scholarly journals DamID transcriptional profiling identifies the Snail/Scratch transcription factor Kahuli as Alk target in the Drosophila visceral mesoderm

2021 ◽  
Author(s):  
Patricia Mendoza-Garcia ◽  
Swaraj Basu ◽  
Sanjay Kumar Sukumar ◽  
Badrul Arefin ◽  
Georg Wolfstetter ◽  
...  

AbstractDevelopment of the midgut visceral muscle of Drosophila crucially depends on Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) signalling, which is needed to specify founder cells (FCs) in the circular visceral mesoderm (VM). While activation of the Alk receptor by its ligand Jelly Belly (Jeb) is well characterized, only a small number of target molecules have been identified. Here, we assayed RNA polymerase II (Pol II) occupancy in VM cells by using the targeted DamID (TaDa) approach. To identify Alk targets we employed comparative analysis of embryos overexpressing Jeb versus embryos with abrogated Alk activity, revealing differential expression of a number of genes, including the Snail/Scratch family transcription factor Kahuli (Kah). Upon further in vivo validation, we confirmed that Alk signalling regulates Kah mRNA expression in the VM. We show that Kah mutants display defects in the formation of midgut constrictions, similar to that of pointed (pnt) mutants. Analysis of publicly available ChIP data defined a Kah target-binding site similar to that of Snail. In addition, we compared genes that were differentially expressed in Kah mutants with publicly available Kah- and Pnt-ChIP datasets identifying a set of common target genes putatively regulated by Kah and Pnt in midgut constriction. Taken together, we (i) report a rich dataset of Alk responsive loci in the embryonic VM, (ii) provide the first functional characterization of the Kah transcription factor, identifying a role in embryonic midgut constriction, and (iii) suggest a model in which Kah and Pnt cooperate in embryonic midgut morphogenesis.

Development ◽  
2021 ◽  
Vol 148 (23) ◽  
Author(s):  
Patricia Mendoza-Garcia ◽  
Swaraj Basu ◽  
Sanjay Kumar Sukumar ◽  
Badrul Arefin ◽  
Georg Wolfstetter ◽  
...  

ABSTRACT Development of the Drosophila visceral muscle depends on Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) signaling, which specifies founder cells (FCs) in the circular visceral mesoderm (VM). Although Alk activation by its ligand Jelly Belly (Jeb) is well characterized, few target molecules have been identified. Here, we used targeted DamID (TaDa) to identify Alk targets in embryos overexpressing Jeb versus embryos with abrogated Alk activity, revealing differentially expressed genes, including the Snail/Scratch family transcription factor Kahuli (Kah). We confirmed Kah mRNA and protein expression in the VM, and identified midgut constriction defects in Kah mutants similar to those of pointed (pnt). ChIP and RNA-Seq data analysis defined a Kah target-binding site similar to that of Snail, and identified a set of common target genes putatively regulated by Kah and Pnt during midgut constriction. Taken together, we report a rich dataset of Alk-responsive loci in the embryonic VM and functionally characterize the role of Kah in the regulation of embryonic midgut morphogenesis.


2021 ◽  
Vol 22 (15) ◽  
pp. 8193
Author(s):  
Daniel Pérez-Cremades ◽  
Ana B. Paes ◽  
Xavier Vidal-Gómez ◽  
Ana Mompeón ◽  
Carlos Hermenegildo ◽  
...  

Background/Aims: Estrogen has been reported to have beneficial effects on vascular biology through direct actions on endothelium. Together with transcription factors, miRNAs are the major drivers of gene expression and signaling networks. The objective of this study was to identify a comprehensive regulatory network (miRNA-transcription factor-downstream genes) that controls the transcriptomic changes observed in endothelial cells exposed to estradiol. Methods: miRNA/mRNA interactions were assembled using our previous microarray data of human umbilical vein endothelial cells (HUVEC) treated with 17β-estradiol (E2) (1 nmol/L, 24 h). miRNA–mRNA pairings and their associated canonical pathways were determined using Ingenuity Pathway Analysis software. Transcription factors were identified among the miRNA-regulated genes. Transcription factor downstream target genes were predicted by consensus transcription factor binding sites in the promoter region of E2-regulated genes by using JASPAR and TRANSFAC tools in Enrichr software. Results: miRNA–target pairings were filtered by using differentially expressed miRNAs and mRNAs characterized by a regulatory relationship according to miRNA target prediction databases. The analysis identified 588 miRNA–target interactions between 102 miRNAs and 588 targets. Specifically, 63 upregulated miRNAs interacted with 295 downregulated targets, while 39 downregulated miRNAs were paired with 293 upregulated mRNA targets. Functional characterization of miRNA/mRNA association analysis highlighted hypoxia signaling, integrin, ephrin receptor signaling and regulation of actin-based motility by Rho among the canonical pathways regulated by E2 in HUVEC. Transcription factors and downstream genes analysis revealed eight networks, including those mediated by JUN and REPIN1, which are associated with cadherin binding and cell adhesion molecule binding pathways. Conclusion: This study identifies regulatory networks obtained by integrative microarray analysis and provides additional insights into the way estradiol could regulate endothelial function in human endothelial cells.


