scholarly journals Functional Analysis of Regulatory Elements in the Gene Promoter for an Abscission-Specific Cellulase from Bean and Isolation, Expression, and Binding Affinity of Three TGA-Type Basic Leucine Zipper Transcription Factors

2002 ◽  
Vol 130 (3) ◽  
pp. 1487-1496 ◽  
Author(s):  
M. L. Tucker
2011 ◽  
Vol 286 (12) ◽  
pp. 10449-10456 ◽  
Author(s):  
Song-iee Han ◽  
Kunio Yasuda ◽  
Kohsuke Kataoka

Pancreatic β-cell-restricted expression of insulin is established through several critical cis-regulatory elements located in the insulin gene promoter region. The principal cis elements are A-boxes, E1, and C1/RIPE3b. The β-cell-enriched transcription factors Pdx1 and Beta2 bind to the A-boxes and E1 element, respectively. A β-cell-specific trans-acting factor binding to C1/RIPE3b (termed RIPE3b1 activator) was detected by electrophoretic mobility shift assay and has been identified as MafA, a member of the Maf family of basic leucine zipper (bZip) proteins. Here, ATF2, a member of the ATF/CREB family of basic leucine zipper proteins, was identified as a component of the RIPE3b1 activator. ATF2 alone was unable to bind to the C1/RIPE3b element but acquired binding capacity upon complex formation with MafA. ATF2 also interacted with Pdx1 and Beta2, and co-expression of ATF2, MafA, Pdx1, and Beta2 resulted in a synergistic activation of the insulin promoter. Immunohistochemical analysis of mouse pancreas tissue sections showed that ATF2 is enriched in islet endocrine cells, including β-cells. RNAi-mediated knockdown of MafA or ATF2 in the MIN6 β-cell line resulted in a significant decrease in endogenous levels of insulin mRNA. These data indicate that ATF2 is an essential component of the positive regulators of the insulin gene expression.


2004 ◽  
Vol 380 (3) ◽  
pp. 695-703 ◽  
Author(s):  
Yongyi BI ◽  
Richard D. PALMITER ◽  
Kristi M. WOOD ◽  
Qiang MA

Phenolic antioxidants, such as tBHQ [2,5-di-(t-butyl)-1,4-hydroquinone], induce Mt1 (metallothionein 1) gene expression and accumulation of MT protein. Induction of Mt1 mRNA does not depend on protein synthesis, and correlates with oxidation–reduction functions of the antioxidants. In the present study, we analysed the biochemical pathway of the induction. Induction depends on the presence of MTF-1 (metal-activated transcription factor 1), a transcription factor that is required for metal-induced transcription of Mt1, but does not require nuclear factor erythroid 2-related factor 2, a tBHQ-activated CNC bZip (cap ‘n’ collar basic leucine zipper) protein, that is responsible for regulating genes encoding phase II drug-metabolizing enzymes. Moreover, tBHQ induces the expression of MRE-βGeo, a reporter gene driven by five metal response elements that constitute an optimal MTF-1 binding site. Reconstitution of Mtf1-null cells with MTF-1 restores induction by both zinc and tBHQ. Unlike activation of phase II genes by tBHQ, induction of Mt1 expression does not occur in the presence of EDTA, when cells are cultured in zinc-depleted medium, or in cells with reduced intracellular ‘free’ zinc due to overexpression of ZnT1, a zinc-efflux transporter, indicating that induction requires zinc. In addition, fluorescence imaging reveals that tBHQ increases cytoplasmic free zinc concentration by mobilizing intracellular zinc pools. These findings establish that phenolic antioxidants activate Mt1 transcription by a zinc-dependent mechanism, which involves MTF-1 binding to metal regulator elements in the Mt1 gene promoter.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2149
Author(s):  
Nkulu Kabange Rolly ◽  
Byung-Wook Yun

