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Transcriptional Activation (transcriptional + activation)
Terms modified by Transcriptional Activation Selected AbstractsThe Design and Synthesis of Novel Orally Active Inhibitors of AP-1 and NF-,B Mediated Transcriptional Activation.CHEMINFORM, Issue 9 2004SAR of in vitro, in vivo Studies. Abstract For Abstract see ChemInform Abstract in Full Text. [source] Specific transcriptional responses induced by 8-methoxypsoralen and UVA in yeastFEMS YEAST RESEARCH, Issue 6 2007Michèle Dardalhon Abstract Treatment of eukaryotic cells with 8-methoxypsoralen plus UVA irradiation (8-MOP/UVA) induces pyrimidine monoadducts and interstrand crosslinks and initiates a cascade of events leading to cytotoxic, mutagenic and carcinogenic responses. Transcriptional activation plays an important part in these responses. Our previous study in Saccharomyces cerevisiae showed that the repair of these lesions involves the transient formation of DNA double-strand breaks and the enhanced expression of landmark DNA damage response genes such as RAD51, RNR2 and DUN1, as well as the Mec1/Rad53 kinase signaling cascade. We have now used DNA microarrays to examine genome-wide transcriptional changes produced after induction of 8-MOP/UVA photolesions. We found that 128 genes were strongly induced and 29 genes strongly repressed. Modifications in gene expression concern numerous biological processes. Compared to other genotoxic treatments, c. 42% of the response genes were specific to 8-MOP/UVA treatment. In addition to common DNA damage response genes and genes induced by environmental stresses, a large fraction of 8-MOP/UVA response genes correspond to membrane-related functions. [source] Transcriptional activation of human mu-opioid receptor gene by insulin-like growth factor-I in neuronal cells is modulated by the transcription factor RESTJOURNAL OF NEUROCHEMISTRY, Issue 6 2008Andrea Bedini Abstract The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. We investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I up-regulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 signaling pathway and this transcription factor, binding to the signal transducer and activator of transcription-1/3 DNA element located in the promoter, increases OPRM1 transcription. We propose that a reduction in REST is a critical switch enabling IGF-I to up-regulate hMOPr. These findings help clarify how hMOPr expression is regulated in neuronal cells. [source] Phosphate availability regulates biosynthesis of two antibiotics, prodigiosin and carbapenem, in Serratia via both quorum-sensing-dependent and -independent pathwaysMOLECULAR MICROBIOLOGY, Issue 2 2003Holly Slater Summary Serratia sp. ATCC 39006 produces two secondary metabolite antibiotics, 1-carbapen-2-em-3-carboxylic acid (Car) and the red pigment, prodigiosin (Pig). We have previously reported that production of Pig and Car is controlled by N -acyl homoserine lactone (N -AHL) quorum sensing, with synthesis of N -AHLs directed by the LuxI homologue SmaI, and is also regulated by Rap, a member of the SlyA family. We now describe further characterization of the SmaI quorum-sensing system and its connection with other regulatory mechanisms. We show that the genes responsible for biosynthesis of Pig, pigA,O, are transcribed as a single polycistronic message in an N -AHL-dependent manner. The smaR gene, transcribed convergently with smaI and predicted to encode the LuxR homologue partner of SmaI, was shown to possess a negative regulatory function, which is uncommon among the LuxR-type transcriptional regulators. SmaR represses transcription of both the pig and car gene clusters in the absence of N -AHLs. Specifically, we show that SmaIR exerts its effect on car gene expression via transcriptional control of carR, encoding a pheromone-independent LuxR homologue. Transcriptional activation of the pig and car gene clusters also requires a functional Rap protein, but Rap dependency can be bypassed by secondary mutations. Transduction of these suppressor mutations into wild-type backgrounds confers a hyper-Pig phenotype. Multiple mutations cluster in a region upstream of the pigA gene, suggesting this region may represent a repressor target site. Two mutations mapped to genes encoding pstS and pstA homologues, which are parts of a high-affinity phosphate transport system (Pst) in Escherichia coli. Disruption of pstS mimicked phosphate limitation and caused concomitant hyper-production of Pig and Car, which was mediated, in part, through increased transcription of the smaI gene. The Pst and SmaIR systems define distinct, yet overlapping, regulatory circuits which form part of a complex regulatory network controlling the production of secondary metabolites in Serratia ATCC 39006. [source] Ribosomal RNA transcriptional activation and processing in hamster rubrospinal motoneurons: Effects of axotomy and testosterone treatmentTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2003Paul D. Storer Abstract Rubrospinal motoneurons (RSMN) represent a population of androgen receptor-expressing central motoneurons with limited regenerative potential relative to their peripheral counterparts. A key determinant of regenerative capability lies in the nucleolar reaction of injured neurons. To date, characterization of the nucleolar reaction in injured central motoneurons has not been accomplished. Furthermore, it has been documented that testosterone propionate (TP) augments peripheral motoneuron regeneration through regulation of the nucleolar reaction to injury. In this study, the effects of injury alone, or in conjunction with TP, on the nucleolar response of injured RSMN were examined using in situ hybridization (ISH) techniques. Castrated adult male hamsters were subjected to right