Schematic representation of functional interactions that modulate basal (upper) and activator-dependent (lower) transcription. The basal transcription factors (TBP, TFIIA, TFIIB, TFIIF, TFIIE), TFIIH, and pol II are donoted by solid symbols, with the general factor contents of a possible holoenzyme enclosed by square brackets. TAFII and non-TAFII coactivators (open symbols) and transcriptional activators (shaded symbols) are shown interacting with their targets in the PIC (Pre-Initiation Complex).