scholarly journals An ancestral Wnt-Brachyury feedback loop and recruitment of mesoderm-determining target genes revealed by comparative Brachyury target screens

2021 ◽  
Author(s):  
Michaela Schwaiger ◽  
Carmen Andrikou ◽  
Rohit Dnyansagar ◽  
Patricio Ferrer Murguia ◽  
Periklis Paganos ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Sea Urchin ◽  
Feedback Loop ◽  
Target Genes ◽  
Sea Anemone ◽  
Vertebrate Lineage ◽  
Evolutionary Transitions ◽  
Ancestral Gene ◽  
A Genome ◽  
Gene Regulatory

Abstract Transcription factors are crucial drivers of cellular differentiation during animal development and often share ancient evolutionary origins. The T-box transcription factor Brachyury plays a pivotal role as an early mesoderm determinant and neural repressor in vertebrates; yet, the ancestral function and key evolutionary transitions of the role of this transcription factor remain obscure. Here, we present a genome-wide target gene screen using ChIP-seq in the sea anemone Nematostella vectensis, an early branching non-bilaterian, and the sea urchin Strongylocentrotus purpuratus, a representative of the sister lineage of chordates. Our analysis reveals an ancestral gene regulatory feedback loop connecting Brachyury, FoxA and canonical Wnt signaling involved in axial patterning that predates the cnidarian-bilaterian split about 700 million years ago. Surprisingly, we also found that part of the gene regulatory network controlling the fate of neuromesodermal progenitors in vertebrates was already present in the common ancestor of cnidarians and bilaterians. However, while several neuronal Brachyury target genes are ancestrally shared, hardly any of the key mesodermal downstream targets in vertebrates are found in the sea anemone or the sea urchin. Our study suggests that a limited number of target genes involved in mesoderm formation were newly acquired in the vertebrate lineage, leading to a dramatic shift in the function of this ancestral developmental regulator.

Autoregulated Expression of Schizosaccharomyces pombe Meiosis-Specific Transcription Factor Mei4 and a Genome-Wide Search for Its Target Genes

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1497-1508 ◽  
Author(s):  
Hiroko Abe ◽  
Chikashi Shimoda
Keyword(s):  
Transcription Factor ◽  
Schizosaccharomyces Pombe ◽  
Target Genes ◽  
Northern Blotting ◽  
Forkhead Transcription Factor ◽  
Gene Encoding ◽  
Putative Promoter Region ◽  
Cis Acting ◽  
A Genome ◽  
Genome Wide Search

Abstract The Schizosaccharomyces pombe mei4+ gene encoding a forkhead transcription factor is necessary for the progression of meiosis and sporulation. We searched for novel meiotic genes, the expression of which is dependent on Mei4p, since only the spo6+ gene has been assigned to its targets. Six known genes responsible for meiotic recombination were examined by Northern blotting, but none were Mei4 dependent for transcription. We determined the important cis-acting element, designated FLEX, to which Mei4p can bind. The S. pombe genome sequence database (The Sanger Centre, UK) was scanned for the central core heptamer and its flanking 3′ sequence of FLEX composed of 17 nucleotides, and 10 candidate targets of Mei4 were selected. These contained a FLEX-like sequence in the 5′ upstream nontranslatable region within 1 kb of the initiation codon. Northern blotting confirmed that 9 of them, named mde1+ to mde9+, were transcriptionally induced during meiosis and were dependent on mei4+. Most mde genes have not been genetically defined yet, except for mde9+, which is identical to spn5+, which encodes one of the septin family of proteins. mde3+ and a related gene pit1+ encode proteins related to Saccharomyces cerevisiae Ime2. The double disruptant frequently produced asci having an abnormal number and size of spores, although it completed meiosis. We also found that the forkhead DNA-binding domain of Mei4p binds to the FLEX-like element in the putative promoter region of mei4 and that the maximum induction level of mei4 mRNA required functional mei4 activity. Furthermore, expression of a reporter gene driven by the authentic mei4 promoter was induced in vegetative cells by ectopic overproduction of Mei4p. These results suggest that mei4 transcription is positively autoregulated.

scholarly journals Functional effects of variation in transcription factor binding highlight long-range gene regulation by epromoters

