Figure 4:

Emerging PIC assembly model. A) In a recent study, Baek et al. performed three-color CoSMoS experiments using mammalian cell extracts to following the association of RNAP II and general transcription factors TFIIF, TFIIE, or TFIIH with a DNA promoter template (87). B) The data support an emerging model whereby RNAP II associated with TFIIF and/or TFIIE binds primarily at the enhancer (UAS) through UAS bound transcription activators. From there, partially assembled PIC can be transferred to the core promoter for binding with TFIIH and additional GTFs for complete PIC assembly, in a branched assembly pathway.