Fig. 7.

Cell division is required for repositioning of the Myogenin-containing LE-TAD 7. (A) Experimental method used to generate and differentially label nuclei within a chimeric syncytium in which nuclei expressing myomaker are labeled with BrdU. (B) Immunofluorescence images of chimeric myotubes generated through coculture or the cognate monocultures. (C) Schematic showing the relationship between cellular identity and differentiation time for either MyoD- expressing cells or myomaker-expressing cells that fuse into a myotube. (D) Example images of how nuclear identity was scored. (Left) LE-TAD 7 DNA FISH (red) and BrdU (green). (Right) Myosin heavy chain (red) and BrdU (green). The DNA counterstain outline is in white. (E) Normalized distance of LE-TAD 7 to the nuclear perimeter. (F) Normalized LE-TAD 7 interallelic distances. (G) Volume of the convex hull of the DAPI stain in BrdU⁺ versus BrdU⁻ nuclei; n = 35. Significance was assayed by the two-sample t test with unequal variance, except for interallelic distance, in which a one-tailed Wilcoxon rank-sum test was used (*P < 0.05; ***P < 0.0005; ^P < 0.05, one-tailed test). Error bars represent 95% CIs of the mean. n >300 individual alleles and n >150 pairs. Results represent pooling of the raw data from a combination of at least four biological replicates. (Scale bar: 10 μm.)