The general transcription factor TFIIB (transcription factor IIB) plays a critical role in the assembly of the RNA polymerase II pre-initiation complex. TFIIB can make sequence-specific DNA contacts both upstream and downstream of the TATA box. This has led to the definition of two core promoter BREs (TFIIB-recognition elements), one upstream [BREu (upstream BRE)] and one downstream of TATA box [BREd (downstream BRE)]. TFIIB–BREu and TFIIB–BREd contacts are mediated by two independent DNA-recognition motifs within the core domain of TFIIB. Both the BREu and the BREd modulate the transcriptional potency of a promoter. However, the net effect of the BREs on promoter activity is dependent on the specific blend of elements present within a core promoter.

You do not currently have access to this content.