UPs and downs in bacterial transcription initiation: The role of the alpha subunit of RNA polymerase in promoter recognition

Abstract

In recent years, it has become clear that promoter recognition by bacterial RNA polymerase involves interactions not only between core promoter elements and the σ subunit, but also between a DNA element upstream of the core promoter and the α subunit. DNA binding by α can increase transcription dramatically. Here we review the current state of our understanding of the α interaction with DNA during basal transcription initiation (i.e. in the absence of proteins other than RNA polymerase) and activated transcription initiation (i.e. when stimulated by transcription factors).