New core promoter element in RNA polymerase II-dependent transcription: sequence-specific DNA binding by transcription factor IIB

Abstract

A sequence element located immediately upstream of the TATA element, and having the consensus sequence 5′-G/C-G/C-G/A-C-G-C-C-3′, affects the ability of transcription factor IIB to enter transcription complexes and support transcription initiation. The sequence element is recognized directly by the transcription factor IIB. Recognition involves α-helices 4′ and 5′ of IIB, which comprise a helix–turn–helix DNA-binding motif. These observations establish that transcription initiation involves a fourth core 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.