Figure 1: Schematic model of transcriptional regulation by cofactors IN ESCs.
(A) Transcriptional activation by coactivators, cohesin and mediators. Coactivators p300/CBP complex, Tip60-p400, SCC, YAP, FACT may recruit chromatin remodelers and histone modifiers to open up the chromatin structure. Mediators and cohesin facilitate DNA loop formation to bring the Distal Enhancer (DE) to proximity of the promoter, and the Pre-initiation Complex (PIC) is assembled to initiate transcription.
(B) Transcriptional repression by corepressors and condensin. Condensin is required for proper chromatin conformation and epigenetic modifications in ES cells. Cohesin can stabilize the DNA loop formed by the insulator CTCF to avoid interactions between the DE and promoter. Corepressors CCR4-Not, Sin3a, NuRD, Trim28 can recruit HDACs to condensed chromatin and prevent transcription factors from binding to genomic DNA. The RNA polymerase II activity will be suppressed. A B Pluripotency and self-renewal gene Condensin PIC Mediator SCC Tip60- p400 p300 /CBP DE TF FACT Cohesin YAP Cohesin Developmental genes DE CTCF CCR4-Not Trim 28 Sin 3a NuRD CTCF Pol