Hfq-dependent alterations of the transcriptome profile and effects on quorum sensing in Pseudomonas aeruginosa.

Sonnleitner, Elisabeth; Schuster, Martin; Sorger-Domenigg, Theresa; Greenberg, Everett Peter; Bläsi, Udo

Sonnleitner, Elisabeth; Schuster, Martin; Sorger-Domenigg, Theresa; Greenberg, Everett Peter; Bläsi, Udo.

Afiliación

Sonnleitner E; Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, Campus Vienna Biocenter, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.

Mol Microbiol ; 59(5): 1542-58, 2006 Mar.

Article en En | MEDLINE | ID: mdl-16468994

RESUMEN

The Pseudomonas aeruginosa quorum-sensing (QS) systems, Las and Rhl, control the production of several virulence factors and other proteins, which are important to sustain adverse conditions. A comparative transcriptome analysis of a rpoS (-) and a rpoS(-)hfq( -) strain indicated that the Sm-like RNA-binding protein Hfq affects approximately 5% of the P. aeruginosa O1 transcripts. Among these transcripts 72 were identified to be QS regulated. Expression studies revealed that Hfq does not control the master regulators of the Las system, LasR and LasI. Upon entry into stationary phase, Hfq exerted a moderate stimulatory effect on translation of the rhlR gene and on the qscR gene, encoding a LasR/RhlR homologue. However, Hfq considerably stimulated translation of the rhlI gene, encoding the synthetase of the autoinducer N-Butyryl-homoserine lactone (C4-HSL). Correspondingly, the C4-HSL levels were reduced in a hfq(-) strain. To elucidate the stimulatory effect of Hfq on rhlI expression we asked whether Hfq affects the stability of the regulatory RNAs RsmY and RsmZ, which have been implicated in sequestration of the translational repressor RsmA, which in turn is known to negatively regulate RhlI synthesis. We demonstrate that Hfq binds to and stabilizes the regulatory RNA RsmY, which is further shown to bind to the regulatory protein RsmA. A model for the Hfq regulatory network is presented, wherein an alleviation of the negative effect of RsmA accounts for the observed stimulation of rhlI expression by Hfq. The model is corroborated by the observation that a rsmY(-) mutant mimics the hfq(-) phenotype with regard to rhlI expression.

Asunto(s)

Proteína de Factor 1 del Huésped/metabolismo; Pseudomonas aeruginosa/fisiología; Proteínas Bacterianas/genética; Secuencia de Bases; Proliferación Celular; Proteínas de Unión al ADN/genética; Regulación Bacteriana de la Expresión Génica; Proteína de Factor 1 del Huésped/genética; Datos de Secuencia Molecular; Mutación; Oxidorreductasas actuantes sobre Donantes de Grupos CH-NH2/genética; ARN Citoplasmático Pequeño/genética; Proteínas Recombinantes de Fusión/genética; Proteínas Recombinantes de Fusión/metabolismo; Proteínas Represoras/genética; Transactivadores/genética; Transcripción Genética; beta-Galactosidasa/genética; beta-Galactosidasa/metabolismo

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Pseudomonas aeruginosa / Proteína de Factor 1 del Huésped Tipo de estudio: Prognostic_studies Idioma: En Revista: Mol Microbiol Asunto de la revista: BIOLOGIA MOLECULAR / MICROBIOLOGIA Año: 2006 Tipo del documento: Article País de afiliación: Austria Pais de publicación: Reino Unido

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