  The contributions of active deformation dynamics in cell nuclei to the
intra-nuclear positioning of hetero- and euchromatin are investigated. We
analyzed the behaviors of model chains containing two types of regions, one
with high and the other with low mobility, confined in a pulsating container.
Here, the regions with high and low mobility represent eu- and heterochromatic
regions, respectively, and the pulsating container simulates a nucleus
exhibiting dynamic deformations. The Brownian dynamics simulations of this
model show that the positioning of low mobility regions transition from sites
near the periphery to the central region of the container if the affinity
between low mobility regions and the container periphery disappears. Here, the
former and latter positioning are similar to the "conventional" and "inverted"
chromatin positioning observed in nuclei of normal differentiated cells and
cells lacking Lamin-related proteins like mouse rod photoreceptor cell.
