転写制御における密度遷移

Transcription of the right genes at the right time is crucial for physiology and often dysregulated in disease. For a process that requires precise outcomes, the underlying molecular interactions regulating transcription can be surprisingly dynamic and short-lived. Various sources of multivalency have been proposed to stabilize short-lived interactions at specific genomic loci. Through multivalent contacts, components of the transcription machinery form complexes and, above-threshold concentrations, can form condensates by undergoing reversible density transitions (i.e., phase separation). Importantly, coupling the density transition to networking generates a condensate-spanning network with emergent properties that soluble complexes do not possess, including enhanced dwell times of relevant components, distinct chemical environments, capillary forces, and biochemically active interfaces. Here, we will review the current evidence for and against the role of density transitions in regulating transcription, discuss best practices for studying the functional roles of these phenomena, and consider how emergent properties may regulate transcription.