Mediator and Cohesin

Cited from the paper The selection and function of cell type-specific enhancers

Through looping of the intervening DNA, enhancers are brought into close proximity of promoters and are thought to affect any or all of the aforementioned processes by increasing the local concentrations of the factors involved. These factors include co-activator complexes such as the Mediator complex, which increases the loading of transcription factors onto promoters and enhancers; scaffold proteins, such as cohesin, that mediate stable and often cell type-specific promoter–enhancer interactions; and factors that are involved in releasing paused Pol II and in the initiation of elongation, such as BRD4.

Cohesin and the Mediator complex are scaffold proteins of the replication machinery and the transcription machinery, respectively.

Cohesin seems to be recruited to enhancers through clusters of lineage-determining transcription factors (LDTFs).