Figure 1.

Phase separation (PS) is a switch-like process mediating the formation of the gene-enhancer interaction. (A) The formation of a phase-separated cluster can mediate the contact between a gene and its enhancer. (B) The fraction of binders N_b/N_tot in the phase-separated cluster as a function of the binding affinity E_b-b among the binders at equilibrium. The concentration c is ∼1.1%. The transition occurs between 2.7 and 3.0 K_BT. (C) The fraction of binders in the cluster as a function of the binder concentration c. The binding affinity is E_b-b = 3.0 K_BT. At the transition point c ∼0.7%, in some cases, the phase-separated cluster could not form within the time window considered. (D) The horizontal red (or blue) bar shows the fraction of binders belonging (or not belonging) to the cluster for different binding affinities E_b-b (y axis) at high concentration (c is ∼1.9%). (E) A three-dimensional phase-diagram of the system. On the z axis, the fraction of times in which the system exhibited the phase transition for a fixed parameter configuration is reported. For all panels, interaction with bs E_b-bs is 3.1 K_BT. Similar results are obtained in the absence of polymer. To see this figure in color, go online.