Promoter-specific repression of fimB expression by the Escherichia coli nucleoid-associated protein H-NS.
J Bacteriol
; 179(21): 6618-25, 1997 Nov.
Article
en En
| MEDLINE
| ID: mdl-9352908
ABSTRACT
The H-NS protein is a major component of the Escherichia coli nucleoid. Mutations in hns, the gene encoding H-NS, have pleiotropic effects on the cell altering both the expression of a variety of unlinked genes and the inversion rate of the DNA element containing the fimA promoter. We investigated the interaction between H-NS and fimB, the gene encoding the bidirectional recombinase that catalyzes fimA promoter flipping. In beta-galactosidase assays, we found that fimB expression increased approximately fivefold in an hns2-tetR insertion mutant. In gel mobility shift assays with purified H-NS, we have also shown that H-NS bound directly and cooperatively to the fimB promoter region with greater affinity than for any other known H-NS-regulated gene. Furthermore, this high-affinity interaction resulted in a promoter-specific inhibition of fimB transcription. The addition of purified H-NS to an in vitro transcription system yielded a fivefold or greater reduction in fimB-specific mRNA production. However, the marked increase in cellular FimB levels in the absence of H-NS was not the primary cause of the mutant rapid inversion phenotype. These results are discussed in regard to both H-NS as a transcriptional repressor of fimB expression and its role in regulating type 1 pilus promoter inversion.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
3_ND
Problema de salud:
3_neglected_diseases
/
3_zoonosis
Asunto principal:
Proteínas Bacterianas
/
Regulación Bacteriana de la Expresión Génica
/
Regiones Promotoras Genéticas
/
Integrasas
/
Proteínas de Escherichia coli
/
Proteínas Fimbrias
/
Proteínas de Unión al ADN
/
ADN Nucleotidiltransferasas
/
Escherichia coli
Tipo de estudio:
Risk_factors_studies
Idioma:
En
Revista:
J Bacteriol
Año:
1997
Tipo del documento:
Article
País de afiliación:
Estados Unidos