Nonequilibrium Physics of Living Matter RIKEN Hakubi Research Team, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program, 2-1 Hirosawa, Wako 351-0198, Japan.
Phys Rev E. 2019 Dec;100(6-1):060401. doi: 10.1103/PhysRevE.100.060401.
We investigate the phase transition properties of the polymer-Potts model, a chain composed of monomers with magnetic degrees of freedom, with the motivation to study the conformation and mark switching dynamics of chromatin. By the mean-field approximation, we find that the phase transition between the swollen-disordered state and the compact-ordered state is discrete; it is first order as in the long-range Potts model, but with a significantly larger jump in magnetization (i.e., mark coherence) upon the ordering transition. The results imply how small changes in epigenetic writer concentrations can lead to a macroscopic switching of the chromatin state, suggesting a simple mechanism of discrete switching observed, for instance, in cell differentiation.
我们研究了聚合物-Potts 模型的相变特性，该模型由具有磁自由度的单体组成，旨在研究染色质的构象和标记转换动力学。通过平均场近似，我们发现肿胀无序态和紧凑有序态之间的相变是离散的；它与长程 Potts 模型一样是一级相变，但在有序相变时磁化强度（即标记相干性）的跃变量显著更大。这些结果表明，表观遗传写入器浓度的微小变化如何导致染色质状态的宏观转变，这表明了一种简单的离散转换机制，例如在细胞分化中观察到的机制。
