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1

Oxysterols suppress constitutive fibrinogen expression.  

PubMed

Elevated levels of both fibrinogen and cholesterol are risk factors in coronary artery disease. Previously we reported a metabolic link between fibrinogen and lipid metabolism in that HepG2 cells that were programmed by transfection of Bbeta-fibrinogen cDNA to overexpress fibrinogen exhibited increased synthesis of cholesterol and increased secretion of apolipoprotein B. In this study we demonstrate that oxysterols, which participate in maintaining cholesterol homeostasis, also down regulate fibrinogen expression. Treatment of HepG2 cells with 25-hydroxycholesterol lowered fibrinogen Aalpha, Bbeta and gamma mRNA levels and inhibited fibrinogen synthesis and secretion but had no effect on alpha1 -antitrypsin which, like fibrinogen, is an acute-phase protein. The inhibition of fibrinogen synthesis by oxysterols was maintained in interleukin-6 treated cells. Other oxysterols, that inhibit cholesterol synthesis by a feedback mechanism, also diminished fibrinogen expression in HepG2, rat H-4-II-E hepatoma cells and in primary human hepatocytes. Overexpression of SREBP-1 and SREBP-2 by transfection of HepG2 cells, or treatment with a synthetic LXRalpha agonist, which affect cholesterol metabolism, did not affect fibrinogen expression. We conclude that fibrinogen and cholesterol may share a novel common regulatory pathway. PMID:12876624

Xia, Hui; Redman, Colvin M

2003-07-01

2

Melanoma immunotherapy using mature DCs expressing the constitutive proteasome  

PubMed Central

Background. Many cancers, including melanoma, exclusively express constitutive proteasomes (cPs) and are unable to express immunoproteasomes (iPs). In contrast, mature DCs used for immunotherapy exclusively express iPs. Since proteasomes generate peptides presented by HLA class I molecules, we hypothesized that mature melanoma antigen–loaded DCs engineered to process antigens through cPs would be superior inducers of antimelanoma immunity in vivo. Methods. Subjects with metastatic melanoma were vaccinated with mature DCs transfected with RNAs encoding melanoma antigens MART1, MAGE-3, gp100, and tyrosinase. These DCs were derived from monocytes that were untransfected (Arm A; n = 4), transfected with control siRNA (Arm B; n = 3), or transfected with siRNAs targeting the 3 inducible iP subunits (Arm C; n = 5). Results. Vaccination stimulated antigen-specific T cell responses in all subjects, which peaked after 3–4 vaccinations, but remained elevated in Arm C subjects. Also in Arm C, circulating melanoma cell levels (as detected by quantitative PCR) fell, and T cell lytic activity against autologous melanoma was induced. In HLA-A2+ subjects, CD8+ T cells that bound tetramers loaded with cP-derived melanoma antigenic peptides were found in the peripheral blood only in Arm C subjects. Of 2 subjects with active disease (both in Arm C), one had a partial clinical response, while the other, who exhibited diffuse dermal and soft tissue metastases, had a complete response. Conclusion. These results suggest that the efficacy of melanoma DC–based immunotherapy is enhanced when tumor antigen–loaded DCs used for vaccination express cPs. Trial registration. Clinicaltrials.gov NCT00672542. Funding. Duke Clinical Research Institute/Duke Translational Medicine Institute, Duke Melanoma Consortium, and Duke University Department of Surgery.

Dannull, Jens; Haley, N. Rebecca; Archer, Gary; Nair, Smita; Boczkowski, David; Harper, Mark; De Rosa, Nicole; Pickett, Nancy; Mosca, Paul J.; Burchette, James; Selim, Maria A.; Mitchell, Duane A.; Sampson, John; Tyler, Douglas S.; Pruitt, Scott K.

2013-01-01

3

The Constitution. GEMS: Greenfield Express Management System. Revised Edition.  

ERIC Educational Resources Information Center

Developed for eighth grade students reading on or above grade level, this self-correcting unit covers the background of the Constitution, the Preamble, the seven articles, and the amendments. Material is divided into two sections. The teacher section outlines activities, materials, evaluation options, and follow-up activities. A crossword puzzle…

Reese, Marianne

4

Constitutive expression of hepatic cytochrome P450 genes  

Microsoft Academic Search

One of the more challenging areas for study of the regulation of P450s is understanding the constitutive regulation of hepatic P450s. In this article, Gonzalez and Lee provide insight into how unique tissue-en- riched transcription factors regulate expression of many of the hepatic P450s that are not under direct control of the \\

FRANK J. GONZALEZ; YING-HUE LEE

1996-01-01

5

Constitutive expression of Botrytis aclada laccase in Pichia pastoris.  

PubMed

The heterologous expression of laccases is important for their large-scale production and genetic engineering--a prerequisite for industrial application. Pichia pastoris is the preferred expression host for fungal laccases. The recently cloned laccase from the ascomycete Botrytis aclada (BaLac) has been efficiently expressed in P. pastoris under the control of the inducible alcohol oxidase (AOX1) promoter. In this study, we compare these results to the constitutive expression in the same organism using the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter. The results show that the amounts of BaLac produced with the GAP system (517 mgL(-1)) and the AOX1 system (495 mgL(-1)) are comparable. The constitutive expression is, however, faster, and the specific activity of BaLac in the culture supernatant is higher (41.3 Umg(-1) GAP, 14.2 Umg(-1) AOX1). In microtiter plates, the constitutive expression provides a clear advantage due to easy manipulation (simple medium, no methanol feeding) and fast enzyme production (high-throughput screening assays can already be performed after 48 h). PMID:22705842

Kittl, Roman; Gonaus, Christoph; Pillei, Christian; Haltrich, Dietmar; Ludwig, Roland

2012-01-01

6

Constitutive expression of calreticulin in osteoblasts inhibits mineralization  

PubMed Central

Recent studies have shown that the multifunctional protein calreticulin can localize to the cell nucleus and regulate gene transcription via its ability to bind a protein motif in the DNA-binding domain of nuclear hormone receptors. A number of known modulators of bone cell function, including vitamin D, act through this receptor family, suggesting that calreticulin may regulate their action in bone cells. We have used a gain-of-function strategy to examine this putative role of calreticulin in MC3T3-E1 osteoblastic cells. Purified calreticulin inhibited the binding of the vitamin D receptor to characterized vitamin D response elements in gel retardation assays. This inhibition was due to direct protein-protein interactions between the vitamin D receptor and calreticulin. Expression of calreticulin transcripts declined during MC3T3-E1 osteoblastic differentiation. MC3T3-E1 cells were transfected with calreticulin expression vectors; stably transfected cell lines overexpressing recombinant calreticulin were established and assayed for vitamin D-induced gene expression and the capacity to mineralize. Constitutive calreticulin expression inhibited basal and vitamin D-induced expression of the osteocalcin gene, whereas osteopontin gene expression was unaffected. This pattern mimicked the gene expression pattern observed in parental cells before down- regulation of endogenous calreticulin expression. In long-term cultures of parental or vector-transfected cells, 1 alpha,25-dihydroxyvitamin D3 (1,25[OH]2D3) induced a two- to threefold stimulation of 45Ca accumulation into the matrix layer. Constitutive expression of calreticulin inhibited the 1,25(OH)2D3-induced 45Ca accumulation. This result correlated with the complete absence of mineralization nodules in long-term cultures of calreticulin-transfected cells. These data suggest that calreticulin can regulate bone cell function by interacting with specific nuclear hormone receptor-mediated pathways.

1995-01-01

7

Genetic Requirements for High Constitutive SOS Expression in recA730 Mutants of Escherichia coli ?  

PubMed Central

The RecA protein in its functional state is in complex with single-stranded DNA, i.e., in the form of a RecA filament. In SOS induction, the RecA filament functions as a coprotease, enabling the autodigestion of the LexA repressor. The RecA filament can be formed by different mechanisms, but all of them require three enzymatic activities essential for the processing of DNA double-stranded ends. These are helicase, 5?–3? exonuclease, and RecA loading onto single-stranded DNA (ssDNA). In some mutants, the SOS response can be expressed constitutively during the process of normal DNA metabolism. The RecA730 mutant protein is able to form the RecA filament without the help of RecBCD and RecFOR mediators since it better competes with the single-strand binding (SSB) protein for ssDNA. As a consequence, the recA730 mutants show high constitutive SOS expression. In the study described in this paper, we studied the genetic requirements for constitutive SOS expression in recA730 mutants. Using a ?-galactosidase assay, we showed that the constitutive SOS response in recA730 mutants exhibits different requirements in different backgrounds. In a wild-type background, the constitutive SOS response is partially dependent on RecBCD function. In a recB1080 background (the recB1080 mutation retains only helicase), constitutive SOS expression is partially dependent on RecBCD helicase function and is strongly dependent on RecJ nuclease. Finally, in a recB-null background, the constitutive SOS expression of the recA730 mutant is dependent on the RecJ nuclease. Our results emphasize the importance of the 5?–3? exonuclease for high constitutive SOS expression in recA730 mutants and show that RecBCD function can further enhance the excellent intrinsic abilities of the RecA730 protein in vivo.

Vlasic, Ignacija; Simatovic, Ana; Brcic-Kostic, Krunoslav

2011-01-01

8

Analytic expressions for the constitutive parameters of magnetoelectric metamaterials  

NASA Astrophysics Data System (ADS)

Electromagnetic metamaterials are artificially structured media typically composed of arrays of resonant electromagnetic circuits, the dimension and spacing of which are considerably smaller than the free-space wavelengths of operation. The constitutive parameters for metamaterials, which can be obtained using full-wave simulations in conjunction with numerical retrieval algorithms, exhibit artifacts related to the finite size of the metamaterial cell relative to the wavelength. Liu [R. Liu, T. J. Cui, D. Huang, B. Zhao, and D. R. Smith, Phys. Rev. E 76, 026606 (2007)] showed that the complicated, frequency-dependent forms of the constitutive parameters can be described by a set of relatively simple analytical expressions. These expressions provide useful insight and can serve as the basis for more intelligent interpolation or optimization schemes. Here, we show that the same analytical expressions can be obtained using a transfer-matrix formalism applied to a one-dimensional periodic array of thin, resonant, dielectric, or magnetic sheets. The transfer-matrix formalism breaks down, however, when both electric and magnetic responses are present in the same unit cell, as it neglects the magnetoelectric coupling between unit cells [C. R. Simovski, Metamaterials 1, 62 (2007)]. We show that an alternative analytical approach based on the same physical model must be applied for such structures. Furthermore, in addition to the intercell coupling, electric and magnetic resonators within a unit cell may also exhibit magnetoelectric coupling. For such cells, we find an analytical expression for the effective index, which displays markedly characteristic dispersion features that depend on the strength of the coupling coefficient. We illustrate the applicability of the derived expressions by comparing to full-wave simulations on magnetoelectric unit cells. We conclude that the design of metamaterials with tailored simultaneous electric and magnetic response—such as negative index materials—will generally be complicated by potentially unwanted magnetoelectric coupling.