Nitrogen (N) is an essential macronutrient, which contributes substantially to the growth and development of plants. In the soil, nitrate (NO3) is the predominant form of N available to the plant and its acquisition by the plant involves several NO3 transporters; however, the mechanism underlying their involvement in the adaptive response under abiotic stress is poorly understood. Initially, we performed an in silico analysis to identify potential binding sites for the basic leucine zipper 62 transcription factor (AtbZIP62 TF) in the promoter of the target genes, and constructed their protein–protein interaction networks. Rather than AtbZIP62, results revealed the presence of cis-regulatory elements specific to two other bZIP TFs, AtbZIP18 and 69. A recent report showed that AtbZIP62 TF negatively regulated AtbZIP18 and AtbZIP69. Therefore, we investigated the transcriptional regulation of AtNPF6.2/NRT1.4 (low-affinity NO3 transporter), AtNPF6.3/NRT1.1 (dual-affinity NO3 transporter), AtNRT2.1 and AtNRT2.2 (high-affinity NO3 transporters), and AtGLU1 and AtGLU2 (both encoding glutamate synthase) in response to drought stress in Col-0. From the perspective of exploring the transcriptional interplay of the target genes with AtbZIP62 TF, we measured their expression by qPCR in the atbzip62 (lacking the AtbZIP62 gene) under the same conditions. Our recent study revealed that AtbZIP62 TF positively regulates the expression of AtPYD1 (Pyrimidine 1, a key gene of the de novo pyrimidine biosynthesis pathway know to share a common substrate with the N metabolic pathway). For this reason, we included the atpyd1-2 mutant in the study. Our findings revealed that the expression of AtNPF6.2/NRT1.4, AtNPF6.3/NRT1.1 and AtNRT2.2 was similarly regulated in atzbip62 and atpyd1-2 but differentially regulated between the mutant lines and Col-0. Meanwhile, the expression pattern of AtNRT2.1 in atbzip62 was similar to that observed in Col-0 but was suppressed in atpyd1-2. The breakthrough is that AtNRT2.2 had the highest expression level in Col-0, while being suppressed in atbzip62 and atpyd1-2. Furthermore, the transcript accumulation of AtGLU1 and AtGLU2 showed differential regulation patterns between Col-0 and atbzip62, and atpyd1-2. Therefore, results suggest that of all tested NO3 transporters, AtNRT2.2 is thought to play a preponderant role in contributing to NO3 transport events under the regulatory influence of AtbZIP62 TF in response to drought stress.


2020 ◽  
Vol 8 (7) ◽  
pp. 1045
Author(s):  
Yuping Xu ◽  
Yongchun Wang ◽  
Huizhang Zhao ◽  
Mingde Wu ◽  
Jing Zhang ◽  
...  

The basic leucine zipper (bZIP) proteins family is one of the largest and most diverse transcription factors, widely distributed in eukaryotes. However, no information is available regarding the bZIP gene family in Coniothyrium minitans, an important biocontrol agent of the plant pathogen Sclerotinia sclerotiorum. In this study, we identified 34 bZIP genes from the C. minitans genome, which were classified into 8 groups based on their phylogenetic relationships. Intron analysis showed that 28 CmbZIP genes harbored a variable number of introns, and 15 of them shared a feature that intron inserted into the bZIP domain. The intron position in bZIP domain was highly conserved, which was related to recognize the arginine (R) and could be treated as a genomic imprinting. Expression analysis of the CmbZIP genes in response to abiotic stresses indicated that they might play distinct roles in abiotic stress responses. Results showed that 22 CmbZIP genes were upregulated during the later stage of conidial development. Furthermore, transcriptome analysis indicated that CmbZIP genes are involved in different stages of mycoparasitism. Among deletion mutants of four CmbZIPs (CmbZIP07, -09, -13, and -16), only ΔCmbZIP16 mutants significantly reduced its tolerance to the oxidative stress. The other mutants exhibited no significant effects on colony morphology, mycelial growth, conidiation, and mycoparasitism. Taken together, our results suggested that CmbZIP genes play important roles in the abiotic stress responses, conidial development, and mycoparasitism. These results provide comprehensive information of the CmbZIP gene family and lay the foundation for further research on the bZIP gene family regarding their biological functions and evolutionary history.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haoyang Li ◽  
Lixia Li ◽  
Guodong ShangGuan ◽  
Chang Jia ◽  
Sinan Deng ◽  
...  

