Figure 13. Regulation of transcription in eukaryotes.

(A) When a gene is in a silent state the surrounding DNA will be in condensed chromatin and the histones will epigenetic modifications which facilitate gene repression (red spheres). (B) A gene that is being transcribed will have activators bound to enhancer sequences, the activators recruit co-activators that acetylate the histone and add other epigenetic modifications that facilitate gene transcription (green spheres). The activator and co-activators will recruit RNA Polymerase and the GTFs to the core promoter.