spinal cord hemisection at the C7/T1 vertebral level. Half the animals were subcutaneously implanted with one Silastic TP capsule, with the other half sham implanted. ISH for precursor 45S and mature 28S rRNA was accomplished with a 3H-labeled ribosomal DNA probe specific to the external transcribed spacer region or to the 28S region of the ribosomal gene, respectively. Postoperative times of 2, 6, and 24 hours were selected for examination of precursor 45S rRNA (i.e., rRNA transcriptional activation) levels and 0.25, 2, 4, and 14 days for examination of mature rRNA (i.e., ribosome) levels. Transcriptional activation of the rRNA gene was rapidly and transiently increased in injured RSMN, analogously to previously documented effects of injury on rRNA transcription in peripheral motoneurons, but, in contrast, this did not translate into an increase in mature ribosomes. TP administration failed to affect positively the nucleolar response of injured RSMN at all. From this study, a key component underlying inherent differences in the regenerative capacity of peripheral vs. central motoneurons has been identified, which can be targeted in future experiments designed to enhance the regenerative potential of selective neuronal populations. J. Comp. Neurol. 458:326,333, 2003. © 2003 Wiley-Liss, Inc. [source] Transcriptional activation of the ,- catenin gene at the invasion front of colorectal liver metastases,THE JOURNAL OF PATHOLOGY, Issue 3 2009Obul R Bandapalli Abstract ,-Catenin is a pivotal molecule of the Wnt-signalling pathway, involved in regulation of developmental and oncogenic processes as well as in intercellular adhesion. So far, ,-catenin has been thought to be regulated mainly at the protein level. Here, we provide evidence for a transcriptional mechanism of ,-catenin regulation at the invasion front of colorectal liver metastases. In a nude mouse/LS174T cell xenograft model of colorectal liver metastases, we observed ,-catenin up-regulation at the mRNA and protein levels and a 13.7-fold increase of ,-catenin promoter activity in the cancer cells of the invasion front. In addition, the promoter activity was five-fold higher in the interior of the tumour than in cells growing in cell culture. In vitro studies revealed binding of TCF-4 to the ,-catenin promoter and reduced promoter activity by over-expression of dominant negative TCF-4, or ,-catenin knock-down and increased activity by ,-catenin over-expression, indicating that ,-catenin acts as co-transcription factor of its own promoter. In 55% (7/13) of clinical specimens, ,-catenin mRNA was markedly elevated in the cancer cells of the invasion front. Elevation of mRNA was paralleled by increased nuclear and cytoplasmic ,-catenin protein concentrations. These data indicate that transcriptional regulation contributes to the dynamic changes of ,-catenin levels upon the confrontation of tumour cells with the host microenvironment. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Mechanism of DNA replication-dependent transcriptional activation of the acetylcholinesterase gene in the Ciona intestinalis embryoDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 9 2009Yumiko Kataoka The acetylcholinesterase-encoding gene in the ascidian Ciona intestinalis (Ci-AChE) is expressed in tail muscle cells from the gastrula stage. When the embryo was continuously treated with aphidicolin from the 32-cell stage, Ci-AChE was not expressed even when control embryos reached the tailbud stage. This result suggests that Ci-AChE acquires the competence to be transcribed after passing through a certain number of DNA replication cycles. A lacZ reporter gene containing the 5, flanking region of Ci-AChE was expressed in the tail muscle cells. Aphidicolin treatment from the 32-cell stage affected, but did not completely suppress, the expression of lacZ. A bisulfite sequencing analysis was carried out to examine the methylation status of four regions within the 5, flanking sequence and the first exon. However, all of these regions remained unmethylated from the 16-cell to 110-cell stages. The results suggested that the DNA of the Ci-AChE locus is not responsible for counting the rounds of replication. We examined the expression of the C. intestinalis MyoD (Ci-MyoD), a transcription factor that activates Ci-AChE. Aphidicolin treatment from the 32-cell stage suppressed the expression of Ci-MyoD, even when control embryos reached the gastrula stage. These results suggest that a lack of Ci-MyoD is critical to the suppression of Ci-AChE in aphidicolin-treated embryos. [source] Drosophila NAB (dNAB) is an orphan transcriptional co-repressor required for correct CNS and eye developmentDEVELOPMENTAL DYNAMICS, Issue 1 2003Mark Clements Abstract The mammalian NAB proteins have been identified previously as potent co-repressors of the EGR family of zinc finger transcription factors. Drosophila NAB (dNAB), like its mammalian counterparts, binds EGR1 and represses EGR1-mediated transcriptional activation from a synthetic promoter. In contrast, dNAB does not bind the Drosophila EGR-related protein klumpfuss. dnab RNA is expressed exclusively in a subset of neuroblasts in the embryonic and larval central nervous system (CNS), as well as in several larval imaginal disc tissues. Here, we describe the creation of targeted deletion mutations in the dnab gene and the identification of additional, EMS-induced dnab mutations by genetic complementation analysis. Null alleles in dnab cause larval locomotion defects and early larval lethality (L1,L2). A putative hypomorphic allele in dnab instead causes early adult lethality due to severe locomotion defects. In the dnab -/- CNS, axon outgrowth/guidance and glial development appear normal; however, a subset of eve+ neurons forms in reduced numbers. In addition, mosaic