PAX 8 activates the enhancer of the human thyroperoxidase gene

In this study we report on a novel natural target of the paired domain transcription factor PAX 8 in the enhancer element of the human thyroperoxidase gene, one of the most important thyroid differentiation markers. It is the primary enzyme involved in thyroid hormone synthesis and PAX 8 has been previously identified as an activating factor of the rat thyroperoxidase gene promoter. In vitro, PAX 8 binds a ciselement of the human enhancer and its exogenous expression induces the enhancer activity in co-transfection experiments in Cos-7 cells. When mutated at this binding site, the enhancer is no longer activated by PAX 8. Our finding strengthens the PAX 8 role in the maintenance of thyroid differentiation and in particular in the tissue-specific thyroperoxidase gene expression.

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Unmethylated thyroglobulin promoter may be repressed by methylation of flanking DNA sequences

Biochemical Journal ◽

10.1042/bj2980537 ◽

1994 ◽

Vol 298 (3) ◽

pp. 537-541 ◽

Cited By ~ 6

Author(s):

B Pichon ◽

C Christophe-Hobertus ◽

G Vassart ◽

D Christophe

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Dna Sequences ◽

Gene Promoter ◽

Proximal Promoter ◽

Enhancer Element ◽

Differentiated Cells ◽

Gene Enhancer ◽

Thyroglobulin Gene

The thyroglobulin gene, like many other tissue-specific genes, appears to be specifically less methylated in the differentiated cell type where it is transcribed. The thyroglobulin gene promoter elements themselves are highly CG-deficient and do not contain any HpaII/MspI sites. In this study, using DNA constructs that were methylated in vitro with HpaII or MspI methylases, we show that DNA methylation of vector sequences is sufficient to repress the activity of the thyroglobulin gene promoter in transient transfection experiments. Reporter-gene expression from a plasmid containing only the proximal thyroglobulin gene promoter is sensitive to DNA methylation even in fully differentiated thyrocytes. Transcription from methylated plasmids containing the thyroglobulin gene enhancer and proximal promoter is also clearly reduced when the transfected cells are maintained under less-differentiated conditions. These results indicate that DNA methylation can influence, from a distance, the activity of an unmodified promoter. Our results also agree with the view that loss of DNA methylation does not constitute a prerequisite for thyroglobulin gene expression in differentiated thyrocytes, where the thyroglobulin gene enhancer and promoter are activated. However, the production of thyroglobulin transcripts could be severely impaired when this activation is not maximal, as is the case in less-differentiated cells or when the enhancer element is lacking. We suggest that DNA methylation helps to maintain the thyroglobulin gene in an inactive state unless all of the conditions required for its expression are fulfilled, and that the thyroid-specific demethylation events are a consequence of the activation state of the gene.

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Mutants of cubitus interruptus that are independent of PKA regulation are independent of hedgehog signaling

Development ◽

10.1242/dev.126.16.3607 ◽

1999 ◽

Vol 126 (16) ◽

pp. 3607-3616 ◽

Cited By ~ 3

Author(s):

Y. Chen ◽

J.R. Cardinaux ◽

R.H. Goodman ◽

S.M. Smolik

Keyword(s):

