Open AccessSignal sensory systems that impact σ 54 ‐dependent transcription
Author(s) -
Shingler Victoria
Publication year - 2011
Publication title -
fems microbiology reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.91
H-Index - 212
eISSN - 1574-6976
pISSN - 0168-6445
DOI - 10.1111/j.1574-6976.2010.00255.x
Subject(s) - biology , rna polymerase , sigma factor , polymerase , rna polymerase ii holoenzyme , transcription factor ii d , transcription (linguistics) , rna polymerase ii , rna polymerase i , genetics , promoter , rna , rna polymerase iii , microbiology and biotechnology , dna , gene , gene expression , linguistics , philosophy
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.