analysis in the eye reveals that dnab -/- clones are either very small or absent. Similarly, dNAB overexpression in the eye causes eyes to be very small with few ommatidia. These dramatic eye-specific phenotypes will prove useful for enhancer/suppressor screens to identify dnab-interacting genes. © 2002 Wiley-Liss, Inc. [source] Identification of some human genes oppositely regulated during esophageal squamous cell carcinoma formation and human embryonic esophagus developmentDISEASES OF THE ESOPHAGUS, Issue 3 2010M. V. Zinovyeva SUMMARY Here we directly compared gene expression profiles in human esophageal squamous cell carcinomas and in human fetal esophagus development. We used the suppression subtractive hybridization technique to subtract cDNAs prepared from tumor and normal human esophageal samples. cDNA sequencing and reverse transcription polymerase chain reaction (RT-PCR) analysis of RNAs from human tumor and the normal esophagus revealed 10 differentially transcribed genes: CSTA, CRNN, CEACAM1, MAL, EMP1, ECRG2, and SPRR downregulated, and PLAUR, SFRP4, and secreted protein that is acidic and rich in cysteine upregulated in tumor tissue as compared with surrounding normal tissue. In turn, genes up- and downregulated in tumor tissue were down- and upregulated, respectively, during development from the fetal to adult esophagus. Thus, we demonstrated that, as reported for other tumors, gene transcriptional activation and/or suppression events in esophageal tumor progression were opposite to those observed during development from the fetal to adult esophagus. This tumor ,embryonization' supports the idea that stem or progenitor cells are implicated in esophageal cancer emergence. [source] Structural and functional differences between the promoters of independently expressed killer cell Ig-like receptorsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2005Bergen, Jeroen van Abstract Killer Ig-like receptors (KIR) are important for the recognition and elimination of diseased cells by human NK cells. Myeloid leukemia patients given a hematopoietic stem cell transplantation, for example, benefit from KIR-mediated NK alloreactivity directed against the leukemia cells. To establish an effective NK cell repertoire, most KIR genes are expressed stochastically, independently of the others. However, the sequences upstream of the coding regions of these KIR genes are highly homologous to the recently identified KIR3DL1 promoter (91.1,99.6% sequence identity), suggesting that they are regulated by similar if not identical mechanisms of transcriptional activation. We investigated the effects of small sequence differences between the KIR3DL1 promoter and other KIR promoters on transcription factor binding and promoter activity. Surprisingly, electrophoretic mobility shift assays and promoter-reporter assays revealed significant structural and functional differences in the cis-acting elements of these highly homologous KIR promoters, suggesting a key role for transcription factors in independent control of expression of specific KIR loci. Thus, the KIR repertoire may be shaped by a combination of both gene-specific and stochastic mechanisms. [source] PU.1 is required for transcriptional activation of the Stat6 response element in the Ig, promoterEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2003Marko Pesu Abstract Signal transducer and activator of transcription 6 (Stat6) has a crucial role in regulation of IL-4-induced gene responses. Stat6-binding sites are present in the promoters of both ubiquitously and cell-type-specifically expressed genes. The promoter regions of IL-4-inducible genes contain cis -acting elements for several transcription factors that act in concert with Stat6 and are also likely to modulate lineage-specific gene expression. We have observed that the Stat6 response element from the B-cell-specific Ig, promoter is readily activated upon IL-4 stimulation in B cells but not in non-hematopoietic cells. A minimal low-affinity PU.1-core-binding sequence (5,-AGAA-3,) was identified within the Stat6 DNA-binding site in the Ig, promoter. Ectopic expression of the myeloid- and B-cell-specific transcription factor PU.1 restored the IL-4-inducibility of the Ig,-Stat6 response element in HepG2 cells, and the induction required an intact PU.1-binding sequence. Both the transactivation and the DNA-binding domains of PU.1 were required for induction of Stat6-mediated transcription. The co-operation between PU.1 and Stat6 in transactivation of the Ig, gene represents a molecular mechanism for the fine-tuning of cell-type-restricted expression of IL-4-induced gene responses. [source] Cooperation between toll-like receptor,2 and,4 in the brain of mice challenged with cell wall components derived from gram-negative and gram-positive bacteriaEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2003Nathalie Laflamme Abstract In this study we investigated whether induction of toll-like receptor,2 (TLR2) amplifies the effect of a cell wall component derived from gram-positive bacteria, namely peptidoglycan (PGN). Mice received a first systemic lipopolysaccharide (LPS) injection to pre-induce TLR2 in various regions of the brain, and 6,h later, a second administration of either LPS or PGN. The data show a robust transcriptional activation of TLR2, TNF-, and monocyte chemotactic protein-1 (MCP-1) in microglial cells of mice challenged twice with LPS, whereas PGN essentially abolished this response. TLR4 plays a critical role in this process, because C3H/HeJ mice no longer responded to LPS but exhibited a normal reaction to PGN. Conversely, a robust signal for genes encoding innate immune proteinswas found in the brain of TLR2-deficient mice challenged with LPS. However, the second LPS bolus failed to trigger TNF-, and IL-12 