Gene Expression ◽

Target Gene ◽

Ectopic Expression ◽

Proteolytic Processing ◽

Dominant Negative ◽

Cubitus Interruptus ◽

Target Gene Expression ◽

Exogenous Expression

Hedgehog (HH) is an important morphogen involved in pattern formation during Drosophila embryogenesis and disc development. cubitus interruptus (ci) encodes a transcription factor responsible for transducing the hh signal in the nucleus and activating hh target gene expression. Previous studies have shown that CI exists in two forms: a 75 kDa proteolytic repressor form and a 155 kDa activator form. The ratio of these forms, which is regulated positively by hh signaling and negatively by PKA activity, determines the on/off status of hh target gene expression. In this paper, we demonstrate that the exogenous expression of CI that is mutant for four consensus PKA sites [CI(m1-4)], causes ectopic expression of wingless (wg) in vivo and a phenotype consistent with wg overexpression. Expression of CI(m1-4), but not CI(wt), can rescue the hh mutant phenotype and restore wg expression in hh mutant embryos. When PKA activity is suppressed by expressing a dominant negative PKA mutant, the exogenous expression of CI(wt) results in overexpression of wg and lethality in embryogenesis, defects that are similar to those caused by the exogenous expression of CI(m1-4). In addition, we demonstrate that, in cell culture, the mutation of any one of the three serine-containing PKA sites abolishes the proteolytic processing of CI. We also show that PKA directly phosphorylates the four consensus phosphorylation sites in vitro. Taken together, our results suggest that positive hh and negative PKA regulation of wg gene expression converge on the regulation of CI phosphorylation.

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Regulation of the twist target gene tinman by modular cis-regulatory elements during early mesoderm development

Development ◽

10.1242/dev.124.24.4971 ◽

1997 ◽

Vol 124 (24) ◽

pp. 4971-4982 ◽

Cited By ~ 12

Author(s):

Z. Yin ◽

X.L. Xu ◽

M. Frasch

Keyword(s):

Homeobox Gene ◽

Regulatory Elements ◽

Bhlh Protein ◽

Expression Domain ◽

Enhancer Activity ◽

Enhancer Element ◽

Mesoderm Development ◽

Visceral Mesoderm

The Drosophila tinman homeobox gene has a major role in early mesoderm patterning and determines the formation of visceral mesoderm, heart progenitors, specific somatic muscle precursors and glia-like mesodermal cells. These functions of tinman are reflected in its dynamic pattern of expression, which is characterized by initial widespread expression in the trunk mesoderm, then refinement to a broad dorsal mesodermal domain, and finally restricted expression in heart progenitors. Here we show that each of these phases of expression is driven by a discrete enhancer element, the first being active in the early mesoderm, the second in the dorsal mesoderm and the third in cardioblasts. We provide evidence that the early-active enhancer element is a direct target of twist, a gene encoding a basic helix-loop-helix (bHLH) protein, which is necessary for tinman activation. This 180 bp enhancer includes three E-box sequences which bind Twist protein in vitro and are essential for enhancer activity in vivo. Ectodermal misexpression of twist causes ectopic activation of this enhancer in ectodermal cells, indicating that twist is the only mesoderm-specific activator of early tinman expression. We further show that the 180 bp enhancer also includes negatively acting sequences. Binding of Even-skipped to these sequences appears to reduce twist-dependent activation in a periodic fashion, thus producing a striped tinman pattern in the early mesoderm. In addition, these sequences prevent activation of tinman by twist in a defined portion of the head mesoderm that gives rise to hemocytes. We find that this repression requires the function of buttonhead, a head-patterning gene, and that buttonhead is necessary for normal activation of the hematopoietic differentiation gene serpent in the same area. Together, our results show that tinman is controlled by an array of discrete enhancer elements that are activated successively by differential genetic inputs, as well as by closely linked activator and repressor binding sites within an early-acting enhancer, which restrict twist activity to specific areas within the twist expression domain.

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Epigenetic Modulation of STAT3 by Histone Deacetylase 6 (HDAC6) Regulates IL-10 Gene Expression and Immune Tolerance Mediated by Antigen-Presenting Cells (APCs)

Blood ◽

10.1182/blood.v118.21.519.519 ◽

2011 ◽

Vol 118 (21) ◽

pp. 519-519 ◽

Cited By ~ 1

Author(s):

