An anti-repression Fur operator upstream of the promoter is required for iron-mediated transcriptional autoregulation in Helicobacter pylori.
Mol Microbiol
; 50(4): 1329-38, 2003 Nov.
Article
em En
| MEDLINE
| ID: mdl-14622419
ABSTRACT
The Fur protein acts as a regulator of iron-dependent gene transcription in bacteria. In Helicobacter pylori, Fur regulates iron-activated and iron-repressed promoters. It also acts as an autoregulatory rheostat of transcription to fine-tune its own expression in response to iron by binding to three operators at its own promoter Pfur. Using biochemical and genetic analyses, here we show that the distal upstream operator III (centred at -110) is essential for iron regulation of Pfur and functions as an anti-repression site that is bound by the iron-free form of Fur to induce transcription. Furthermore, operator I (centred at -50) may have a dual role both as a high-affinity binding site for Fur and as an UP element. We propose that its role is ensuring that Fur expression is not repressed below a minimum threshold level. Our data supports a novel promoter architecture and mechanism of regulation by Fur.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
/
Proteínas de Bactérias
/
Transcrição Gênica
/
Regulação Bacteriana da Expressão Gênica
/
Helicobacter pylori
/
Regiões Operadoras Genéticas
/
Ferro
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Mol Microbiol
Ano de publicação:
2003
Tipo de documento:
Article