scholarly journals Light-inducible carotenoid production controlled by a MarR-type regulator in Corynebacterium glutamicum

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Satoru Sumi ◽  
Yuto Suzuki ◽  
Tetsuro Matsuki ◽  
Takahiro Yamamoto ◽  
Yudai Tsuruta ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Gene Cluster ◽  
Transcriptional Start Site ◽  
Transcriptional Regulator ◽  
Carotenoid Biosynthesis ◽  
Transcriptional Analysis ◽  
Dependent Manner ◽  
Biosynthesis Gene Cluster ◽  
Carotenoid Production

Abstract Carotenoid production in some non-phototropic bacteria occurs in a light-dependent manner to protect cells from photo-oxidants. Knowledge regarding the transcriptional regulator involved in the light-dependent production of carotenoids of non-phototrophic bacteria has been mainly confined to coenzyme B12-based photo-sensitive regulator CarH/LitR family proteins belonging to a MerR family transcriptional regulator. In this study, we found that bacteria belonging to Micrococcales and Corynebacteriales exhibit light-dependent carotenoid-like pigment production including an amino acid-producer Corynebacterium glutamicum AJ1511. CrtR is a putative MarR family transcriptional regulator located in the divergent region of a carotenoid biosynthesis gene cluster in the genome of those bacteria. A null mutant for crtR of C. glutamicum AJ1511 exhibited constitutive production of carotenoids independent of light. A complemented strain of the crtR mutant produced carotenoids in a light-dependent manner. Transcriptional analysis revealed that the expression of carotenoid biosynthesis genes is regulated in a light-dependent manner in the wild type, while the transcription was upregulated in the crtR mutant irrespective of light. In vitro experiments demonstrated that a recombinant CrtR protein binds to the specific sequences within the intergenic region of crtR and crtE, which corresponds to −58 to −7 for crtE, and +26 to −28 for crtR with respect to the transcriptional start site, and serves as a repressor for crtE transcription directed by RNA polymerase containing SigA. Taken together, the results indicate that CrtR light-dependently controls the expression of the carotenoid gene cluster in C. glutamicum and probably closely related Actinobacteria.

scholarly journals Light-Induced Carotenogenesis in Streptomyces coelicolor A3(2): Identification of an Extracytoplasmic Function Sigma Factor That Directs Photodependent Transcription of the Carotenoid Biosynthesis Gene Cluster

2005 ◽  
Vol 187 (5) ◽  
pp. 1825-1832 ◽  
Author(s):  
Hideaki Takano ◽  
Saemi Obitsu ◽  
Teruhiko Beppu ◽  
Kenji Ueda
Keyword(s):  
Gene Expression ◽  
Gene Cluster ◽  
Sigma Factor ◽  
Streptomyces Coelicolor ◽  
Regulatory Region ◽  
Carotenoid Biosynthesis ◽  
Biosynthesis Gene Cluster ◽  
Biosynthesis Gene ◽  
Extracytoplasmic Function Sigma Factor

ABSTRACT Carotenoids are produced by a variety of organisms, but the mechanisms that regulate gene expression leading to carotenoid biosynthesis have been characterized for only a few organisms. In this study, we found that Streptomyces coelicolor A3(2), a gram-positive filamentous bacterium, produces carotenoids under blue light induction. The carotenoid fraction isolated from the cell extract contained multiple compounds, including isorenieratene and β-carotene. The carotenoid biosynthesis gene cluster of S. coelicolor consists of two convergent operons, crtEIBV and crtYTU, as previously shown for Streptomyces griseus. The crtEIBV null mutant completely lost its ability to produce carotenoids. The crt gene cluster is flanked by a regulatory region that consists of two divergent operons, litRQ and litSAB. The lit (light-induced transcription) genes encode a MerR-type transcriptional regulator (LitR), a possible oxidoreductase (LitQ), an extracytoplasmic function sigma factor (σLitS), a putative lipoprotein (LitA), and a putative anti-sigma factor (LitB). S1 protection assay revealed that the promoters preceding crtE (PcrtE), crtY (PcrtY), litR (PlitR), and litS (PlitS) are activated upon illumination. A litS mutant lost both the ability to produce carotenoids and the activities of PcrtE, PcrtY, and PlitS, which suggested that σLitS directs light-induced transcription from these promoters. An RNA polymerase holocomplex containing purified σLitS recombinant protein generated specific PcrtE and PcrtY transcripts in an in vitro runoff transcriptional assay. A litR mutant that had an insertion of the kanamycin resistance gene was defective both in the ability to produce carotenoids and in all of the light-dependent promoter activities. Overexpression of litS resulted in constitutive carotenoid production in both the wild type and the litR mutant. These results indicate that σLitS acts as a light-induced sigma factor that directs transcription of the crt biosynthesis gene cluster, whose activity is controlled by an unknown LitR function. This is the first report to describe light-inducible gene expression in Streptomyces.

