An Intrinsic Disordered Region Mediated Confinement State Contributes to Dynamics and Function of Transcription Factors

In this study we used single-molecule tracking and machine-learning based classification to directly measure the nuclear mobility of the glucocorticoid receptor (GR) in live cells. We revealed two distinct and dynamic sub-diffusive populations. One accounts for specific binding to chromatin, while the other represents a confinement state that requires an intrinsically disordered region (IDR), consistent with liquid-liquid condensate subdomains. Further analysis showed that the dwell times of both subpopulations follow a power-law distribution, consistent with a broad distribution of affinities on the GR cistrome and interactome. Altogether, our data link IDRs with a confinement state that is functionally distinct from specific chromatin binding and modulates the transcriptional output by increasing the local concentration of TFs at specific sites. Overall design: Genome-wide occupancy profiling of GR ChIP-seq from mouse mammary adenocarcinoma cell lines (3617) knock-out of endogenous GR (3617-KOGR) and stably integrated with GFP-tagged GR mutants, in biological duplicates, using Illumina NextSeq 500. GRwt binding data from the 3617-KOGR cells was used as comparison standard for GR (GSE108634).