scholarly journals Locally acting transcription factors are required for p53-dependent cis-regulatory element activity

2019 ◽  
Author(s):  
Allison N. Catizone ◽  
Gizem Karsli Uzunbas ◽  
Petra Celadova ◽  
Sylvia Kuang ◽  
Daniel Bose ◽  
...  

AbstractThe master tumor suppressor p53 controls transcription of a wide-ranging gene network involved in apoptosis, cell cycle arrest, DNA damage repair, and senescence. Recent studies revealed pervasive binding of p53 to cis-regulatory elements (CRE), which are non-coding segments of DNA that spatially and temporally control transcription through the combinatorial binding of local transcription factors (TFs). Although the role of p53 as a strong trans-activator of gene expression is well known, the co-regulatory factors and local sequences acting at p53-bound CREs are comparatively understudied. We designed and executed a massively parallel reporter assay (MPRA) to investigate the effect of transcription factor binding motifs and local sequence context on p53-bound CRE activity. Our data indicate that p53-bound CREs are both positively and negatively affected by alterations in local sequence context and changes to co-regulatory TF motifs. We identified a SP1/KLF family motif located in an intronic p53 CRE that is required for the endogenous expression of the p53-dependent gene CCNG1. We also identified ATF3 as a factor that co-regulates the expression of the p53-dependent gene GDF15 through binding with p53 in an upstream CRE. Loss of either p53 or ATF3 severely reduces CRE activity and alters endogenous GDF15 mRNA levels in the cell. Our data suggests that p53 has the flexibility to cooperate with a variety of transcription factors in order to regulate CRE activity. By utilizing different sets of co-factors across CREs, we hypothesize that p53 activity is guarded against loss of any one regulatory partner allowing for dynamic and redundant control of p53-mediated transcription.

2020 ◽  
Vol 48 (8) ◽  
pp. 4195-4213 ◽  
Author(s):  
Allison N Catizone ◽  
Gizem Karsli Uzunbas ◽  
Petra Celadova ◽  
Sylvia Kuang ◽  
Daniel Bose ◽  
...  

Abstract The master tumor suppressor p53 controls transcription of a wide-ranging gene network involved in apoptosis, cell cycle arrest, DNA damage repair, and senescence. Recent studies revealed pervasive binding of p53 to cis-regulatory elements (CREs), which are non-coding segments of DNA that spatially and temporally control transcription through the combinatorial binding of local transcription factors. Although the role of p53 as a strong trans-activator of gene expression is well known, the co-regulatory factors and local sequences acting at p53-bound CREs are comparatively understudied. We designed and executed a massively parallel reporter assay (MPRA) to investigate the effect of transcription factor binding motifs and local sequence context on p53-bound CRE activity. Our data indicate that p53-bound CREs are both positively and negatively affected by alterations in local sequence context and changes to co-regulatory TF motifs. Our data suggest p53 has the flexibility to cooperate with a variety of transcription factors in order to regulate CRE activity. By utilizing different sets of co-factors across CREs, we hypothesize that global p53 activity is guarded against loss of any one regulatory partner, allowing for dynamic and redundant control of p53-mediated transcription.


2020 ◽  
Vol 21 (2) ◽  
pp. 460 ◽  
Author(s):  
Yong-Un Jeong ◽  
Young-Jin Park

Ergosterol peroxide is a natural compound of the steroid family found in many fungi, and it possesses antioxidant, anti-inflammatory, anticancer and antiviral activities. The anti-obesity activity of several edible and medicinal mushrooms has been reported, but the effect of mushroom-derived ergosterol peroxide on obesity has not been studied. Therefore, we analyzed the effect of ergosterol peroxide on the inhibition of triglyceride synthesis at protein and mRNA levels and differentiation of 3T3-L1 adipocytes. Ergosterol peroxide inhibited lipid droplet synthesis of differentiated 3T3-L1 cells, expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAT/enhancer-binding protein alpha (C/EBPα), the major transcription factors of differentiation, and also the expression of sterol regulatory element-binding protein-1c (SREBP-1c), which promotes the activity of PPARγ, resulting in inhibition of differentiation. It further inhibited the expression of fatty acid synthase (FAS), fatty acid translocase (FAT), and acetyl-coenzyme A carboxylase (ACC), which are lipogenic factors. In addition, it inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) involved in cell proliferation and activation of early differentiation transcription factors in the mitotic clonal expansion (MCE) stage. As a result, ergosterol peroxide significantly inhibited the synthesis of triglycerides and differentiation of 3T3-L1 cells, and is, therefore, a possibile prophylactic and therapeutic agent for obesity and related metabolic diseases.


2004 ◽  
Vol 379 (1) ◽  
pp. 151-159 ◽  
Author(s):  
Sarita NEGI ◽  
Saurabh K. SINGH ◽  
Nirupma PATI ◽  
Vikas HANDA ◽  
Ruchi CHAUHAN ◽  
...  

