  During the eukaryotic cell cycle, chromatin undergoes several conformational
changes, which are believed to play key roles in gene expression regulation
during interphase, and in genome replication and division during mitosis. In
this paper, we propose a scenario for chromatin structural reorganization
during mitosis, which bridges all the different scales involved in chromatin
architecture, from nucleosomes to chromatin loops. We build a model for
chromatin, based on available data, taking into account both physical and
topological constraints DNA has to deal with. Our results suggest that the
mitotic chromosome condensation/decondensation process is induced by a
structural change at the level of the nucleosome itself.
