Characterization of relA and codY mutants of Listeria monocytogenes: identification of the CodY regulon and its role in virulence.
Mol Microbiol
; 63(5): 1453-67, 2007 Mar.
Article
em En
| MEDLINE
| ID: mdl-17302820
ABSTRACT
Listeria monocytogenes is a Gram-positive intracellular parasite and the causative organism of human listeriosis. In this article we demonstrate that L. monocytogenes encodes a functional member of the CodY family of global regulatory proteins that is responsive to both GTP and branched chain amino acids. By transcript analyses we identified the CodY regulon in L. monocytogenes and demonstrated that it comprises genes involved in amino acid metabolism, nitrogen assimilation as well as genes involved in sugar uptake and incorporation, indicating a role for CodY in L. monocytogenes in both carbon and nitrogen assimilation. A DeltarelA mutation reduced expression of the CodY regulon in early stationary phase and introduction of a DeltacodY mutation into a DeltarelA strain restored virulence. These data indicate that the avirulence of the DeltarelA mutant can in part be explained by the continued repression of the CodY regulon. The phenotypes of DeltarelA and DeltacodY mutants were studied in J774.A1 and Caco-2 cells and the DeltarelA mutation shown to effect intracellular growth. These results provide the first direct evidence that the activity of a CodY-type protein influences pathogenesis and provides new information on the physiological adaptation of L. monocytogenes to post-exponential phase growth and virulence.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
/
Proteínas de Bactérias
/
Regulon
/
Ligases
/
Listeria monocytogenes
/
Mutação
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
/
Female
/
Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article