Signal sensory systems that impact σ⁵⁴ -dependent transcription.
Alternative σ-factors of bacteria bind core RNA polymerase to program the specific promoter selectivity of the holoenzyme. Signal-responsive changes in the availability of different σ-factors redistribute the RNA polymerase among the distinct promoter classes in the genome for appropriate adaptive, developmental and survival responses. The σ(54) -factor is structurally and functionally distinct from all other σ-factors. Consequently, binding of σ(54) to RNA polymerase confers unique features on the cognate holoenzyme, which requires activation by an unusual class of mechano-transcriptional activators, whose activities are highly regulated in response to environmental cues. This review summarizes the current understanding of the mechanisms of transcriptional activation by σ(54) -RNA polymerase and highlights the impact of global regulatory factors on transcriptional efficiency from σ(54) -dependent promoters. These global factors include the DNA-bending proteins IHF and CRP, the nucleotide alarmone ppGpp, and the RNA polymerase-targeting protein DksA.
Department of Molecular Biology, Umeå University, Umeå, Sweden. victoria.shingler@molbiol.umu.se
Victoria
V
Shingler
D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D051877:RNA Polymerase Sigma 54 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54