Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

Maddocks, Sarah; Oyston, Petra C. F.

doi:10.1099/mic.0.2008/022772-0

Cited by 748 publications

(987 citation statements)

References 135 publications

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“…However, this is not an absolute rule and LTTRs may activate or repress distantly located genes and operons and have a more global role in regulation (Maddocks & Oyston, 2008). The LTTR-binding site generally consists of two subsites, an upstream regulatory-binding site (RBS) and an activation-binding site (ABS) that may overlap the promoter, each showing an imperfect palindromic sequence (T-N 11 -A), which can vary in both base pair composition and length.…”

Section: Discussionmentioning

confidence: 99%

“…LysR-type transcriptional regulators (LTTRs) are known as transcriptional activators of a single gene or operon, transcribed divergently with respect to their own negatively autoregulated gene (Maddocks & Oyston, 2008). However, this is not an absolute rule and LTTRs may activate or repress distantly located genes and operons and have a more global role in regulation (Maddocks & Oyston, 2008).…”

Section: Discussionmentioning

confidence: 99%

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The Pseudomonas aeruginosa oxidative stress regulator OxyR influences production of pyocyanin and rhamnolipids: protective role of pyocyanin

et al. 2010

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The LysR-type transcriptional regulator (LTTR) OxyR orchestrates the defence of the opportunistic pathogen Pseudomonas aeruginosa against reactive oxygen species. In previous work we also demonstrated that OxyR is needed for the utilization of the ferrisiderophore pyoverdine, stressing the importance of this regulator. Here, we show that an oxyR mutant is unable to swarm on agar plates, probably as a consequence of absence of production of rhamnolipid surfactant molecules. Another obvious phenotypic change was the increased production of the phenazine redox-active molecule pyocyanin in the oxyR mutant. As already described, the oxyR mutant could not grow in LB medium, unless high numbers of cells (>108 ml−1) were inoculated. However, its growth in Pseudomonas P agar (King's A), a medium inducing pyocyanin production, was like that of the wild-type, suggesting a protective action of this redox-active phenazine compound. This was confirmed by the restoration of the capacity to grow in LB medium upon addition of pure pyocyanin. Although both rhamnolipid and pyocyanin production are controlled by quorum sensing, no obvious changes were observed in the production of N-acylhomoserine lactones or the Pseudomonas quinolone signal (PQS). Complementation of rhamnolipid production and motility, and restoration of normal pyocyanin levels, was only possible when the oxyR gene was in single copy, while pyocyanin levels were increased when oxyR was present in a multicopy vector. Conversely, plating efficiency was increased only when the oxyR gene was present in multicopy, but not when in single copy in the chromosome, due to lower expression of oxyR compared with the wild-type, suggesting that some phenotypes are differently affected in function to the levels of OxyR molecules in the cell. Analysis of transcripts of oxidative stress-response enzymes showed a strong decrease of katB, ahpC and ahpB expression in the oxyR mutant grown in LB, but this was not the case when the mutant was grown on P agar, suggesting that the OxyR dependency for the transcription of these genes is not total.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The Pseudomonas aeruginosa oxidative stress regulator OxyR influences production of pyocyanin and rhamnolipids: protective role of pyocyanin

et al. 2010

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“…Regarding the autoregulatory nature of most characterized LysRtype transcriptional activators it should be mentioned that, although the 'classical' type of regulation is by transcriptional activation and negative autoregulation, 20 there is an increasing body of knowledge indicating that an additional class of LysR-type regulators, acting as transcriptional activators or repressors, is subjected to positive autoregulation. 19 The data presented here suggest that ThnI belongs to this class of positively autoregulatory activators of the LysR family.…”

Section: Regulation Of Thienamycin Biosynthesis In Streptomyces Cattlmentioning

confidence: 65%

“…Most studied LysR-type transcriptional activators interact with DNA boxes that contain the T-N 11 -A conserved motif sequence within an inverted repeat, usually in regions of overlapping divergent promoters that allow simultaneous bidirectional control of transcription. 19,20 Although several putative LysR T-N 11 -A boxes were found in the nucleotide sequence upstream of thnQ, thnH, thnP and thnK coding regions, additional studies are required to identify the binding sites for ThnI to exert its regulatory role. Regarding the autoregulatory nature of most characterized LysRtype transcriptional activators it should be mentioned that, although the 'classical' type of regulation is by transcriptional activation and negative autoregulation, 20 there is an increasing body of knowledge indicating that an additional class of LysR-type regulators, acting as transcriptional activators or repressors, is subjected to positive autoregulation.…”

Section: Regulation Of Thienamycin Biosynthesis In Streptomyces Cattlmentioning

confidence: 99%

Transcriptional organization of ThnI-regulated thienamycin biosynthetic genes in Streptomyces cattleya

et al. 2010

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“…In addition, several HTGs have been reported in the previous studies to show possibility of horizontal transfer, e.g. dihydroorotate dehydrogenase and BDS1 transferred from bacteria to eukaryotes (Hall et al 2005), and LysR-type transcriptional regulators transferred among bacteria (Maddocks and Oyston 2008). Taken together, a substantial portion of the 111 HTGs coincides with the genes, which have been reported to have potential of horizontal transfer to exchange genomic components through functional or nonfunctional accessory genetic elements.…”

Section: Discussionmentioning

confidence: 80%

Analysis of genomic characters reveals that four distinct gene clusters are correlated with different functions in Burkholderia cenocepacia AU 1054

Yuan

Yang

Ren

et al. 2013

Appl Microbiol Biotechnol

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Possessing three circular chromosomes is a distinct genomic characteristic of Burkholderia cenocepacia AU 1054, a clinically important pathogen in cystic fibrosis. In this study, base composition, codon usage and functional role category were analyzed in the B. cenocepacia AU 1054 genome. Although no bias in the base and codon usage was detected between any two chromosomes, function differences did exist in the genes of each chromosome. Similar base composition and differential functional role categories indicated that genes on these three chromosomes were relatively stable and that a proper division of labor was established. Based on variations in the base or codon usage, four small gene clusters were observed in all of the genes. Multivariate analysis revealed that protein hydrophobicity played a predominant role in shaping base usage bias, while horizontal gene transfer and the gene expression level were the two most important factors that affected the codon usage bias. Interestingly, we also found that these gene clusters were correlated with different biological functions: (i) 45 pyrimidine-leadingcodon preferred genes were predominantly involved in regulatory function; (ii) most drug resistance-related genes involved in 826 genes that coding for hydrophobic proteins; (iii) most of the 111 horizontal transfer genes were responsible for genomic plasticity; and (iv) 73 highly expressed genes (predicted by their codon adaptation index values) showed environmental adaptation to cystic fibrosis. Our results showed that genes with base or codon usage bias were affected by mutational pressure and natural selection, and their functions could contribute to drug assistance and transmissible activity in B. cenocepacia.

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Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

Cited by 748 publications

References 135 publications

The Pseudomonas aeruginosa oxidative stress regulator OxyR influences production of pyocyanin and rhamnolipids: protective role of pyocyanin

The Pseudomonas aeruginosa oxidative stress regulator OxyR influences production of pyocyanin and rhamnolipids: protective role of pyocyanin

Transcriptional organization of ThnI-regulated thienamycin biosynthetic genes in Streptomyces cattleya

Analysis of genomic characters reveals that four distinct gene clusters are correlated with different functions in Burkholderia cenocepacia AU 1054

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