摘要：SummaryCTCF is a predominant insulator protein required for three-dimensional chromatin organization. However, the roles of its insulation of enhancers in a 3D nuclear organization have not been fully explained. Here, we found that the CTCF DNA-binding domain (DBD) forms dynamic self-interacting clusters. Strikingly, CTCF DBD clusters were found to incorporate other insulator proteins but are not coenriched with transcriptional activators in the nucleus. This property is not observed in other domains of CTCF or the DBDs of other transcription factors. Moreover, endogenous CTCF shows a phenotype consistent with the DBD by forming small protein clusters and interacting with CTCF motif arrays that have fewer transcriptional activators bound. Our results reveal an interesting phenomenon in which CTCF DBD interacts with insulator proteins and selectively localizes to nuclear positions with lower concentrations of transcriptional activators, providing insights into the insulation function of CTCF.Graphical abstractDisplay OmittedHighlights•The CTCF DNA-binding domain forms protein clustersin vivoandin vitro•CTCF DBD clusters colocalize with insulator proteins but not with activators•Arginine residues of CTCF DBD are frequently mutated in cancers•Multiple transcription factor DBDs form protein clustersBiological sciences; Molecular biology; Molecular interaction