1999 ◽  
Vol 19 (11) ◽  
pp. 7589-7599 ◽  
Author(s):  
Mariano Ubeda ◽  
Mario Vallejo ◽  
Joel F. Habener

ABSTRACT The transcription factor CHOP (C/EBP homologous protein 10) is a bZIP protein induced by a variety of stimuli that evoke cellular stress responses and has been shown to arrest cell growth and to promote programmed cell death. CHOP cannot form homodimers but forms stable heterodimers with the C/EBP family of activating transcription factors. Although initially characterized as a dominant negative inhibitor of C/EBPs in the activation of gene transcription, CHOP-C/EBP can activate certain target genes. Here we show that CHOP interacts with members of the immediate-early response, growth-promoting AP-1 transcription factor family, JunD, c-Jun, and c-Fos, to activate promoter elements in the somatostatin, JunD, and collagenase genes. The leucine zipper dimerization domain is required for interactions with AP-1 proteins and transactivation of transcription. Analyses by electrophoretic mobility shift assays and by an in vivo mammalian two-hybrid system for protein-protein interactions indicate that CHOP interacts with AP-1 proteins inside cells and suggest that it is recruited to the AP-1 complex by a tethering mechanism rather than by direct binding of DNA. Thus, CHOP not only is a negative or a positive regulator of C/EBP target genes but also, when tethered to AP-1 factors, can activate AP-1 target genes. These findings establish the existence of a new mechanism by which CHOP regulates gene expression when cells are exposed to cellular stress.


Blood ◽  
2005 ◽  
Vol 106 (6) ◽  
pp. 1938-1947 ◽  
Author(s):  
Tomohiko Tamura ◽  
Pratima Thotakura ◽  
Tetsuya S. Tanaka ◽  
Minoru S. H. Ko ◽  
Keiko Ozato

Abstract Interferon regulatory factor-8 (IRF-8)/interferon consensus sequence–binding protein (ICSBP) is a transcription factor that controls myeloid-cell development. Microarray gene expression analysis of Irf-8-/- myeloid progenitor cells expressing an IRF-8/estrogen receptor chimera (which differentiate into macrophages after addition of estradiol) was used to identify 69 genes altered by IRF-8 during early differentiation (62 up-regulated and 7 down-regulated). Among them, 4 lysosomal/endosomal enzyme-related genes (cystatin C, cathepsin C, lysozyme, and prosaposin) did not require de novo protein synthesis for induction, suggesting that they were direct targets of IRF-8. We developed a reporter assay system employing a self-inactivating retrovirus and analyzed the cystatin C and cathepsin C promoters. We found that a unique cis element mediates IRF-8–induced activation of both promoters. Similar elements were also found in other IRF-8 target genes with a consensus sequence (GAAANN[N]GGAA) comprising a core IRF-binding motif and an Ets-binding motif; this sequence is similar but distinct from the previously reported Ets/IRF composite element. Chromatin immunoprecipitation assays demonstrated that IRF-8 and the PU.1 Ets transcription factor bind to this element in vivo. Collectively, these data indicate that IRF-8 stimulates transcription of target genes through a novel cis element to specify macrophage differentiation.


