Ralston E, Lu Z, Biscocho N, Soumaka E, Mavroidis M, Prats C, Lømo T, Capetanaki Y, Ploug T
Office of Science and Technology, National Institute of Arthritis, Musculoskeletal and Skin Diseases/NIH, Bethesda, MD 20892, USA.
J Cell Physiol. 2006 Dec;209(3):874-82. doi: 10.1002/jcp.20780.
Skeletal muscle fibers contain hundreds to thousands of nuclei which lie immediately under the plasmalemma and are spaced out along the fiber, except for a small cluster of specialized nuclei at the neuromuscular junction. How the nuclei attain their positions along the fiber is not understood. Here we show that the nuclei are preferentially localized near blood vessels (BV), particularly in slow-twitch, oxidative fibers. Thus, in rat soleus muscle fibers, 81% of the nuclei appear next to BV. Lack of desmin markedly perturbs the distribution of nuclei along the fibers but does not prevent their close association with BV. Consistent with a role for desmin in the spacing of nuclei, we show that denervation affects the organization of desmin filaments as well as the distribution of nuclei. During chronic stimulation of denervated muscles, new BV form, along which muscle nuclei align themselves. We conclude that the positioning of nuclei along muscle fibers is plastic and that BV and desmin intermediate filaments each play a distinct role in the control of this positioning.
骨骼肌纤维含有数百到数千个细胞核，这些细胞核紧邻质膜下方，并沿纤维分布，除了神经肌肉接头处有一小群特化的细胞核。细胞核如何沿纤维到达其位置尚不清楚。在这里，我们表明细胞核优先定位于血管（BV）附近，特别是在慢肌、氧化型纤维中。因此，在大鼠比目鱼肌纤维中，81%的细胞核出现在BV旁边。结蛋白的缺失明显扰乱了细胞核沿纤维的分布，但并不妨碍它们与BV的紧密关联。与结蛋白在细胞核间距中的作用一致，我们表明去神经支配会影响结蛋白丝的组织以及细胞核的分布。在对去神经支配的肌肉进行慢性刺激期间，会形成新的BV，肌细胞核会沿着这些BV排列。我们得出结论，细胞核沿肌纤维的定位是可塑的，并且BV和结蛋白中间丝在控制这种定位中各自发挥着独特的作用。
