Data from: A simple biophysical model emulates budding yeast chromosome condensation

Mitotic chromosomes were one of the first cell biological structures to be described, yet their molecular architecture remains poorly understood. We have devised a simple biophysical model of a 300 kb-long nucleosome chain, the size of a budding yeast chromosome, constrained by interactions between binding sites of the chromosomal condensin complex, a key component of interphase and mitotic chromosomes. Comparisons of computational and experimental (4C) interaction maps, and other biophysical features, allow us to predict a mode of condensin action. Stochastic condensin-mediated pairwise interactions along the nucleosome chain generate native-like chromosome features and recapitulate chromosome compaction and individualization during mitotic condensation. Higher order interactions between condensin binding sites explain the data less well. Our results suggest that basic assumptions about chromatin behavior go a long way to explain chromosome architecture and are able to generate a molecular model of what the inside of a chromosome is likely to look like.有丝分裂染色体（Mitotic chromosomes）是首批被描述的细胞生物学结构之一，但其分子层面的组装架构至今仍未得到充分解析。本研究构建了一条长度为300千碱基对（kb）的核小体链的简易生物物理模型——该链的尺寸与酿酒酵母单条染色体相当，模型的约束条件来源于染色体凝缩蛋白复合物（condensin complex，细胞间期与有丝分裂染色体的关键组分）的结合位点之间的相互作用。通过对比计算模拟与实验（4C）获得的相互作用图谱及其他生物物理特征，本研究得以预测凝缩蛋白发挥作用的分子模式。核小体链上由凝缩蛋白介导的随机成对相互作用，可生成近乎天然状态的染色体特征，并重现有丝分裂凝缩过程中染色体的压实与个体化过程。凝缩蛋白结合位点之间的高阶相互作用则难以较好地解释本研究的实验数据。本研究结果表明，针对染色质行为的基础假设足以在很大程度上阐释染色体的组装架构，并可构建出染色体内部结构的分子模型。