Acid stress response in Escherichia coli: mechanism of regulation of gadA transcription by RcsB and GadE.
Nucleic Acids Res
; 38(11): 3546-54, 2010 Jun.
Article
em En
| MEDLINE
| ID: mdl-20189963
ABSTRACT
Escherichia coli can survive extreme acid stress for several hours. The most efficient acid resistance system is based on glutamate decarboxylation by the GadA and GadB decarboxylases and the import of glutamate via the GadC membrane protein. The expression of the corresponding genes is controlled by GadE, the central activator of glutamate-dependent acid resistance (GDAR). We have previously shown by genetic approaches that as well as GadE, the response regulator of the Rcs system, RcsB is absolutely required for control of gadA/BC transcription. In the presence of GadE, basal activity of RcsB stimulates the expression of gadA/BC, whereas activation of RcsB leads to general repression of the gad genes. We report here the results of various in vitro assays that show RcsB to regulate by direct binding to the gadA promoter region. Furthermore, activation of gadA transcription requires a GAD box and binding of an RcsB/GadE heterodimer. In addition, we have identified an RcsB box, which lies just upstream of the -10 element of gadA promoter and is involved in repression of this operon.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
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Regulação Bacteriana da Expressão Gênica
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Proteínas de Escherichia coli
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Escherichia coli
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Glutamato Descarboxilase
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Proteínas de Membrana
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article