in TLR2-deficient mice, while the same treatment caused a strong induction of these genes in the cerebral tissue of wild-type littermates. The present data provide evidence that cooperation exists between TLR4 and TLR2. While TLR4 is absolutely necessary to engage the innate immune response in the brain, TLR2 participates in the regulation of genes encoding TNF-, and IL-12 during severe endotoxemia. Such collaboration between TLR4 and TLR2 may be determinant for the transfer from the innate to the adaptive immunity within the CNS of infected animals. [source] Biological activity of RE-1 silencing transcription factor (REST) towards distinct transcriptional activatorsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2001Michael Lietz Abstract The zinc finger protein RE-1 silencing transcription factor (REST) is a transcriptional repressor that represses neuronal genes in non-neuronal tissues. We have analyzed the ability of REST and the REST mutants, REST,N and REST,C lacking either the N-terminal or C-terminal repression domains of REST, to inhibit transcription mediated by distinct transcriptional activator proteins. For this purpose we have designed an activator specific assay where transcription is activated as a result of only one distinct activation domain. In addition, binding sites for REST were inserted in the 5,-untranslated region or at a distant position downstream of the polyadenylation signal. The results show that REST or the REST mutants containing only one repression domain were able to block transcriptional activation mediated by the transcriptional activation domains derived from p53, AP2, Egr-1, and GAL4. Moreover, REST, as well as the REST mutants, blocked the activity of the phosphorylation-dependent activation domain of Elk1. However, the activity of the activation domain derived from cAMP response element binding protein 2 (CREB2), was not inhibited by REST, REST,N or REST,C, suggesting that REST is able to distinguish between distinct transcriptional activation domains. Additionally, the activator specific assay, together with a positive-dominant mutant of REST that activated instead of repressed transcription, was used in titration experiments to show that REST has transcriptional repression and no transcriptional activation properties when bound to the 5,-untranslated region of a gene. [source] MBP-1 is efficiently encoded by an alternative transcript of the ENO1 gene but post-translationally regulated by proteasome-dependent protein turnoverFEBS JOURNAL, Issue 20 2010Jrhau Lung The c-myc promoter-binding protein-1 (MBP-1) is a transcriptional suppressor of tumorigenesis and thought to be the product of alternative translation initiation of the ,-enolase (ENO1) transcript. In the present study, we cloned a 2552-bp novel cDNA with a putative coding sequence of MBP-1 and functionally examined its ability to encode the MBP-1 protein. Similarly to ENO1, the obtained MBP-1 was widely and differentially expressed in a variety of normal tissues and cancer cells. Experiments using MBP-1 promoter-driven luciferase reporter assays, biochemical cell fractionation followed by RT-PCR detection of the cytoplasmic mRNA, and transcription/translation-coupled reactions, consistently demonstrated that this novel transcript was alternatively transcribed from intron III of the ENO1 gene and was feasible for MBP-1 production. Hypoxia treatments significantly increased the transcriptional activation of the MBP-1 gene. Blocking the proteasomal degradation by MG132 stabilized the MBP-1 protein in cells. Compared with the translation efficiency for production of the MBP-1 protein, the MBP-1 transcript was 17.8 times more efficient than the ENO1 transcript. Thus, we suggest that this newly discovered transcript is a genuine template for the protein synthesis of MBP-1 in cells, and optimal expression of this gene in tumors may lead to effective clinical therapies for cancers. [source] A novel N-terminal hydrophobic motif mediates constitutive degradation of serum- and glucocorticoid-induced kinase-1 by the ubiquitin,proteasome pathwayFEBS JOURNAL, Issue 13 2006Agata M. Bogusz Serum- and glucocorticoid-induced protein kinase-1 (SGK-1) plays a critical role in regulation of the epithelial sodium channel, ENaC. SGK-1 also shares significant catalytic domain homology with protein kinase B (PKB/AKT-1) and is a downstream effector of antiapoptotic phosphoinositide 3-kinase signaling. Steady-state levels of an active SGK-1 are tightly regulated by rapid transcriptional activation and post-translational modification including phosphorylation. We show here that endogenous SGK-1 protein is polyubiquitinated and rapidly degraded by the 26S proteasome. In contrast to other rapidly degraded kinases, neither the catalytic activity of SGK-1 nor activation site phosphorylation was required for its ubiquitin modification and degradation. Instead, SGK-1 degradation required a lysine-less six-amino-acid (amino acids 19,24) hydrophobic motif (GMVAIL) within the N-terminal domain. Deletion of amino acids 19,24 significantly increased the half-life of SGK1 and prevented its ubiquitin modification. Interestingly, this minimal region was also required for the association of SGK-1 with the endoplasmic reticulum. Ubiquitin modification and degradation of SGK-1 were increasingly inhibited by the progressive mutation of six N-terminal lysine residues surrounding the GMVAIL motif. Mutation of all six lysines to arginine did not disrupt the subcellular localization of SGK-1 despite a significant decrease in ubiquitination, implying that this modification per se was not required for targeting to the endoplasmic reticulum. These results suggest that constitutive ubiquitin-mediated degradation of SGK-1 is an important mechanism regulating its biological