1986 ◽  
Vol 6 (12) ◽  
pp. 4723-4733
Author(s):  
L A Chodosh ◽  
R W Carthew ◽  
P A Sharp

A simple approach has been developed for the unambiguous identification and purification of sequence-specific DNA-binding proteins solely on the basis of their ability to bind selectively to their target sequences. Four independent methods were used to identify the promoter-specific RNA polymerase II transcription factor MLTF as a 46-kilodalton (kDa) polypeptide. First, a 46-kDa protein was specifically cross-linked by UV irradiation to a body-labeled DNA fragment containing the MLTF binding site. Second, MLTF sedimented through glycerol gradients at a rate corresponding to a protein of native molecular weight 45,000 to 50,000. Third, a 46-kDa protein was specifically retained on a biotin-streptavidin matrix only when the DNA fragment coupled to the matrix contained the MLTF binding site. Finally, proteins from the most highly purified fraction which were eluted and renatured from the 44- to 48-kDa region of a sodium dodecyl sulfate-polyacrylamide gel exhibited both binding and transcription-stimulatory activities. The DNA-binding activity was purified 100,000-fold by chromatography through three conventional columns plus a DNA affinity column. Purified MLTF was characterized with respect to the kinetic and thermodynamic properties of DNA binding. These parameters indicate a high degree of occupancy of MLTF binding sites in vivo.


2016 ◽  
Vol 37 (4) ◽  
Author(s):  
Aimee Iberg-Badeaux ◽  
Samuel Collombet ◽  
Benoit Laurent ◽  
Chris van Oevelen ◽  
Kuo-Kai Chin ◽  
...  

ABSTRACT Short-term and long-term transcriptional memory is the phenomenon whereby the kinetics or magnitude of gene induction is enhanced following a prior induction period. Short-term memory persists within one cell generation or in postmitotic cells, while long-term memory can survive multiple rounds of cell division. We have developed a tissue culture model to study the epigenetic basis for long-term transcriptional memory (LTTM) and subsequently used this model to better understand the epigenetic mechanisms that enable heritable memory of temporary stimuli. We find that a pulse of transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα) induces LTTM on a subset of target genes that survives nine cell divisions. The chromatin landscape at genes that acquire LTTM is more repressed than at those genes that do not exhibit memory, akin to a latent state. We show through chromatin immunoprecipitation (ChIP) and chemical inhibitor studies that RNA polymerase II (Pol II) elongation is important for establishing memory in this model but that Pol II itself is not retained as part of the memory mechanism. More generally, our work reveals that a transcription factor involved in lineage specification can induce LTTM and that failure to rerepress chromatin is one epigenetic mechanism underlying transcriptional memory.


2010 ◽  
Vol 9 (4) ◽  
pp. 514-531 ◽  
Author(s):  
Barbara Heise ◽  
Julia van der Felden ◽  
Sandra Kern ◽  
Mario Malcher ◽  
Stefan Brückner ◽  
...  

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.


2004 ◽  
Vol 279 (50) ◽  
pp. 52183-52190 ◽  
Author(s):  
Pascale Jackers ◽  
Gabor Szalai ◽  
Omar Moussa ◽  
Dennis K. Watson

Megakaryopoiesis is the process by which hematopoietic stem cells in the bone marrow differentiate into mature megakaryocytes. The expression of megakaryocytic genes during megakaryopoiesis is controlled by specific transcription factors. Fli-1 and GATA-1 transcription factors are required for development of megakaryocytes and promoter analysis has definedin vitrofunctional binding sites for these factors in several megakaryocytic genes, includingGPIIb,GPIX, andC-MPL. Herein, we utilize chromatin immunoprecipitation to examine the presence of Ets-1, Fli-1, and GATA-1 on these promotersin vivo. Fli-1 and Ets-1 occupy the promoters ofGPIIb,GPIX, andC-MPLgenes in both Meg-01 and CMK11-5 cells. WhereasGPIIbis expressed in both Meg-01 and CMK11-5 cells,GPIXandC-MPLare only expressed in the more differentiated CMK11–5 cells. Thus,in vivooccupancy by an Ets factor is not sufficient to promote transcription of some megakaryocytic genes. GATA-1 and Fli-1 are both expressed in CMK11-5 cells and co-occupy theGPIXandC-MPLpromoters. Transcription of all three megakaryocytic genes is correlated with the presence of acetylated histone H3 and phosphorylated RNA polymerase II on their promoters. We also show that exogenous expression of GATA-1 in Meg-01 cells leads to the expression of endogenous c-mpl and gpIX mRNA. WhereasGPIIb,GPIX, andC-MPLare direct target genes for Fli-1, both Fli-1 and GATA-1 are required for formation of an active transcriptional complex on theC-MPLandGPIXpromotersin vivo. In contrast,GPIIbexpression appears to be independent of GATA-1 in Meg-01 cells.


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