Fig. 2.

Two proposed mechanisms to change between normal and inverted nuclei. The sphere represents the nucleus membrane, and each quartile represents one model in the normal (right) or inverted (left) conformation. Upper quartiles represent the mechanism modelled by Falk et al., which emphasises the role of specific interaction forces [22]. On the left, heterochromatin (blue) appears in the centre because of its self-attraction, stronger than of euchromatin (green). But heterochromatin moves to the periphery (right) upon attraction to the nuclear membrane mediated by laminar proteins (purple). Bottom quartiles represent the mechanism modelled by Cook and Marenduzzo, which emphasises the role of entropy [13]. Heterochromatin is denser, thicker and stiffer than euchromatin and appears at the centre of the nucleus sphere. But it moves to the periphery when the nuclear volume decreases and the nuclear environment becomes more crowded and dense.