scholarly journals Transcriptional analysis of the gap-pgk-tpi-ppc gene cluster of Corynebacterium glutamicum.

1993 ◽  
Vol 175 (12) ◽  
pp. 3905-3908 ◽  
Author(s):  
J W Schwinde ◽  
N Thum-Schmitz ◽  
B J Eikmanns ◽  
H Sahm
Keyword(s):  
Corynebacterium Glutamicum ◽  
Gene Cluster ◽  
Transcriptional Analysis

scholarly journals AraR, an l-Arabinose-Responsive Transcriptional Regulator in Corynebacterium glutamicum ATCC 31831, Exerts Different Degrees of Repression Depending on the Location of Its Binding Sites within the Three Target Promoter Regions

2015 ◽  
Vol 197 (24) ◽  
pp. 3788-3796 ◽  
Author(s):  
Takayuki Kuge ◽  
Haruhiko Teramoto ◽  
Masayuki Inui
Keyword(s):  
Corynebacterium Glutamicum ◽  
Binding Sites ◽  
Large Scale ◽  
Transcriptional Regulator ◽  
Scale Production ◽  
Primary Role ◽  
Promoter Regions ◽  
Independent Manner ◽  
Content Type

ABSTRACTInCorynebacterium glutamicumATCC 31831, a LacI-type transcriptional regulator AraR, represses the expression ofl-arabinose catabolism (araBDA), uptake (araE), and the regulator (araR) genes clustered on the chromosome. AraR binds to three sites: one (BSB) between the divergent operons (araBDAandgalM-araR) and two (BSE1and BSE2) upstream ofaraE.l-Arabinose acts as an inducer of the AraR-mediated regulation. Here, we examined the roles of these AraR-binding sites in the expression of the AraR regulon. BSBmutation resulted in derepression of botharaBDAandgalM-araRoperons. The effects of BSE1and/or BSE2mutation onaraEexpression revealed that the two sites independently function as theciselements, but BSE1plays the primary role. However, AraR was shown to bind to these sites with almost the same affinityin vitro. Taken together, the expression ofaraBDAandaraEis strongly repressed by binding of AraR to a single site immediately downstream of the respective transcriptional start sites, whereas the binding site overlapping the −10 or −35 region of thegalM-araRandaraEpromoters is less effective in repression. Furthermore, downregulation ofaraBDAandaraEdependent onl-arabinose catabolism observed in the BSBmutant and the AraR-independentaraRpromoter identified withingalM-araRadd complexity to regulation of the AraR regulon derepressed byl-arabinose.IMPORTANCECorynebacterium glutamicumhas a long history as an industrial workhorse for large-scale production of amino acids. An important aspect of industrial microorganisms is the utilization of the broad range of sugars for cell growth and production process. MostC. glutamicumstrains are unable to use a pentose sugarl-arabinose as a carbon source. However, genes forl-arabinose utilization and its regulation have been recently identified inC. glutamicumATCC 31831. This study elucidates the roles of the multiple binding sites of the transcriptional repressor AraR in the derepression byl-arabinose and thereby highlights the complex regulatory feedback loops in combination withl-arabinose catabolism-dependent repression of the AraR regulon in an AraR-independent manner.

