UMR S 787 INSERM, Université Pierre et Marie Curie Paris 6, Paris 75634, France.
EMBO Rep. 2012 Aug;13(8):741-9. doi: 10.1038/embor.2012.89. Epub 2012 Jun 26.
Cells actively position their nucleus within the cytoplasm. One striking example is observed during skeletal myogenesis. Differentiated myoblasts fuse to form a multinucleated myotube with nuclei positioned in the centre of the syncytium by an unknown mechanism. Here, we describe that the nucleus of a myoblast moves rapidly after fusion towards the central myotube nuclei. This movement is driven by microtubules and dynein/dynactin complex, and requires Cdc42, Par6 and Par3. We found that Par6β and dynactin accumulate at the nuclear envelope of differentiated myoblasts and myotubes, and this accumulation is dependent on Par6 and Par3 proteins but not on microtubules. These results suggest a mechanism where nuclear movement after fusion is driven by microtubules that emanate from one nucleus that are pulled by dynein/dynactin complex anchored to the nuclear envelope of another nucleus.
细胞在细胞质中主动定位其细胞核。在骨骼肌发生过程中可以观察到一个显著的例子。分化的成肌细胞融合形成多核肌管，细胞核通过未知的机制定位于合胞体的中心。在这里，我们描述了成肌细胞的细胞核在融合后迅速向中心肌管细胞核移动。这种运动是由微管和动力蛋白/动力蛋白复合物驱动的，需要 Cdc42、Par6 和 Par3。我们发现 Par6β 和动力蛋白复合物在分化的成肌细胞和肌管的核膜上积累，这种积累依赖于 Par6 和 Par3 蛋白，但不依赖于微管。这些结果表明，融合后核运动的机制是由从一个细胞核发出的微管驱动的，这些微管被锚定在另一个细胞核的核膜上的动力蛋白/动力蛋白复合物拉动。
