Underproduction of sigma 70 mimics a stringent response. A proteome approach.
J Biol Chem
; 278(2): 968-73, 2003 Jan 10.
Article
en En
| MEDLINE
| ID: mdl-12421813
When Escherichia coli cells enter stationary phase due to carbon starvation the synthesis of ribosomal proteins is rapidly repressed. In a DeltarelA DeltaspoT mutant, defective in the production of the alarmone guanosine tetraphosphate (ppGpp), this regulation of the levels of the protein synthesizing system is abolished. Using a proteomic approach we demonstrate that the production of the vast majority of detected E. coli proteins are decontrolled during carbon starvation in the DeltarelA DeltaspoT strain and that the starved cells behave as if they were growing exponentially. In addition we show that the inhibition of ribosome synthesis by the stringent response can be qualitatively mimicked by artificially lowering the levels of the housekeeping sigma factor, sigma(70). In other words, genes encoding the protein-synthesizing system are especially sensitive to reduced availability of sigma(70) programmed RNA polymerase. This effect is not dependent on ppGpp since lowering the levels of sigma(70) gives a similar but less pronounced effect in a ppGpp(0) strain. The data is discussed in view of the models advocating for a passive control of gene expression during stringency based on alterations in RNA polymerase availability.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Factor sigma
/
ARN Polimerasas Dirigidas por ADN
/
Proteoma
/
Escherichia coli
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Biol Chem
Año:
2003
Tipo del documento:
Article
País de afiliación:
Suecia
Pais de publicación:
Estados Unidos