Modulation of RNA polymerase core functions by basal transcription factor TFB/TFIIB

摘要

The archaeal basal transcriptional machinery consists of TBP (TATA-binding protein),TFB (transcription factor B;a homologue of eukaryotic TFIIB) and an RNA polymerase that is structurally very similar to eukaryotic RNA polymerase II.This constellation of factors is sufficient to assemble specifically on a TATA box-containing promoter and to initiate transcription at a specific start site.We have used this system to study the functional interaction between basal transcription factors and RNA polymerase,with special emphasis on the post-recruitment function of TFB.A bioinformatics analysis of the B-finger of archaeal TFB and eukaryotic TFIIB reveals that this structure undergoes rapid and apparently systematic evolution in archaeal and eukaryotic evolutionary domains.We provide a detailed analysis of these changes and discuss their possible functional implications.