Abstract

Phase separated domains (PSDs) are ubiquitous in cell biology, representing nanoregions of high molecular concentration. PSDs appear at diverse cellular domains, such as neuronal synapses but also in eukaryotic cell nucleus, limiting the access of transcription factors and thus preventing gene expression. We will present here some properties of PSDs derived from polymer models. Increasing the number of cross-linkers generate a polymer condensation, preventing the access of diffusing molecules. To investigate how the PSDs restrict the motion of diffusing molecules, we estimate the mean residence and first escaping times. Finally, by computing the mean square displacement of single particle trajectories, we can reconstruct the properties of PSDs in term of a continuum range of anomalous exponents. To conclude, PSDs can result from a condensed chromatin, where the number of cross-linkers control the molecular access.