Smith, D. R.

2010-03-01

9

Fish granulocytes express a constitutively active androgen receptor variant.  

PubMed

In humans, alternative splicing of androgen receptor (AR) is usually involved in some diseases. However, our knowledge about the presence of AR variants in other species and its importance for immunity is scant. Here, we report the identification of a constitutively active AR variant lacking the ligand-binding domain (LBD), AR?LBD, in the fish gilthead seabream. AR?LBD is expressed in the testis and the head-kidney (HK), and its expression varies with the reproductive stage and is correlated with plasma testosterone (T). In addition, AR?LBD is expressed in acidophilic granulocytes (AGs), which are the functional equivalent of mammalian neutrophils, but not in macrophages, and its expression is modulated by both T and immune stimuli. Notably, AR and AR?LBD were able to interact, being the activity of AR dominant at all concentrations tested of the ligand. These results reveal a new mechanism for the regulation of neutrophil biology in vertebrates and explain the conflicting results that suggest that androgens are less important than AR in human and mouse neutrophil homeostasis. PMID:24509065

Sánchez-Hernández, Miriam; Arizcun, Marta; García-Alcázar, Alicia; Sarropoulou, Elena; Mulero, Victoriano; García-Ayala, Alfonsa

2014-07-01

10

Achieving efficient protein expression in Trichoderma reesei by using strong constitutive promoters  

PubMed Central

Backgrounds The fungus Trichoderma reesei is an important workhorse for expression of homologous or heterologous genes, and the inducible cbh1 promoter is generally used. However, constitutive expression is more preferable in some cases than inducible expression that leads to production of unwanted cellulase components. In this work, constitutive promoters of T. reesei were screened and successfully used for high level homologous expression of xylanase II. Results The transcriptional profiles of 13 key genes that participate in glucose metabolism in T. reesei were analyzed by quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR). The results indicated that the mRNA levels of pdc (encoding pyruvate decarboxylase) and eno (encoding enolase) genes were much higher than other genes under high glucose conditions. Recombinant T. reesei strains that homologously expressed xylanase II were constructed by using the promoters of the pdc and eno genes, and they respectively produced 9266?IU/ml and 8866?IU/ml of xylanase activities in the cultivation supernatant in a medium with high glucose concentration. The productivities of xylanase II were 1.61?g/L (with the pdc promoter) and 1.52?g/L (with the eno promoter), approximately accounted for 83% and 82% of the total protein secreted by T. reesei, respectively. Conclusions This work demonstrates the screening of constitutive promoters by using RT-qPCR in T. reesei, and has obtained the highest expression of recombinant xylanase II to date by using these promoters.

2012-01-01

11

Increased platelet activation and thrombosis in transgenic mice expressing constitutively active P2Y12 receptor  

PubMed Central

Summary Background In our previous in vitro study we reported a constitutively active chimeric P2Y12 receptor (cP2Y12) and found AR-C78511 is a potent inverse agonist at this receptor. The role of this cP2Y12 receptor in platelet activation and thrombosis is not clear. Objectives To investigate the physiological implications of the constitutively active P2Y12 receptor in platelet activation, thrombus formulation and evaluate the antiplatelet activity of AR-C78511 as an inverse agonist. Methods and Results We generated transgenic mice conditionally and platelet-specifically expressing cP2Y12. High expression of cP2Y12 receptor in platelets increased platelet reactivity as evidenced by increased platelet aggregation in response to multiple platelet agonists. Moreover, transgenic mice displayed shortened bleeding time, more rapid and stable thrombus formation in mesenteric artery injured with FeCl3. The constitutive activity of cP2Y12 in platelets was confirmed by decreased platelet cAMP levels and constitutive Akt phosphorylation in the absence of agonists. AR-C78511 reversed the cAMP decrease in transgenic mouse platelets, and exhibited superior antiplatelet effect over AR-C69931MX in transgenic mice. Conclusions These findings further emphasize the importance of P2Y12 in platelet activation, hemostasis and thrombosis, as well as the prothrombotic role of constitutive activity of P2Y12. Our data also validates the in vivo inverse agonist activity of AR-C78511 and confirms its superior antiplatelet activity over neutral antagonist.

Zhang, Y.; Ye, J.; Hu, L.; Zhang, S.; Zhang, S.H.; Li, Y.; Kunapuli, S.P.; Ding, Z.

2012-01-01

12

A constitutive gene expression system derived from the tCUP cryptic promoter elements  

Microsoft Academic Search

A limited number of constitutive promoters have been used to direct transgene expression in plants and they are often derived from non-plant sources. Here, we describe novel gene-regulatory elements which are associated with a cryptic constitutive promoter from tobacco, tCUP, and modifications that were made to create a strong gene-expression system that is effective across all living cell types from

K. Malik; K. Wu; X.-Q. Li; T. Martin-Heller; M. Hu; E. Foster; L. Tian; C. Wang; K. Ward; M. Jordan; D. Brown; S. Gleddie; D. Simmonds; S. Zheng; J. Simmonds; B. Miki

2002-01-01

13

Constitutive expression of ciliary neurotrophic factor in mouse hypothalamus  

PubMed Central

Ciliary neurotrophic factor (CNTF) is a potent survival molecule for a large number of neuronal and glial cells in culture; its expression in glial cells is strongly upregulated after a variety of nerve tissue injuries. Exogenously administered CNTF produces an anorectic effect via activation of hypothalamic neurons and stimulates neurogenesis in mouse hypothalamus. To determine whether CNTF is produced endogenously in the hypothalamus, we sought cellular sources and examined their distribution in adult mouse hypothalamus by immunohistochemistry. CNTF immunoreactivity (IR) was predominantly detected in the ependymal layer throughout the rostrocaudal extension of the third ventricle, where numerous ependymocytes and tanycytes exhibited specific staining. Some astrocytes in the grey matter of the anterior hypothalamus and in the median eminence of the hypothalamic tuberal region were also positive. Stimulation of cells bearing CNTF receptor ? (CNTFR?) induces specific activation of the signal transducer and activator of transcription 3 (STAT3) signalling system. Treatment with recombinant CNTF and detection of the nuclear expression of phospho-STAT3 (P-STAT3) showed that CNTF-producing ependymal cells and tanycytes were intermingled with, or very close to, P-STAT3-positive, CNTFR?-bearing cells. A fraction of CNTF-producing ependymal cells and tanycytes and some median eminence astrocytes also exhibited P-STAT3 IR. Thus, in normal adult mice the ependyma of the third ventricle is both a source of and a target for CNTF, which may play hitherto unknown roles in hypothalamic function in physiological conditions.

Severi, Ilenia; Carradori, Maria Rita; Lorenzi, Teresa; Amici, Adolfo; Cinti, Saverio; Giordano, Antonio

2012-01-01

14

A Dedicated Promoter Drives Constitutive Expression of the Cell-Autonomous Immune Resistance GTPase, Irga6 (IIGP1) in Mouse Liver  

PubMed Central

Background In general, immune effector molecules are induced by infection. Methodology and Principal Findings However, strong constitutive expression of the cell-autonomous resistance GTPase, Irga6 (IIGP1), was found in mouse liver, contrasting with previous evidence that expression of this protein is exclusively dependent on induction by IFN?. Constitutive and IFN?-inducible expression of Irga6 in the liver were shown to be dependent on transcription initiated from two independent untranslated 5? exons, which splice alternatively into the long exon encoding the full-length protein sequence. Irga6 is expressed constitutively in freshly isolated hepatocytes and is competent in these cells to accumulate on the parasitophorous vacuole membrane of infecting Toxoplasma gondii tachyzoites. Conclusions and Significance The role of constitutive hepatocyte expression of Irga6 in resistance to parasites invading from the gut via the hepatic portal system is discussed.

Zeng, Jia; Parvanova, Iana Angelova; Howard, Jonathan C.

2009-01-01

15

The Homeobox Gene Caudal Regulates Constitutive Local Expression of Antimicrobial Peptide Genes in Drosophila Epithelia  

Microsoft Academic Search

In Drosophila melanogaster, although the NF-B transcription factors play a pivotal role in the inducible expression of innate immune genes, such as antimicrobial peptide genes, the exact regulatory mechanism of the tissue-specific constitutive expression of these genes in barrier epithelia is largely unknown. Here, we show that the Drosophila homeobox gene product Caudal functions as the innate immune transcription modulator

Ji-Hwan Ryu; Ki-Bum Nam; Chun-Taek Oh; Hyuck-Jin Nam; Sung-Hee Kim; Joo-Heon Yoon; Je-Kyeong Seong; Mi-Ae Yoo; In-Hwan Jang; Paul T. Brey; Won-Jae Lee

2004-01-01

16

Constitutive versus Responsive Gene Expression Strategies for Growth in Changing Environments  

Microsoft Academic Search

Microbes respond to changing environments by adjusting gene expression levels to the demand for the corresponding proteins. Adjusting protein levels is slow, consequently cells may reach the optimal protein level only by a time when the demand changed again. It is therefore not a priori clear whether expression “on demand” is always the optimal strategy. Indeed, many genes are constitutively

Nico Geisel

2011-01-01

17

Gene Expression Regulation by Agonist-Independent Constitutive Signaling of Melanocortin-1 Receptor  

PubMed Central

Background Melanocortin-1 receptor (Mc1r), a key signaling receptor for melanogenesis, has been reported to mediate migration of B16F10 melanoma cells. Interestingly, this activity appears to be a part of the constitutive signaling of Mc1r. Methods We carried out small interfering RNA-mediated knock-down of Mc1r on murine melanoma B16F10 cells and performed microarray analysis to characterize changes in the gene expression profile. Results We isolated 22 and four genes whose expression decreased and increased, respectively, by 2.5-fold or higher as the result of Mc1r knock-down. Several down-regulated genes have been proposed to be involved in cell migration. Among these genes are several members of the chemokine gene family. Conclusion We provide a gene set for further functional analyses of Mc1r. The Mc1r target genes we present may be particularly relevant for understanding the ligand-independent activity of Mc1r. Further examination of the mode of action may lead to novel strategies in regulating the migration and metastasis of melanoma cells.

