scholarly journals Constitutive expression of transcription factor SirZ blocks pathogenicity in Leptosphaeria maculans independently of sirodesmin production

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252333
Author(s):  
Andrew S. Urquhart ◽  
Candace E. Elliott ◽  
Wei Zeng ◽  
Alexander Idnurm
Keyword(s):  
Transcription Factor ◽  
Pathogenic Fungus ◽  
Leptosphaeria Maculans ◽  
Constitutive Expression ◽  
Blackleg Disease ◽  
Gene Encoding ◽  
Over Expression ◽  
Expression Construct ◽  
New Strategies

Sirodesmin, the major secondary metabolite produced by the plant pathogenic fungus Leptosphaeria maculans in vitro, has been linked to disease on Brassica species since the 1970s, and yet its role has remained ambiguous. Re-examination of gene expression data revealed that all previously described genes and two newly identified genes within the sir gene cluster in the genome are down-regulated during the crucial early establishment stages of blackleg disease on Brassica napus. To test if this is a strategy employed by the fungus to avoid damage to and then detection by the host plant during the L. maculans asymptomatic biotrophic phase, sirodesmin was produced constitutively by overexpressing the sirZ gene encoding the transcription factor that coordinates the regulation of the other genes in the sir cluster. The sirZ over-expression strains had a major reduction in pathogenicity. Mutation of the over-expression construct restored pathogenicity. However, mutation of two genes, sirP and sirG, required for specific steps in the sirodesmin biosynthesis pathway, in the sirZ over-expression background resulted in strains that were unable to synthesize sirodesmin, yet were still non-pathogenic. Elucidating the basis for this pathogenicity defect or finding ways to overexpress sirZ during disease may provide new strategies for the control of blackleg disease.

scholarly journals Cystine/glutamate antiporter xCT (SLC7A11) facilitates oncogenic RAS transformation by preserving intracellular redox balance

2019 ◽  
Vol 116 (19) ◽  
pp. 9433-9442 ◽  
Author(s):  
Jonathan K. M. Lim ◽  
Alberto Delaidelli ◽  
Sean W. Minaker ◽  
Hai-Feng Zhang ◽  
Milena Colovic ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Redox Balance ◽  
Gene Encoding ◽  
Oncogenic Ras ◽  
Opposing Effects ◽  
Whole Transcriptome ◽  
Intracellular Redox

The RAS family of proto-oncogenes are among the most commonly mutated genes in human cancers and predict poor clinical outcome. Several mechanisms underlying oncogenic RAS transformation are well documented, including constitutive signaling through the RAF-MEK-ERK proproliferative pathway as well as the PI3K-AKT prosurvival pathway. Notably, control of redox balance has also been proposed to contribute to RAS transformation. However, how homeostasis between reactive oxygen species (ROS) and antioxidants, which have opposing effects in the cell, ultimately influence RAS-mediated transformation and tumor progression is still a matter of debate and the mechanisms involved have not been fully elucidated. Here, we show that oncogenic KRAS protects fibroblasts from oxidative stress by enhancing intracellular GSH levels. Using a whole transcriptome approach, we discovered that this is attributable to transcriptional up-regulation of xCT, the gene encoding the cystine/glutamate antiporter. This is in line with the function of xCT, which mediates the uptake of cystine, a precursor for GSH biosynthesis. Moreover, our results reveal that the ETS-1 transcription factor downstream of the RAS-RAF-MEK-ERK signaling cascade directly transactivates the xCT promoter in synergy with the ATF4 endoplasmic reticulum stress-associated transcription factor. Strikingly, xCT was found to be essential for oncogenic KRAS-mediated transformation in vitro and in vivo by mitigating oxidative stress, as knockdown of xCT strongly impaired growth of tumor xenografts established from KRAS-transformed cells. Overall, this study uncovers a mechanism by which oncogenic RAS preserves intracellular redox balance and identifies an unexpected role for xCT in supporting RAS-induced transformation and tumorigenicity.

