Proteins that bind to enhancers, or regulatory regions of DNA, that speed transcription dramatically, are called ___________.

• A. RNA polymerases
• B. Transcription factors
• C. Transcription activators
• D. Nucleases

Answer: (C)

Enhancers are DNA elements that boost gene transcription when bound by specific proteins. The proteins that bind to enhancers and dramatically accelerate transcription are transcription activators. They have a DNA-binding domain to recognize the enhancer sequence and an activation domain that recruits coactivators and the transcription machinery, often by looping the DNA so the enhancer can interact with the promoter. This recruitment of RNA polymerase II and other factors increases transcription levels far above baseline. While transcription factors is a broad term that includes activators and repressors, the ones that specifically enhance transcription via enhancers are the activators.