Fengdong Cheng ◽

Zi Wang ◽

Hongwei Wang ◽

Karrune V. Woan ◽

Eva Sahakian ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Cd4 T Cells ◽

Transcriptional Activity ◽

Gene Promoter ◽

B Cell Lymphoma ◽

Gene Promoters ◽

Enhanced Production ◽

Stat3 Phosphorylation

Abstract Abstract 519 We have previously shown that the pan-HDAC inhibitors LAQ824 and LBH589 inhibit IL-10 production in APCs, rendering these cells more inflammatory and capable of effectively priming naïve antigen-specific CD4+ T-cells and restoring the responsiveness of tolerant T-cells1. These findings led us to explore which HDAC(s) might be involved in the regulation of IL-10 gene transcription and be the putative target(s) of HDI-mediated IL-10 inhibition. To answer these questions we subjected the macrophage cell line RAW264.7 to shRNA screening using specific shRNAs to knockdown each known HDAC. We found that among all the HDACs, knocking down HDAC6 (HDAC6KD) was associated with a significant decrease in IL-10 mRNA and protein in response to LPS stimulation. Furthermore, HDAC6KD clones display an enhanced expression of the co-stimulatory molecule B7.2. Functionally, HDAC6KD cells were better activators of anti-HA (hemagglutinin-influenza) transgenic CD4+ T cells, leading to significantly enhanced production of IL-2 and IFN-g in response to cognate antigen. More importantly, anti-HA CD4+ anergic T cells isolated from animals bearing HA-expressing A20 B-cell lymphoma regained their ability to produce IL-2 and IFN-g when cultured in vitro with HDAC6KD cells. These results have been confirmed in APCs isolated from HDAC6 knock-out mice and in wild type APCs treated in vitro with isotype-selective HDAC6 inhibitors. Given that HDACs do not bind to DNA and they need to interact with transcription factors to regulate gene expression, we investigate next which transcription factor(s) HDAC6 might be associated with, to regulate IL-10 transcriptional activity. One likely candidate was Stat3, a well-known transcriptional activator of IL-10 gene expression that we have previously shown to play a central role in tolerance induction by APCs2. By co-immunoprecipitation studies we found that HDAC6 indeed interacts physically with Stat3. Of note, knocking down HDAC6 in APCs resulted in absence of Stat3 phosphorylation and decreased recruitment of Stat3 to the IL-10 gene promoter which might explain the inability of HDAC6KD cells to produce IL-10. The additional findings that IL-10 production by HDAC6KD cells was restored when these cells were transfected with a constitutively active mutant version of Stat3 (Stat3c) provides additional support for the important role of HDAC6 upon Stat3 activation. Further confirmation for a concerted regulatory mechanism involving HDAC6 and Stat3 in IL-10 gene regulation was provided by studies using CPA-7, a specific Stat3 inhibitor that disrupts Stat3 recruitment and binding to gene promoters. As expected, a complete abrogation of Stat3 recruitment to the IL-10 gene promoter was observed in CPA-7 treated APCs. Interestingly, such an effect was accompanied by a parallel decrease in HDAC6 recruitment to the IL-10 promoter and inhibition of IL-10 gene transcriptional activity. Taken together, we have shown for the first time that HDAC6 interacts physically with Stat3 and is required for its phosphorylation. Since Stat3 phosphorylation is absolutely necessary for activation of Stat3 target genes, HDAC6 inhibition is an enticing molecular approach to disrupt the Stat3/IL-10 axis and overcome tolerogenic mechanisms in APCs. Disclosures: No relevant conflicts of interest to declare.

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Identification of an Adeno-Associated Virus Rep Protein Binding Site in the Adenovirus E2a Promoter

Journal of Virology ◽

10.1128/jvi.79.1.28-38.2005 ◽

2005 ◽

Vol 79 (1) ◽

pp. 28-38 ◽

Cited By ~ 10

Author(s):

John M. Casper ◽

Jennifer M. Timpe ◽

John David Dignam ◽

James P. Trempe

Keyword(s):

