RAP74 INDUCES PROMOTER CONTACTS BY RNA-POLYMERASE-II UPSTREAM AND DOWNSTREAM OF A DNA BEND CENTERED ON THE TATA BOX

RAP74, the large subunit of transcription factor IIF, associates with a preinitiation complex containing RNA polymerase II (pol II) and othe r general initiation factors. We have mapped the location of RAP74 in close proximity to promoter DNA at similar distances both upstream and downstream of a DNA bend centered on the TATA box. Binding of RAP74 i nduces a conformational change that affects the position of pol II rel ative to that of the DNA. This reorganization of the preinitiation com plex minimally requires the N-terminal region of RAP74 containing both its RAP30-binding domain and another region necessary for accurate tr anscription in vitro. We propose a role for RAP74 in controlling the t opological organization of the pol II preinitiation complex.