NEW CORE PROMOTER ELEMENT IN RNA-POLYMERASE II-DEPENDENT TRANSCRIPTION - SEQUENCE-SPECIFIC DNA-BINDING BY TRANSCRIPTION FACTOR IIB

A sequence element located immediately upstream of the TATA element, a nd having the consensus sequence 5'-G/C-G/C-G/A-C-G-C-C-3', affects th e ability of transcription factor IIB to enter transcription complexes and support transcription initiation. The sequence element is recogni zed directly by the transcription factor IIB, Recognition involves alp ha-helices 4' and 5' of IIB, which comprise a helix-turn-helix DNA-bin ding motif. These observations establish that transcription initiation involves a fourth tore promoter element, the IIB recognition element (BRE), in addition to the TATA element, the initiator element, and the downstream promoter element, and involves a second sequence-specific general transcription factor, IIB, in addition to transcription factor IID.