Seong, Ikjoo

2014-01-01

18

Human and Rat Neutrophils Constitutively Express Neural Nitric Oxide Synthase mRNA  

Microsoft Academic Search

Freshly isolated rat circulating neutrophils (PMN) constitutively expressed neural nitric oxide synthase (nNOS) mRNA and nNOS protein and exhibited spontaneous basal release of low concentrations of nitrate and nitrite anion (RNI). In contrast, rat peripheral monocytes and macrophages were devoid of nNOS mRNA and protein and did not exhibit basal or spontaneous release of RNI. Constitutive neural NOS mRNA was

Stan S. Greenberg; Jie Ouyang; Xinfang Zhao; Thomas D. Giles

1998-01-01

19

Stable expression of constitutively-activated STAT3 in benign prostatic epithelial cells changes their phenotype to that resembling malignant cells  

Microsoft Academic Search

BACKGROUND: Signal transducers and activators of transcription (STATs) are involved in growth regulation of cells. They are usually activated by phosphorylation at specific tyrosine residues. In neoplastic cells, constitutive activation of STATs accompanies growth dysregulation and resistance to apoptosis through changes in gene expression, such as enhanced anti-apoptotic gene expression or reduced pro-apoptotic gene expression. Activated STAT3 is thought to

Hosea F Huang; Thomas F Murphy; Ping Shu; Arnold B Barton; Beverly E Barton

2005-01-01

20

Constitutive homologous expression of phosphoglucomutase and transaldolase increases the metabolic flux of Fusarium oxysporum  

PubMed Central

Background Fusarium oxysporum is among the few filamentous fungi that have been reported of being able to directly ferment biomass to ethanol in a consolidated bioprocess. Understanding its metabolic pathways and their limitations can provide some insights on the genetic modifications required to enhance its growth and subsequent fermentation capability. In this study, we investigated the hypothesis reported previously that phosphoglucomutase and transaldolase are metabolic bottlenecks in the glycolysis and pentose phosphate pathway of the F. oxysporum metabolism. Results Both enzymes were homologously overexpressed in F. oxysporum F3 using the gpdA promoter of Aspergillus nidulans for constitutive expression. Transformants were screened for their phosphoglucomutase and transaldolase genes expression levels with northern blot. The selected transformant exhibited high mRNA levels for both genes, as well as higher specific activities of the corresponding enzymes, compared to the wild type. It also displayed more than 20 and 15% higher specific growth rate upon aerobic growth on glucose and xylose, respectively, as carbon sources and 30% higher biomass to xylose yield. The determination of the relative intracellular amino and non-amino organic acid concentrations at the end of growth on glucose revealed higher abundance of most determined metabolites between 1.5- and 3-times in the recombinant strain compared to the wild type. Lower abundance of the determined metabolites of the Krebs cycle and an 68-fold more glutamate were observed at the end of the cultivation, when xylose was used as carbon source. Conclusions Homologous overexpression of phosphoglucomutase and transaldolase in F. oxysporum was shown to enhance the growth characteristics of the strain in both xylose and glucose in aerobic conditions. The intracellular metabolites profile indicated how the changes in the metabolome could have resulted in the observed growth characteristics.

2014-01-01

21

High Level Constitutive Expression of Luciferase Reporter by lsd90 Promoter in Fission Yeast  

PubMed Central

Because of a large number of molecular similarities with higher eukaryotes, the fission yeast Schizosaccharomyces pombe has been considered a potentially ideal host for expressing human proteins having therapeutic and pharmaceutical applications. However, efforts in this direction are hampered by lack of a strong promoter. Here, we report the isolation and characterization of a strong, constitutive promoter from S. pombe. A new expression vector was constructed by cloning the putative promoter region of the lsd90 gene (earlier reported to be strongly induced by heat stress) into a previously reported high copy number vector pJH5, which contained an ARS element corresponding to the mat2P flanking region and a truncated URA3m selectable marker. The resulting vector was used to study and compare the level of expression of the luciferase reporter with that achieved with the known vectors containing regulatable promoter nmt1 and the strong constitutive promoter adh1 in S. pombe and the methanol-inducible AOX1 promoter in Pichia pastoris. Following growth in standard media the new vector containing the putative lsd90 promoter provided constitutive expression of luciferase, at a level, which was 19-, 39- and 10-fold higher than that achieved with nmt1, adh1 and AOX1 promoters, respectively. These results indicate a great potential of the new lsd90 promoter-based vector for commercial scale expression of therapeutic proteins in S. pombe.

Verma, Hemant Kumar; Shukla, Poonam; Alfatah, Md.; Khare, Asheesh Kumar; Upadhyay, Udita; Ganesan, Kaliannan; Singh, Jagmohan

2014-01-01

22

Neurons expressing trace amine-associated receptors project to discrete glomeruli and constitute an olfactory subsystem  

PubMed Central

Some chemoreceptors of the trace amine-associated receptor (TAAR) family detect innately aversive odors and are proposed to activate hardwired olfactory circuits. However, the wiring of TAAR neurons, the regulatory mechanisms of Taar gene choice, and the subcellular localization of TAAR proteins remain unknown. Here, we reveal similarities between neurons expressing TAARs and odorant receptors (ORs), but also unexpected differences. Like ORs, TAARs seem to be monoallelically expressed and localized both in cilia, the site of odor detection, and in axons, where they may participate in guidance. TAAR neurons project to discrete glomeruli predominantly localized to a confined bulb region. Taar expression involves different regulatory logic than OR expression, as neurons choosing a Taar5 knockout allele frequently express a second Taar without silencing the deleted allele. Moreover, the epigenetic signature of OR gene choice is absent from Taar genes. The unique molecular and anatomical features of the TAAR neurons suggest that they constitute a distinct olfactory subsystem.

Johnson, Mark A.; Tsai, Lulu; Roy, Dheeraj S.; Valenzuela, David H.; Mosley, Colleen; Magklara, Angeliki; Lomvardas, Stavros; Liberles, Stephen D.; Barnea, Gilad

2012-01-01

23

Neurons expressing trace amine-associated receptors project to discrete glomeruli and constitute an olfactory subsystem.  

PubMed

Some chemoreceptors of the trace amine-associated receptor (TAAR) family detect innately aversive odors and are proposed to activate hardwired olfactory circuits. However, the wiring of TAAR neurons, the regulatory mechanisms of Taar gene choice, and the subcellular localization of TAAR proteins remain unknown. Here, we reveal similarities between neurons expressing TAARs and odorant receptors (ORs), but also unexpected differences. Like ORs, TAARs seem to be monoallelically expressed and localized both in cilia, the site of odor detection, and in axons, where they may participate in guidance. TAAR neurons project to discrete glomeruli predominantly localized to a confined bulb region. Taar expression involves different regulatory logic than OR expression, as neurons choosing a Taar5 knockout allele frequently express a second Taar without silencing the deleted allele. Moreover, the epigenetic signature of OR gene choice is absent from Taar genes. The unique molecular and anatomical features of the TAAR neurons suggest that they constitute a distinct olfactory subsystem. PMID:22837392

Johnson, Mark A; Tsai, Lulu; Roy, Dheeraj S; Valenzuela, David H; Mosley, Colleen; Magklara, Angeliki; Lomvardas, Stavros; Liberles, Stephen D; Barnea, Gilad

2012-08-14

24

Methods to detect cell surface expression and constitutive activity of GPR6  

PubMed Central

GPR6 is a constitutively active Gs-coupled receptor that can signal from intracellular compartments. We present different methods used to study cell surface expression of receptors and other membrane proteins. A comparison of these methods shows that methods based on susceptibility to proteolytic enzymes are more efficient at providing estimates of cell surface expression than the commonly used cell-surface biotinylation method. We also present different methods that can be used to detect constitutive activity of Gs-coupled receptors. Imaging based assays to detect intracellular cyclic AMP accumulation are well suited to study signaling at a single cell level. These assays are particularly useful when the cells of interest form a small fraction of the culture such as primary cultures with low transfection efficiency.

Prasad, Balakrishna M.; Hollins, Bettye; Lambert, Nevin A.

2014-01-01

25

Conditional Derepression of Ferritin Synthesis in Cells Expressing a Constitutive IRP1 Mutant  

Microsoft Academic Search

Iron regulatory protein 1 (IRP1), a major posttranscriptional regulator of cellular iron and energy metab- olism, is controlled by an iron-sulfur cluster switch. Cysteine-437 is critical for coordinating the cluster, and its replacement yields mutants that do not respond to iron perturbations and constitutively bind to cognate mRNA iron-responsive elements (IREs). The expression of IRP1C437S in cells has been associated

Jian Wang; Kostas Pantopoulos

2002-01-01

26

Constitutive Expression of Human Bcl2 Modulates Nitrogen Mustard and Camptothecin Induced Apoptosis  

Microsoft Academic Search

Bcl-2 is a novel protooncogene which prolongs cell survival and sup presses apoptosis. We examined whether constitutive expression of trans- fected human bcl-2 conferred resistance to two different DNA damaging drugs, nitrogen mustard (HN2) and camptothecin (CPT) in a murine, IL-3 dependent cell line (FL5.12). HN2 treatment produced 2-fold less cell death and DNA degradation in cells overexpressing bcl-2 relative

M. I. Walton; D. Whysong; P. M. O'Connor; D. Hockenbery; S. J. Korsmeyer; K. W. Kohn

1993-01-01

27

Proline Reverses the Abnormal Phenotypes of Colletotrichum trifolii Associated with Expression of Endogenous Constitutively Active Ras  

Microsoft Academic Search

Colletotrichum trifolii is the causative organism of alfalfa anthracnose. We previously cloned and character- ized the small prototypical G protein, Ras, of C. trifolii, which is involved in the signaling pathways that mediate interaction between the pathogen and its host. Transformants expressing constitutively active forms of Ras have growth medium-dependent phenotypes. In nutrient-rich media (e.g., yeast extract and peptone), the

Stephen D. Memmott; Young-sil Ha; Martin B. Dickman

2002-01-01

28

Constitutive Expression of a Novel-Type Ammonium Transporter OsAMT2 in Rice Plants  

Microsoft Academic Search

; To characterize ammonium transport pathways in rice, two cDNAs with high homology to MEP\\/AMT2-type ammonium transporters, OsAMT2;1 and OsAMT3;1, were isolated. Expression of OsAMT2;1 in an ammonium- uptake-defective yeast mutant showed that this gene encodes functional ammonium transporters. OsAMT2;1 was constitutively expressed in both roots and shoots irre- spective of the supply of inorganic nitrogen to the medium, whereas

Arata Suenaga; Kanami Moriya; Yutaka Sonoda; Akira Ikeda; Nicolaus von Wirén; Toshihiko Hayakawa; Junji Yamaguchi; Tomoyuki Yamaya

2003-01-01

29

Elevated expression of CD30 in adult T-cell leukemia cell lines: possible role in constitutive NF-?B activation  

PubMed Central

Background Human T-cell leukemia virus type 1 (HTLV-1) is associated with the development of adult T-cell leukemia (ATL). HTLV-1 encoded Tax1 oncoprotein activates the transcription of genes involved in cell growth and anti-apoptosis through the NF-?B pathway, and is thought to play a critical role in the pathogenesis of ATL. While Tax1 expression is usually lost or minimal in ATL cells, these cells still show high constitutive NF-?B activity, indicating that genetic or epigenetic changes in ATL cells induce activation independent of Tax1. The aim of this study was to identify the molecules responsible for the constitutive activation of NF-?B in ATL cells using a retroviral functional cloning strategy. Results Using enhanced green fluorescent protein (EGFP) expression and blasticidin-resistance as selection markers, several retroviral cDNA clones exhibiting constitutive NF-?B activity in Rat-1 cells, including full-length CD30, were obtained from an ATL cell line. Exogenous stable expression of CD30 in Rat-1 cells constitutively activated NF-?B. Elevated expression of CD30 was identified in all ATL lines examined, and primary ATL cells from a small number of patients (8 out of 66 cases). Conclusion Elevated CD30 expression is considered one of the causes of constitutive NF-?B activation in ATL cells, and may be involved in ATL development.