activity. [source] Identification of ERR, as a specific partner of PGC-1, for the activation of PDK4 gene expression in muscleFEBS JOURNAL, Issue 8 2006Makoto Araki Pyruvate dehydrogenase kinase 4 (PDK4) is a key regulatory enzyme involved in switching the energy source from glucose to fatty acids in response to physiological conditions. Transcription of the PDK4 gene is activated by fasting or by the administration of a PPAR, ligand in a tissue-specific manner. Here, we show that the two mechanisms are independent, and that ERR, is directly involved in PPAR,-independent transcriptional activation of the PDK4 gene with PGC-1, as a specific partner. This conclusion is based on the following evidence. First, detailed mutation analyses of the cloned PDK4 gene promoter sequence identified a possible ERR,-binding motif as the PGC-1, responsive element. Second, overexpression of ERR, by cotransfection enhanced, and the knockout of it by shRNAs diminished, PGC-1,-dependent activation. Third, specific binding of ERR, to the identified PGC-1, responsive sequence was confirmed by the electrophoresis mobility shift assay. Finally, cell-type-specific responsiveness to PGC-1, was observed and this could be explained by differences in the expression levels of ERR,, however, ectopic expression of ERR, in poorly responsive cells did not restore PGC-1, responsiveness, indicating that ERR, is necessary, but not sufficient for the response. [source] ISC1-encoded inositol phosphosphingolipid phospholipase C is involved in Na+/Li+ halotolerance of Saccharomyces cerevisiaeFEBS JOURNAL, Issue 16 2002Christian Betz In Saccharomyces cerevisiae, toxic concentrations of Na+ orLi+ ions induce the expression of the cation-extrusion ATPase gene, ENA1. Several well-studied signal transduction pathways are known correlating high salinity to the transcriptional activation of ENA1. Nevertheless, information on the actual sensing mechanism initiating these pathways is limited. Here, we report that the ISC1 -encoded phosphosphingolipid-specific phospholipase C appears to be involved in stimulation of ENA1 expression and, consequently, in mediating Na+ and Li+ tolerance in yeast. Deletion of ISC1 distinctly decreased cellular Na+ and Li+ tolerance as growth of the ,isc1::HIS5 mutant, DZY1, was severely impaired by 0.5 m NaCl or 0.01 m LiCl. In contrast,K+ tolerance and general osmostress regulation wereunaffected. Isc1, mutant growth with 0.9 m KCl and glycerol accumulation in the presence of 0.9 m NaCl or 1.5 m sorbitol were comparable to that of the wild-type. ENA1 -lacZ reporter studies suggested that the increased salt sensitivity of the isc1, mutant is related to a significant reduction of Na+/Li+ -stimulated ENA1 expression. Correspondingly, Ena1p-dependent extrusion of Na+/Li+ ions was less efficient in the isc1, mutant than in wild-type cells. Itis suggested that ISC1 -dependent hydrolysis of an unidentified yeast inositol phosphosphingolipid represents an early event in one of the salt-induced signalling pathways of ENA1 transcriptional activation. [source] DNase I hypersensitive sites and transcriptional activation of the lamin A/C geneFEBS JOURNAL, Issue 5 2000Kazuhiko Nakamachi The lamin A/C gene encodes subtypes of nuclear lamins, which are involved in nuclear envelope formation, and was recently identified as the responsible gene for the autosomal dominant Emery,Dreifuss muscular dystrophy. Expression of the lamin A/C gene is developmentally regulated but little is known about the regulatory mechanism. Previous studies of lamin A/C expression suggested that the chromatin structure is important for the regulation of its expression. To elucidate the regulatory mechanism of the lamin A/C gene expression, we have analysed the functional region of the mouse lamin A/C promoter and the chromatin structure of the gene in terms of nucleosome structure and DNase I hypersensitivity. Our analyses revealed disruption of the nucleosome array at the promoter region and the presence of multiple DNase I hypersensitive sites (HSs) which were specifically associated with expression of the lamin A/C gene. Inclusion of a segment which contained the HSs in a lamin A/C promoter-luciferase reporter plasmid showed no effect on the transfected promoter activity in transient expression assays. On the other hand, substantial enhancement of the promoter activity was detected when the transfected DNA was stably integrated into the genome, suggesting the importance of the HSs in the regulation of lamin A/C expression. [source] Identification of direct and indirect targets of the Gln3 and Gat1 activators by transcriptional profiling in response to nitrogen availability in the short and long termFEMS YEAST RESEARCH, Issue 5 2006Bart Scherens Abstract Nitrogen catabolite repression (NCR) consists in the specific inhibition of transcriptional activation of genes encoding the permeases and catabolic enzymes needed to degrade poor nitrogen sources. Under nitrogen limitation or rapamycin treatment, NCR genes are activated by Gln3 or Gat1, or by both factors. To compare the sets of genes responding to rapamycin or to nitrogen limitation, we used DNA microarrays to establishing the expression profiles of a wild type strain, and of a double gln3,,gat1, strain, grown on glutamine, after addition of rapamycin, on proline, or after a shift from glutamine to proline. Analysis of microarray data revealed 392 genes whose expression was dependent on the nitrogen source quality. 