Motorized Chromosome Models of Mitosis
arXiv:2501.09873 · doi:10.1038/s41467-025-66025-y
Abstract
During mitosis, near-spherical chromosomes reconfigure into rod-like structures to ensure their accurate segregation to daughter cells. We explore here, the interplay between the nonequilibrium activity of molecular motors in determining the chromosomal organization in mitosis and its characteristic symmetry-breaking events. We present a hybrid motorized chromosome model that highlights the distinct roles of condensin I and II in shaping mitotic chromosomes. Guided by experimental observations, the simulations suggest that condensin II facilitates large-scale scaffold formation, while condensin I is paramount in local helical loop arrangement. Together, these two distinct grappling motors establish the hierarchical helical structure characteristic of mitotic chromosomes, which exhibit striking local and, sometimes global, chirality and contribute to the robust mechanical properties of mitotic chromosomes. Accompanying the emergence of rigidity, the model provides mechanisms of forming defects, including perversions and entanglements, and shows how these may be partially resolved through condensin activity and topoisomerase action. This framework bridges coarse-grained energy landscape models of chromosome dynamics and non-equilibrium molecular dynamics, advancing the understanding of chromosome organization during cell division and beyond.
45 pages, 6 figures
References in corpus (16)
- Stochastic thermodynamics, fluctuation theorems, and molecular machines
- FreeSASA: An open source C library for solvent accessible surface area calculations
- From a melt of rings to chromosome territories: The role of topological constraints in genome folding
- Broken detailed balance and non-equilibrium dynamics in living systems
- The effective temperature
- Phase diagram of glassy systems in an external field
- Statistical mechanics of a correlated energy landscape model for protein folding funnels
- Anomalous diffusion in fractal globules
- Active contractility in actomyosin networks
- Shape Transitions and Chiral Symmetry Breaking in the Energy Landscape of the Mitotic Chromosome
- Synergy of Topoisomerase and Structural-Maintenance-of-Chromosomes Proteins Creates a Universal Pathway to Simplify Genome Topology
- On the spontaneous collective motion of active matter
- Topological and non-topological mechanisms of loops formation in chromosomes: effects on the contact probability
- Fluidification of Entangled Polymers by Loop Extrusion
- Delayed excitations induce polymer looping and coherent motion
- Fractal and knot-free chromosomes facilitate nucleoplasmic transport