Abstract The basic leucine zipper (bZIP) is a widely known transcription factors family in eukaryotes. In plants, the role of bZIP proteins are crucial in various biological functions such as plant growth and development, seed maturation, response to light signal and environmental stress. To date, bZIP protein family has been comprehensively identified in Arabidopsis, castor, rice, ramie, soybean and other plant species, however, the complete genome-wide investigation of Carthamus tinctorius-bZIP family still remains unexplained. Here, we identified 52 putative bZIP genes from Carthamus tinctorius using a draft genome assembly and further analyzed their evolutionary classification, physicochemical properties, Conserved domain analysis, functional differentiation and the investigation of expression level in different tissues. Based on the common bZIP domain, CtbZIP family were clustered into 12 subfamilies renamed as (A–J, S, X), of which the X is a unique subfamily to Carthamus tinctorius. A total of 20 conserved protein motifs were found in CtbZIP proteins. The expression profiling of CtbZIP genes deciphered their tissue-specific pattern. Furthermore, the changes in CtbZIP transcript abundance suggested that their transcription regulation could be highly influenced by light intensity and hormones. Collectively, this study highlights all functional and regulatory elements of bZIP transcription factors family in Carthamus tinctorius which may serve as potential candidates for functional characterization in future.


2003 ◽  
Vol 374 (2) ◽  
pp. 423-431 ◽  
Author(s):  
Christopher D. DEPPMANN ◽  
Tina M. THORNTON ◽  
Fransiscus E. UTAMA ◽  
Elizabeth J. TAPAROWSKY

BATF is a member of the AP-1 (activator protein-1) family of bZIP (basic leucine zipper) transcription factors that form transcriptionally inhibitory, DNA binding heterodimers with Jun proteins. In the present study, we demonstrate that BATF is phosphorylated in vivo on multiple serine and threonine residues and at least one tyrosine residue. Reverse-polarity PAGE revealed that serine-43 and threonine-48 within the DNA binding domain of BATF are phosphorylated. To model phosphorylation of the BATF DNA binding domain, serine-43 was replaced by an aspartate residue. BATF(S43D) retains the ability to dimerize with Jun proteins in vitro and in vivo, and the BATF(S43D):Jun heterodimer localizes properly to the nucleus of cells. Interestingly, BATF(S43D) functions like wild-type BATF to reduce AP-1-mediated gene transcription, despite the observed inability of the BATF(S43D):Jun heterodimer to bind DNA. These data demonstrate that phosphorylation of serine-43 converts BATF from a DNA binding into a non-DNA binding inhibitor of AP-1 activity. Given that 40% of mammalian bZIP transcription factors contain a residue analogous to serine-43 of BATF in their DNA binding domains, the phosphorylation event described here represents a mechanism that is potentially applicable to the regulation of many bZIP proteins.


2000 ◽  
Vol 148 (6) ◽  
pp. 1165-1176 ◽  
Author(s):  
Sirpa Aho ◽  
Monique Buisson ◽  
Tiina Pajunen ◽  
Young W. Ryoo ◽  
Jean-Francois Giot ◽  
...  

The major target tissues for Epstein-Barr virus (EBV) infection are B lymphocytes and epithelial cells of the oropharyngeal zone. The product of the EBV BZLF1 early gene, EB1, a member of the basic leucine-zipper family of transcription factors, interacts with both viral and cellular promoters and transcription factors, modulating the reactivation of latent EBV infection. Here, we characterize a novel cellular protein interacting with the basic domains of EB1 and c-Jun, and competing of their binding to the AP1 consensus site. The transcript is present in a wide variety of human adult, fetal, and tumor tissues, and the protein is detected in the nuclei throughout the human epidermis and as either grainy or punctuate nuclear staining in the cultured keratinocytes. The overexpression of tagged cDNA constructs in keratinocytes revealed that the NH2 terminus is essential for the nuclear localization, while the central domain is responsible for the interaction with EB1 and for the phenotype of transfected keratinocytes similar to terminal differentiation. The gene was identified in tail-to-tail orientation with the periplakin gene (PPL) in human chromosome 16p13.3 and in a syntenic region in mouse chromosome 16. We designated this novel ubiquitously expressed nuclear protein as ubinuclein and the corresponding gene as UBN1.


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