How do enhancers communicate with promoters if they are located far away?

How do enhancers communicate with promoters if they are located far away?

• A. Enhancers communicate with promoters via direct binding of RNA polymerase II at the enhancer DNA.
• B. Enhancers are promoters themselves.
• C. Enhancers communicate with promoters via chromatin looping that brings bound factors into proximity with the promoter.
• D. Enhancers regulate transcription by looping text but not bound to promoter.

Answer: (C)

Enhancers regulate transcription by forming chromatin loops that bring enhancer-bound transcription factors and coactivators into close proximity with the promoter and its transcription machinery. Even when the enhancer is far away along the linear sequence, the DNA folds in three dimensions so the enhancer and promoter are juxtaposed. This looping, often stabilized by proteins like Mediator and cohesin, allows signals assembled at the enhancer to influence the promoter and boost transcription. Direct binding of RNA polymerase II at the enhancer isn’t the usual mechanism, and enhancers are not promoters themselves; they act from a distance by looping to the promoter to communicate regulatory information.

Enhancers regulate transcription by forming chromatin loops that bring enhancer-bound transcription factors and coactivators into close proximity with the promoter and its transcription machinery. Even when the enhancer is far away along the linear sequence, the DNA folds in three dimensions so the enhancer and promoter are juxtaposed. This looping, often stabilized by proteins like Mediator and cohesin, allows signals assembled at the enhancer to influence the promoter and boost transcription. Direct binding of RNA polymerase II at the enhancer isn’t the usual mechanism, and enhancers are not promoters themselves; they act from a distance by looping to the promoter to communicate regulatory information.