scholarly journals Tobacco TGA7 mediates gene expression dependent and independent of salicylic acid

2018 ◽  
Author(s):  
Vlatka Stos-Zweifel ◽  
David Neeley ◽  
Evelyn Konopka ◽  
Meike Meissner ◽  
Meike Hermann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Leucine Zipper ◽  
Gene Activation ◽  
Chimeric Protein ◽  
Leaf Tissue ◽  
Terminal Region ◽  
Family Control ◽  
Transcription Activity ◽  
Tga Factors

ABSTRACTBasic region leucine zipper (bZIP) transcription factors of the TGA family control gene expression in response to diverse stimuli. Arabidopsis clade II and clade III TGA factors mediate salicylic acid (SA)-induced expression of PATHOGENESIS-RELATED GENE1 (PR-1) via interplay with NONEXPRESSOR OF PR GENES1 (NPR1, a.k.a. NIM1). Interaction with TGA factors occurs through the central ankyrin repeat domain of NPR1. In a yeast two-hybrid screen with the NPR1 bait, we identified TGA7, a novel member of the tobacco (Nt) TGA family grouping to clade III. TGA7 is most similar to NtTGA1a, and, like NtTGA1a, TGA7 displays transcription activity in yeast. Unexpectedly, TGA7 preferentially and uniquely interacts with the SA-sensitive C-terminal region of NtNPR1, demonstrating that NtNPR1 harbors multiple distinct TGA factor binding sites. Interaction with NPR1 impairs TGA7 transcription activity in yeast. Furthermore, TGA7 binding to the NtNPR1 C-terminus is outcompeted by SA-induced type 2 NIM1-INTERACTING (NIMIN) proteins. In tobacco plants, a TGA7–Gal4 DNA-binding domain chimeric protein (TGA7GBD) mediates SA-responsive reporter gene expression in young leaf tissue and spontaneous reporter activation in older leaves displaying PR-1 gene expression. Astonishingly, TGA7GBD is also able to activate the reporter independent from PR-1 gene expression in noninduced cotyledons of tobacco seedlings. Together, our findings support a model in which TGA7 mediates both SA-dependent and SA-independent gene activation controlled by the plant’s developmental stage and by the C-terminal region of constitutively accumulating NtNPR1.

scholarly journals Transcriptional activation of Il36A by C/EBPβ via a half-CRE•C/EBP element in murine macrophages is independent of its CpG methylation level

2021 ◽  
Author(s):  
Andreas Nerlich ◽  
Nina Janze ◽  
Ralph Goethe
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Methylation Status ◽  
Gene Activation ◽  
Cell Types ◽  
Cpg Methylation ◽  
Basic Leucine Zipper ◽  
Murine Macrophages ◽  
Copy Numbers

Interleukin-36α (Il-36α) is a member of the novel Il-1-like proinflammatory cytokine family that is highly expressed in epithelial tissues and several myeloid-derived cell types. We have recently shown that CCAAT enhancer binding proteinβ (C/EBPβ) binds specifically to an essential half cAMP response element (half-CRE)•C/EBP motif in the Il36A promoter to induce Il36A expression upon LPS stimulation. C/EBPs are transcription factors belonging to the basic leucine zipper (bZIP) family of transcriptional regulators. C/EBP proteins can form homo- and heterodimers and regulate gene expression by binding to C/EBP specific recognition sequences and composite sites that can contain 5’-cytosine-phosphate-guanine-3’ dinucleotides (CpG). CpG methylation of such elements has been shown to influence transcription factor binding and gene expression. Here we show that the half-CRE•C/EBP element in the Il36A promoter is differentially methylated in the murine RAW264.7 macrophage cell line and in primary murine macrophages. By using electrophoretic mobility gel shift and fluorescence polarization assays we demonstrate that C/EBPβ binding to the half-CRE•C/EBP element in the Il36A promoter following LPS stimulation is insensitive to CpG methylation. Transfection assays also show that methylation of the CpG in the half-CRE•C/EBP element does not alter LPS-induced Il36A promoter activity. A direct comparison of Il36A mRNA copy numbers as well as the pro-Il-36α protein level in RAW264.7 and primary macrophages revealed similar amounts in both cell types. Taken together, our data suggest that C/EBPβ binding to the half-CRE•C/EBP element and C/EBPβ mediated gene activation occurs independently of the CpG methylation status of the target DNA sequence and underline the potential of C/EBPβ to recognize methylated as well as unmethylated binding sites.