Higuchi, Masaya; Matsuda, Takehiro; Mori, Naoki; Yamada, Yasuaki; Horie, Ryouichi; Watanabe, Toshiki; Takahashi, Masahiko; Oie, Masayasu; Fujii, Masahiro

2005-01-01

30

Constitutive Type VI Secretion System Expression Gives Vibrio cholerae Intra- and Interspecific Competitive Advantages  

PubMed Central

The type VI secretion system (T6SS) mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae – the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria) and a eukaryote (the social amoeba Dictyostelium discoideum). Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition.

Miyata, Sarah T.; Bachmann, Verena; Brooks, Teresa M.; Moloney, Jessica; Sosa, Oscar; Silva, David; Duran-Gonzalez, Jorge; Provenzano, Daniele; Pukatzki, Stefan

2012-01-01

31

Constitutive expression of short hairpin RNA in vivo triggers buildup of mature hairpin molecules.  

PubMed

RNA interference (RNAi) has become the cornerstone technology for studying gene function in mammalian cells. In addition, it is a promising therapeutic treatment for multiple human diseases. Virus-mediated constitutive expression of short hairpin RNA (shRNA) has the potential to provide a permanent source of silencing molecules to tissues, and it is being devised as a strategy for the treatment of liver conditions such as hepatitis B and hepatitis C virus infection. Unintended interaction between silencing molecules and cellular components, leading to toxic effects, has been described in vitro. Despite the enormous interest in using the RNAi technology for in vivo applications, little is known about the safety of constitutively expressing shRNA for multiple weeks. Here we report the effects of in vivo shRNA expression, using helper-dependent adenoviral vectors. We show that gene-specific knockdown is maintained for at least 6 weeks after injection of 1?×?10(11) viral particles. Nonetheless, accumulation of mature shRNA molecules was observed up to weeks 3 and 4, and then declined gradually, suggesting the buildup of mature shRNA molecules induced cell death with concomitant loss of viral DNA and shRNA expression. No evidence of well-characterized innate immunity activation (such as interferon production) or saturation of the exportin-5 pathway was observed. Overall, our data suggest constitutive expression of shRNA results in accumulation of mature shRNA molecules, inducing cellular toxicity at late time points, despite the presence of gene silencing. PMID:21780944

Ahn, M; Witting, S R; Ruiz, R; Saxena, R; Morral, Núria

2011-12-01

32

Constitutive Expression of Short Hairpin RNA in Vivo Triggers Buildup of Mature Hairpin Molecules  

PubMed Central

Abstract RNA interference (RNAi) has become the cornerstone technology for studying gene function in mammalian cells. In addition, it is a promising therapeutic treatment for multiple human diseases. Virus-mediated constitutive expression of short hairpin RNA (shRNA) has the potential to provide a permanent source of silencing molecules to tissues, and it is being devised as a strategy for the treatment of liver conditions such as hepatitis B and hepatitis C virus infection. Unintended interaction between silencing molecules and cellular components, leading to toxic effects, has been described in vitro. Despite the enormous interest in using the RNAi technology for in vivo applications, little is known about the safety of constitutively expressing shRNA for multiple weeks. Here we report the effects of in vivo shRNA expression, using helper-dependent adenoviral vectors. We show that gene-specific knockdown is maintained for at least 6 weeks after injection of 1?×?1011 viral particles. Nonetheless, accumulation of mature shRNA molecules was observed up to weeks 3 and 4, and then declined gradually, suggesting the buildup of mature shRNA molecules induced cell death with concomitant loss of viral DNA and shRNA expression. No evidence of well-characterized innate immunity activation (such as interferon production) or saturation of the exportin-5 pathway was observed. Overall, our data suggest constitutive expression of shRNA results in accumulation of mature shRNA molecules, inducing cellular toxicity at late time points, despite the presence of gene silencing.

Ahn, M.; Witting, S.R.; Ruiz, R.; Saxena, R.

2011-01-01

33

Expression of regulated secretory proteins is sufficient to generate granule-like structures in constitutively secreting cells.  

PubMed

The formation of secretory granules and regulated secretion are generally assumed to occur only in specialized endocrine, neuronal, or exocrine cells. We discovered that regulated secretory proteins such as the hormone precursors pro-vasopressin, pro-oxytocin, and pro-opiomelanocortin, as well as the granins secretogranin II and chromogranin B but not the constitutive secretory protein alpha(1)-protease inhibitor, accumulate in granular structures at the Golgi and in the cell periphery in transfected COS-1 fibroblast cells. The accumulations were observed in 30-70% of the transfected cells expressing the pro-hormones and for virtually all of the cells expressing the granins. Similar structures were also generated in other cell lines believed to be lacking a regulated secretory pathway. The accumulations resembled secretory granules morphologically in immunofluorescence and electron microscopy. They were devoid of markers of the endoplasmic reticulum, endosomes, and lysosomes but in part stained positive for the trans-Golgi network marker TGN46, consistent with their formation at the trans-Golgi network. When different regulated proteins were coexpressed, they were frequently found in the same granules, whereas alpha(1)-protease inhibitor could not be detected in accumulations formed by secretogranin II, demonstrating segregation of regulated from constitutive secretory proteins. In pulse-chase experiments, significant intracellular storage of secretogranin II and chromogranin B was observed and secretion of retained secretogranin II was stimulated with the calcium ionophore A23187. The results suggest that expression of regulated cargo proteins is sufficient to generate structures that resemble secretory granules in the background of constitutively secreting cells, supporting earlier proposals on the mechanism of granule formation. PMID:14996840

Beuret, Nicole; Stettler, Hansruedi; Renold, Anja; Rutishauser, Jonas; Spiess, Martin

2004-05-01

34

Expression of constitutive and inducible chemical defenses in native and invasive populations of Alliaria petiolata.  

PubMed

The Evolution of Increased Competitive Ability (EICA) hypothesis posits that invasive plants in introduced habitats with reduced herbivore pressure will evolve reduced levels of costly resistance traits. In light of this hypothesis, we examined the constitutive and inducible expression of five chemical defense traits in Alliaria petiolata from four invasive North American and seven native European populations. When grown under common conditions, significant variation among populations within continents was found for trypsin inhibitors and peroxidase activity, and glucosinolates and trypsin inhibitors were significantly jasmonate-inducible across populations. Across populations, constitutive levels of glucosinolates and trypsin inhibitors were negatively correlated with their degree of induction, with three North American populations tending to have lower constitutive levels and higher inducibility of glucosinolates than the seven European populations. Alliarinoside and isovitexin 6"-O-beta-glucopyranoside levels were both higher in North American plants than in European plants, but levels of these compounds were generally increased by jasmonate in European plants and decreased by the same treatment in North American plants. Aside from the tendency for invasive populations to have reduced constitutive glucosinolate levels coupled with increased inducibility, little support for the predictions of EICA was evident in the chemical defenses that we studied. PMID:16222770

Cipollini, Don; Mbagwu, Jeanne; Barto, Kathryn; Hillstrom, Carl; Enright, Stephanie

2005-06-01

35

Proline Reverses the Abnormal Phenotypes of Colletotrichum trifolii Associated with Expression of Endogenous Constitutively Active Ras  

PubMed Central

Colletotrichum trifolii is the causative organism of alfalfa anthracnose. We previously cloned and characterized the small prototypical G protein, Ras, of C. trifolii, which is involved in the signaling pathways that mediate interaction between the pathogen and its host. Transformants expressing constitutively active forms of Ras have growth medium-dependent phenotypes. In nutrient-rich media (e.g., yeast extract and peptone), the phenotype of the transformants was indistinguishable from that of the wild type. However, during nutrient starvation, the transformants lose polarity, have distended hyphae, and fail to sporulate and produce appressoria. Since peptone caused the phenotype to revert, amino acids were tested singly and in combination to identify the responsible amino acid(s). We found that 1.6 mM proline in the medium reverses the constitutively active Ras phenotype.

Memmott, Stephen D.; Ha, Young-sil; Dickman, Martin B.

2002-01-01

36

Isolation of cyanophycin from tobacco and potato plants with constitutive plastidic cphATe gene expression.  

PubMed

A chimeric cyanophycin synthetase gene composed of the cphATe coding region from the cyanobacterium Thermosynechococcus elongatus BP-1, the constitutive 35S promoter and the plastid targeting sequence of the integral photosystem II protein PsbY was transferred to the tobacco variety Petit Havanna SRI and the commercial potato starch production variety Albatros. The resulting constitutive expression of cyanophycin synthetase leads to polymer contents in potato leaf chloroplasts of up to 35 mg/g dry weight and in tuber amyloplasts of up to 9 mg/g dry weight. Both transgenic tobacco and potato were used for the development of isolation methods applicable for large-scale extraction of the polymer. Two different procedures were developed which yielded polymer samples of 80 and 90% purity, respectively. PMID:22244982

Neubauer, Katja; Hühns, Maja; Hausmann, Tina; Klemke, Friederike; Lockau, Wolfgang; Kahmann, Uwe; Pistorius, Elfriede K; Kragl, Udo; Broer, Inge

2012-03-31

37

Development of a stable insect cell line constitutively expressing rotavirus VP2.  

PubMed

An insect High-Five cell line was generated constitutively and stably expressing the VP2 protein of rotavirus RF strain leading to the formation of core-like particles. The integration of the VP2 gene was confirmed by PCR, Real-time PCR and Southern blot, and the protein expression was confirmed by Western blot and immunofluorescence microscopy. Integrity and self assembly of VP2 as core-like particles was demonstrated by electron microscopy. The High-Five cell system stably expressing rotavirus core-like particles can be applied to the study of viral protein structure and functions; it may be useful for vaccine development, gene therapy and drug delivery. PMID:23287060

Shoja, Zabihollah; Tagliamonte, Maria; Jalilvand, Somayeh; Mokhtari-Azad, Talat; Hamkar, Rasool; Shahmahmoodi, Shohreh; Rezaei, Farhad; Tornesello, MariaLina; Buonaguro, Franco M; Buonaguro, Luigi; Nategh, Rakhshandeh

2013-03-01

38

The gene S promoter of hepatitis B virus confers constitutive gene expression.  