scholarly journals The Transcriptional Regulator VqmA Increases Expression of the Quorum-Sensing Activator HapR in Vibrio cholerae

2006 ◽  
Vol 188 (7) ◽  
pp. 2446-2453 ◽  
Author(s):  
Zhi Liu ◽  
Ansel Hsiao ◽  
Adam Joelsson ◽  
Jun Zhu
Keyword(s):  
Quorum Sensing ◽  
Vibrio Cholerae ◽  
Diarrheal Disease ◽  
Constitutive Expression ◽  
Physiological Role ◽  
Transcriptional Regulator ◽  
Protease Production ◽  
Dependent Manner ◽  
Cell Densities

ABSTRACT Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. A number of environmental stimuli regulate virulence gene expression in V. cholerae, including quorum-sensing signals. At high cell densities, quorum sensing in V. cholerae invokes a series of signal transduction pathways in order to activate the expression of the master regulator HapR, which then represses the virulence regulon and biofilm-related genes and activates protease production. In this study, we identified a transcriptional regulator, VqmA (VCA1078), that activates hapR expression at low cell densities. Under in vitro inducing conditions, constitutive expression of VqmA represses the virulence regulon in a HapR-dependent manner. VqmA increases hapR transcription as measured by the activity of the hapR-lacZ reporter, and it increases HapR production as measured by Western blotting. Using a heterogenous luxCDABE cosmid, we found that VqmA stimulates quorum-sensing regulation at lower cell densities and that this stimulation bypasses the known LuxO-small-RNA regulatory circuits. Furthermore, we showed that VqmA regulates hapR transcription directly by binding to its promoter region and that expression of vqmA is cell density dependent and autoregulated. The physiological role of VqmA is also discussed.

scholarly journals Identification and Functional Analysis of the Gene Cluster for l-Arabinose Utilization in Corynebacterium glutamicum

2009 ◽  
Vol 75 (11) ◽  
pp. 3419-3429 ◽  
Author(s):  
Hideo Kawaguchi ◽  
Miho Sasaki ◽  
Alain A. Vertès ◽  
Masayuki Inui ◽  
Hideaki Yukawa
Keyword(s):  
Growth Rate ◽  
Corynebacterium Glutamicum ◽  
Gene Cluster ◽  
Wild Type Strain ◽  
Transcriptional Regulator ◽  
Transcriptional Unit ◽  
Gene Products ◽  
Wild Type ◽  
Mutant Cells ◽  
Arabinose Isomerase

ABSTRACT Corynebacterium glutamicum ATCC 31831 grew on l-arabinose as the sole carbon source at a specific growth rate that was twice that on d-glucose. The gene cluster responsible for l-arabinose utilization comprised a six-cistron transcriptional unit with a total length of 7.8 kb. Three l-arabinose-catabolizing genes, araA (encoding l-arabinose isomerase), araB (l-ribulokinase), and araD (l-ribulose-5-phosphate 4-epimerase), comprised the araBDA operon, upstream of which three other genes, araR (LacI-type transcriptional regulator), araE (l-arabinose transporter), and galM (putative aldose 1-epimerase), were present in the opposite direction. Inactivation of the araA, araB, or araD gene eliminated growth on l-arabinose, and each of the gene products was functionally homologous to its Escherichia coli counterpart. Moreover, compared to the wild-type strain, an araE disruptant exhibited a >80% decrease in the growth rate at a lower concentration of l-arabinose (3.6 g liter−1) but not at a higher concentration of l-arabinose (40 g liter−1). The expression of the araBDA operon and the araE gene was l-arabinose inducible and negatively regulated by the transcriptional regulator AraR. Disruption of araR eliminated the repression in the absence of l-arabinose. Expression of the regulon was not repressed by d-glucose, and simultaneous utilization of l-arabinose and d-glucose was observed in aerobically growing wild-type and araR deletion mutant cells. The regulatory mechanism of the l-arabinose regulon is, therefore, distinct from the carbon catabolite repression mechanism in other bacteria.

scholarly journals Isolation and Characterization of Canthaxanthin Biosynthesis Genes from the Photosynthetic Bacterium Bradyrhizobiumsp. Strain ORS278

