Novel target genes of PsrA transcriptional regulator of<i>Pseudomonas aeruginosa</i>

Kojić, Milan; Jovčić, Branko; Vindigni, Alessandro; Odreman, Federico; Venturi, Vittorio

doi:10.1016/j.femsle.2005.04.003

Cited by 39 publications

(59 citation statements)

References 20 publications

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“…Experimentally determined PsrA binding sites in the promoter regions of the PsrA-repressed genes psrA, PA0506 (acdH), and PA2952 (etfB) coincide with the predicted PsrA binding sites (20). For the rpoS gene, which is positively regulated by PsrA at the stationary phase, the experimentally determined PsrA binding site is located 411 bp upstream of its translational start point (19) and was thus missed by our procedure.…”

Section: Vol 191 2009 Comparative Genomics Of Fa and Ilv Degradatiomentioning

confidence: 63%

“…Their representatives in P. aeruginosa were previously described as being LiuR and PsrA. In particular, the P. aeruginosa regulator PsrA from the TetR family was originally shown to be involved in the stationary-phase-induced transcriptional regulation of rpoS and some other genes (18,19,20). Here, we perform a comparative genomic reconstruction of the respective regulons in proteobacteria and report that their major targets are the ILV degradation and FAD pathways, respectively.…”

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confidence: 96%

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Comparative Genomics of Regulation of Fatty Acid and Branched-Chain Amino Acid Utilization in Proteobacteria

et al. 2009

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Bacteria can use branched-chain amino acids (ILV, i.e., isoleucine, leucine, valine) and fatty acids (FAs) as sole carbon and energy sources converting ILV into acetyl-coenzyme A (CoA), propanoyl-CoA, and propionylCoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate transcription factor binding sites in groups of phylogenetically related genomes. The reconstructed ILV/FA regulatory network demonstrates considerable variability and involves six transcriptional factors from the MerR, TetR, and GntR families binding to 11 distinct DNA motifs. The ILV degradation genes in gamma-and betaproteobacteria are regulated mainly by a novel regulator from the MerR family (e.g., LiuR in Pseudomonas aeruginosa) (40 species); in addition, the TetR-type regulator LiuQ was identified in some betaproteobacteria (eight species). Besides the core set of ILV utilization genes, the LiuR regulon in some lineages is expanded to include genes from other metabolic pathways, such as the glyoxylate shunt and glutamate synthase in Shewanella species. The FA degradation genes are controlled by four regulators including FadR in gammaproteobacteria (34 species), PsrA in gamma-and betaproteobacteria (45 species), FadP in betaproteobacteria (14 species), and LiuR orthologs in alphaproteobacteria (22 species). The remarkable variability of the regulatory systems associated with the FA degradation pathway is discussed from functional and evolutionary points of view.Proteobacteria comprise one of the largest divisions within prokaryotes and incorporate species possessing a very complex collection of phenotypic and physiological attributes including many phototrophs, heterotrophs, and chemolithotrophs. The proteobacterial group is of great biological significance, as it includes a large number of pathogens and symbionts of animals and plants. Thus, proteobacteria display an amazing versatility in their abilities to use various carbon sources such as carbohydrates, nucleotides, amino acids, and lipids. The degradation of branched-chain amino acids valine, leucine, and isoleucine (ILV) and fatty acids (FAs) is used for ATP and energy production by many proteobacteria.The ILV degradation pathways are outlined in Fig. 1A. The first reaction is transamination to the corresponding ␣-keto acids using either branched-chain amino acid aminotransferase or leucine dehydrogenase. The second step is oxidative decarboxylation to the corresponding acyl-coenzyme A (CoA) derivative coupled to dehydrogenation, which is carried out by a common branched-chain ␣-keto acid dehydrogenase (BCDH) (EC 1.2.4.4) complex. The further conversion of branchedchain acyl-CoA derivatives of ILV amino acids, namely, isovaleryl-CoA for leucine, 2-methylbutanoyl-CoA for isoleucine, and isobutyryl-CoA for valine, into acetyl-CoA and propionyl-CoA is...