Over-expression of GbRac1 gene in transgenic tobacco enhances disease resistance to Alternaria alternata in vitro

2005 ◽  
Vol 2 (2) ◽  
pp. 73-77 ◽  
Author(s):  
Li Wei-Min ◽  
Wang Zhi-Xing ◽  
Jia Shi-Rong
Keyword(s):  
Disease Resistance ◽  
Transgenic Plants ◽  
Alternaria Alternata ◽  
Northern Blot Analysis ◽  
Challenge Test ◽  
Constitutive Expression ◽  
Degenerate Primers ◽  
Over Expression ◽  
Detached Leaves

AbstractGbRac1 gene was cloned from Gossypium barbadense with degenerate primers and 3′-RACE. Northern blot analysis indicated that GbRac1 mRNA was expressed abundantly in G. barbadense seedlings inoculated with Verticillium dehliae compared with mock-inoculated plants. A plant constitutive expression vector pRac harbouring GbRac1 gene was constructed and leaf discs of tobacco (Nicotiana tabacum L. cv. NC89) were transformed with pRac by Agrobacterium-mediated transformation. Disease challenge test of detached leaves of the transgenic plants by inoculation with Alternaria alternata showed that resistance was enhanced dramatically compared with the non-transgenic plants. Results suggest that GbRac1 gene might have potential application in the genetic engineering of plants with enhanced disease resistance.

scholarly journals Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors inEnterococcus faecalis

2018 ◽  
Vol 200 (18) ◽  
Author(s):  
Dawn A. Manias ◽  
Gary M. Dunny
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Enterococcus Faecalis ◽  
Opportunistic Infections ◽  
Structural Genes ◽  
Gene Encoding ◽  
Collagen Binding ◽  
Content Type ◽  
Surface Adhesins

ABSTRACTIt was shown previously that the disruption of theahrCgene encoding a predicted ArgR family transcription factor results in a severe defect in biofilm formationin vitro, as well as a significant attenuation of virulence ofEnterococcus faecalisstrain OG1RF in multiple experimental infection models. Using transcriptome sequencing (RNA-seq), we observedahrC-dependent changes in the expression of more than 20 genes. AhrC-repressed genes included predicted determinants of arginine catabolism and several other metabolic genes and predicted transporters, while AhrC-activated genes included determinants involved in the production of surface protein adhesins. Most notably, the structural and regulatory genes of theebplocus encoding adhesive pili were positively regulated, as well as theacegene, encoding a collagen-binding adhesin. UsinglacZtranscription reporter fusions, we determined thatahrCand a secondargRtranscription factor gene,argR2, both function to activate the expression ofebpR, which directly activates the transcription of the pilus structural genes. Our data suggest that in the wild-typeE. faecalis, the low levels of EbpR limit the expression of pili and that biofilm biomass is also limited by the amount of pili expressed by the bacteria. The expression ofaceis similarly enhanced by AhrC and ArgR2, butaceexpression is not dependent on EbpR. Our results demonstrate the existence of novel regulatory cascades controlled by a pair of ArgR family transcription factors that might function as a heteromeric protein complex.IMPORTANCECell surface adhesins play critical roles in the formation of biofilms, host colonization, and the pathogenesis of opportunistic infections byEnterococcus faecalis. Here, we present new results showing that the expression of two major enterococcal surface adhesins,ebppili, and the collagen-binding protein Ace is positively regulated at the transcription level by twoargRfamily transcription factors, AhrC and ArgR2. In the case of pili, the direct target of regulation is theebpRgene, previously shown to activate the transcription of the pilus structural genes, while the activation ofacetranscription appears to be directly impacted by the two ArgR proteins. These transcription factors may represent new targets for blocking enterococcal infections.

scholarly journals Increased Expression of RUNX1 in Liver Correlates with NASH Activity Score in Patients with Non-Alcoholic Steatohepatitis (NASH)

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1277 ◽  
Author(s):  
Kaur ◽  
Rawal ◽  
Siddiqui ◽  
Rohilla ◽  
Sharma ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Activity Score ◽  
Over Expression ◽  
Alcoholic Steatohepatitis ◽  
Related Transcription Factor ◽  
Underlying Mechanisms ◽  
Parenchymal Cells ◽  
Transcription Factor 1