2019 ◽  
Author(s):  
Joanna Mitchelmore ◽  
Nastasiya Grinberg ◽  
Chris Wallace ◽  
Mikhail Spivakov
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Statistical Power ◽  
Target Genes ◽  
Allelic Variation ◽  
Regulatory Function ◽  
Regulatory Sequences ◽  
Distal Enhancer ◽  
Association Testing ◽  
Gene Regulatory

AbstractIdentifying DNA cis-regulatory modules (CRMs) that control the expression of specific genes is crucial for deciphering the logic of transcriptional control. Natural genetic variation can point to the possible gene regulatory function of specific sequences through their allelic associations with gene expression. However, comprehensive identification of causal regulatory sequences in brute-force association testing without incorporating prior knowledge is challenging due to limited statistical power and effects of linkage disequilibrium. Sequence variants affecting transcription factor (TF) binding at CRMs have a strong potential to influence gene regulatory function, which provides a motivation for prioritising such variants in association testing. Here, we generate an atlas of CRMs showing predicted allelic variation in TF binding affinity in human lymphoblastoid cell lines (LCLs) and test their association with the expression of their putative target genes inferred from Promoter Capture Hi-C and immediate linear proximity. We reveal over 1300 CRM TF-binding variants associated with target gene expression, the majority of them undetected with standard association testing. A large proportion of CRMs showing associations with the expression of genes they contact in 3D localise to the promoter regions of other genes, supporting the notion of ‘epromoters’: dual-action CRMs with promoter and distal enhancer activity.

scholarly journals The TEA Transcription Factor Tec1 Confers Promoter-Specific Gene Regulation by Ste12-Dependent and -Independent Mechanisms

2010 ◽  
Vol 9 (4) ◽  
pp. 514-531 ◽  
Author(s):  
Barbara Heise ◽  
Julia van der Felden ◽  
Sandra Kern ◽  
Mario Malcher ◽  
Stefan Brückner ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Target Genes ◽  
Specific Gene ◽  
Dependent Manner ◽  
A Genome ◽  
Regulated Gene Expression

ABSTRACT In Saccharomyces cerevisiae, the TEA transcription factor Tec1 is known to regulate target genes together with a second transcription factor, Ste12. Tec1-Ste12 complexes can activate transcription through Tec1 binding sites (TCSs), which can be further combined with Ste12 binding sites (PREs) for cooperative DNA binding. However, previous studies have hinted that Tec1 might regulate transcription also without Ste12. Here, we show that in vivo, physiological amounts of Tec1 are sufficient to stimulate TCS-mediated gene expression and transcription of the FLO11 gene in the absence of Ste12. In vitro, Tec1 is able to bind TCS elements with high affinity and specificity without Ste12. Furthermore, Tec1 contains a C-terminal transcriptional activation domain that confers Ste12-independent activation of TCS-regulated gene expression. On a genome-wide scale, we identified 302 Tec1 target genes that constitute two distinct classes. A first class of 254 genes is regulated by Tec1 in a Ste12-dependent manner and is enriched for genes that are bound by Tec1 and Ste12 in vivo. In contrast, a second class of 48 genes can be regulated by Tec1 independently of Ste12 and is enriched for genes that are bound by the stress transcription factors Yap6, Nrg1, Cin5, Skn7, Hsf1, and Msn4. Finally, we find that combinatorial control by Tec1-Ste12 complexes stabilizes Tec1 against degradation. Our study suggests that Tec1 is able to regulate TCS-mediated gene expression by Ste12-dependent and Ste12-independent mechanisms that enable promoter-specific transcriptional control.

scholarly journals Identification of key tissue-specific, biological processes by integrating enhancer information in maize gene regulatory networks

2020 ◽  
Author(s):  
Maud Fagny ◽  
Marieke Lydia Kuijjer ◽  
Maike Stam ◽  
Johann Joets ◽  
Olivier Turc ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Binding Sites ◽  
Regulatory Network ◽  
Tissue Specificity ◽  
Target Genes ◽  
Specific Gene ◽  
Tissue Specific ◽  
Genome Wide ◽  
Gene Regulatory