The apo(a) [apolipoprotein(a)] gene is responsible for variations in plasma lipoprotein(a), high levels of which are a risk factor for atherosclerosis and myocardial infarction. The apo(a) promoter stimulates the expression of reporter genes in HepG2 cells, but not in HeLa cells. In the present study, we demonstrate that the 1.4 kb apo(a) promoter comprises two composite regulatory regions: a distal negative regulatory module (positions −1432 to −716) and a proximal tissue-specific module (−716 to −616). The distal negative regulatory module contains two strong negative regulatory regions [polymorphic PNR (pentanucleotide repeat region) and NREβ (negative regulatory element β)], which sandwich the postive regulatory region PREβ (positive regulatory element β). The PNR was shown to bind to transcription factors in a tissue-specific manner, whereas the ubiquitous transcription factors hepatocyte nuclear factor 3α and GATA binding protein 4 bound to NREβ to repress gene transcription. The proximal tissue-specific module contains two regulatory elements: an activating region (PREα) that activates transcription in HepG2 cells, and NREα, which is responsible for repressing the apo(a) gene in HeLa cells. NREα binds to a HeLa-specific repressor. These multiple regulatory elements might work co-operatively to finely regulate apo(a) gene expression. Although the tissue-specific module is required for apo(a) gene activation and repression in a tissue-specific manner, the combinatorial interplay of the distal and proximal regulators might define the complex pathway(s) of apo(a) gene regulation.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4763-4763
Author(s):  
Donghoon Yoon ◽  
Hyojin Kim ◽  
Minyoung Jang ◽  
Jihyun Song ◽  
Gregory E Arnold ◽  
...  

Abstract Hypoxia regulates erythropoiesis and other essential processes via hypoxia-inducible transcription factors (HIFs). HIFs are heterodimers that consist of an α subunit (3 isotypes with significant homology; HIF-1α, HIF-2α, HIF-3α), and a common b-subunit; HIF-1 and HIF-2, in some instances exhibiting tissue- and gene-specific gene regulation. Erythropoietin (EPO) was the first identified HIF-1 target gene with the defined HIF-1 binding sequence. However, subsequent works suggested that HIF-2 also regulates EPO transcription and that there are other regulatory elements of EPO gene (i.e. Kidney Inducible Element KIE, Negative Regulatory Element NRE, and Negative Regulatory Liver specific Element NRLE). In silico analysis of the human EPO genome found two additional potential HIF-binding elements in the KIE and NRE regions. The comparative analysis of phylogenically conserved sequences of human, mouse, dog, and rat Epo genes further refined these mouse Epo gene HIF-binding elements as mKIE, mNRE1, mNRE2, and mNRLE2. We treated mice in hypoxia chamber (8% O2) and monitored changes of Epo mRNA levels in liver, kidney, brain, spleen, and bone marrow. All tested tissues increased Epo transcription during hypoxia. Bone marrow, spleen, kidney, and brain showed a peak of induction of Epo transcript at 3 hours of hypoxia treatment, while liver reached the highest level at 6 hours. Mice were sacrificed and organs were harvested, and in vivo chromatin immunoprecipitation (ChIPs) was performed with antibodies against HIF-1α and HIF- 2α and tissue-specific binding regions were defined. The results from these studies are summarized below. HIF-1 mKIE rnNRE mNRE2 mNRLE2 Norm Hyp Norm Hyp Norm Hyp Norm Hyp Liver − + − − + − ? ? Kidney − + − − + − + − Brain − + − − − + − + BM − + − − − − − + Splsen − + − − − − − + HIF-2 mKIE mNRE mNRE2 mNRLE2 Norm Hyp Norm Hyp Norm Hyp Norm Hyp “+” denotes presence and “-” absence of binding of HIF-1 and HIF-2, “?” – indicates inconclusive results. “Norm” - normoxia, “Hyp” - hypoxia. Liver − + − − − + − + Kidney + − − − + − ? ? Brain − − − − − − − + BM − − − − − − + − Spleen − + − − − − − + In conclusion, we demonstrate the differential hypoxia-induced binding of HIF-1 and HIF-2 at different HIF binding elements in the tissues known to express Epo. Further studies will be required to define the function of these HIF-1 and HIF-2 binding elements in tissue specific Epo expression and their role in health and disease.


2005 ◽  
Vol 387 (2) ◽  
pp. 355-365 ◽  
Author(s):  
Thierry ROGER ◽  
Isabelle MICONNET ◽  
Anne-Laure SCHIESSER ◽  
Hirofumi KAI ◽  
Kensuke MIYAKE ◽  
...  