91 genes were activated in a GATA factor-dependent manner in all growth conditions, suggesting a direct role of Gln3 and Gat1 in their expression. Other genes were only transiently up-regulated (stress-responsive genes) or down-regulated (genes encoding ribosomal proteins and translational factors) upon nitrogen limitation, and this regulation was delayed in a gln3,,gat1, strain. Repression of amino acid and nucleotide biosynthetic genes after a nitrogen shift did not depend on Gcn4. Several transporter genes were repressed as a consequence of enhanced levels of NCR-responsive permeases present at the plasma membrane. [source] ERK5 is involved in TCR-induced apoptosis through the modification of Nur77GENES TO CELLS, Issue 5 2008Yasushi Fujii Nur77 is a nuclear orphan steroid receptor that has been implicated in negative selection when immature T cells are strongly activated through interaction with self peptide-MHC complexes. The expression of Nur77 in thymocytes and T cell lines leads to apoptosis in a manner dependent on its transcriptional activity. It is well established that Nur77 function is negatively regulated by post-translational modification. Here we demonstrate that the MAPK-induced phosphorylation of Nur77 during T cell activation plays a critical role in the induction of apoptosis. Upon T cell receptor (TCR) stimulation, ERK5 (also known as big MAP kinase 1, BMK1), a member of the MAPK family, phosphorylates Nur77, leading to its transcriptional activation. In contrast, the activation of the ERK2 signaling pathway failed to activate Nur77 although ERK2 is also able to phosphorylate Nur77. Furthermore, the blockade of ERK5 signaling pathway suppressed TCR-induced cell death. These results indicate that ERK5 regulates Nur77 function through its phosphorylation. [source] Essential role of C/EBP, in G-CSF-induced transcriptional activation and chromatin modification of myeloid-specific genesGENES TO CELLS, Issue 4 2008Satoshi Iida Granulocyte colony-stimulating factor (G-CSF) regulates the proliferation and differentiation of neutrophilic progenitor cells. Here, we investigated the roles of CCAAT/enhancer-binding protein (C/EBP), in the G-CSF-induced transcriptional activation and chromatin modification of the CCR2 and myeloperoxidase (MPO) genes in IL-3-dependent myeloid FDN1.1 cells. Chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays revealed that G-CSF activates C/EBP, to bind target promoters. ChIP mapping experiments across the CCR2 and MPO genes showed that G-CSF induces histone H3 modifications: the acetylation of Lys9, trimethylation of Lys4 and trimethylation of Lys9. The distribution profile of the trimethylated Lys9 was distinct from that of the two other modifications. All the G-CSF-induced C/EBP, recruitment, transcriptional activation and histone modifications were reversed by re-stimulation with IL-3, and were abolished by short hairpin RNA (shRNA)-mediated knockdown of C/EBP,. These results indicate that C/EBP, is activated by G-CSF to bind target promoters, and plays critical roles in the transcriptional activation and dynamic chromatin modification of target genes during neutrophil differentiation. [source] SEI family of nuclear factors regulates p53-dependent transcriptional activationGENES TO CELLS, Issue 8 2005Rie Watanabe-Fukunaga SEI family proteins, p34SEI-1 and SEI-2(TRIP-Br2), are nuclear factors that are implicated in cell cycle regulation through interaction with CDK4/CyclinD and E2F-1/DP-1 complexes. Here we report that the SEI family proteins regulate transcriptional activity of p53 tumor suppressor protein. Expression of SEI-1, SEI-2 or SEI-3 strongly stimulates p53-dependent gene activation in HeLa and U2OS cells but not in p53-deficient Saos2 or p53-knockdown HeLa cells. SEI proteins possess an intrinsic transactivation activity, interact with the coactivator CREB-binding protein, and cooperate synergistically with the ING family of chromatin-associated proteins to stimulate the transactivation function of p53. Doxycycline-induced expression of SEI proteins results in activation of the p21 gene and inhibition of cell growth, but the growth arrest was not suppressed by the siRNA-mediated knockdown of the endogenous p53 protein. These results indicate that the SEI family of nuclear proteins regulates p53 transcriptional activity and a p53-independent signaling pathway leading to growth inhibition. [source] Induction of CspA, an E. coli major cold-shock protein, upon nutritional upshift at 37,°CGENES TO CELLS, Issue 4 2001Kunitoshi Yamanaka Background The synthesis of CspA, the major cold-shock protein of Escherichia coli, is dramatically induced upon cold shock. It was recently reported that there is massive presence of CspA under nonstress conditions, and it is thus claimed that CspA as the cold-shock protein is a misnomer. Results Here, we re-examined and confirmed that CspA is induced upon culture dilution at 37 °C. However, its induction level is one-sixth of the cold-shock-induced level, clearly indicating that the major stress that induces CspA is cold shock. It was further found that CspA induction can be achieved not only by culture dilution but also by the simple addition of nutrients, and that it was almost completely abolished in the presence of rifampicin or nalidixic acid. Nutritional upshift causes the induction of only CspA but not other cold-shock-inducible CspA homologues. The amount of cspA mRNA rapidly and transiently increased by culture dilution, but its stability was not significantly changed. Conclusions These results suggest that CspA is a nutritional-upshift stress protein as well as a cold-shock stress protein, and that CspA induction following nutritional upshift may be due to transcriptional activation. [source] Hes7: a bHLH-type repressor gene regulated by Notch and expressed in the presomitic mesodermGENES TO CELLS, Issue 2 2001Yasumasa Bessho Background: Whereas Notch signalling is essential for somitogenesis, mice deficient for the basic helix-loop-helix (bHLH) genes Hes1 and Hes5, downstream Notch effectors, display normal somite formation, indicating that there may