2000 ◽  
Vol 182 (13) ◽  
pp. 3850-3853 ◽  
Author(s):  
Laure Hannibal ◽  
Jean Lorquin ◽  
Nicolas Angles D'Ortoli ◽  
Nelly Garcia ◽  
Clemence Chaintreuil ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Photosynthetic Bacterium ◽  
Carotenoid Biosynthesis ◽  
Open Reading Frame ◽  
Biosynthesis Gene Cluster ◽  
Reading Frame ◽  
Functional Assignment ◽  
Isolation And Characterization ◽  
Biosynthesis Gene

ABSTRACT A carotenoid biosynthesis gene cluster involved in canthaxanthin production was isolated from the photosyntheticBradyrhizobium sp. strain ORS278. This cluster includes five genes identified as crtE, crtY,crtI, crtB, and crtW that are organized in at least two operons. The functional assignment of each open reading frame was confirmed by complementation studies.

scholarly journals Analysis of a DtxR-Regulated Iron Transport and Siderophore Biosynthesis Gene Cluster in Corynebacterium diphtheriae

2005 ◽  
Vol 187 (2) ◽  
pp. 422-433 ◽  
Author(s):  
Carey A. Kunkle ◽  
Michael P. Schmitt
Keyword(s):  
Gene Cluster ◽  
Iron Uptake ◽  
Iron Transport ◽  
Genetic Locus ◽  
Corynebacterium Diphtheriae ◽  
Transcriptional Analysis ◽  
Biosynthesis Gene Cluster ◽  
Iron Source ◽  
Siderophore Biosynthesis ◽  
Siderophore Transport

ABSTRACT This report describes a genetic locus associated with siderophore biosynthesis and transport in Corynebacterium diphtheriae. A BLAST search of the C. diphtheriae genome identified a seven-gene cluster that included four genes, designated ciuA, ciuB, ciuC, and ciuD, whose predicted products are related to ABC-type iron transporters. Downstream from ciuD is the ciuE gene, whose predicted product is similar to the aerobactin biosynthetic enzymes IucA and IucC. The CiuE protein, which has a predicted mass of 121,582 Da and is approximately twice the size of either IucC or IucA, is homologous to each of these proteins in both its N- and C-terminal regions. C. diphtheriae ciuE deletion mutants exhibited a defect in siderophore production, iron uptake, and growth in low-iron medium. Mutations in the ciuA gene, whose predicted product is a lipoprotein component of an iron transport system, resulted in a severe defect in iron uptake and reduced ability to use the C. diphtheriae siderophore as an iron source. Site-directed mutations in irp6A, a gene previously reported to be associated with siderophore transport, had no effect on iron uptake or the utilization of the C. diphtheriae siderophore as an iron source. Transcriptional analysis demonstrated that expression of ciuA and ciuE is DtxR and iron regulated, and DNase I protection experiments confirmed the presence of DtxR binding sites upstream from each of these genes. Thus, this iron- and DtxR-regulated gene cluster is involved in the synthesis and transport of the C. diphtheriae siderophore.

scholarly journals Functional and Molecular Characterization of PD1+ Tumor-Infiltrating Lymphocytes From Lung Cancer Patients

2021 ◽  
Author(s):  
Jesse Lipp ◽  
Limei Wang ◽  
Nathalie Harrer ◽  
Stefan Mueller ◽  
Sabina Berezowska ◽  
...  
Keyword(s):  
Lung Cancer ◽  
T Cells ◽  
T Cell ◽  
Wnt Signaling ◽  
Cell Activation ◽  
Effector Function ◽  
Transcriptional Analysis ◽  
Molecular Profile ◽  
Dependent Manner