Gene Expression ◽

Random Sequence ◽

Gene Promoter ◽

Helper Virus ◽

Host Cells ◽

Mobility Shift ◽

Adeno Associated Virus ◽

Rep Protein

ABSTRACT Adeno-associated virus (AAV) and other parvoviruses inhibit proliferation of nonpermissive cells. The mechanism of this inhibition is not thoroughly understood. To learn how AAV interacts with host cells, we investigated AAV's interaction with adenovirus (Ad), AAV's most efficient helper virus. Coinfection with Ad and AAV results in an AAV-mediated inhibition of Ad5 gene expression and replication. The AAV replication proteins (Rep) activate and repress gene expression from AAV and heterologous transcription promoters. To investigate the role of Rep proteins in the suppression of Ad propagation, we performed chromatin immunoprecipitation analyses that demonstrated in vivo AAV Rep protein interaction with the Ad E2a gene promoter. In vitro binding of purified AAV Rep68 protein to the Ad E2a promoter was characterized by electrophoretic mobility shift assays (Kd = 200 ± 25 nM). A 38 bp, Rep68-protected region (5′-TAAGAGTCAGCGCGCAGTATTTACTGAAGAGAGCCT-3′) was identified by DNase I footprint analysis. The 38-bp protected region contains the weak E2a TATA box, sequence elements that resemble the Rep binding sites identified by random sequence oligonucleotide selection, and the transcription start site. These results suggest that Rep binding to the E2a promoter contributes to the inhibition of E2a gene expression from the Ad E2a promoter and may affect Ad replication.

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Imprinted gene expression at the Dlk1-Dio3 cluster is controlled by both maternal and paternal IG-DMRs in a tissue-specific fashion

10.1101/536102 ◽

2019 ◽

Cited By ~ 1

Author(s):

Katherine A. Alexander ◽

María J. García-García

Keyword(s):

Gene Expression ◽

Regulatory Elements ◽

Enhancer Activity ◽

Enhancer Element ◽

Tissue Specific ◽

Imprinted Gene ◽

Imprinting Control Region ◽

Regulatory Landscape ◽

Insight Into ◽

Different Tissues

ABSTRACTImprinting at the Dlk1-Dio3 cluster is controlled by the IG-DMR, an imprinting control region differentially methylated between maternal and paternal chromosomes. The maternal IG-DMR is essential for imprinting control, functioning as a cis enhancer element. Meanwhile, DNA methylation at the paternal IG-DMR is thought to prevent enhancer activity. To explore whether suppression of enhancer activity at the methylated IG-DMR requires the transcriptional repressor TRIM28, we analyzed Trim28chatwo embryos and performed epistatic experiments with IG-DMR deletion mutants. We found that while TRIM28 regulates the enhancer properties of the paternal IG-DMR, it also controls imprinting through other mechanisms. Additionally, we found that the paternal IG-DMR, previously deemed dispensable for imprinting, is required in certain tissues, demonstrating that imprinting is regulated in a tissue-specific manner. Using PRO-seq to analyze nascent transcription, we identified 30 novel transcribed regulatory elements, including 23 that are tissue-specific. These results demonstrate that different tissues have a distinctive regulatory landscape at the Dlk1-Dio3 cluster and provide insight into potential mechanisms of tissue-specific imprinting control. Together, our findings challenge the premise that Dlk1-Dio3 imprinting is regulated through a single mechanism and demonstrate that different tissues use distinct strategies to accomplish imprinted gene expression.

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Functional analysis of haplotypes and promoter activity at the 5' region of the DRD2 gene and associations with schizophrenia.

10.21203/rs.3.rs-15812/v1 ◽

2020 ◽

Author(s):

Xicen Zhang ◽

Mei Ding ◽

Yi Liu ◽

Yongping Liu ◽

Jiaxin Xing ◽

...

Keyword(s):

