An unusual feature associated with LEE1 P1 promoters in enteropathogenic Escherichia coli (EPEC).
Transcription start points in bacteria are influenced by the nature of the RNA polymerase·promoter interaction. For Escherichia coli RNA polymerase holoenzyme containing σ70, it is presumed that specific sequence in one or more of the -10, extended -10 and -35 elements of the promoter guides the RNAP to select the cognate start point. Here, we investigated the promoter driving expression of the LEE1 operon in enteropathogenic E. coli and found two promoters separated by 10 bp, LEE1 P1A (+1) and LEE1 P1B (+10) using various in vitro biochemical tools. A unique feature of P1B was the presence of multiple transcription starts from five neighbouring As at the initial transcribed region. The multiple products did not arise from stuttering synthesis. Analytical software based on information theory was employed to determine promoter elements. The concentration of the NTP pool altered the preferred transcription start points, albeit the underlying mechanism is elusive. Under in vivo conditions, dominant P1B, but not P1A, was subject to regulation by IHF.
Center for Host Defense against Enteropathogenic Bacteria Infection, Department of Microbiology, Chonnam National University Medical School, Kwangju, South Korea.
Jae-Ho
JH
Jeong
Hyun-Ju
HJ
Kim
Kun-Hee
KH
Kim
Minsang
M
Shin
Yeongjin
Y
Hong
Joon Haeng
JH
Rhee
Thomas D
TD
Schneider
Hyon E
HE
Choy
D001483:Base Sequence; D054308:Enteropathogenic Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000235:genetics*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; C465556:Ler protein, E coli; D015534:Trans-Activators