Figure 6. H3K9me2-enriched LADs are positioned at the nuclear lamina in interphase cells and the position is inherited through mitosis.

(A) Localization of LADs and non-LADs in interphase mouse embryonic stem cells (mESCs). Left panels show representative immuno-FISH images (top) and 3D image reconstructions (bottom) of cells hybridized with fluorescent DNA oligopaint probes targeting individual LADs (red) and non-LADs (green), and immunostained for Lamin B1 (cyan) and DAPI (blue). Scale bar: 5 μm. Dot plots show distribution of distances to the nuclear periphery (as defined by Lamin B1) of individual LAD and non-LAD probes for individual cells (middle) and cumulative over all cells (right) in interphase. (B) As in panel A for prometaphase-metaphase-anaphase cells. (C) As in panel A for telophase cells. For dot plots, nuclear periphery defined by Lamin B1 or DNA edge; black line: median value; cyan boxes indicate average thickness of H3K9me2 peripheral heterochromatin layer. Box plots display 5, 25, 50, 75 and 95 percentiles. n ≥ 20 individual nuclei; N = 870–1399 individual LADs or non-LADs per condition. Statistical analysis performed using two-tailed t-test; ****p<0.0001; ns: not significant.

Figure 6—figure supplement 1. Location of the oligopaint DNA probes targeting LADs and non-LADs on mouse chromosomes.

Displayed are H3K9me2 and LaminB ChIP-seq tracks from mESCs with each region of 41 ‘LADs’ (enriched for H3K9me2 and Lamin B signal) shown as a red bar above tracks and each region of 41 ‘non-LADs’ (depleted for H3K9me2 and Lamin B) shown as a green bar; probes for each region span 250 kb of the mouse genome (mm9).

Figure 6—figure supplement 2. Localization of LADs and non-LADs in interphase and mitotic mESCs.

Representative 3D reconstructions of interphase and mitotic cells illustrate localization of LAD and non-LAD oligopaint probes. Pericentromeric heterochromatin/chromocenters localize centrally during mitosis and thus both LADs and non-LADs are distributed in the chromosome arms.