Figure 1.

A Polymer Model for Lamina-Mediated Chromosome Organization in Different Cell States

(A) A subsection of the nuclear periphery and human chromosome 20 were simulated. Chromatin was modeled as a flexible bead-spring chain, with red beads representing euchromatin (EC) and blue beads representing heterochromatin (HC). The nuclear lamina (NL) was represented as a layer of static beads (gray). Chromatin beads were labeled HC if the corresponding genomic region was enriched in H3K9me3 and/or LaminB1. Beads corresponding to the centromeric region (26.4–29.4 Mb) were also treated as HC. All of the other beads were labeled EC. EC and HC beads can interact with beads of the same kind with interaction strength ${\mathrm{ϵ}}_{\text{EE}}$ and ${\mathrm{ϵ}}_{\text{HH}}$, respectively. HC beads can also interact with the NL beads with interaction strength ${\mathrm{ϵ}}_{\text{HL}}$.

(B) A simulation snapshot of the model when the HC-HC and HC-NL interactions are weak.