be an as-yet unidentified Hes1 -related bHLH gene. Results: We identified a novel bHLH gene, designated Hes7, from mouse embryos. Hes7 has a conserved bHLH domain in the amino-terminal region and the WRPW domain at the carboxy-terminal end, like Hes1. The mouse Hes7 gene is located next to Aloxe3, which is mapped to a position 37.0 cM from the centromere on chromosome 11. In a transfection analysis, Hes7 represses transcription from the N box- and E box-containing promoters. In addition, Hes7 suppresses the E47-induced transcriptional activation. Promoter analysis indicated that Hes7 expression is controlled by Notch signalling. Strikingly, Hes7 is specifically expressed in the presomitic mesoderm in a dynamic manner. We also identified two related bHLH genes from human: one is closely related to mouse Hes7 and therefore designated hHes7 and the other designated hHes4. Conclusion: The structure, transcriptional activity and expression pattern in the presomitic mesoderm of Hes7 are very similar to those of Hes1, suggesting that Hes7, together with Hes1, may play a role in somite formation under the control of Notch signalling. [source] Rearrangement of upstream sequences of the hTERT gene during cellular immortalizationGENES, CHROMOSOMES AND CANCER, Issue 11 2009Yuanjun Zhao Telomerase expression, resulting from transcriptional activation of the hTERT gene, allows cells to acquire indefinite proliferative potential during cellular immortalization and tumorigenesis. However, mechanisms of hTERT gene activation in many immortal cell lines and cancer cells are poorly understood. Here, we report our studies on hTERT activation using genetically related pairs of telomerase-negative (Tel,) and -positive (Tel+) fibroblast lines. First, whereas transiently transfected plasmid reporters did not recapitulate the endogenous hTERT promoter, the promoter in chromosomally integrated bacterial artificial chromosome (BAC) reporters was activated in a subset of Tel+ cells, indicating that activation of the hTERT promoter required native chromatin context and/or distal regulatory elements. Second, the hTERT gene, located near the telomere of chromosome 5p, was translocated in all three Tel+ cell lines but not in their parental precrisis cells and Tel, immortal siblings. The breakage points were mapped to regions upstream of the hTERT promoter, indicating that the hTERT gene was the target of these chromosomal rearrangements. In two Tel+ cell lines, translocation of the endogenous hTERT gene appeared to be the major mechanism of its activation as the activity of hTERT promoter in many chromosomally integrated BAC reporters, with intact upstream and downstream neighboring loci, remained relatively low. Therefore, our results suggest that rearrangement of upstream sequences is an important new mechanism of hTERT promoter activation during cellular immortalization. The chromosomal rearrangements likely occurred during cellular crisis and facilitated by telomere dysfunction. Such translocations allowed the hTERT promoter to escape from the native condensed chromatin environment. © 2009 Wiley-Liss, Inc. [source] A novel mutation in the GATA4 gene in patients with Tetralogy of Fallot,,HUMAN MUTATION, Issue 3 2006Georges Nemer Abstract In vertebrates, heart formation which integrates different structures and cell types is a complex process that involves a network of genes regulated by transcription factors. Proper spatiotemporal expression of these factors ensure the highly needed tight control of each step in organogenesis. A mistake at any step from cell-commitment to valve formation will have a major impact on heart morphogenesis and function leading to congenital heart disease (CHD). Cardiac abnormalities occur with an incidence of one per 100 live births and represent 25% of all congenital malformations. As an alternative approach to linkage-analysis of familial cases of CHD, we started screening familial and sporadic cases of CHDs in a highly consanguineous population for mutations in genes encoding cardiac-enriched transcription factors. The evolutionarily conserved role of these proteins in cardiac development suggested a role in CHD. In this study, we report a mutation in the gene encoding GATA4, one of the earliest markers of heart development. This mutation was found in two out of 26 patients with Tetralogy of Fallot (TOF), and in none of the 94 patients with different phenotypes included in the study, nor in 223 healthy individuals. The heterozygous mutation results in an amino acid substitution in the first zinc finger of GATA4 that reduced its transcriptional activation of downstream target genes, without affecting GATA4 ability to bind DNA, nor its interaction with ZFPM2. © 2006 Wiley-Liss, Inc. [source] Regulation of IL-4 production in mast cells: a paradigm for cell-type-specific gene expressionIMMUNOLOGICAL REVIEWS, Issue 1 2001Deborah L. Weiss Summary: The role of interleukin (IL)-4 as an important immunomodulatory cytokine is well established. IL-4 exhibits a highly restricted pattern of expression by cells of distinct lineages. The cell types that produce IL-4 are located in anatomically distinct locations (e.g. circulating T cells vs. fixed tissue mast cells) and thus have access to different IL-4-responsive target cells. In addition, these cells appear to regulate IL-4 expression in cell-type-specific ways. These findings suggest that an understanding of IL-4 gene regulation in T and mast cells could provide the means to specifically control IL-4 release in a lineage- and site-specific manner. In this article we review the current knowledge regarding the cell-type specific regulation of IL-4 gene expression in mast cells and compare this to what has been defined in T cells. We show that there are distinct yet parallel events that