scholarly journals Insight into the bZIP Gene Family in Solanum tuberosum: Genome and Transcriptome Analysis to Understand the Roles of Gene Diversification in Spatiotemporal Gene Expression and Function

2020 ◽  
Vol 22 (1) ◽  
pp. 253
Author(s):  
Venura Herath ◽  
Jeanmarie Verchot
Keyword(s):  
Gene Expression ◽  
Gene Family ◽  
Functional Groups ◽  
Leucine Zipper ◽  
Expression Profiles ◽  
Crop Improvement ◽  
Potato Virus X ◽  
Tissue Growth ◽  
Abiotic Stress Response ◽  
Sequence Alignments

The basic region-leucine zipper (bZIP) transcription factors (TFs) form homodimers and heterodimers via the coil–coil region. The bZIP dimerization network influences gene expression across plant development and in response to a range of environmental stresses. The recent release of the most comprehensive potato reference genome was used to identify 80 StbZIP genes and to characterize their gene structure, phylogenetic relationships, and gene expression profiles. The StbZIP genes have undergone 22 segmental and one tandem duplication events. Ka/Ks analysis suggested that most duplications experienced purifying selection. Amino acid sequence alignments and phylogenetic comparisons made with the Arabidopsis bZIP family were used to assign the StbZIP genes to functional groups based on the Arabidopsis orthologs. The patterns of introns and exons were conserved within the assigned functional groups which are supportive of the phylogeny and evidence of a common progenitor. Inspection of the leucine repeat heptads within the bZIP domains identified a pattern of attractive pairs favoring homodimerization, and repulsive pairs favoring heterodimerization. These patterns of attractive and repulsive heptads were similar within each functional group for Arabidopsis and S. tuberosum orthologs. High-throughput RNA-seq data indicated the most highly expressed and repressed genes that might play significant roles in tissue growth and development, abiotic stress response, and response to pathogens including Potato virus X. These data provide useful information for further functional analysis of the StbZIP gene family and their potential applications in crop improvement.

scholarly journals The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

2021 ◽  
Author(s):  
Huaming He ◽  
Jordi Denecker ◽  
Katrien Van Der Kelen ◽  
Patrick Willems ◽  
Robin Pottie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Negative Regulator ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
A Genome ◽  
Oxidative Stress Responses

Abstract Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.

scholarly journals Aspergillus nidulans wetA activates spore-specific gene expression.

1991 ◽  
Vol 11 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M A Marshall ◽  
W E Timberlake
Keyword(s):  
Gene Expression ◽  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Gene Activation ◽  
Regulatory Function ◽  
Specific Gene ◽  
Coding Region ◽  
Vegetative Cells ◽  
Mutant Strains ◽  
Late Stages

The Aspergillus nidulans wetA gene is required for synthesis of cell wall layers that make asexual spores (conidia) impermeable. In wetA mutant strains, conidia take up water and autolyze rather than undergoing the final stages of maturation. wetA is activated during conidiogenesis by sequential expression of the brlA and abaA regulatory genes. To determine whether wetA regulates expression of other sporulation-specific genes, its coding region was fused to a nutritionally regulated promoter that permits gene activation in vegetative cells (hyphae) under conditions that suppress conidiation. Expression of wetA in hyphae inhibited growth and caused excessive branching. It did not lead to activation of brlA or abaA but did cause accumulation of transcripts from genes that are normally expressed specifically during the late stages of conidiation and whose mRNAs are stored in mature spores. Thus, wetA directly or indirectly regulates expression of some spore-specific genes. At least one gene (wA), whose mRNA does not occur in spores but rather accumulates in the sporogenous phialide cells, was activated by wetA, suggesting that wetA may have a regulatory function in these cells as well as in spores. We propose that wetA is responsible for activating a set of genes whose products make up the final two conidial wall layers or direct their assembly and through this activity is responsible for acquisition of spore dormancy.