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Section: Vol 191 2009 Comparative Genomics Of Fa and Ilv Degradatiomentioning

confidence: 63%

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confidence: 96%

Comparative Genomics of Regulation of Fatty Acid and Branched-Chain Amino Acid Utilization in Proteobacteria

et al. 2009

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“…The PAO1-P fadBA5 -lacZ fusion strain was used in transposon mutagenesis to identify a regulator for fadBA5, which is PsrA (PA3006). The DNA recognition sequence for PsrA binding is well established (Kojic et al, 2005;Shen et al, 2006). Downstream of the fadBA5 promoter region, there were two putative PsrA binding sites (Figs 2a and 7).…”

Section: Discussionmentioning

confidence: 98%

“…It has been suggested elsewhere that PsrA, a member of the TetR family of repressors, could affect global gene expression (Kojic et al, 2005;Shen et al, 2006), including activation of rpoS (Kojic et al, 2002) and the type III secretion system exsCEBA operon (Shen et al, 2006). A proteomic study has shown that PsrA influences the expression of a few proteins, including FadBA5, but the signal (inducer) and mechanism of regulation by PsrA have not been demonstrated (Kojic et al, 2005).…”

Section: Psra Affects Gene Expression Globallymentioning

confidence: 99%

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The Pseudomonas aeruginosa PsrA responds to long-chain fatty acid signals to regulate the fadBA5 β-oxidation operon

et al. 2008

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The Pseudomonas aeruginosa PsrA responds to long-chain fatty acid signals to regulate the fadBA5 b-oxidation operon b-Oxidative enzymes for fatty acid degradation (Fad) of long-chain fatty acids (LCFAs) are induced in vivo during lung infection in cystic fibrosis patients, and this may contribute to nutrient acquisition and pathogenesis of Pseudomonas aeruginosa. The promoter region of one P. aeruginosa b-oxidation operon, fadBA5 (PA3014 and PA3013), was mapped. Focusing on the transposon mutagenesis of strain PAO1 carrying the P fadBA5 -lacZ fusion, a regulator for the fadBA5 operon was identified to be PsrA (PA3006). Transcriptome analysis of the DpsrA mutant indicated its importance in regulating b-oxidative enzymes. These microarray data were confirmed by real-time RT-PCR analyses of the fadB5 and lipA (encoding a lipase) genes. Induction of the fadBA5 operon was demonstrated to respond to novel LCFA signals, and this induction required the presence of PsrA, suggesting that LCFAs bind to PsrA to derepress fadBA5. Electrophoretic mobility shift assays indicate specific binding of PsrA to the fadBA5 promoter region. This binding is disrupted by specific LCFAs (C 18 : 1 D9 , C 16 : 0 , C 14 : 0 and, to a lesser extent, C 12 : 0 ), but not by other medium-or short-chain fatty acids or the first intermediate of b-oxidation, acyl-CoA. It is shown here that PsrA is a fadBA5 regulator that binds and responds to LCFA signals in P. aeruginosa. INTRODUCTIONPseudomonas aeruginosa is an opportunistic pathogen, and the spectrum of infections and diseases it causes is second to none. P. aeruginosa can cause infections of the ear, bone, joint, skin and soft tissue, and more serious infections, including meningitis, bacteraemia, endocarditis, ocular infections, hospital-acquired pneumonia, and lung infections in cystic fibrosis (CF) patients (Baltch & Griffin, 1977;Bowton, 1999;Fleiszig et al., 1995;Greenberger, 1997;Lode et al., 2000;Pruitt et al., 1998;Reyes & Lerner, 1983;Richards et al., 1999;Schaberg et al., 1991). P. aeruginosa lung infections transpire in nosocomial pneumonia and in CF patients. Nosocomial pneumonia is the second most common of all nosocomial infections, and P. aeruginosa has been the most frequently isolated microbe responsible (Pennington, 1994;Richards et al., 1999). In addition, over 93 % of CF patients between the ages of 18 and 24 have been infected with P. aeruginosa (Doring, 1997).Fatty acid degradation (Fad) pathways may play critical roles in P. aeruginosa pathogenesis. It has recently been demonstrated that the Fad pathways of P. aeruginosa may have important implications in nutrient acquisition and pathogenesis within the CF lung (Son et al., 2007), through the degradation of an essential lung surfactant component phosphatidylcholine (PC). The degradation of one PC component, long-chain fatty acid (LCFA), potentially occurs through three different b-oxidation pathways, involving three fadBA operons (fadAB1, PA1737 and PA1736; fadAB4, PA4786 and PA4785; and fadBA5, PA3014 and PA3013) (Son e...

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