Centromeres reposition to the nuclear periphery during L6E9 myogenesis in vitro.

To test the hypothesis that genome architecture in interphase is related to nuclear function, we have compared the disposition of centromeres in nuclei of undifferentiated rat L6E9 myoblasts with that in nuclei of L6E9 myotubes differentiated in vitro. Immunofluorescence labeling showed that centromeres repositioned to the nuclear periphery during differentiation, and condensed chromatin was more prominent at the myotube nuclear envelope by electron microscopy. These data indicate that, in parallel with considerable changes in gene expression, the spatial order of the genome undergoes substantial rearrangement during myogenesis.