scholarly journals Influence of the Valine Zipper Region on the Structure and Aggregation of the Basic Leucine Zipper (bZIP) Domain of Activating Transcription Factor 5 (ATF5)

2012 ◽  
Vol 9 (11) ◽  
pp. 3190-3199 ◽  
Author(s):  
Natalie A. Ciaccio ◽  
T. Steele Reynolds ◽  
C. Russell Middaugh ◽  
Jennifer S. Laurence
Keyword(s):  
Transcription Factor ◽  
Leucine Zipper ◽  
Basic Leucine Zipper ◽  
Bzip Domain ◽  
Activating Transcription Factor

scholarly journals Divest Yourself of a Preconceived Idea: Transcription Factor ATF6 Is Not a Soluble Protein!

2010 ◽  
Vol 21 (9) ◽  
pp. 1435-1438 ◽  
Author(s):  
Kazutoshi Mori
Keyword(s):  
Transcription Factor ◽  
Er Stress ◽  
Transcriptional Activation ◽  
Intracellular Signaling ◽  
Leucine Zipper ◽  
Transmembrane Protein ◽  
Basic Leucine Zipper ◽  
Induction Program ◽  
Activating Transcription Factor ◽  
The Unfolded Protein Response

The unfolded protein response (UPR), an evolutionarily conserved transcriptional induction program that is coupled with intracellular signaling from the endoplasmic reticulum (ER) to the nucleus, is activated to cope with ER stress and to maintain the homeostasis of the ER. In 1996, we isolated a basic leucine zipper protein, which had been previously named activating transcription factor (ATF)6, as a candidate transcription factor responsible for the mammalian UPR. Subsequent analysis, however, was confounding. The problem was eventually tracked down to an unusual property of ATF6: rather than being a soluble nuclear protein, as expected for an active transcription factor, ATF6 was instead synthesized as a transmembrane protein embedded in the ER, which was activated by ER stress-induced proteolysis. ATF6 was thus unique: an ER stress sensor/transducer that is involved in all steps of the UPR, from the sensing step in the ER to the transcriptional activation step in the nucleus.

Targeted disruption of the activating transcription factor 4 gene results in severe fetal anemia in mice

Blood ◽  
2002 ◽  
Vol 99 (3) ◽  
pp. 736-745 ◽  
Author(s):  
Howard C. Masuoka ◽  
Tim M. Townes
Keyword(s):  
Transcription Factor ◽  
Leucine Zipper ◽  
Cellular Proliferation ◽  
Fetal Liver ◽  
Embryonic Stem ◽  
Adenosine Monophosphate ◽  
Basic Leucine Zipper ◽  
Activating Transcription Factor

Abstract Activating transcription factor (ATF) 4 is a ubiquitous basic leucine-zipper transcription factor that is a member of the ATF/cyclic adenosine monophosphate responsive element–binding (CREB) protein family. To determine the in vivo function of ATF4, the ATF4 gene in murine embryonic stem cells was deleted and homozygous mutant mice were generated. ATF4 null fetuses were severely anemic because of an impairment in fetal-liver definitive hematopoiesis; the hematocrit in 15.5-day mutant fetuses was 0.15, whereas that in controls was 0.35. The fetal livers in homozygous ATF4 mutants were pale and hypoplastic. In vitro culture of fetal-liver cells showed fewer hematopoietic progenitors per embryo and a dramatic decrease in the size of progenitor colonies. Culture of primary murine embryonic fibroblasts showed a proliferative defect. These results suggest that ATF4 is critical, in a cell-autonomous manner, for normal cellular proliferation, especially for the high-level proliferation required during fetal-liver hematopoiesis.

scholarly journals Induction of metallothionein I by phenolic antioxidants requires metal-activated transcription factor 1 (MTF-1) and zinc

2004 ◽  
Vol 380 (3) ◽  
pp. 695-703 ◽  
Author(s):  
Yongyi BI ◽  
Richard D. PALMITER ◽  
Kristi M. WOOD ◽  
Qiang MA
Keyword(s):  
Transcription Factor ◽  
Phase Ii ◽  
Leucine Zipper ◽  
Gene Promoter ◽  
Phenolic Antioxidants ◽  
Related Factor ◽  
Basic Leucine Zipper ◽  
Free Zinc ◽  
Genes Encoding ◽  
Transcription Factor 1

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.

Basic leucine zipper transcription factor OsbZIP16 positively regulates drought resistance in rice

Plant Science ◽  
2012 ◽  
Vol 193-194 ◽  
pp. 8-17 ◽  
Author(s):  
Hao Chen ◽  
Wei Chen ◽  
Junli Zhou ◽  
Hang He ◽  
Liangbi Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drought Resistance ◽  
Leucine Zipper ◽  
Basic Leucine Zipper

scholarly journals Regulation of Nitrate (NO3) Transporters and Glutamate Synthase-Encoding Genes under Drought Stress in Arabidopsis: The Regulatory Role of AtbZIP62 Transcription Factor

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2149
Author(s):  
Nkulu Kabange Rolly ◽  
Byung-Wook Yun
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Leucine Zipper ◽  
Target Genes ◽  
De Novo ◽  
In Silico Analysis ◽  
Glutamate Synthase ◽  
Regulatory Elements ◽  
Transcript Accumulation ◽  
Basic Leucine Zipper

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.

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