Gene Expression ◽

Cell Lines ◽

Promoter Region ◽

Regulatory Region ◽

Gene Promoter ◽

Luciferase Reporter ◽

Drd2 Gene ◽

Functional Regions

Abstract Background: In previous studies, we researched the association of the DRD2 gene promoter region SNP loci rs7116768, rs1047479195, rs1799732, rs1799978 and schizophrenia using Sanger sequencing. rs7116768 and rs1799978 were found to be slightly associated with schizophrenia. This study investigated the effects of haplotypes consisted of the four SNPs on protein expression level in vitro and identified the functional sequence in the 5’ regulatory region of DRD2 gene which has a potential link with schizophrenia.Methods: Recombinant plasmids with haplotypes, SNPs and 13 recombinant vectors containing deletion fragments from the DRD2 gene 5' regulatory region were transfected into HEK293 and SK-N-SH cell lines. Relative luciferase activity of the haplotypes, SNPs and different sequences was compared using a dual luciferase reporter assay system.Results: Haplotype H4(G-C-InsC-G) could significantly increase the gene expression in SK-N-SH cell lines. Allele C of rs7116768, allele A of rs1047479195 and allele del C of rs1799732 could up-regulate the gene expression. There were 5~7 functional regions in the promoter region of DRD2 gene that could affect the level of gene expression.Conclusion: We cannot rule out the possibility that different haplotypes may influence DRD2 gene expression in vivo. We observed that allele C of rs7116768, allele A of rs1047479195 and allele del C of rs1799732 could up-regulate gene expression. The truncation results confirmed the existence of functional regions in the promoter region of DRD2 gene that could affect the level of gene expression.

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Sustained Gene Expression in Retrovirally Transduced, Engrafting Human Hematopoietic Stem Cells and Their Lympho-Myeloid Progeny

Blood ◽

10.1182/blood.v92.1.83.413k09_83_92 ◽

1998 ◽

Vol 92 (1) ◽

pp. 83-92 ◽

Cited By ~ 62

Author(s):

Linzhao Cheng ◽

Changchun Du ◽

Catherine Lavau ◽

Shirley Chen ◽

Jie Tong ◽

...

Keyword(s):

Gene Expression ◽

Stem Cells ◽

Hematopoietic Stem Cells ◽

Growth Factor Receptor ◽

Retroviral Vector ◽

Human Bone ◽

Differentiation Markers ◽

Hematopoietic Stem ◽

Immunodeficient Mice

Inefficient retroviral-mediated gene transfer to human hematopoietic stem cells (HSC) and insufficient gene expression in progeny cells derived from transduced HSC are two major problems associated with HSC-based gene therapy. In this study we evaluated the ability of a murine stem cell virus (MSCV)-based retroviral vector carrying the low-affinity human nerve growth factor receptor (NGFR) gene as reporter to maintain gene expression in transduced human hematopoietic cells. CD34+ cells lacking lineage differentiation markers (CD34+Lin−) isolated from human bone marrow and mobilized peripheral blood were transduced using an optimized clinically applicable protocol. Under the conditions used, greater than 75% of the CD34+ cell population retained the Lin− phenotype after 4 days in culture and at least 30% of these expressed a high level of NGFR (NGFR+) as assessed by fluorescence-activated cell sorter analysis. When these CD34+Lin−NGFR+ cells sorted 2 days posttransduction were assayed in vitro in clonogenic and long-term stromal cultures, sustained reporter expression was observed in differentiated erythroid and myeloid cells derived from transduced progenitors, and in differentiated B-lineage cells after 6 weeks. Moreover, when these transduced CD34+Lin−NGFR+ cells were used to repopulate human bone grafts implanted in severe combined immunodeficient mice, MSCV-directed NGFR expression could be detected on 37% ± 6% (n = 5) of the donor-type human cells recovered 9 weeks postinjection. These findings suggest potential utility of the MSCV retroviral vector in the development of effective therapies involving gene-modified HSC.

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Antagonistic effects of phorbol esters on insulin regulation of insulin-like growth factor-binding protein-1 (IGFBP-1) but not glucose-6-phosphatase gene expression

Biochemical Journal ◽

10.1042/bj3590611 ◽

2001 ◽

Vol 359 (3) ◽

pp. 611-619 ◽

Cited By ~ 4

Author(s):

Satish PATEL ◽

Pamela A. LOCHHEAD ◽

Graham RENA ◽

Calum SUTHERLAND

Keyword(s):

