Initiation of transcription at the bacterial glnAp2 promoter by purified E. coli components is facilitated by enhancers.
The initiation of transcription from the nitrogen-regulated promoter glnAp2 requires RNA polymerase containing sigma 54, the transcriptional activator NRI, and the protein kinase NRII, responsible for the conversion of NRI to the active NRI-phosphate. NRI-phosphate does not increase the ability of sigma 54-containing RNA polymerase to bind to the promoter, but rather stimulates the conversion of an initial promoter:polymerase complex to the transcriptionally active open complex. The presence on the DNA template of high-affinity binding sites for NRI/NRI-phosphate, normally located 130 and 100 bp upstream of the site of transcription initiation, results in a 4- to 5-fold lowering of the concentration of NRI required for the formation of the open complex. These high-affinity NRI binding sites facilitate open complex formation when they are moved to positions 700 bp further upstream or 950 bp downstream of glnAp2 on linear DNA templates.
Ninfa
A J
AJ
Reitzer
L J
LJ
Magasanik
B
B
D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000032:analysis / Q000235:genetics*; D005809:Genes, Regulator; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D012318:RNA Polymerase I / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D014157:Transcription Factors; D011494:Protein Kinases; D012318:RNA Polymerase I