Hit-and-run transcriptional control by bZIP1 mediates rapid nutrient signaling in Arabidopsis
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE54049 | GEO | 2014/06/23
SECONDARY ACCESSION(S): PRJNA234482
REPOSITORIES: GEO
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Project description:To identify potential transient interactions between a TF and its targets, we developed an approach that can identify primary targets based either on TF-induced regulation or TF-binding, assayed in the same samples. Our studies focused on the TF bZIP1 (BASIC LEUCINE ZIPPER 1), a central integrator of cellular and metabolic signaling. To discern the mechanisms by which bZIP1 regulates a gene netowork in response to a nitrogen (N)-signal perceived in vivo, we perturbed both bZIP1 and the N-signal that it transduces in a cell-based transient expression system called TARGET (Transient Assay Reporting Genome-wide Effects of Transcription factors). To identify the genome-wide targets of bZIP1 in response to a N-signal, we transiently perturbed both the TF and the signal in the TARGET cell-based system. Specifically, bZIP1 was transiently overexpressed in root protoplasts following transfection with a 35S::GR::bZIP1 construct containing an RFP (red fluorescent protein) selectable marker gene. bZIP1 transfected cells were sequentially treated with: i) an inorganic nitrogen signal (+/-N), ii) cycloheximide (CHX) to block the synthesis of proteins, and iii) dexamethasone (DEX) to induce nuclear import of the GR::bZIP1 protein. To identify both the TF-regulated and the TF-bound genes, transcriptome analysis of transfected cells and micro-ChIP data (using anti-GR antibodies), were carried out in parallel . This submission represents transcriptome component of study.
2014-06-23 | E-GEOD-54049 | biostudies-arrayexpress
Project description:BACKGROUND:Dynamic transcriptional regulation is critical for an organism's response to environmental signals and yet remains elusive to capture. Such transcriptional regulation is mediated by master transcription factors (TF) that control large gene regulatory networks. Recently, we described a dynamic mode of TF regulation named "hit-and-run". This model proposes that master TF can interact transiently with a set of targets, but the transcription of these transient targets continues after the TF dissociation from the target promoter. However, experimental evidence validating active transcription of the transient TF-targets is still lacking. RESULTS:Here, we show that active transcription continues after transient TF-target interactions by tracking de novo synthesis of RNAs made in response to TF nuclear import. To do this, we introduced an affinity-labeled 4-thiouracil (4tU) nucleobase to specifically isolate newly synthesized transcripts following conditional TF nuclear import. Thus, we extended the TARGET system (Transient Assay Reporting Genome-wide Effects of Transcription factors) to include 4tU-labeling and named this new technology TARGET-tU. Our proof-of-principle example is the master TF Basic Leucine Zipper 1 (bZIP1), a central integrator of metabolic signaling in plants. Using TARGET-tU, we captured newly synthesized mRNAs made in response to bZIP1 nuclear import at a time when bZIP1 is no longer detectably bound to its target. Thus, the analysis of de novo transcripomics demonstrates that bZIP1 may act as a catalyst TF to initiate a transcriptional complex ("hit"), after which active transcription by RNA polymerase continues without the TF being bound to the gene promoter ("run"). CONCLUSION:Our findings provide experimental proof for active transcription of transient TF-targets supporting a "hit-and-run" mode of action. This dynamic regulatory model allows a master TF to catalytically propagate rapid and broad transcriptional responses to changes in environment. Thus, the functional read-out of de novo transcripts produced by transient TF-target interactions allowed us to capture new models for genome-wide transcriptional control. Root protoplasts were transfected with 35S::GR::bZIP1 or Empty vector (EV=pJD385_35S::GR) constructs and cells were sequentially treated with: i) the nitrogen signal (N), ii) cycloheximide (CHX), iii) dexamethasone (DEX; for review see Bargmann et. al 2013). Cells were exposed to 4tU to affinity-label newly synthesized transcripts prior RNA extraction followed by specific pull down of 4tu-fractions and hybridization on Arabidopsis ATH1 microarray chips.
2016-02-08 | E-GEOD-69389 | biostudies-arrayexpress
Project description:BACKGROUND:Dynamic transcriptional regulation is critical for an organism's response to environmental signals and yet remains elusive to capture. Such transcriptional regulation is mediated by master transcription factors (TF) that control large gene regulatory networks. Recently, we described a dynamic mode of TF regulation named "hit-and-run". This model proposes that master TF can interact transiently with a set of targets, but the transcription of these transient targets continues after the TF dissociation from the target promoter. However, experimental evidence validating active transcription of the transient TF-targets is still lacking. RESULTS:Here, we show that active transcription continues after transient TF-target interactions by tracking de novo synthesis of RNAs made in response to TF nuclear import. To do this, we introduced an affinity-labeled 4-thiouracil (4tU) nucleobase to specifically isolate newly synthesized transcripts following conditional TF nuclear import. Thus, we extended the TARGET system (Transient Assay Reporting Genome-wide Effects of Transcription factors) to include 4tU-labeling and named this new technology TARGET-tU. Our proof-of-principle example is the master TF Basic Leucine Zipper 1 (bZIP1), a central integrator of metabolic signaling in plants. Using TARGET-tU, we captured newly synthesized mRNAs made in response to bZIP1 nuclear import at a time when bZIP1 is no longer detectably bound to its target. Thus, the analysis of de novo transcripomics demonstrates that bZIP1 may act as a catalyst TF to initiate a transcriptional complex ("hit"), after which active transcription by RNA polymerase continues without the TF being bound to the gene promoter ("run"). CONCLUSION:Our findings provide experimental proof for active transcription of transient TF-targets supporting a "hit-and-run" mode of action. This dynamic regulatory model allows a master TF to catalytically propagate rapid and broad transcriptional responses to changes in environment. Thus, the functional read-out of de novo transcripts produced by transient TF-target interactions allowed us to capture new models for genome-wide transcriptional control.