AbstractEnhancers are important regulators of gene expression during numerous crucial processes including tissue differentiation across development. In plants, their recent molecular characterization revealed their capacity to activate the expression of several target genes through the binding of transcription factors. Nevertheless, identifying these target genes at a genome-wide level remains a challenge, in particular in species with large genomes, where enhancers and target genes can be hundreds of kilobases away. Therefore, the contribution of enhancers to regulatory network is still poorly understood in plants. In this study, we investigate the enhancer-driven regulatory network of two maize tissues at different stages: leaves at seedling stage and husks (bracts) at flowering. Using a systems biology approach, we integrate genomic, epigenomic and transcriptomic data to model the regulatory relationship between transcription factors and their potential target genes. We identify regulatory modules specific to husk and V2-IST, and show that they are involved in distinct functions related to the biology of each tissue. We evidence enhancers exhibiting binding sites for two distinct transcription factor families (DOF and AP2/ERF) that drive the tissue-specificity of gene expression in seedling immature leaf and husk. Analysis of the corresponding enhancer sequences reveals that two different transposable element families (TIR transposon Mutator and MITE Pif/Harbinger) have shaped the regulatory network in each tissue, and that MITEs have provided new transcription factor binding sites that are involved in husk tissue-specificity.SignificanceEnhancers play a major role in regulating tissue-specific gene expression in higher eukaryotes, including angiosperms. While molecular characterization of enhancers has improved over the past years, identifying their target genes at the genome-wide scale remains challenging. Here, we integrate genomic, epigenomic and transcriptomic data to decipher the tissue-specific gene regulatory network controlled by enhancers at two different stages of maize leaf development. Using a systems biology approach, we identify transcription factor families regulating gene tissue-specific expression in husk and seedling leaves, and characterize the enhancers likely to be involved. We show that a large part of maize enhancers is derived from transposable elements, which can provide novel transcription factor binding sites crucial to the regulation of tissue-specific biological functions.

P1-055: A genome-wide search for STOX1 target genes, a transcription factor associated with Alzheimer's disease

2010 ◽  
Vol 6 ◽  
pp. S189-S189
Author(s):  
Daan Van Abel ◽  
Marie Van Dijk ◽  
Dennis Y.M. Lo ◽  
Rossa W.K. Chiu ◽  
Fiona M.F. Lun ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transcription Factor ◽  
Target Genes ◽  
Genome Wide ◽  
A Genome ◽  
Genome Wide Search

scholarly journals Functional effects of variation in transcription factor binding highlight long-range gene regulation by epromoters

2020 ◽  
Vol 48 (6) ◽  
pp. 2866-2879 ◽  
Author(s):  
Joanna Mitchelmore ◽  
Nastasiya F Grinberg ◽  
Chris Wallace ◽  
Mikhail Spivakov
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Statistical Power ◽  
Target Genes ◽  
Allelic Variation ◽  
Regulatory Function ◽  
Regulatory Sequences ◽  
Distal Enhancer ◽  
Association Testing ◽  
Gene Regulatory

Abstract Identifying DNA cis-regulatory modules (CRMs) that control the expression of specific genes is crucial for deciphering the logic of transcriptional control. Natural genetic variation can point to the possible gene regulatory function of specific sequences through their allelic associations with gene expression. However, comprehensive identification of causal regulatory sequences in brute-force association testing without incorporating prior knowledge is challenging due to limited statistical power and effects of linkage disequilibrium. Sequence variants affecting transcription factor (TF) binding at CRMs have a strong potential to influence gene regulatory function, which provides a motivation for prioritizing such variants in association testing. Here, we generate an atlas of CRMs showing predicted allelic variation in TF binding affinity in human lymphoblastoid cell lines and test their association with the expression of their putative target genes inferred from Promoter Capture Hi-C and immediate linear proximity. We reveal >1300 CRM TF-binding variants associated with target gene expression, the majority of them undetected with standard association testing. A large proportion of CRMs showing associations with the expression of genes they contact in 3D localize to the promoter regions of other genes, supporting the notion of ‘epromoters’: dual-action CRMs with promoter and distal enhancer activity.