TLR4 (Toll-like receptor 4) is essential for sensing the endotoxin of Gram-negative bacteria. Mutations or deletion of the TLR4 gene in humans or mice have been associated with altered predisposition to or outcome of Gram-negative sepsis. In the present work, we studied the expression and regulation of the Tlr4 gene of mouse. In vivo, TLR4 levels were higher in macrophages compared with B, T or natural killer cells. High basal TLR4 promoter activity was observed in RAW 264.7, J774 and P388D1 macrophages transfected with a TLR4 promoter reporter vector. Analysis of truncated and mutated promoter constructs identified several positive [two Ets (E twenty-six) and one AP-1 (activator protein-1) sites] and negative (a GATA-like site and an octamer site) regulatory elements within 350 bp upstream of the transcriptional start site. The myeloid and B-cell-specific transcription factor PU.1 bound to the proximal Ets site. In contrast, none among PU.1, Ets-1, Ets-2 and Elk-1, but possibly one member of the ESE (epithelium-specific Ets) subfamily of Ets transcription factors, bound to the distal Ets site, which was indispensable for Tlr4 gene transcription. Endotoxin did not affect macrophage TLR4 promoter activity, but it decreased TLR4 steady-state mRNA levels by increasing the turnover of TLR4 transcripts. TLR4 expression was modestly altered by other pro- and anti-inflammatory stimuli, except for PMA plus ionomycin which strongly increased promoter activity and TLR4 mRNA levels. The mouse and human TLR4 genes were highly conserved. Yet, notable differences exist with respect to the elements implicated in gene regulation, which may account for species differences in terms of tissue expression and modulation by microbial and inflammatory stimuli.


2021 ◽  
Author(s):  
Jennifer A. Noble ◽  
Alex Seddon ◽  
Sahra Uygun ◽  
Steven E. Smith ◽  
Shin-Han Shiu ◽  
...  

Synergid cells in the micropylar end of the female gametophyte are required for critical cell-cell signaling interactions between the pollen tube and the ovule that precede double fertilization and seed formation in flowering plants. LORELEI (LRE) encodes a GPI-anchored protein that is expressed primarily in the synergid cells, and together with FERONIA, a receptor-like kinase, it controls pollen tube reception by the receptive synergid cell. Still, how LRE expression is controlled in synergid cells remains poorly characterized. We identified candidate cis-regulatory elements enriched in LRE and other synergid cell-expressed genes. One of the candidate motifs (TAATATCT) in the LRE promoter was an uncharacterized variant of the Evening Element motif that we named as the Short Evening Element-like (SEEL) motif. Deletion or point mutations in the SEEL motif of the LRE promoter resulted in decreased reporter expression in synergid cells, demonstrating that the SEEL motif is important for expression of LRE in synergid cells. Additionally, we found that LRE expression is decreased in the loss of function mutants of REVEILLE (RVE) transcription factors, which are clock genes known to bind the SEEL and other closely related motifs. We propose that RVE transcription factors regulate LRE expression in synergid cells by binding to the SEEL motif in the LRE promoter. Identification of a cis-regulatory element and transcription factors involved in the expression of LRE will serve as a foundation to characterize the gene regulatory networks in synergid cells and investigate the potential connection between circadian rhythm and fertilization.


Development ◽  
2002 ◽  
Vol 129 (19) ◽  
pp. 4571-4580 ◽  
Author(s):  
Lydia Teboul ◽  
Juliette Hadchouel ◽  
Philippe Daubas ◽  
Dennis Summerbell ◽  
Margaret Buckingham ◽  
...  

Vertebrate myogenesis is controlled by four transcription factors known as the myogenic regulatory factors (MRFs): Myf5, Mrf4, myogenin and MyoD. During mouse development Myf5 is the first MRF to be expressed and it acts by integrating multiple developmental signals to initiate myogenesis. Numerous discrete regulatory elements are involved in the activation and maintenance of Myf5 gene expression in the various muscle precursor populations, reflecting the diversity of the signals that control myogenesis. Here we focus on the enhancer that recapitulates the first phase of Myf5 expression in the epaxial domain of the somite, in order to identify the subset of cells that first transcribes the gene and therefore gain insight into molecular, cellular and anatomical facets of early myogenesis. Deletion of this enhancer from a YAC reporter construct that recapitulates the Myf5 expression pattern demonstrates that this regulatory element is necessary for expression in the early epaxial somite but in no other site of myogenesis. Importantly, Myf5 is subsequently expressed in the epaxial myotome under the control of other elements located far upstream of the gene. Our data suggest that the inductive signals that control Myf5 expression switch rapidly from those that impinge on the early epaxial enhancer to those that impinge on the other enhancers that act later in the epaxial somite, indicating that there are significant changes in either the signalling environment or the responsiveness of the cells along the rostrocaudal axis. We propose that the first phase of Myf5 epaxial expression, driven by the early epaxial enhancer in the dermomyotome, is necessary for early myotome formation, while the subsequent phases are associated with cytodifferentiation within the myotome.


