What is the function of enhancers in transcription regulation?

• A. They act as promoters for RNA polymerase
• B. They bind repressors to silence transcription
• C. They are DNA sequences that bind transcription activators to increase transcription
• D. They code for transcription factors

Answer: (C)

Enhancers are DNA sequences that bind transcription activators to increase transcription. By bringing these activators near the promoter—often through DNA looping—the transcriptional machinery and coactivators are more effectively recruited to initiate and boost RNA polymerase II activity. This boost can happen even when the enhancer is located far away from the promoter or in a different orientation, and it often depends on the cell type or signaling context because different activators are present in different conditions.

This helps distinguish enhancers from promoters, which are the sites where RNA polymerase II assembles to start transcription, and from silencers, which recruit repressors to decrease transcription. Enhancers also don’t code for transcription factors themselves; they are regulatory DNA sequences that control when and how much a gene is transcribed.