Lineage-Specific Mitotic Bookmarking by Hematopoietic Transcription Factor GATA1

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 547-547
Author(s):  
Stephan Kadauke ◽  
Jan M Pawlicki ◽  
Maheshi Udugama ◽  
Jordan C Achtman ◽  
Yong Cheng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Target Genes ◽  
Confocal Imaging ◽  
Erythroid Precursor ◽  
Cell Divisions ◽  
A Genome ◽  
Target Sites ◽  
Lineage Stability ◽  
Mitotic Chromatin

Abstract Abstract 547 Hematopoietic lineage choice decisions are stably maintained throughout many cell divisions. For example, erythroid precursor cells undergo several rounds of cell division during their maturation. During each mitosis, most transcription factors separate from chromatin causing transcription to cease globally. Mitosis therefore poses a challenge for transcription factors to re-associate with the appropriate target sites in chromatin of newborn cells. The epigenetic mechanisms that cement lineage stability and resist cell reprogramming during mitosis are poorly understood, although recent evidence supports the existence of “bookmarking” factors that remain bound to mitotic chromatin. Since the hematopoietic transcription factor GATA1 controls the expression of essentially all erythroid-specific genes, we asked whether it might play a role in maintaining erythroid gene expression programs throughout the cell cycle. Live cell confocal imaging revealed that foci of high GATA1 density are present within mitotic chromatin. Using a novel approach that combines mitotic cell sorting with ChIP-Seq, we defined mitotic GATA1 binding sites on a genome-wide scale. Remarkably, whereas GATA1 vacated the great majority of its target sites during mitosis, including the archetypical GATA1 regulated genes α- and β-globin, those target sites where GATA1 was maintained during mitosis showed a strong tendency to reside near genes encoding key developmental regulators of hematopoiesis (e.g., Zfpm1, Nfe2, Klf1, Gata1, Gata2, Runx1). Tissue-specific GATA1 co-regulators such as FOG-1 and the SCL complex dissociated from GATA1-occupied elements during mitosis, suggesting that GATA1 persists at these sites to facilitate their spatially and temporally appropriate reassembly upon exit from mitosis. Consistent with the notion that GATA1 acts as a mitotic bookmark for its mitotic target genes, timed primary transcript analysis revealed that genes that are marked by GATA1 during mitosis re-activate more rapidly upon G1 entry than those that are not. To directly address the functional importance of mitotic chromatin binding, we developed a version of GATA1 that is selectively degraded during mitosis but remains stable during interphase. This strategy allowed us to prove, for the first time, that the presence of a transcription factor is required specifically during mitosis for timely reactivation of its mitotic target genes. In addition, mitotically disrupted GATA1 failed to fully repress markers of immature erythroid precursors (e.g., Kit, Lyl1), highlighting a potential role of mitotic GATA1 bookmarking for establishing and maintaining lineage- and developmental stage-specific transcriptional programs. Follow-up mechanistic experiments to define the mode by which GATA1 operates during mitosis are underway and will be discussed at the meeting. Together, these studies establish GATA1 as a bona fide mitotic bookmarking factor and provide a deeper understanding by which transcription programs are faithfully perpetuated through cell divisions to maintain lineage stability. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Activation of silent secondary metabolite gene clusters by nucleosome map-guided positioning of the synthetic transcription factor VPR-dCas9

2020 ◽  
Author(s):  
Andreas Schüller ◽  
Lisa Wolansky ◽  
Harald Berger ◽  
Lena Studt ◽  
Agnieszka Gacek-Matthews ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Negative Impact ◽  
Gene Clusters ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Activation Domains ◽  
Turn On ◽  
Binding Domains ◽  
A Genome

AbstractCurrent methods for forced expression of selected target genes are based on promoter exchange or on overexpressing native or hybrid transcriptional activators in which gene-specific DNA binding domains are coupled to strong activation domains. While these approaches are very useful for promoters with known or synthetically introduced transcription factor binding sites, they are not suitable to turn on genes in biosynthetic gene clusters which often lack pathway-specific activators. To expand the discovery toolbox, we designed a Cas9-based RNA guided synthetic transcription activation system for Aspergillus nidulans based on enzymatically disabled dCas9 fused to three consecutive activation domains (VPR-dCas9). Targeting two biosynthetic gene clusters involved in the production of secondary metabolites, we demonstrate the utility of the system. Especially in silent regions facultative heterochromatin and strictly positioned nucleosomes can constitute a relevant obstacle to the transcriptional machinery. To avoid this negative impact and to facilitate optimal positioning of RNA-guided VPR-dCas9 to our targeted promoters we have created a genome-wide nucleosome map to identify the cognate nucleosome-free-regions (NFRs). Based on these maps, different single-guide RNAs (sgRNA) were designed and tested for their targeting and activation potential. Our results demonstrate that the system can be used to activate silent BGCs in A. nidulans, partially to very high expression levels and also open the opportunity to stepwise turn on individual genes within a BGC that allows to decipher the correlated biosynthetic pathway.