PubMed Central

The properties of the promoter of the hepatitis B surface antigen (HBsAg) were studied using recombinants containing either this promoter or the SV40 early promoter. Mouse L cells were transfected with these recombinants and the levels of gene expression obtained with the two promoters were compared. The level of expression of a cellular gene, the human fibroblast interferon gene, obtained with the HBsAg promoter was comparable to that obtained with the SV40 early promoter. Similarly when the HBsAg gene was controlled by the SV40 early promoter the level of HBsAg synthesis is in the same range as that observed with its own promoter. Together these results suggest that although the HBsAg gene codes for a structural viral protein, its expression is constitutive as for an early gene. The implications of these observations on the synthesis of HBV particles in vivo are discussed. Images

Malpiece, Y; Michel, M L; Carloni, G; Revel, M; Tiollais, P; Weissenbach, J

1983-01-01

39

Constitutive expression of interferon gamma-inducible protein 10 in lymphoid organs and inducible expression in T cells and thymocytes  

PubMed Central

Interferon gamma-inducible protein 10 (IP-10), a member of a family of small proinflammatory chemotactic polypeptides, is expressed in interferon gamma-stimulated keratinocytes, macrophages, fibroblasts, and endothelial cells. Here we report that IP-10 is also expressed by activated but not resting T hybridoma cells, normal T cells, and thymocytes. Although resting lymphocytes did not synthesize IP-10, surprisingly high levels of IP-10 transcripts were found in lymphoid organs (spleen, thymus, and lymph nodes). Thymic and splenic stromal cells were found to express constitutively high levels of both IP-10 mRNA and protein, accounting for the high level of spontaneous expression in lymphoid tissue. Therefore, in addition to its role as a proinflammatory cytokine, IP-10 may participate in T cell effector function and perhaps T cell development.

1994-01-01

40

Human CD4+ CD25+ Foxp3+ regulatory T cells do not constitutively express IL-35.  

PubMed

EBV-induced gene 3 (EBI3) can associate with p28 to form the heterodimeric cytokine IL-27, or with the p35 subunit of IL-12 to form the EBI3/p35 heterodimer, recently named IL-35. In mice, IL-35 has been shown to be constitutively expressed by CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg cells) and suggested to contribute to their suppressive activity. In this study, we investigated whether human Treg cells express IL-35. Double-staining analysis of human thymuses showed that neither Foxp3(+) nor CD25(+) cells coexpressed EBI3. Similarly, Foxp3(+) cells present in human lymph nodes, tonsils, spleens, and intestines did not express EBI3. Consistent with these in situ observations, Treg cells purified from blood or tonsils were negative for EBI3 by immunoblotting. Other human T cell subsets, including effector T cells, naive and memory CD4(+) T cells, CD8(+) and gammadelta T cells also did not constitutively express EBI3, which contrasts with IL-35 expression observed in murine CD8(+) and gammadelta T cells. Furthermore, although CD3/CD28 stimulation consistently induced low levels of EBI3 in various CD4(+) T cell subsets, no EBI3 could be detected in CD3/CD28-stimulated Treg cells. RT-PCR analysis showed that, whereas p35 transcripts were detected in both Teff and Treg cells, EBI3 transcripts were detected only in activated Teff cells, but not in resting or activated Treg cells. Thus, in contrast to their murine counterpart, human Treg cells do not express detectable amounts of IL-35. PMID:18981109

Bardel, Emilie; Larousserie, Frédérique; Charlot-Rabiega, Pascaline; Coulomb-L'Herminé, Aurore; Devergne, Odile

2008-11-15

41

Constitutive expression of transgenes encoding derivatives of the synthetic antimicrobial peptide BP100: impact on rice host plant fitness  

PubMed Central

Background The Biopeptide BP100 is a synthetic and strongly cationic ?-helical undecapeptide with high, specific antibacterial activity against economically important plant-pathogenic bacteria, and very low toxicity. It was selected from a library of synthetic peptides, along with other peptides with activities against relevant bacterial and fungal species. Expression of the BP100 series of peptides in plants is of major interest to establish disease-resistant plants and facilitate molecular farming. Specific challenges were the small length, peptide degradation by plant proteases and toxicity to the host plant. Here we approached the expression of the BP100 peptide series in plants using BP100 as a proof-of-concept. Results Our design considered up to three tandemly arranged BP100 units and peptide accumulation in the endoplasmic reticulum (ER), analyzing five BP100 derivatives. The ER retention sequence did not reduce the antimicrobial activity of chemically synthesized BP100 derivatives, making this strategy possible. Transformation with sequences encoding BP100 derivatives (bp100der) was over ten-fold less efficient than that of the hygromycin phosphotransferase (hptII) transgene. The BP100 direct tandems did not show higher antimicrobial activity than BP100, and genetically modified (GM) plants constitutively expressing them were not viable. In contrast, inverted repeats of BP100, whether or not elongated with a portion of a natural antimicrobial peptide (AMP), had higher antimicrobial activity, and fertile GM rice lines constitutively expressing bp100der were produced. These GM lines had increased resistance to the pathogens Dickeya chrysanthemi and Fusarium verticillioides, and tolerance to oxidative stress, with agronomic performance comparable to untransformed lines. Conclusions Constitutive expression of transgenes encoding short cationic ?-helical synthetic peptides can have a strong negative impact on rice fitness. However, GM plants expressing, for example, BP100 based on inverted repeats, have adequate agronomic performance and resistant phenotypes as a result of a complex equilibrium between bp100der toxicity to plant cells, antimicrobial activity and transgene-derived plant stress response. It is likely that these results can be extended to other peptides with similar characteristics.

2012-01-01

42

Conditional expression of constitutively active estrogen receptor {alpha} in chondrocytes impairs longitudinal bone growth in mice  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Conditional transgenic mice expressing constitutively active estrogen receptor {alpha} (caER{alpha}) in chondrocytes were developed. Black-Right-Pointing-Pointer Expression of caER{alpha} in chondrocytes impaired longitudinal bone growth in mice. Black-Right-Pointing-Pointer caER{alpha} affects chondrocyte proliferation and differentiation. Black-Right-Pointing-Pointer This mouse model is useful for understanding the physiological role of ER{alpha}in vivo. -- Abstract: Estrogen plays important roles in the regulation of chondrocyte proliferation and differentiation, which are essential steps for longitudinal bone growth; however, the mechanisms of estrogen action on chondrocytes have not been fully elucidated. In the present study, we generated conditional transgenic mice, designated as caER{alpha}{sup ColII}, expressing constitutively active mutant estrogen receptor (ER) {alpha} in chondrocytes, using the chondrocyte-specific type II collagen promoter-driven Cre transgenic mice. caER{alpha}{sup ColII} mice showed retardation in longitudinal growth, with short bone lengths. BrdU labeling showed reduced proliferation of hypertrophic chondrocytes in the proliferating layer of the growth plate of tibia in caER{alpha}{sup ColII} mice. In situ hybridization analysis of type X collagen revealed that the maturation of hypertrophic chondrocytes was impaired in caER{alpha}{sup ColII} mice. These results suggest that ER{alpha} is a critical regulator of chondrocyte proliferation and maturation during skeletal development, mediating longitudinal bone growth in vivo.

Ikeda, Kazuhiro [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan)] [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Tsukui, Tohru [Experimental Animal Laboratory, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan)] [Experimental Animal Laboratory, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Imazawa, Yukiko; Horie-Inoue, Kuniko [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan)] [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Inoue, Satoshi, E-mail: INOUE-GER@h.u-tokyo.ac.jp [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan) [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan)

2012-09-07

43

A minimal regulatory region maintains constitutive expression of the max gene.  

PubMed Central

Max is a basic helix-loop-helix/leucine zipper protein that forms heterodimers with the Myc family of proteins to promote cell growth and with the Mad/Mxi1 family of proteins to inhibit cell growth. The role of Max as the obligate binding partner for these two protein families necessitates the observed constitutive expression and relatively long half-life of the max mRNA under a variety of growth conditions. In this study, we have used the chicken max gene to map DNA elements maintaining max gene expression in vertebrate cells. We have identified a minimal regulatory region (MRR) that resides within 115 bp of the max translation initiation site and that possesses an overall structure typical of TATA-less promoters. Within the MRR are two consensus binding sites for Sp1, a ubiquitously expressed transcription factor that plays a role in the expression of many constitutive genes. Interestingly, we show that direct binding by Sp1 to these sites is not required for MRR-mediated transcription. Instead, the integrity of a 20-bp DNA element in the MRR is required for transcriptional activity, as is the interaction of this DNA element with a 90-kDa cellular protein. Our data suggest that it is the persistence of this 90-kDa protein in vertebrate cells which drives max gene expression, insulates the max promoter from the dramatic changes in transcription that accompany cell growth and development, and ensures that adequate levels of Max will be available to facilitate the function of the Myc, Mad, and Mxi1 families of proteins.

Peters, M A; Sollenberger, K G; Kao, T L; Taparowsky, E J

1997-01-01

44

Constitutive expression of a native human interferon-alpha 1 gene in Escherichia coli.  

PubMed

1. A plasmid for constitutive expression of the human interferon-alpha 1 (hIFN-alpha 1) gene in Escherichia coli is constructed on the basis of the cloning plasmid pBR322 using a strong synthetic promoter, synthetic ribosome binding site and a native hIFN-alpha 1 gene excised from a chromosomal clone. 2. The yield of recombinant hIFN-alpha 1 from E. coli LE392 cells transformed with the expression plasmid pJP1R9-hIFN-alpha 1 is evaluated to be 2-6 x 10(7) U/l bacterial culture for metabolic shaker and 6-8 x 10(7) U/l for fermentor. PMID:2687058

Ivanov, I; Markova, N; Bachvarov, D; Alexciev, K; Saraffova, A; Maximova, V; Tsaneva, I; Markov, G

1989-01-01

45

Islet neogenesis from the constitutively nestin expressing human umbilical cord matrix derived mesenchymal stem cells.  