2018 ◽  
Author(s):  
Francesco N. Carelli ◽  
Angélica Liechti ◽  
Jean Halbert ◽  
Maria Warnefors ◽  
Henrik Kaessmann

ABSTRACTThe spatiotemporal control of gene expression exerted by promoters and enhancers is central for organismal development, physiology and behaviour. These two types of regulatory elements have long been distinguished from each other based on their function, but recent work highlighted common architectural and functional features. It also suggested that inheritable alterations in the epigenetic and sequence context of regulatory elements might underlie evolutionary changes of their principal activity, which could result in changes in the transcriptional profile of genes under their control or even facilitate the birth of new genes. Here, based on integrated cross-mammalian analyses of DNase hypersensitivity, chromatin modification and transcriptional data, we provide support for this hypothesis by detecting 449 regulatory elements with signatures of activity turnover in sister species from the primate and rodent lineages (termed “P/E” elements). Through the comparison with outgroup species, we defined the directionality of turnover events, which revealed that most instances represent transformations of ancestral enhancers into promoters, leading to the emergence of species-specific transcribed loci or 5’ exons. Notably, P/E elements have distinct GC sequence compositions and stabilizing 5’ splicing (U1) regulatory motif patterns, which may predispose them to functional repurposing during evolution. Moreover, we trace changes in the U1 and polyadenylation signal densities and distributions that accompanied and likely drove the evolutionary activity switches. Overall, our work suggests rather widespread evolutionary remodelling of regulatory element functions. Functional repurposing thus represents a notable mechanism that likely facilitated regulatory innovation and the origination of new genes and exons during mammalian evolution.


2017 ◽  
Vol 131 (16) ◽  
pp. 2161-2182 ◽  
Author(s):  
Rocio Rojo ◽  
Clare Pridans ◽  
David Langlais ◽  
David A. Hume

The proliferation, differentiation, and survival of cells of the macrophage lineage depends upon signals from the macrophage colony-stimulating factor (CSF) receptor (CSF1R). CSF1R is expressed by embryonic macrophages and induced early in adult hematopoiesis, upon commitment of multipotent progenitors to the myeloid lineage. Transcriptional activation of CSF1R requires interaction between members of the E26 transformation-specific family of transcription factors (Ets) (notably PU.1), C/EBP, RUNX, AP-1/ATF, interferon regulatory factor (IRF), STAT, KLF, REL, FUS/TLS (fused in sarcoma/ranslocated in liposarcoma) families, and conserved regulatory elements within the mouse and human CSF1R locus. One element, the Fms-intronic regulatory element (FIRE), within intron 2, is conserved functionally across all the amniotes. Lineage commitment in multipotent progenitors also requires down-regulation of specific transcription factors such as MYB, FLI1, basic leucine zipper transcriptional factor ATF-like (BATF3), GATA-1, and PAX5 that contribute to differentiation of alternative lineages and repress CSF1R transcription. Many of these transcription factors regulate each other, interact at the protein level, and are themselves downstream targets of CSF1R signaling. Control of CSF1R transcription involves feed–forward and feedback signaling in which CSF1R is both a target and a participant; and dysregulation of CSF1R expression and/or function is associated with numerous pathological conditions. In this review, we describe the regulatory network behind CSF1R expression during differentiation and development of cells of the mononuclear phagocyte system.


1999 ◽  
Vol 339 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Mun Seog CHANG ◽  
Hae Yong YOO ◽  
Hyune Mo RHO

Cu/Zn-superoxide dismutase (SOD1) catalyses the dismutation of superoxide radicals and neutralizes the oxidative effects of various chemicals. Deletion analysis of the upstream region of the rat SOD1 gene revealed that the promoter contains a positive regulatory element (PRE) and a negative regulatory element (NRE), which encompass the regions from -576 to -412 and from -412 to -305 respectively from the site of initiation of transcription. These DNA elements showed enhancer and silencer activities respectively in the natural context and in a heterologous promoter system. Using an electrophoretic-mobility-shift assay and a supershift assay with a specific antibody, the cis-elements of the PRE and NRE were identified as binding sites for transcription factors Elk1 and YY1 (Ying-Yang 1) respectively. Consistent with the presumed roles of the PRE and NRE, Elk1 increased SOD1 gene transcription about 4–5-fold, whereas YY1 exerted a negative effect of about 6-fold. Mutations of the Elk1- and YY1-binding sites led to diminution and elevation respectively of transcriptional activities, both in the natural context and in heterologous promoter systems. These results suggest that the transcription factors Elk1 and YY1, binding in the PRE and NRE respectively, co-ordinate the expression of the SOD1 gene.


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