fibre protrusions is in agreement with its supposed role in sarcomere formation, viz. the integration of thin and thick filaments. The absence of a terminal Z line from sarcomeres with well-registered A bands suggests that this structure is not essential for the anchorage of connective (titin) filame
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