Fig. 2. A four-step model for how TAF_II250 contributes to transcriptional activation. In each step, the panel on the left depicts the general event and the panel on the right depicts the specific contribution of TAF_II250 to the event. Activators are denoted by a red circle labeled A; TFIIA is denoted by a green oval labeled A; TFIIE is denoted by a green circle labeled E; TFIIF is denoted by a blue circle labeled F; histones are labeled H1, H2A, H2B, H3 or H4; and TFIID is denoted by a collection of objects labeled 250, 150 and TBP. The balance of the general transcription machinery, which is not specifically identified, is indicated by a collection of objects labeled GTM.