Abstract Background The majority of infiltrating T-cells (TILs) in lung cancer are contained in the memory compartment and overexpress PD1 and have been associated with dysfunction. Antibody-mediated cancer immunotherapy targets inhibitory surface molecules, such as PD1, PD-L1, and CTLA-4, aiming to re-invigorate dysfunctional T cells.Methods Using fluorescence-activated cell sorting (FACS), we purified CD45RO+ memory CD8+ and CD4+ TILs and their patient-matched non-tumor counterparts from treatment-naïve NSCLC patient biopsies to better evaluate the effect of PD1 expression on the functional and molecular profile of tumor-resident T cells. Moreover, we compared the functional, molecular, and clonal composition of TIL preparations after TCR-dependent in vitro expansion with their freshly isolated counterparts in matched patients.Results We show that PD1+CD8+ TILs have elevated expression of the transcriptional regulator ID3 and that the overall cytotoxic potential of CD8 T cells can be improved by knocking down ID3, defining it as a potential regulator of T cell effector function. PD1+CD4+ memory TILs remain functionally intact and despite overexpressing key transcriptional activators known to negatively regulate CD8 function such as TOX and TOX2, display transcriptional patterns consistent with both follicular helper and regulator function and robustly facilitate B cell activation and expansion in response to TCR-dependent stimulation. Furthermore, we show that expanding ex vivo-prepared TILs in vitro in a TCR-dependent manner broadly preserves their functionality with respect to tumor cell killing, expansion and activation of B cells, and TCR repertoire. Although purified PD1+CD8+ TILs generally maintain an exhausted phenotype upon expansion in vitro, transcriptional analysis reveals a downregulation of markers of T cell dysfunction, including the co-inhibitory molecules PD1 and CTLA-4 and the transcription factors ID3, TOX and TOX2, while genes involved in cell cycle and DNA repair are upregulated. We find reduced expression of WNT signaling components to be a hallmark of PD1+CD8+ exhausted T cells in vivo and in vitro and demonstrate that restoring WNT signaling, by pharmacological blockade of GSK3β, can improve effector function. Conclusions These data unveil novel targets for tumor immunotherapy and have promising implications for development of a personalized adoptive TIL-based cell therapy for lung cancer.

scholarly journals Characterization of the 2-Hydroxy-acid Dehydrogenase McyI, Encoded within the Microcystin Biosynthesis Gene Cluster of Microcystis aeruginosa PCC7806

2006 ◽  
Vol 282 (7) ◽  
pp. 4681-4692 ◽  
Author(s):  
Leanne A. Pearson ◽  
Kevin D. Barrow ◽  
Brett A. Neilan
Keyword(s):  
Gene Cluster ◽  
Microcystis Aeruginosa ◽  
Hydroxy Acid ◽  
Biosynthesis Gene Cluster ◽  
Glutamate Mutase ◽  
Acid Dehydrogenase ◽  
Methyl Aspartate ◽  
Catalyzed Reactions

The cyanobacterium Microcystis aeruginosa is widely known for its production of the potent hepatotoxin microcystin. This cyclic heptapeptide is synthesized non-ribosomally by the thio-template function of a large modular enzyme complex encoded within the 55-kb microcystin synthetase gene (mcy) cluster. The mcy gene cluster also encodes several stand-alone enzymes, putatively involved in the tailoring and export of microcystin. This study describes the characterization of the 2-hydroxy-acid dehydrogenase McyI, putatively involved in the production of d-methyl aspartate at position 3 within the microcystin cyclic structure. A combination of bioinformatics, molecular, and biochemical techniques was used to elucidate the structure, function, regulation, and evolution of this unique enzyme. The recombinant McyI enzyme was overexpressed in Escherichia coli and enzymatically characterized. The hypothesized native activity of McyI, the interconversion of 3-methyl malate to 3-methyl oxalacetate, was demonstrated using an in vitro spectrophotometric assay. The enzyme was also able to reduce α-ketoglutarate to 2-hydroxyglutarate and to catalyze the interconversion of malate and oxalacetate. Although NADP(H) was the preferred cofactor of the McyI-catalyzed reactions, NAD(H) could also be utilized, although rates of catalysis were significantly lower. The combined results of this study suggest that hepatotoxic cyanobacteria such as M. aeruginosa PCC7806 are capable of producing methyl aspartate via a novel glutamate mutase-independent pathway, in which McyI plays a pivotal role.

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