2016-02-08 | GSE69389 | GEO
Project description:It was our goal to discern the epigenomic signatures of the ventral hippocampus, in male and female mice in a double hit model of acute stress: one hit of acute restraint stress followed by forced swim stress one week later.
2022-06-20 | GSE200670 | GEO
Project description:Cell-based reporting system of primary TF targets.
| PRJNA234383 | ENA
Project description:Soil salinity increasingly causes crop losses worldwide. Although roots are the primary targets of salt stress, the signaling networks that facilitate metabolic reprogramming to induce stress tolerance are less understood than those in leaves. Here, a combination of transcriptomic and metabolic approaches was performed in salt-treated Arabidopsis thaliana roots, which revealed that the group S1 basic leucine zipper transcription factors bZIP1 and bZIP53 reprogram primary C- and N-metabolism. In particular, gluconeogenesis and amino acid catabolism are affected by these transcription factors. Importantly, bZIP1 expression reflects cellular stress and energy status in roots. In addition to the well-described abiotic stress response pathway initiated by the hormone abscisic acid (ABA) and executed by SnRK2 (Snf1-RELATED-PROTEIN-KINASE2) and AREB-like bZIP factors, we identify a structurally related ABA-independent signaling module consisting of SnRK1s and S1 bZIPs. Crosstalk between these signaling pathways recruits particular bZIP factor combinations to establish at least four distinct gene expression patterns. Understanding this signaling network provides a framework for securing future crop productivity. RNA from roots from Control and salt treated hydroponically grown seedlings were extracted and subjected to microarray analysis
2015-09-02 | E-GEOD-71001 | biostudies-arrayexpress
Project description:Soil salinity increasingly causes crop losses worldwide. Although roots are the primary targets of salt stress, the signaling networks that facilitate metabolic reprogramming to induce stress tolerance are less understood than those in leaves. Here, a combination of transcriptomic and metabolic approaches was performed in salt-treated Arabidopsis thaliana roots, which revealed that the group S1 basic leucine zipper transcription factors bZIP1 and bZIP53 reprogram primary C- and N-metabolism. In particular, gluconeogenesis and amino acid catabolism are affected by these transcription factors. Importantly, bZIP1 expression reflects cellular stress and energy status in roots. In addition to the well-described abiotic stress response pathway initiated by the hormone abscisic acid (ABA) and executed by SnRK2 (Snf1-RELATED-PROTEIN-KINASE2) and AREB-like bZIP factors, we identify a structurally related ABA-independent signaling module consisting of SnRK1s and S1 bZIPs. Crosstalk between these signaling pathways recruits particular bZIP factor combinations to establish at least four distinct gene expression patterns. Understanding this signaling network provides a framework for securing future crop productivity.
2015-09-02 | GSE71001 | GEO
Project description:During the maturation of myofibers, the expression and activity of the basic leucine zipper TF Maf are increased compared to developmental stages. To determine the gene program regulated by this TF, we performed ChIP-seq against Maf and H3K27ac in adult gastrocnemius and quadriceps skeletal muscles.
2023-05-31 | GSE211541 | GEO
Project description:The Arabidopsis basic leucine zipper transcription factor bZIP29 of the bZIP group I TF family, expressed mainly in proliferative tissues, is functionally characterized in this study. Genes bound by bZIP29 were mapped genome-wide using a tandem ChIP procedure (TChAP) on cell cultures expressing the TF fused to the His-Bio-His tag. The generated data suggests that bZIP29 might be an important player in the reorganization of cell walls during cell proliferation.
2017-05-13 | E-MTAB-3754 | biostudies-arrayexpress
Project description:Most transcription factors possess at least one long intrinsically disordered transactivation domain that binds to a variety of co-activators and co-repressors and plays a key role in modulating the transcriptional activity. Despite the crucial importance of these mechanisms, the structural and functional basis of transactivation domain in yet poorly understood. Here, we focused on ATF4/CREB-2, an essential transcription factor for cellular stress adaptation. We found that the N-terminal region of the transactivation domain is involved in transient long-range interactions with the basic-leucine zipper domain. In vitro phosphorylation assays with the protein kinase CK2 show that the presence of the basic-leucine zipper domain is required for optimal phosphorylation of the transactivation domain. This study uncovers the intricate coupling existing between the transactivation and basic-leucine zipper domains of ATF4 and highlights its potential functional relevance.
2023-03-11 | PXD029704 | Pride