scholarly journals A Positive Regulatory Feedback Loop Between 1 EKLF/ KLF1 and TAL1/SCL2 Sustaining the Erythropoiesis

2021 ◽  
Author(s):  
Chun-Hao Hung ◽  
Yu-Szu Huang ◽  
Tung-Liang Lee ◽  
Kang-Chung Yang ◽  
Yu-Chiau Shyu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Feedback Loop ◽  
Target Genes ◽  
Fetal Liver ◽  
Erythroid Differentiation ◽  
Cellular Analysis ◽  
Direct Target ◽  
Regulatory Feedback Loop

The erythroid Krppel-like factor EKLF/KLF1 is a hematopoietic transcription factor binding to CACCC DNA motif and participating in the regulation of erythroid differentiation. With combined use of microarray-based gene expression profiling and promoter-based ChIP-chip assay of E14.5 fetal liver cells from wild type (WT) and EKLF-knockout (Eklf-/-) mouse embryos, we have identified the pathways and direct target genes activated or repressed by EKLF. This genome-wide study together with molecular/ cellular analysis of mouse erythroleukemic cells (MEL) indicate that among the downstream direct target genes of EKLF is Tal1/Scl. Tal1/Scl encodes another DNA-binding hematopoietic transcription factor TAL1/SCL known to be an Eklf activator and essential for definitive erythroid differentiation. Further identification of the authentic Tall gene promoter in combination with in vivo genomic footprinting approach and DNA reporter assay demonstrate that EKLF activates Tall gene through binding to a specific CACCC motif located in its promoter. These data establish the existence of a previously unknow positive regulatory feedback loop between two DNA-binding hematopoietic transcription factors that sustains the mammalian erythropoiesis.

scholarly journals Filtering of Data-Driven Gene Regulatory Networks Using Drosophila melanogaster as a Case Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Yesid Cuesta-Astroz ◽  
Guilherme Gischkow Rucatti ◽  
Leandro Murgas ◽  
Carol D. SanMartín ◽  
Mario Sanhueza ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drosophila Melanogaster ◽  
Gene Regulatory Networks ◽  
Binding Sites ◽  
Regulatory Networks ◽  
Target Genes ◽  
Regulation Of Gene Expression ◽  
Whole Genomes ◽  
Gene Regulatory

Gene Regulatory Networks (GRNs) allow the study of regulation of gene expression of whole genomes. Among the most relevant advantages of using networks to depict this key process, there is the visual representation of large amounts of information and the application of graph theory to generate new knowledge. Nonetheless, despite the many uses of GRNs, it is still difficult and expensive to assign Transcription Factors (TFs) to the regulation of specific genes. ChIP-Seq allows the determination of TF Binding Sites (TFBSs) over whole genomes, but it is still an expensive technique that can only be applied one TF at a time and requires replicates to reduce its noise. Once TFBSs are determined, the assignment of each TF and its binding sites to the regulation of specific genes is not trivial, and it is often performed by carrying out site-specific experiments that are unfeasible to perform in all possible binding sites. Here, we addressed these relevant issues with a two-step methodology using Drosophila melanogaster as a case study. First, our protocol starts by gathering all transcription factor binding sites (TFBSs) determined with ChIP-Seq experiments available at ENCODE and FlyBase. Then each TFBS is used to assign TFs to the regulation of likely target genes based on the TFBS proximity to the transcription start site of all genes. In the final step, to try to select the most likely regulatory TF from those previously assigned to each gene, we employ GENIE3, a random forest-based method, and more than 9,000 RNA-seq experiments from D. melanogaster. Following, we employed known TF protein-protein interactions to estimate the feasibility of regulatory events in our filtered networks. Finally, we show how known interactions between co-regulatory TFs of each gene increase after the second step of our approach, and thus, the consistency of the TF-gene assignment. Also, we employed our methodology to create a network centered on the Drosophila melanogaster gene Hr96 to demonstrate the role of this transcription factor on mitochondrial gene regulation.

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