Nuclear movement during myotube formation is microtubule and dynein dependent and is regulated by Cdc42, Par6 and Par3.
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.
UMR S 787 INSERM, Université Pierre et Marie Curie Paris 6, Paris 75634, France.
Bruno
B
Cadot
Vincent
V
Gache
Elena
E
Vasyutina
Sestina
S
Falcone
Carmen
C
Birchmeier
Edgar R
ER
Gomes
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002459:Cell Fusion; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism; D021381:Protein Transport; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; C518597:Par6 protein, mouse; C115084:Pard3 protein, mouse; D004398:Dyneins; D020764:cdc42 GTP-Binding Protein