Given the important role of angiogenesis in liver pathology, the current study investigated the role of Runt-related transcription factor 1 (RUNX1), a regulator of developmental angiogenesis, in the pathogenesis of non-alcoholic steatohepatitis (NASH). Quantitative RT-PCRs and a transcription factor analysis of angiogenesis-associated differentially expressed genes in liver tissues of healthy controls, patients with steatosis and NASH, indicated a potential role of RUNX1 in NASH. The gene expression of RUNX1 was correlated with histopathological attributes of patients. The protein expression of RUNX1 in liver was studied by immunohistochemistry. To explore the underlying mechanisms, in vitro studies using RUNX1 siRNA and overexpression plasmids were performed in endothelial cells (ECs). RUNX1 expression was significantly correlated with inflammation, fibrosis and NASH activity score in NASH patients. Its expression was conspicuous in liver non-parenchymal cells. In vitro, factors from steatotic hepatocytes and/or VEGF or TGF- significantly induced the expression of RUNX1 in ECs. RUNX1 regulated the expression of angiogenic and adhesion molecules in ECs, including CCL2, PECAM1 and VCAM1, which was shown by silencing or over-expression of RUNX1. Furthermore, RUNX1 increased the angiogenic activity of ECs. This study reports that steatosis-induced RUNX1 augmented the expression of adhesion and angiogenic molecules and properties in ECs and may be involved in enhancing inflammation and disease severity in NASH.

scholarly journals Neuronal over-expression of Oxr1 is protective against ALS-associated mutant TDP-43 mislocalisation in motor neurons and neuromuscular defects in vivo

2019 ◽  
Vol 28 (21) ◽  
pp. 3584-3599 ◽  
Author(s):  
Matthew G Williamson ◽  
Mattéa J Finelli ◽  
James N Sleigh ◽  
Amy Reddington ◽  
David Gordon ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Gene Encoding ◽  
Over Expression ◽  
Neuromuscular Abnormalities ◽  
And Function ◽  
Lateral Sclerosis

Abstract A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and the related neurodegenerative disorder frontotemporal dementia, is the cellular mislocalization of transactive response DNA-binding protein 43 kDa (TDP-43). Additionally, multiple mutations in the TARDBP gene (encoding TDP-43) are associated with familial forms of ALS. While the exact role for TDP-43 in the onset and progression of ALS remains unclear, the identification of factors that can prevent aberrant TDP-43 localization and function could be clinically beneficial. Previously, we discovered that the oxidation resistance 1 (Oxr1) protein could alleviate cellular mislocalization phenotypes associated with TDP-43 mutations, and that over-expression of Oxr1 was able to delay neuromuscular abnormalities in the hSOD1G93A ALS mouse model. Here, to determine whether Oxr1 can protect against TDP-43-associated phenotypes in vitro and in vivo, we used the same genetic approach in a newly described transgenic mouse expressing the human TDP-43 locus harbouring an ALS disease mutation (TDP-43M337V). We show in primary motor neurons from TDP-43M337V mice that genetically-driven Oxr1 over-expression significantly alleviates cytoplasmic mislocalization of mutant TDP-43. We also further quantified newly-identified, late-onset neuromuscular phenotypes of this mutant line, and demonstrate that neuronal Oxr1 over-expression causes a significant reduction in muscle denervation and neuromuscular junction degeneration in homozygous mutants in parallel with improved motor function and a reduction in neuroinflammation. Together these data support the application of Oxr1 as a viable and safe modifier of TDP-43-associated ALS phenotypes.

scholarly journals Transcription factor GCN4 for control of amino acid biosynthesis also regulates the expression of the gene for lipoamide dehydrogenase

1999 ◽  
Vol 340 (3) ◽  
pp. 855-862 ◽  
Author(s):  
Zafar ZAMAN ◽  
Susan B. BOWMAN ◽  
Geoff D. KORNFELD ◽  
Alistair J. P. BROWN ◽  
Ian W. DAWES
Keyword(s):  
Transcription Factor ◽  
Amino Acid ◽  
Amino Acid Biosynthesis ◽  
Upstream Region ◽  
Northern Analysis ◽  
General Control ◽  
Acid Biosynthesis ◽  
Gene Encoding ◽  
Lipoamide Dehydrogenase

The yeast LPD1 gene encoding lipoamide dehydrogenase is subject to the general control of amino acid biosynthesis mediated by the GCN4 transcription factor. This is striking in that it demonstrates that GCN4-mediated regulation extends much farther upstream than simply to the direct pathways for amino acid and purine biosynthesis. In yeast, lipoamide dehydrogenase functions in at least three multienzyme complexes: pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase (which function in the entry of pyruvate into, and metabolism via, the citric acid cycle) and glycine decarboxylase. When wild-type cells were shifted from growth on amino acid-rich to amino acid-deficient medium, the expression of lipoamide dehydrogenase was induced approx. 2-fold. In a similar experiment no such induction was observed in isogenic gcn4 mutant cells. Northern analysis indicated that amino acid starvation affected levels of the LPD1 transcript. In the upstream region of LPD1 are three matches to the consensus for control mediated by GCN4. Directed mutagenesis of each site, and of all combinations of sites, suggests that only one site might be important for the general control response under the conditions tested. Gel-retardation analysis with GCN4 protein synthesized in vitro has indicated that GCN4 can bind in vitro to at least two of the consensus motifs.

