FIGURE 1.

Chromatin organization and topological domains. Chromosomes occupy distinct territories in the nucleus (shaded with different colors). Long-range chromatin looping, at the sub-megabase level, partitions the chromosomal region into Topologically Associating Domains (TADs; individuals illustrated on the rights. The TADs remain largely unchanged in differentiated cells and stem cells. However, at a finer levH pluripotency factors and chromatin architectural proteins organize higher-order chromatin connectivity during reprogramming. Pluripotency factors co-localize and occupy distinct spatial regions from PcG proteins in stem cells. Such chromatin reorganization induced by pluripotency factors is important for cell-specific gene expression.