PubMed

The scarcity of islets for transplantation calls for an alternative sources of islets. The human umbilical cord has been shown to be a reservoir of multipotent stem cells with capacity to differentiate into ectodermal, mesodermal and endodermal lineages. The present investigation deals with isolation and characterization of mesenchymal stem sells (MSC) derived from human umbilical cord and their differentiation into functional islets. Since these MSCs were found to constitutively express nestin we hypothesized that these would be ideal candidates for islet neogenesis without any further manipulation. Human umbilical cord matrix stem cells (hUCMSCs) were found to express CD29, CD44, CD73, CD90, CD105, smooth muscle actin, nestin, vimentin, proliferation marker Ki67 and embryonic markers Oct4, SSEA4. These were found to be negative for CD33, CD34, CD45 and HLA DR. Human UCMSCs exhibited high proliferating capacity for extended period indicating potential for scaling up. When subjected to a cocktail of specific differentiating factors, these cells differentiated into fat, cartilage, bone, neurons and islet like clusters (ILCs). These ILCs stained positive for diphenylthiocarbazone (DTZ) and expressed human C-peptide, insulin and glucagon. Real time qPCR analysis of newly generated islets further demonstrated abundance of Pdx-1, Ngn3, insulin, glucagon and somatostatin transcripts. On transplantation in experimental diabetic mice these ILCs restored normoglycemia, body weight and exhibited normal glucose tolerance test indicating their functional status. Thus, the present study demonstrates potential of constitutively expressing nestin positive progenitor from umbilical cord as a novel source for islet neogenesis and their usage in cell replacement therapy for diabetes. PMID:21099303

Kadam, Sachin S; Bhonde, Ramesh R

2010-01-01

46

Resistance to simian immunodeficiency virus low dose rectal challenge is associated with higher constitutive TRIM5? expression in PBMC  

PubMed Central

Background At least six host-encoded restriction factors (RFs), APOBEC3G, TRIM5?, tetherin, SAMHD1, schlafen 11, and Mx2 have now been shown to inhibit HIV and/or SIV replication in vitro. To determine their role in vivo in the resistance of macaques to mucosally-acquired SIV, we quantified both pre-exposure (basal) and post-exposure mRNA levels of these RFs, Mx1, and IFN? in PBMC, lymph nodes, and duodenum of rhesus macaques undergoing weekly low dose rectal exposures to the primary isolate, SIV/DeltaB670. Results Repetitive challenge divided the monkeys into two groups with respect to their susceptibility to infection: highly susceptible (2–3 challenges, 5 monkeys) and poorly susceptible (?6 challenges, 3 monkeys). Basal RF and Mx1 expression varied among the three tissues examined, with the lowest expression generally detected in duodenal tissues, and the highest observed in PBMC. The one exception was A3G whose basal expression was greatest in lymph nodes. Importantly, significantly higher basal expression of TRIM5? and Mx1 was observed in PBMC of animals more resistant to mucosal infection. Moreover, individual TRIM5? levels were stable throughout a year prior to infection. Post-exposure induction of these genes was also observed after virus appearance in plasma, with elevated levels in PBMC and duodenum transiently occurring 7–10 days post infection. They did not appear to have an effect on control of viremia. Interestingly, minimal to no induction was observed in the resistant animal that became an elite controller. Conclusions These results suggest that constitutively expressed TRIM5? appears to play a greater role in restricting mucosal transmission of SIV than that associated with type I interferon induction following virus entry. Surprisingly, this association was not observed with the other RFs. The higher basal expression of TRIM5? observed in PBMC than in duodenal tissues emphasizes the understated role of the second barrier to systemic infection involving the transport of virus from the mucosal compartment to the blood. Together, these observations provide a strong incentive for a more comprehensive examination of the intrinsic, variable control of constitutive expression of these genes in the sexual transmission of HIV.

2014-01-01

47

Integrating constitutive gene expression and chemoactivity: mining the NCI60 anticancer screen.  

PubMed

Studies into the genetic origins of tumor cell chemoactivity pose significant challenges to bioinformatic mining efforts. Connections between measures of gene expression and chemoactivity have the potential to identify clinical biomarkers of compound response, cellular pathways important to efficacy and potential toxicities; all vital to anticancer drug development. An investigation has been conducted that jointly explores tumor-cell constitutive NCI60 gene expression profiles and small-molecule NCI60 growth inhibition chemoactivity profiles, viewed from novel applications of self-organizing maps (SOMs) and pathway-centric analyses of gene expressions, to identify subsets of over- and under-expressed pathway genes that discriminate chemo-sensitive and chemo-insensitive tumor cell types. Linear Discriminant Analysis (LDA) is used to quantify the accuracy of discriminating genes to predict tumor cell chemoactivity. LDA results find 15% higher prediction accuracies, using ?30% fewer genes, for pathway-derived discriminating genes when compared to genes derived using conventional gene expression-chemoactivity correlations. The proposed pathway-centric data mining procedure was used to derive discriminating genes for ten well-known compounds. Discriminating genes were further evaluated using gene set enrichment analysis (GSEA) to reveal a cellular genetic landscape, comprised of small numbers of key over and under expressed on- and off-target pathway genes, as important for a compound's tumor cell chemoactivity. Literature-based validations are provided as support for chemo-important pathways derived from this procedure. Qualitatively similar results are found when using gene expression measurements derived from different microarray platforms. The data used in this analysis is available at http://pubchem.ncbi.nlm.nih.gov/andhttp://www.ncbi.nlm.nih.gov/projects/geo (GPL96, GSE32474). PMID:23056181

Covell, David G

2012-01-01

48

Differential Requirements of Two recA Mutants for Constitutive SOS Expression in Escherichia coli K-12  

PubMed Central

Background Repairing DNA damage begins with its detection and is often followed by elicitation of a cellular response. In E. coli, RecA polymerizes on ssDNA produced after DNA damage and induces the SOS Response. The RecA-DNA filament is an allosteric effector of LexA auto-proteolysis. LexA is the repressor of the SOS Response. Not all RecA-DNA filaments, however, lead to an SOS Response. Certain recA mutants express the SOS Response (recAC) in the absence of external DNA damage in log phase cells. Methodology/Principal Findings Genetic analysis of two recAC mutants was used to determine the mechanism of constitutive SOS (SOSC) expression in a population of log phase cells using fluorescence of single cells carrying an SOS reporter system (sulAp-gfp). SOSC expression in recA4142 mutants was dependent on its initial level of transcription, recBCD, recFOR, recX, dinI, xthA and the type of medium in which the cells were grown. SOSC expression in recA730 mutants was affected by none of the mutations or conditions tested above. Conclusions/Significance It is concluded that not all recAC alleles cause SOSC expression by the same mechanism. It is hypothesized that RecA4142 is loaded on to a double-strand end of DNA and that the RecA filament is stabilized by the presence of DinI and destabilized by RecX. RecFOR regulate the activity of RecX to destabilize the RecA filament. RecA730 causes SOSC expression by binding to ssDNA in a mechanism yet to be determined.

Long, Jarukit Edward; Renzette, Nicholas; Centore, Richard C.; Sandler, Steven J.

2008-01-01

49

Type 2 innate lymphoid cells constitutively express arginase-I in the naive and inflamed lung.  

PubMed

Arg1 is produced by AAMs and is proposed to have a regulatory role during asthma and allergic inflammation. Here, we use an Arg1 reporter mouse to identify additional cellular sources of the enzyme in the lung. We demonstrate that ILC2s express Arg1 at rest and during infection with the migratory helminth Nippostrongylus brasiliensis. In contrast to AAMs, which express Arg1 following IL-4/IL-13-mediated STAT6 activation, ILC2s constitutively express the enzyme in a STAT6-independent manner. Although ILC2s deficient in the IL-33R subunit T1/ST2 maintain Arg1 expression, IL-33 can regulate total lung Arg1 by expanding the ILC2 population and by activating macrophages indirectly via STAT6. Finally, we find that ILC2 Arg1 does not mediate ILC2 accumulation, ILC2 production of IL-5 and IL-13, or collagen production during N. brasiliensis infection. Thus, ILC2s are a novel source of Arg1 in resting tissue and during allergic inflammation. PMID:23924659

Bando, Jennifer K; Nussbaum, Jesse C; Liang, Hong-Erh; Locksley, Richard M

2013-11-01

50

Effect of constitutive expression of bacterial phytoene desaturase CRTI on photosynthetic electron transport in Arabidopsis thaliana.  

PubMed

The constitutive expression of the bacterial carotene desaturase (CRTI) in Arabidopsis thaliana leads to increased susceptibility of leaves to light-induced damage. Changes in the photosynthetic electron transport chain rather than alterations of the carotenoid composition in the antenna were responsible for the increased photoinhibition. A much higher level of superoxide/hydrogen peroxide was generated in the light in thylakoid membranes from the CRTI expressing lines than in wild-type while the level of singlet oxygen generation remained unchanged. The increase in reactive oxygen species was related to the activity of plastid terminal oxidase (PTOX) since their generation was inhibited by the PTOX-inhibitor octyl gallate, and since the protein level of PTOX was increased in the CRTI-expressing lines. Furthermore, cyclic electron flow was suppressed in these lines. We propose that PTOX competes efficiently with cyclic electron flow for plastoquinol in the CRTI-expressing lines and that it plays a crucial role in the control of the reduction state of the plastoquinone pool. PMID:24378845

Galzerano, Denise; Feilke, Kathleen; Schaub, Patrick; Beyer, Peter; Krieger-Liszkay, Anja

2014-03-01

51

Identification and refinement of two strong constitutive promoters for gene expression system of Schizosaccharomyces pombe.  

PubMed

Fission yeast Schizosaccharomyces pombe shares various important properties with higher eukaryotes and is now considered a useful host for elevated production of mammalian proteins for medicinal applications. The full-length nmt1 promoter has been widely used as a strong promoter in S. pombe expression system. In the present study, the promoters of the eno101 and gpd3 genes in S. pombe were identified as strong constitutive promoters. For convenient applications in the plasmids of S. pombe, these promoters were refined to 276-bp eno and 273-bp gpd promoters by deleting undesired sequences and examining the expression of reporter genes including lacZ and xynA. Both the refined eno and gpd promoters provided approximately 1.5-fold higher expression of LacZ than nmt1 promoter. Furthermore, gene expression under the control of the eno or gpd promoter was not repressed by the components of YES medium while nmt1 promoter was inhibited by thiamine in yeast extract. Therefore, both eno and gpd promoters offer opportunities for efficient production of recombinant proteins by S. pombe in high cell-density fermentation. PMID:24452856

Wang, Hongcheng; Wang, Haiyang; Wang, Meng; Zhang, Lei; Wang, Ren; Mei, Yanzhen; Shao, Weilan

2014-06-01

52

Expression of constitutively active erythropoietin receptor in pyramidal neurons of cortex and hippocampus boosts higher cognitive functions in mice  

PubMed Central

Background Erythropoietin (EPO) and its receptor (EPOR) are expressed in the developing brain and their transcription is upregulated in adult neurons and glia upon injury or neurodegeneration. We have shown neuroprotective effects and improved cognition in patients with neuropsychiatric diseases treated with EPO. However, the critical EPO targets in brain are unknown, and separation of direct and indirect effects has remained difficult, given the role of EPO in hematopoiesis and brain oxygen supply. Results Here we demonstrate that mice with transgenic expression of a constitutively active EPOR isoform (cEPOR) in pyramidal neurons of cortex and hippocampus exhibit enhancement of spatial learning, cognitive flexibility, social memory, and attentional capacities, accompanied by increased impulsivity. Superior cognitive performance is associated with augmented long-term potentiation of cEPOR expressing neurons in hippocampal slices. Conclusions Active EPOR stimulates neuronal plasticity independent of any hematopoietic effects and in addition to its neuroprotective actions. This property of EPOR signaling should be exploited for defining novel strategies to therapeutically enhance cognitive performance in disease conditions.