Survivin Is Negatively Regulated by Early Growth Response (Egr)-1 Transcription Factor in Acute Myeloid Leukemia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1943-1943 ◽  
Author(s):  
Ingo Tamm ◽  
Karin Schmelz ◽  
Bernd Dörken ◽  
Mandy Wagner
Keyword(s):  
Transcription Factor ◽  
Cell Lines ◽  
Growth Response ◽  
Survivin Expression ◽  
Early Growth ◽  
Survivin Promoter ◽  
Over Expression ◽  
Early Growth Response ◽  
Induced Apoptosis

Abstract Survivin, a member of the inhibitor of apoptosis protein family, is involved in both, inhibition of apoptosis and regulation of cell division. It is expressed in embryonic and fetal tissues as well as in the majority of human leukemias, but is undetectable in normal differentiated adult tissue in vivo. The molecular mechanisms involved in the cancer-specific re-expression of survivin are unclear. In this study, we describe a novel mechanism for over-expression of survivin in AML. Using electrophoretic mobility shift assays (EMSA), we show that the early growth response (Egr)-1 transcription factor binds to the sequence 5′ GAGGGGGCG 3′ within the human survivin promoter after induction by phorbol 12-myristate-13-acetate (PMA) in vitro. Furthermore, chromatin immunoprecipitation (ChIP) analysis confirmed the specific binding of Egr-1 to the proximal survivin promoter in PMA treated entire leukemia cells. To further analyze the functionality of the Egr-1 site within the survivin promoter in entire cells, transient transfections of p53 wildtype and mutated cell lines with wildtype Egr-1 expression vector were performed. In these overexpression experiments, mRNA and protein levels of survivin but not of control protein were downregulated after exogenous expression of wildtype Egr-1. Using reporter-gene assays, basal survivin promoter activity was decreased significantly by wildtype Egr-1 transfection, whereas mutant Egr-1 did not change activity of the survivin promoter, implying that Egr-1 specifically blocks survivin expression at the transcriptional level. In addition, Egr-1 over-expression sensitized cells to TRAIL-induced apoptosis. To investigate the expression pattern of Egr-1 in different AML cell lines and control samples from healthy donors, we analyzed the expression of Egr-1 by RT-PCR. Fitting with the above shown data, Egr-1 was expressed at significantly lower levels in AML cell lines expressing high survivin levels than in healthy control samples with low survivin levels. Taken together, we show that the transcription factor Egr-1 binds to the human survivin promoter in vitro and in entire cells, downregulates survivin expression independently of p53 and sensitizes cells to TRAIL-induced apoptosis. Since Survivin is often overexpressed in AML, downregulating Survivin expression by activating Egr-1 may be an interesting therapeutic option.

scholarly journals Interleukin-4 and -13 Induce Upregulation of the Murine Macrophage 12/15-Lipoxygenase Activity: Evidence for the Involvement of Transcription Factor STAT6

Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2503-2510 ◽  
Author(s):  
Dagmar Heydeck ◽  
Leo Thomas ◽  
Kerstin Schnurr ◽  
Frank Trebus ◽  
William E. Thierfelder ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Constitutive Expression ◽  
Peritoneal Macrophages ◽  
Lipoxygenase Activity ◽  
Interleukin 4 ◽  
Control Mechanisms ◽  
Dependent Manner ◽  
Murine Macrophage ◽  
12 Lipoxygenase

