Rodier Clement, Estabrook Ian D, Chan Eunice HoYee, Rice Gavin, Loreau Vincent, Raunser Stefan, Görlich Dirk, Friedrich Benjamin M, Schnorrer Frank
CNRS, IBDM, Turing Centre for Living Systems, Aix Marseille University, Marseille, France.
Cluster of Excellence "Physics of Life," Technical University Dresden, Dresden, Germany.
Sci Adv. 2025 Jul 11;11(28):eadw9445. doi: 10.1126/sciadv.adw9445. Epub 2025 Jul 9.
The sarcomere is the elementary contractile unit of muscles. Adult muscle cells are large and chain thousands of sarcomeres into long periodic myofibrils that attach to the skeleton. During development, muscle cells must increase in length to maintain the mechanical connection to the growing skeleton. How muscles add new sarcomeres to facilitate muscle growth is unknown. Using live imaging and high-throughput image analysis, we have now tracked the sarcomere components during the developmental growth of muscle and found that individual sarcomeres divide along the myofibril tension axis into daughter sarcomeres. This way, new sarcomeres can be inserted into contractile and mechanically intact myofibrils. We propose that sarcomere division is triggered by tension and local sarcomere damage originating from skeletal growth and muscle contractions. Sarcomere divisions repair damaged sarcomeres, ensure their mechanical integrity, and synchronize sarcomere addition with skeletal growth during animal development.
肌节是肌肉的基本收缩单位。成年肌肉细胞很大，将数千个肌节连成附着在骨骼上的长周期肌原纤维。在发育过程中，肌肉细胞必须增长长度以维持与生长中的骨骼的机械连接。肌肉如何添加新的肌节以促进肌肉生长尚不清楚。利用实时成像和高通量图像分析，我们现在追踪了肌肉发育生长过程中的肌节成分，发现单个肌节沿肌原纤维张力轴分裂为子肌节。通过这种方式，新的肌节可以插入到收缩性和机械完整性良好的肌原纤维中。我们提出，肌节分裂是由骨骼生长和肌肉收缩引起的张力和局部肌节损伤触发的。肌节分裂修复受损的肌节，确保其机械完整性，并在动物发育过程中使肌节添加与骨骼生长同步。