DDRE-30. CELL-PENETRATING PEPTIDE ANTAGONIST OF CCAAT/ENHANCER BINDING PROTEIN ß DISPLAYS POTENT ANTI-GLIOBLASTOMA ACTIVITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi80-vi81
Author(s):  
Jim Rotolo ◽  
Lila Ghamsari ◽  
Ricardo Ramierez ◽  
Mark Koester ◽  
Siok Leong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Leucine Zipper ◽  
Binding Protein ◽  
Xenograft Model ◽  
Mesenchymal Transition ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Subcutaneous Xenograft ◽  
Peptide Antagonist ◽  
Anti Tumor Activity

Abstract CCAAT/Enhancer Binding Protein Beta (C/EBPß) is a transcription factor overexpressed in glioblastoma (GBM). Mechanistically, C/EBPß is a master regulator of mesenchymal transition in GBM, and its increased expression correlates with mesenchymal differentiation and predicts poor clinical outcome. C/EBPß activity requires dimerization with co-factors such as CREB/ATF family members via leucine zipper interactions. ST101 is a novel peptide antagonist of C/EBPß currently being evaluated in a Phase 1/2 clinical study in patients with advanced unresectable and metastatic solid tumors. ST101 binds to the C/EBPß leucine zipper, thereby preventing dimer formation and inhibiting its transcriptional activity, resulting in selective tumor cell cytotoxicity. Here, we describe ST101 non-clinical anti-tumor activity against GBM. In vitro studies in T98G and U251 cells demonstrate ST101 dose-dependent impact of cell viability (EC50 of 2.2 and 1.2 μM, respectively), accompanied by significant impact on C/EBPß-mediated gene expression as determined by qPCR analysis. In contrast, normal human mononuclear and epithelial cells were not sensitive to ST101 (EC50 > 80 μM). In vivo, ST101 displayed significant anti-tumor activity in a U251 GBM subcutaneous xenograft model, resulting in 81.4% tumor growth inhibition (TGI) vs. control and undetectable tumors in 50% of animals. Following ST101 exposure tumors displayed reduced BIRC3 and ID2 gene expression, and significantly increased cleaved caspase 3 immunostaining indicative of cell death induction. In U251 tumors, subtherapeutic ST101 (< 5% TGI) in combination with temozolomide (< 5% TGI) resulted in 52.8% TGI, significantly greater than either single-agent alone. Similarly, in a temozolomide-refractory T98G GBM subcutaneous xenograft model, ST101 (41.6% TGI) in combination with TMZ (< 5% TGI) resulted in significant anti-GBM response (72.4% TGI). These data emphasize the potential of ST101 as a potent peptide therapeutic for GBM.

scholarly journals Symbiotic Gene Activation is Interrupted by Endocrine Disrupting Chemicals

2001 ◽  
Vol 1 ◽  
pp. 653-655 ◽  
Author(s):  
Jennifer E. Fox ◽  
Matthew E. Burow ◽  
John A. McLachlan
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Estrogen Receptors ◽  
Mammalian Cell Culture ◽  
Endocrine Disrupting Chemicals ◽  
Gene Activation ◽  
Symbiotic Gene ◽  
Endocrine Disrupting ◽  
Plant Chemicals ◽  
By Products

Endocrine disrupting chemicals (EDCs) include organochlorine pesticides, plastics manufacturing by-products, and certain herbicides[1]. These chemicals have been shown to disrupt hormonal signaling in exposed wildlife, lab animals, and mammalian cell culture by binding to estrogen receptors (ER-α and ER-β) and affecting the expression of estrogen responsive genes[2,3]. Additionally, certain plant chemicals, termed phytoestrogens, are also able to bind to estrogen receptors and modulate gene expression, and as such also may be considered EDCs[4]. One example of phytoestrogen action is genistein, a phytochemical produced by soybeans, binding estrogen receptors, and changing expression of estrogen responsive genes which certain studies have linked to a lower incidence of hormonally related cancers in Japanese populations[5]. Why would plants make compounds that are able to act as estrogens in the human body? Obviously, soybeans do not intentionally produce phytoestrogens to prevent breast cancer in Japanese women.

scholarly journals Global impacts of chromosomal imbalance on gene expression in Arabidopsis and other taxa

2018 ◽  
Vol 115 (48) ◽  
pp. E11321-E11330 ◽  
Author(s):  
Jie Hou ◽  
Xiaowen Shi ◽  
Chen Chen ◽  
Md. Soliman Islam ◽  
Adam F. Johnson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Transcription Factors ◽  
Leaf Tissue ◽  
Global Gene Expression ◽  
Published Data ◽  
Chromosomal Imbalance ◽  
Regulatory Processes ◽  
Expression Of Genes ◽  
Global Impacts