2011-01-01

53

The Isolation and Characterization of Saccharomyces Cerevisiae Mutants That Constitutively Express Purine Biosynthetic Genes  

PubMed Central

In response to an external source of adenine, yeast cells repress the expression of purine biosynthesis pathway genes. To identify necessary components of this signalling mechanism, we have isolated mutants that are constitutively active for expression. These mutants were named bra (for bypass of repression by adenine). BRA7 is allelic to FCY2, the gene encoding the purine cytosine permease and BRA9 is ADE12, the gene encoding adenylosuccinate synthetase. BRA6 and BRA1 are new genes encoding, respectively, hypoxanthine guanine phosphoribosyl transferase and adenylosuccinate lyase. These results indicate that uptake and salvage of adenine are important steps in regulating expression of purine biosynthetic genes. We have also shown that two other salvage enzymes, adenine phosphoribosyl transferase and adenine deaminase, are involved in activating the pathway. Finally, using mutant strains affected in AMP kinase or ribonucleotide reductase activities, we have shown that AMP needs to be phosphorylated to ADP to exert its regulatory role while reduction of ADP into dADP by ribonucleotide reductase is not required for adenine repression. Together these data suggest that ADP or a derivative of ADP is the effector molecule in the signal transduction pathway.

Guetsova, M. L.; Lecoq, K.; Daignan-Fornier, B.

1997-01-01

54

The constitutive expression of a two transgene construct enhances the abiotic stress tolerance of chrysanthemum.  

PubMed

Various abiotic stresses downgrade the quality and productivity of chrysanthemum. A construct carrying both CcSOS1 (from Chrysanthemum crassum) and CdICE1 (from Chrysanthemum dichrum) was constitutively expressed in the chrysanthemum variety 'Jinba'. The transgenic plants were superior to the wild type (WT) ones with respect to their sensitivity to low temperature, drought and salinity, as measured by visible damage and plant survival. Salinity stressed transgenic plants accumulated more proline, and their level of superoxide dismutase and peroxidase activity was higher than in WT plants. At the physiological level, they suffered less loss of viable leaf area, maintained a lower leaf electrolyte conductivity and retained more chlorophyll (a+b). The ratio between the K(+) and Na(+) content was higher in the root, stem and median leaves of salinity stressed transgenic plants than in those of WT plants. PMID:24751398

Song, Aiping; An, Juan; Guan, Zhiyong; Jiang, Jiafu; Chen, Fadi; Lou, Wanghuai; Fang, Weimin; Liu, Zhaolei; Chen, Sumei

2014-07-01

55

Premature lethality, hyperactivity, and aberrant phosphorylation in transgenic mice expressing a constitutively active form of Fyn  

PubMed Central

The kinase Fyn, the microtubule-associated protein tau and the peptide amyloid-? (A?) constitute a toxic triad in Alzheimer's disease (AD). Tau's subcellular localization is mainly regulated by phosphorylation whereas Fyn's localization is dictated by palmitoylation targeting it to the plasma membrane in a reversible manner. We have previously shown that tau is required for Fyn to be targeted to the dendritic spine. We had also shown that a truncated form of tau (?tau) that accumulates in the cell soma is capable of trapping Fyn and preventing it from entering the spine. Here we determined that palmitoylation is required for Fyn's membrane and spine localization. We further evaluated the functional consequences of neuronal over-expression of the constitutively active Y531F mutant form of Fyn (FynCA) in transgenic mice. We found that the FynCA transgenic mice displayed a reduced weight, a massively reduced lifespan and a high level of hyperactivity. The lifespan of the FynCA mice was only slightly extended by crossing them with ?tau transgenic mice, possibly reflecting differences in expression patterns of the transgenes and high levels of transgenic FynCA compared to endogenous Fyn. Analysis of synaptosomes revealed that FynCA accumulated at high levels in the spine, resulting in increased levels of the NMDA receptor subunit NR2b phosphorylated at residue Y1472. Tau was strongly phosphorylated at the AT8 epitope S202/T205 as shown by Western blot and immunohistochemistry indicating that an increased tyrosine kinase activity of Fyn has down-stream consequences for serine/threonine-directed phosphorylation.

Xia, Di; Gotz, Jurgen

2014-01-01

56

Expression of constitutively active 4EBP-1 enhances p27Kip1 expression and inhibits proliferation of MCF7 breast cancer cells  

PubMed Central

Background Eukaryotic initiation factor 4E (eIF4E) is essential for cap-dependent initiation of translation. Cell proliferation is associated with increased activity of eIF4E and elevated expression of eIF4E leads to tumorigenic transformation. Many tumors express very high levels of eIF4E and this may be a critical factor in progression of the disease. In contrast, overexpression of 4EBP, an inhibitor of eIF4E, leads to cell cycle arrest and phenotypic reversion of some transformed cells. Results A constitutively active form of 4EBP-1 was inducibly expressed in the human breast cancer cell line MCF7. Induction of constitutively active 4EBP-1 led to cell cycle arrest. This was not associated with a general inhibition of protein synthesis but rather with changes in specific cell cycle regulatory proteins. Cyclin D1 was downregulated while levels of the CDK inhibitor p27Kip1 were increased. The levels of cyclin E and CDK2 were unaffected but the activity of CDK2 was significantly reduced due to increased association with p27Kip1. The increase in p27Kip1 did not reflect changes in p27Kip1 mRNA or degradation rates. Rather, it was associated with enhanced synthesis of the protein, even though 4EBP-1 is expected to inhibit translation. This could be explained, at least in part, by the ability of the p27Kip1 5'-UTR to mediate cap-independent translation, which was also enhanced by expression of constitutively active 4EBP-1. Conclusions Expression of active 4EBP-1 in MCF7 leads to cell cycle arrest which is associated with downregulation of cyclin D1 and upregulation of p27Kip1. Upregulation of p27Kip1reflects increased synthesis which corresponds to enhanced cap-independent translation through the 5'-UTR of the p27Kip1 mRNA.

Jiang, Hong; Coleman, Jennifer; Miskimins, Robin; Miskimins, W Keith

2003-01-01

57

Barley Dhn13 encodes a KS-type dehydrin with constitutive and stress responsive expression.  

PubMed

Dehydrins (DHNs) compose a family of intrinsically unstructured proteins that have high water solubility and accumulate during late seed development, low temperature or water deficit conditions, and are thought to play a protective role in freezing and drought tolerance in plants. Twelve Dhn genes were previously described in the barley genome. Here, we report an additional member of this multigene family, Dhn13. The Dhn13 gene is located in chromosome 4 near marker MWG634 and encodes a 107-amino acid KS-type DHN. Semi-quantitative reverse transcriptase PCR data indicated that Dhn13 is constitutively expressed in seedling tissues and embryos of developing seeds. Microarray data were consistent with these results and showed a considerable increase of Dhn13 transcripts when plants were subjected to chilling and freezing temperatures. The highest transcript levels where observed in anthers. The presence of ABRE, MYC, DRE, and POLLEN1LELAT52 regulatory elements in the putative Dhn13 promoter region is in agreement with expression data. PMID:15711789

Rodríguez, E M; Svensson, J T; Malatrasi, M; Choi, D-W; Close, T J

2005-03-01

58

Constitutive Expression of Thermobifida fusca Thermostable Acetylxylan Esterase Gene in Pichia pastoris  

PubMed Central

A gene encoding the thermostable acetylxylan esterase (AXE) in Thermobifida fusca NTU22 was amplified by PCR, sequenced and cloned into the Pichia pastoris X-33 host strain using the vector pGAPZ?A, allowing constitutive expression and secretion of the protein. Recombinant expression resulted in high levels of extracellular AXE production, as high as 526 U/mL in the Hinton flask culture broth. The purified enzyme showed a single band at about 28 kDa by SDS-polyacrylamide gel electrophoresis after being treated with endo-?-N-acetylglycosaminidase H; this agrees with the predicted size based on the nucleotide sequence. About 70% of the original activity remained after heat treatment at 60 °C for three hours. The optimal pH and temperature of the purified enzyme were 8.0 and 60 °C, respectively. The properties of the purified AXE from the P. pastoris transformant are similar to those of the AXE from an E. coli transformant.

Yang, Chao-Hsun; Lin, Kun-I; Chen, Gen-Hung; Chen, Yu-Fen; Chen, Cheng-Yu; Chen, Wei-Lin; Huang, Yu-Chun

2010-01-01

59

CSF1-induced and constitutive Il6 gene expression in mouse macrophages: evidence for PKC-dependent and -independent pathways  

Microsoft Academic Search

It has been recently shown that CSF-1 enhanced the constitutive expression of the Il6 gene in resident mouse peritoneal macrophages (PM phi) but little is known about the pathways involved. In this report, we show that both constitutive and CSF-1-induced IL-6 release were enhanced and prolonged in the presence of the PKC inhibitors, staurosporine (SP) and its derivative, GF-109203X. Enhancement

S J Kamdar; J A Fuller; R Evans

1997-01-01

60

Constitutive and cytokine-induced expression of the melanoma growth stimulatory activity/GRO alpha gene requires both NF-kappa B and novel constitutive factors.  

PubMed

Melanoma growth stimulatory activity (MGSA)/growth regulated (GRO) and interleukin-8 (IL-8) are highly related chemokines that have a causal role in melanoma progression. Expression of these chemokines is similar in that both require the NF-kappa B element and additional regions such as the CAAT/enhancer binding protein (C/EBP) element of the IL-8 promoter. The constitutive and cytokine IL-1-induced promoter activity of the chemokine MGSA/GRO alpha in normal retinal pigment epithelial and the Hs294T melanoma cells is partially regulated through the NF-kappa B element, which binds both NF-kappa B p50 and RelA (NF-kappa B p65) homodimers and heterodimers. Mutational analysis of the MGSA/GRO alpha promoter reveals that, in addition to the NF-kappa B element, the immediate upstream region (IUR) is necessary for basal expression in retinal pigment epithelial and Hs294T cells. Gel mobility shift and UV cross-linking analyses demonstrate that several constitutive DNA binding proteins interact with the IUR. Although this region has sequence similarity to the several transcription factor elements including C/EBP, the IUR includes sequences that have no similarity to previously identified enhancer regions. Furthermore, RelA transactivates through either the NF-kappa B element or the IUR, suggesting a putative interaction between NF-kappa B and this novel complex. PMID:8530498

Wood, L D; Richmond, A

1995-12-22

61

Constitutive expression of the maltose fermentative enzymes in Saccharomyces carlsbergensis is dependent upon the mutational activation of a nonessential homolog of MAL63.  