Gene Expression ◽

Growth Factor ◽

Map Kinases ◽

Phorbol Esters ◽

Binding Protein ◽

Gene Promoter ◽

Dependent Manner ◽

Insulin Like Growth Factor ◽

Factor Binding

Glucose-6-phosphatase (G6Pase) and insulin-like growth factor-binding protein-1 (IGFBP-1) genes contain a homologous promoter sequence that is required for gene repression by insulin. Interestingly, this element interacts with members of the forkhead family of transcription factors [e.g. HNF3 (hepatic nuclear factor 3), FKHR (forkhead in rhabdomyosarcoma)] in vitro, while insulin promotes the phosphorylation and inactivation of FKHR in a phosphatidylinositol 3-kinase- and protein kinase B (PKB)-dependent manner. This mechanism has been proposed to underlie insulin action on G6Pase and IGFBP-1 gene transcription. However, we find that treatment of cells with phorbol esters mimics the effect of insulin on G6Pase, but not IGFBP-1, gene expression. Indeed, phorbol ester treatment actually blocks the ability of insulin to repress IGFBP-1 gene expression. In addition, the action of phorbol esters is significantly reduced by inhibition of the p42/p44 mitogen-activated protein (MAP) kinase pathway. However insulin-induced phosphorylation of PKB or FKHR is not affected by the presence of phorbol esters. Therefore we suggest that activation of p42/p44 MAP kinases will reduce the sensitivity of the IGFBP-1 gene promoter, but not the G6Pase gene promoter, to insulin. Importantly, the activation of PKB and phosphorylation of FKHR is not, in itself, sufficient to reduce IGFBP-1 gene expression in the presence of phorbol esters.

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Regulation of the Human Secretin Gene Is Controlled by the Combined Effects of CpG Methylation, Sp1/Sp3 Ratio, and the E-Box Element

Molecular Endocrinology ◽

10.1210/me.2003-0461 ◽

2004 ◽

Vol 18 (7) ◽

pp. 1740-1755 ◽

Cited By ~ 37

Author(s):

Leo Tsz-On Lee ◽

Kian-Cheng Tan-Un ◽

Ronald Ting-Kai Pang ◽

David Tai-Wai Lam ◽

Billy Kwok-Chong Chow

Keyword(s):

Gene Expression ◽

Hepg2 Cells ◽

Cpg Island ◽

Methylation Status ◽

Gene Promoter ◽

Mobility Shift ◽

Specific Pcr ◽

E Box

Abstract To unravel the mechanisms that regulate the human secretin gene expression, in this study, we have used secretin-expressing (HuTu-80 cells, human duodenal adenocarcinoma) and non-secretin-expressing [PANC-1 (human pancreatic ductile carcinoma) and HepG2 (human hepatocellular carcinoma) cells] cell models for in vitro and in vivo analyses. By transient transfection assays, within the promoter region (−11 to −341 from ATG, relative to the ATG initiation codon), we have initially identified several functional motifs including an E-box and 2 GC-boxes. Results from gel mobility shift and chromatin immunoprecipitation assays confirmed further that NeuroD, E2A, Sp1, and Sp3 bind to these E- and GC-boxes in HuTu-80 cells in vitro and in vivo, whereas only high levels of Sp3 is observed to bind the promoter in HepG2 cells. In addition, overexpression of Sp3 resulted in a dose-dependent repression of the Sp1-mediated transactivation. Collectively, these data suggest that the Sp1/Sp3 ratio is instrumental to controlling secretin gene expression in secretin-producing and non-secretin-producing cells. The functions of GC-box and Sp proteins prompted us to investigate the possible involvement of DNA methylation in regulating this gene. Consistent with this idea, we found a putative CpG island (−336 to 262 from ATG) that overlaps with the human secretin gene promoter. By methylation-specific PCR, all the CpG dinucleo-tides (26 of them) within the CpG island in HuTu-80 cells are unmethylated, whereas all these sites are methylated in PANC-1 and HepG2 cells. The expressions of secretin in PANC-1 and HepG2 cells were subsequently found to be significantly activated by a demethylation agent, 5′-Aza-2′ deoxycytidine. Taken together, our data indicate that the human secretin gene is controlled by the in vivo Sp1/Sp3 ratio and the methylation status of the promoter.

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