Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois, 61801, USA.
Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India.
Soft Matter. 2023 Feb 15;19(7):1348-1355. doi: 10.1039/d2sm01170k.
A living cell is an active environment where the organization and dynamics of chromatin are affected by different forms of activity. Optical experiments report that loci show subdiffusive dynamics and the chromatin fiber is seen to be coherent over micrometer-scale regions. Using a bead-spring polymer chain with dipolar active forces, we study how the subdiffusive motion of the loci generate large-scale coherent motion of the chromatin. We show that in the presence of extensile (contractile) activity, the dynamics of the loci grows faster (slower) and the spatial correlation length increases (decreases) compared to the case with no dipolar forces. Hence, both the dipolar active forces modify the elasticity of the chain. Interestingly in our model, the dynamics and organization of such dipolar active chains largely differ from the passive chain with renormalized elasticity.
活细胞是一个活跃的环境，其中染色质的组织和动力学受到不同形式的活性的影响。光学实验报告表明，基因座表现出亚扩散动力学，并且在微米尺度区域可以看到染色质纤维具有相干性。使用带有偶极力的珠-弹簧聚合物链，我们研究了基因座的亚扩散运动如何产生染色质的大尺度相干运动。我们表明，在存在伸展（收缩）活性的情况下，与没有偶极力的情况相比，基因座的动力学增长更快（更慢），空间相关长度增加（减小）。因此，偶极力都改变了链的弹性。有趣的是，在我们的模型中，这种偶极力的活性链的动力学和组织与具有重正化弹性的无源链有很大的不同。
