Fig. 3.

A speculative model of high-order chromatin structure alterations during senescence. Recent data suggest a ‘modular’ rearrangement of chromatin during senescence—an unwinding of chromatin and a de-condensation of canonical heterochromatin, its spatial reorganization and a refolding of chromatin. (a) It is unknown how general the features of unwinding are (i.e., loss of LADs, TADs etc.) and the extent of these may vary between types of senescence. Here, we illustrate two possible states following refolding (SAHF −ve and +ve), although a spectrum of states is likely. Although we have depicted chromatin as linear in the SAHF −ve state, various higher-order structures may exist