Question

In Eukaryotic transcription, what is the difference between an enhancer, a mediator, a coactivator and a trascriptional activator protein? In your answer, for each one include (a) if it's the term refers to a DNA sequence or a protein, and if it's a protein (b) if it interacts with DNA, with another protein, or with both. Also how are enhancers different from promoters in affecting gene transcription in eukaryotes? Make sure that you include in your discussion: (c) their relative position to the transcription initiation site; (d) the role of binding sites for proteins; (e) how each affects initiation and transcriptional regulation (in the latter, make a distinction between the core and the regulatory promoter