[Campbell Biology P.423] A particular enhancer is located 50,000 nucleotides upstream from i... | Practice Question

A particular enhancer is located 50,000 nucleotides upstream from its associated gene's promoter. Based on the provided text, what is the most direct mechanism by which this distant enhancer, when bound by activators, is able to influence the gene's transcription?

  • A: The activators bound to the enhancer directly recruit RNA polymerase II to the distant promoter.
  • B: The enhancer region, with bound activators, physically moves along the DNA until it reaches the promoter.
  • C: Protein-mediated DNA bending brings the enhancer-bound activators into contact with mediator proteins and general transcription factors at the promoter.
  • D: The activators bound to the enhancer release signaling molecules that diffuse to the promoter and activate transcription.

Explanation

The text explicitly states: "Protein-mediated bending of the DNA brings the bound activators into contact with a group of mediator proteins, which in turn interact with general transcription factors at the promoter. These protein-protein interactions help assemble and position the initiation complex on the promoter."