Activation by NarL at the Escherichia coli ogt promoter.
Biochem J
; 477(15): 2807-2820, 2020 08 14.
Article
em En
| MEDLINE
| ID: mdl-32662815
ABSTRACT
The Escherichia coli NarX/NarL two-component response-regulator system regulates gene expression in response to nitrate ions and the NarL protein is a global transcription factor, which activates transcript initiation at many target promoters. One such target, the E. coli ogt promoter, which controls the expression of an O6-alkylguanine-DNA-alkyltransferase, is dependent on NarL binding to two DNA targets centred at positions -44.5 and -77.5 upstream from the transcript start. Here, we describe ogt promoter derivatives that can be activated solely by NarL binding either at position -44.5 or position -77.5. We show that NarL can also activate the ogt promoter when located at position -67.5. We present data to argue that NarL-dependent activation of transcript initiation at the ogt promoter results from a direct interaction between NarL and a determinant in the C-terminal domain of the RNA polymerase α subunit. Footprinting experiments show that, at the -44.5 promoter, NarL and the C-terminal domain of the RNA polymerase α subunit bind to opposite faces of promoter DNA, suggesting an unusual mechanism of transcription activation. Our work suggests new organisations for activator-dependent transcription at promoters and future applications for biotechnology.
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MEDLINE
Assunto principal:
Regiões Promotoras Genéticas
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Proteínas de Escherichia coli
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Escherichia coli K12
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Proteínas de Ligação a DNA
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Metiltransferases
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article