control developmentally determined chromatin modifications, allowing accessibility of the locus, and provide the potential for transcription. In differentiated cells, a subset of unique cell activation signals initiates the cascade of events that lead to transcriptional activation of the IL-4 gene. This work was supported by the National Science Foundation (DLW), the National Institutes of Health and the Multiple Sclerosis Society (MAB). We appreciate the technical and intellectual contributions of many colleagues including Doris Powell, John Hural, Tammy Nachman, Ben Hock, David Tara, Greg Henkel, Susan Lee, Millie Kwan, Melanie Sherman and Ginny Secor. [source] Catalposide, a compound isolated from Catalpa Ovata, attenuates induction of intestinal epithelial proinflammatory gene expression and reduces the severity of trinitrobenzene sulfonic acid-induced colitis in miceINFLAMMATORY BOWEL DISEASES, Issue 5 2004Sang-Wook Kim MD Abstract Certain irinoid-producing plants have been used as herbal anti-inflammatory remedies. Here we evaluated whether catalposide (CATP), a single compound isolated from irinoid-producing plant Catalpa ovata, has a potential for preventing or ameliorating diseases characterized by mucosal inflammation. Preliminary microarray-based gene expression test revealed that CATP, which alone did not significantly affect expression of any of the >8,000 genes analyzed, attenuated the expression of tumor necrosis factor-, (TNF-,)-induced proinflammatory genes including interleukin-8 (IL-8) in human intestinal epithelial HT-29 cells. Down-regulation of IL-8 mRNA accumulation was also reflected by the decreased IL-8 secretion in CATP-treated HT-29 cells. The signal transduction study revealed that CATP significantly attenuates TNF-,-mediated p38 and extracellular signal-regulated kinase (ERK) phosphorylation. Further, CATP reduced NF-,B-mediated transcriptional activation as well as I,-B, degradation. To establish the in vivo relevance of these findings, we examined whether CATP could affect intestinal inflammation in vivo using the mouse model of trinitrobenzene sulfonic acid (TNBS)-induced inflammatory colitis. Intrarectal administration of CATP dramatically reduced the weight loss, colonic damage, and mucosal ulceration that characterize TNBS colitis. Moreover, CATP suppressed the expression of TNF-,, interleukin-1,, and intercellular adhesion molecule-1 along with the inhibition of NF-, B p65 translocation into nucleus in TNBS colitis. Collectively, current results demonstrate that CATP may be an effective agent for the treatment of diseases characterized by mucosal inflammation. [source] Transcriptional upregulation of HSP70-2 by HIF-1 in cancer cells in response to hypoxiaINTERNATIONAL JOURNAL OF CANCER, Issue 2 2009Wen-Jie Huang Abstract Heat shock protein 70-2 (HSP70-2) can be expressed by cancer cells and act as an important regulator of cancer cell growth and survival. Here, we show the molecular mechanisms by which hypoxia regulate HSP70-2 expression in cancer cells. When cells were subjected to hypoxia (1% O2), the expression of HSP70-2 had a significant increase in cancer cells. Such increase was due to the direct binding of hypoxia-inducible factor to hypoxia-responsive elements (HREs) in the HSP70-2 promoter. By luciferase assays, we demonstrated that the HRE1 at position ,446 was essential for transcriptional activation of HSP70-2 promoter under hypoxic conditions. We also demonstrated that HIF-1, binds to the HSP70-2 promoter and the binding is specific, as revealed by HIF binding/competition and chromatin immunoprecipitation assays. Consequently, the upregulation of HSP70-2 enhanced the resistance of tumor cells to hypoxia-induced apoptosis. These findings provide a new insight into how tumor cells overcome hypoxic stress and survive, and also disclose a new regulatory mechanism of HSP70-2 expression in tumor cells. © 2008 Wiley-Liss, Inc. [source] Regulation of E-cadherin and ,-catenin by Ca2+ in colon carcinoma is dependent on calcium-sensing receptor expression and functionINTERNATIONAL JOURNAL OF CANCER, Issue 7 2007Narasimharao Bhagavathula Abstract An siRNA directed against the extracellular calcium-sensing receptor (CaSR) was used to down-regulate this protein in CBS colon carcinoma cells. In additional studies, we utilized a variant of the parental CBS line that demonstrates CaSR expression but does not upregulate this protein in response to extracellular Ca2+. In neither the siRNA-transfected cells nor the Ca2+ -nonresponsive variant cells did inclusion of Ca2+ in the culture medium inhibit proliferation or induce morphological alterations. Extracellular Ca2+ also failed to induce E-cadherin production or a shift in ,-catenin from the cytoplasm to the cell membrane. In mock-transfected cells and in a Ca2+ -responsive variant line derived from the same parental CBS cells, Ca2+ treatment resulted in growth-reduction. This was accompanied by increased E-cadherin production and a shift in ,-catenin distribution from the cytoplasm to the cell membrane. Additionally, down-regulation of c-myc and cyclin D1 expression was observed in mock-transfected cells and in the Ca2+ -responsive variant line (along with reduced T cell factor transcriptional activation). Neither c-myc nor cyclin D1 was significantly down-regulated in the siRNA-transfected cells or in the Ca2+ -nonresponsive variant cells upon Ca2+ stimulation. In histological sections of human colon carcinoma CaSR was significantly reduced as compared to the level in normal colonic crypt epithelial cells. Where CaSR expression was high, strong surface staining for E-cadherin and ,-catenin was observed. Where CaSR expression was reduced, ,-catenin surface expression was likewise reduced. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||