Changes in dosage of part of the genome (aneuploidy) have long been known to produce much more severe phenotypic consequences than changes in the number of whole genomes (ploidy). To examine the basis of these differences, global gene expression in mature leaf tissue for all five trisomies and in diploids, triploids, and tetraploids of Arabidopsis thaliana was studied. The trisomies displayed a greater spread of expression modulation than the ploidy series. In general, expression of genes on the varied chromosome ranged from compensation to dosage effect, whereas genes from the remainder of the genome ranged from no effect to reduced expression approaching the inverse level of chromosomal imbalance (2/3). Genome-wide DNA methylation was examined in each genotype and found to shift most prominently with trisomy 4 but otherwise exhibited little change, indicating that genetic imbalance is generally mechanistically unrelated to DNA methylation. Independent analysis of gene functional classes demonstrated that ribosomal, proteasomal, and gene body methylated genes were less modulated compared with all classes of genes, whereas transcription factors, signal transduction components, and organelle-targeted protein genes were more tightly inversely affected. Comparing transcription factors and their targets in the trisomies and in expression networks revealed considerable discordance, illustrating that altered regulatory stoichiometry is a major contributor to genetic imbalance. Reanalysis of published data on gene expression in disomic yeast and trisomic mouse cells detected similar stoichiometric effects across broad phylogenetic taxa, and indicated that these effects reflect normal gene regulatory processes.

scholarly journals Transcriptional activation and repression by Fos are independent functions: the C terminus represses immediate-early gene expression via CArG elements.

1990 ◽  
Vol 10 (8) ◽  
pp. 4243-4255 ◽  
Author(s):  
D Gius ◽  
X M Cao ◽  
F J Rauscher ◽  
D R Cohen ◽  
T Curran ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
Early Gene ◽  
Immediate Early ◽  
Striking Similarity ◽  
Independent Functions

The Fos-Jun complex has been shown to activate transcription through the regulatory element known as the AP-1 binding site. We show that Fos down regulates several immediate-early genes (c-fos, Egr-1, and Egr-2) after mitogenic stimulation. Specifically, we demonstrate that the target for this repression is a sequence of the form CC(A/T)6GG, also known as a CArG box. Whereas Fos bound to the AP-1 site through a domain rich in basic amino acids and associated with Jun via a leucine zipper interaction, mutant Fos proteins lacking these structures were still capable of causing repression. Furthermore, Jun neither enhanced nor inhibited down regulation by Fos. Critical residues required for repression are located within the C-terminal 27 amino acids of c-Fos, since v-Fos and C-terminal truncations of c-Fos did not down regulate. In addition, transfer of 180 c-Fos C-terminal amino acids to Jun conferred upon it the ability to repress. Finally, Fra-1, a Fos-related protein which has striking similarity to Fos in its C-terminal 40 amino acids, also down regulated Egr-1 expression. Thus, Fos is a transcriptional regulator that can activate or repress gene expression by way of two separate functional domains that act on distinct regulatory elements.

scholarly journals HOS15 is a transcriptional corepressor of NPR1-mediated gene activation of plant immunity

2020 ◽  
Vol 117 (48) ◽  
pp. 30805-30815
Author(s):  
Mingzhe Shen ◽  
Chae Jin Lim ◽  
Junghoon Park ◽  
Jeong Eun Kim ◽  
Dongwon Baek ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ubiquitin Ligase ◽  
Transcriptional Activation ◽  
Plant Immunity ◽  
Gene Activation ◽  
Transcriptional Corepressor ◽  
Defense Gene Expression ◽  
Dynamic Regulation ◽  
Defense Gene ◽  
Transcriptional Corepressors

Transcriptional regulation is a complex and pivotal process in living cells. HOS15 is a transcriptional corepressor. Although transcriptional repressors generally have been associated with inactive genes, increasing evidence indicates that, through poorly understood mechanisms, transcriptional corepressors also associate with actively transcribed genes. Here, we show that HOS15 is the substrate receptor for an SCF/CUL1 E3 ubiquitin ligase complex (SCFHOS15) that negatively regulates plant immunity by destabilizing transcriptional activation complexes containing NPR1 and associated transcriptional activators. In unchallenged conditions, HOS15 continuously eliminates NPR1 to prevent inappropriate defense gene expression. Upon defense activation, HOS15 preferentially associates with phosphorylated NPR1 to stimulate rapid degradation of transcriptionally active NPR1 and thus limit the extent of defense gene expression. Our findings indicate that HOS15-mediated ubiquitination and elimination of NPR1 produce effects contrary to those of CUL3-containing ubiquitin ligase that coactivate defense gene expression. Thus, HOS15 plays a key role in the dynamic regulation of pre- and postactivation host defense.

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