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BP: Fachverband Biologische Physik

BP 39: The Collapsed State of Polymers: From Physical Concepts to Applications and Biological Systems (accompanying session, joint CPP/BP/DY)

BP 39.5: Invited Talk

Thursday, April 3, 2014, 16:00–16:30, ZEU 250

Universal aspects of chromosome folding — •Angelo Rosa — Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste (Italy)

The dynamics of the mm-long chromatin (i.e, DNA+histones) fibers in the cell nucleus is subject to strong topological constraints [Sikorav & Jannink (1994)]. In particular, their incomplete equilibration during interphase [Rosa & Everaers (2008)] results in territorial, crumpled globule-like chromosome conformations [Grosberg et al. (1993)].

It has been suggested [Rosa & Everaers, ibid.; Vettorel et al. (2009)], that this incomplete relaxation might underlie a subtle analogy between interphase chromosomes and corresponding solutions of non-concatenated ring polymers. Here, we start from our recent multi-scale computational approach for explicit construction of equilibrated solutions of giant ring polymers [Rosa & Everaers (2013); see talk by R. Everaers] to further explore the physical and biological consequences of this analogy.

We show that not only the territorial confinement [Cremer & Cremer (2001)] but also other characteristic features of chromosome folding such as their conformational statistics [Sachs et al. (1995); Lieberman-Aiden et al. (2009)] and the loop-on-loop structure of internal contacts [Cook (2010)] arise as a generic consequence of the polymeric nature of chromosomes. Integrated with biological information on intra- and inter-chromosomal interactions, our results pave the way for the systematic modeling of the nuclear structure and dynamics.