Abstract When human monocytes or alveolar macrophages are cultured in the presence of interleukin (IL)-4 or IL-13, the expression of the reticulocyte-type 15-lipoxygenase is induced. In mice a 15-lipoxygenase is not expressed, but a leukocyte-type 12-lipoxygenase is present in peritoneal macrophages. To investigate whether both lipoxygenase isoforms exhibit a similar regulatory response toward cytokine stimulation, we studied the regulation of the leukocyte-type 12-lipoxygenase of murine peritoneal macrophages by interleukins and found that the activity of this enzyme is upregulated in a dose-dependent manner when the cells were cultured in the presence of the IL-4 or IL-13 but not by IL-10. When peripheral murine monocytes that do not express the lipoxygenase were treated with IL-4 expression of 12/15-lipoxygenase mRNA was induced, suggesting pretranslational control mechanisms. In contrast, no upregulation of the lipoxygenase activity was observed when the macrophages were prepared from homozygous STAT6-deficient mice. Peritoneal macrophages of transgenic mice that systemically overexpress IL-4 exhibited a threefold to fourfold higher 12-lipoxygenase activity than cells prepared from control animals. A similar upregulation of 12-lipoxygenase activity was detected in heart, spleen, and lung of the transgenic animals. Moreover, a strong induction of the enzyme was observed in red cells during experimental anemia in mice. The data presented here indicate that (1) the 12-lipoxygenase activity of murine macrophages is upregulated in vitro and in vivo by IL-4 and/or IL-13, (2) this upregulation requires expression of the transcription factor STAT6, and (3) the constitutive expression of the enzyme appears to be STAT6 independent. The cytokine-dependent upregulation of the murine macrophage 12-lipoxygenase and its induction during experimental anemia suggests its close relatedness with the human reticulocyte-type 15-lipoxygenase despite their differences in the positional specificity of arachidonic acid oxygenation.

scholarly journals NFATC3 promotes IRF7 transcriptional activity in plasmacy­­toid dendritic cells

2016 ◽  
Vol 213 (11) ◽  
pp. 2383-2398 ◽  
Author(s):  
Musheng Bao ◽  
York Wang ◽  
Ying Liu ◽  
Peiqing Shi ◽  
Hongbo Lu ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Transcription Factor ◽  
Nuclear Translocation ◽  
Constitutive Expression ◽  
Toll Like Receptor ◽  
Cpg Dna ◽  
Specialized Function

Plasmacytoid dendritic cells (pDCs) rapidly produce large amounts of type 1 interferon (IFN) after Toll-like receptor 7 and 9 engagements. This specialized function of type 1 IFN production is directly linked to the constitutive expression of IRF7, the master transcription factor for type 1 IFN production. However, the IRF7 regulatory network in pDCs remains largely unknown. In this study, we identify that the transcription factor NFATC3 specifically binds to IRF7 and enhances IRF7-mediated IFN production. Furthermore, knockout of NFATC3 greatly reduced the CpG DNA–induced nuclear translocation of IRF7, which resulted in impaired type 1 IFN production in vitro and in vivo. In addition, we found that NFATC3 and IRF7 both bound to type 1 IFN promoters and that the NFAT binding site in IFN promoters was required for IRF7-mediated IFN expression. Collectively, our study shows that the transcription factor NFATC3 binds to IRF7 and functions synergistically to enhance IRF7-mediated IFN expression in pDCs.

scholarly journals The Bacterial Component Flagellin Induces Anti-Sepsis Protection Through TLR-5, IL-1RN and VCAN During Polymicrobial Sepsis in Mice

2015 ◽  
Vol 36 (2) ◽  
pp. 446-456 ◽  
Author(s):  
Jiang Zhu ◽  
Guangjie Duan ◽  
Lang Lang ◽  
Yao Liu ◽  
Junmin Zhu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
In Vitro Culture ◽  
Cecal Ligation ◽  
Cecal Ligation And Puncture ◽  
Relevant Model ◽  
Over Expression ◽  
Endothelial Repair ◽  
Endothelial Proliferation ◽  
Expression Construct

Background: The present study was designed to observe the effects of the bacterial component flagellin on anti-sepsis protection through TLR-5, VCAN and IL-1RN. Methods: A clinically relevant model of sepsis was induced by cecal ligation and puncture (CLP). An in vitro culture of endothelial cells was analyzed. Results: Flagellin induced anti-sepsis protection through inhibition of inflammation and induction of endothelial proliferation by down-regulating the expression of TLR 3, TLR 4, and IL-1RN and promoting the expression of VCAN in mice 24 h post-CLP. In vitro, flagellin promoted the proliferation of endothelial cells. These effects could be inhibited by transfection of endothelial cells with VCAN siRNA or IL-1RN over-expression constructs. VCAN expression decreased after transfection of the cells with an IL-1RN over-expression construct and increased after transfection of the cells with an IL-1RN siRNA construct. IL-1RN expression remained unchanged after transfection of the cells with VCAN over-expression or siRNA constructs. Conclusions: These data suggest that flagellin pretreatment promoted anti-sepsis protection through the TLR-5, IL-1RN and VCAN pathway. This pathway is necessary to mediate endothelial repair and thereby promote survival following sepsis challenge.

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