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KynR, a Lrp/AsnC-type transcriptional regulator, directly controls the kynurenine pathway in Pseudomonas aeruginosa.
Knoten, Claire A; Hudson, L Lynn; Coleman, James P; Farrow, John M; Pesci, Everett C.
Afiliação
  • Knoten CA; Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, 600 Moye Blvd., Greenville, NC 27834, USA.
J Bacteriol ; 193(23): 6567-75, 2011 Dec.
Article em En | MEDLINE | ID: mdl-21965577
ABSTRACT
The opportunistic pathogen Pseudomonas aeruginosa can utilize a variety of carbon sources and produces many secondary metabolites to help survive harsh environments. P. aeruginosa is part of a small group of bacteria that use the kynurenine pathway to catabolize tryptophan. Through the kynurenine pathway, tryptophan is broken down into anthranilate, which is further degraded into tricarboxylic acid cycle intermediates or utilized to make numerous aromatic compounds, including the Pseudomonas quinolone signal (PQS). We have previously shown that the kynurenine pathway is a critical source of anthranilate for PQS synthesis and that the kynurenine pathway genes (kynA and kynBU) are upregulated in the presence of kynurenine. A putative Lrp/AsnC-type transcriptional regulator (gene PA2082, here called kynR), is divergently transcribed from the kynBU operon and is highly conserved in gram-negative bacteria that harbor the kynurenine pathway. We show that a mutation in kynR renders P. aeruginosa unable to utilize L-tryptophan as a sole carbon source and decreases PQS production. In addition, we found that the increase of kynA and kynB transcriptional activity in response to kynurenine was completely abolished in a kynR mutant, further indicating that KynR mediates the kynurenine-dependent expression of the kynurenine pathway genes. Finally, we found that purified KynR specifically bound the kynA promoter in the presence of kynurenine and bound the kynB promoter in the absence or presence of kynurenine. Taken together, our data show that KynR directly regulates the kynurenine pathway genes.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Pseudomonas aeruginosa / Proteínas de Bactérias / Fatores de Transcrição / Regulação Bacteriana da Expressão Gênica / Cinurenina Idioma: En Ano de publicação: 2011 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Pseudomonas aeruginosa / Proteínas de Bactérias / Fatores de Transcrição / Regulação Bacteriana da Expressão Gênica / Cinurenina Idioma: En Ano de publicação: 2011 Tipo de documento: Article