Organisation of complex Escherichia coli promoters

Promoters are locations on a chromosome that are responsible for the recruitment of RNA polymerase to different transcription units. This recruitment is tightly regulated and this chapter discusses how this regulation is effected at the molecular level in Escherichia coli. Transcription factors play a major role in this regulation and the different mechanisms by which they control transcription initiation at simple and complex promoters are outlined. At some promoters, the actions of transcription factors are modulated by nucleoid associated proteins. Two examples where this occurs, the regulatory regions of the Escherichia coli nir and dps genes, are described in detail.