PubMed Central

Maltose fermentation in Saccharomyces carlsbergensis is dependent upon the MAL6 locus. This complex locus is composed of the MAL61 and MAL62 genes, which encode maltose permease and maltase, respectively, and a third gene, MAL63, which codes for a trans-acting positive regulatory product. In wild-type strains, expression of the MAL61 and MAL62 mRNAs and proteins is induced by maltose and induction is dependent upon the MAL63 gene. Mutants constitutively expressing the MAL61 and MAL62 gene products have been isolated in mal63 backgrounds, and the mutations which have been analyzed map to a fourth MAL6-linked gene, MAL64. Cloning and characterization of this new gene are described in this report. The results revealed that the MAL64-C alleles present in constitutive strains encode a trans-acting positive function required for constitutive expression of the MAL61 and MAL62 gene products. In inducible strains, the MAL64 gene is dispensable, as deletion of the gene had no effect on maltose fermentation or maltose-regulated induction. MAL64 encoded transcripts of 2.0 and 1.4 kilobase pairs. While both MAL64 mRNAs were constitutively expressed in constitutive strains, they were maltose inducible in wild-type strains and induction was dependent upon the MAL63 gene. The MAL63 and MAL64 genes are at least partially structurally homologous, suggesting that they control MAL61 and MAL62 transcript accumulation by similar mechanisms. Images

Dubin, R A; Charron, M J; Haut, S R; Needleman, R B; Michels, C A

1988-01-01

62

Constitutive expression of hZnT4 zinc transporter in human breast epithelial cells.  

PubMed Central

Zinc is an essential trace element required by all living organisms. An adequate supply of zinc is particularly important in the neonatal period. Zinc is a significant component of breast milk, which is transported across the maternal epithelia during lactation. The mechanisms by which zinc becomes a constituent of breast milk have not been elucidated. The function of the zinc transporter ZnT4 in the transport of zinc into milk during lactation was previously demonstrated by studies of a mouse mutant, the 'lethal milk' mouse, where a mutation in the ZnT4 gene decreased the transport of zinc into milk. In the present study, we have investigated the expression of the human orthologue of ZnT4 (hZnT4) in the human breast. We detected hZnT4 mRNA expression in the tissue from the resting and lactating human breast, using reverse-transcriptase PCR. Western-blot analysis using antibodies to peptide sequences of hZnT4 detected a major band of the predicted size of 47 kDa and a minor band of 77 kDa, in extracts from the resting and lactating breast tissues. There was no difference in the hZnT4 expression levels between lactating and resting breasts. The hZnT4 protein was present in the luminal cells of the ducts and alveoli where it had a granular distribution. A cultured human breast epithelial cell line PMC42 was used to investigate the subcellular distribution of hZnT4 and this showed a granular label throughout the cytoplasm, consistent with a vesicular localization. The presence of zinc-containing intracellular vesicles was demonstrated by using the zinc-specific fluorphore Zinquin (ethyl-[2-methyl-8-p-toluenesulphonamido-6-quinolyloxy]acetate). Double labelling indicated that there was no obvious overlap between Zinquin and the hZnT4 protein, suggesting that hZnT4 was not directly involved in the transport of zinc into vesicles. We detected expression of two other members of the hZnT family, hZnT1 and hZnT3, in human breast epithelial cells. We conclude that hZnT4 is constitutively expressed in the human breast and may be one of the several members of the ZnT family involved in the transport of zinc into milk.

Michalczyk, Agnes A; Allen, Justin; Blomeley, Rachael C; Ackland, M Leigh

2002-01-01

63

Constitutive patterns of gene expression regulated by RNA-binding proteins  

PubMed Central

Background RNA-binding proteins regulate a number of cellular processes, including synthesis, folding, translocation, assembly and clearance of RNAs. Recent studies have reported that an unexpectedly large number of proteins are able to interact with RNA, but the partners of many RNA-binding proteins are still uncharacterized. Results We combined prediction of ribonucleoprotein interactions, based on catRAPID calculations, with analysis of protein and RNA expression profiles from human tissues. We found strong interaction propensities for both positively and negatively correlated expression patterns. Our integration of in silico and ex vivo data unraveled two major types of protein–RNA interactions, with positively correlated patterns related to cell cycle control and negatively correlated patterns related to survival, growth and differentiation. To facilitate the investigation of protein–RNA interactions and expression networks, we developed the catRAPID express web server. Conclusions Our analysis sheds light on the role of RNA-binding proteins in regulating proliferation and differentiation processes, and we provide a data exploration tool to aid future experimental studies.

2014-01-01

64

Plasma membrane localization and potential endocytosis of constitutively expressed XA21 proteins in transgenic rice.  

PubMed

The rice pattern recognition receptor (PRR) XA21 confers race-specific resistance in leaf infection by bacterial blight Xathomonas oryzae pv. oryzae (Xoo), and was shown to be primarily localized to the endoplasmic reticulum (ER) when expressed with its native promoter or overexpressed in the protoplast. However, whether the protein is still ER-localization in the intact cell when overexpressed remains to be identified. Here, we showed that XA21, its kinase-dead mutant XA21P(K736EP), and the triple autophosphorylation mutant XA21P(S686A/T688A/S699A) GFP fusions were primarily localized to the plasma membrane (PM) when overexpressed in the intact transgenic rice cell, and also localized to the ER in the transgenic protoplast. The transgenic plants constitutively expressing the wild-type XA21 or its GFP fusion displayed race-specific resistance to Xoo at the adult and seedling stages. XA21 and XA21P(K736EP) could be internalized probably via the SCAMP-positive early endosomal compartment in the protoplast, suggesting that XA21 might be endocytosed to initiate resistance responses during pathogen infection. We also established a root infection system and demonstrated that XA21 also mediated race-specific resistance responses to Xoo in the root. Our current study provides an insight into the nature of the XA21-mediated resistance and a practical approach using the root cell system to further dissect the cellular signaling of the PRR during the rice-Xoo interaction. PMID:20616165

Chen, Fang; Gao, Ming-Jun; Miao, Yan-Song; Yuan, Yue-Xing; Wang, Mu-Yang; Li, Qun; Mao, Bi-Zeng; Jiang, Li-Wen; He, Zu-Hua

2010-09-01

65

Expression of constitutive androstane receptor splice variants in rat liver and lung and their functional properties.  

PubMed

The mammalian constitutive androstane receptor (CAR) is a transcription factor that participates in controlling the expression of xenobiotic metabolizing and transporting genes in response to xenobiotics in an organ-specific manner. In addition to the wild-type CAR (CAR WT) mRNA, mRNAs for five splice variants (SVs) could be detected in the liver of 7-week-old male Wistar rats by RT-PCR using primer pairs covering a full-length mRNA derived from 9 exons; insertion of 18 bp at the 5'-end of intron 8 with or without deletion of 3 bp from the 5'-end of exon 7 (CAR SV1 or SV2), deletion of 4 bp from the 5'-end of exon 8 (CAR SV3), insertion of 195 bp intron 7 (CAR SV4), and insertion of 91 bp intron 6 (CAR SV5). In contrast, only CAR SV5 was detected in lung. Due to the introduction of novel stop codons, all the SVs were considered to code for premature proteins. The liver homogenate gave two protein bands in the vicinity of 37 kDa on Western blotting. They were attributable to CAR WT and SV-complex, respectively, based on their putative molecular weights in descending order. Upon cotransfection with the reporter plasmid, only the cells transfected with the CAR SV4-expression plasmid showed enhanced luciferase activity similar to the WT-transfected cells, for which the further splicing of the remaining intron 7 seemed to be responsible. The transactivation-defective SVs downregulated CAR WT-induced luciferase activity to some extent in the cotransfection experiments. PMID:16272689

Kanno, Yuichiro; Aoki, Sho; Mochizuki, Megumi; Mori, Emi; Nakahama, Takayuki; Inouye, Yoshio

2005-11-01

66

Constitutive Expression and Enzymatic Cleavage of ICAM-1 in the Spontaneously Hypertensive Rat  

PubMed Central

Background/Aims: Leukocyte adhesion to the endothelium is abnormal in hypertension. We have recently shown that spontaneously hypertensive rats (SHRs) have circulating leukocytes with enhanced CD18 receptor cleavage. In the current study, we investigate expression levels of its counter receptor, intercellular adhesion molecule (ICAM-1), and its possible proteolytic cleavage in the SHR and control Wistar rat. Methods ICAM-1 was labeled on tissue sections with two antibodies targeting its extracellular and intracellular domains and evaluated by light absorption measurements. The in situ cleavage of ICAM-1 was assessed by treating vessel sections with matrix metalloproteinase (MMP)-7, MMP-9 and elastase. Results SHRs showed a significant increase in ICAM-1 expression in liver and kidney compared with Wistar rats. The liver and kidney glomeruli exhibit a discrepancy in label density between intra- and extracellular antibodies, which suggests that enzymatic cleavage may be a factor determining ICAM-1 distribution. MMP-7 and MMP-9, which are elevated in SHR plasma, and elastase, which has elevated activity in SHR neutrophils, cleave the extracellular domain of ICAM-1 when applied to the tissue. Conclusion ICAM-1 expression in SHRs is upregulated in a tissue-specific manner. Proteolytic cleavage of the extracellular domain of ICAM-1 and accumulation in kidney glomeruli may play a role in the renal involvement of inflammation.

Tong, Sheng; Neboori, Hanmanth J.; Tran, Edward D.; Schmid-Schonbein, Geert W.

2011-01-01

67

Identification of DDB2 Protein as a Transcriptional Regulator of Constitutive SOD2 Gene Expression in Human Breast Cancer Cells*  

PubMed Central

Manganese superoxide dismutase plays a role in breast tumor cell growth, which depends on its constitutive expression. However, the mechanisms responsible for the regulation of constitutive SOD2 gene expression at different malignant phenotype in breast cancers remain to be determined. The present study reports the identification and characterization of a DNA sequence located in the proximal promoter of the SOD2 gene, which forms a complex with a nuclear protein from breast tumor MCF-7 cells. Purification of this complex showed that it contained DDB2 (damaged DNA binding 2), a well known protein involved in nucleotide excision DNA repair and cell cycle regulation. Functional analysis of the proximal promoter of the SOD2 gene or modulation of DDB2 expression allowed us to demonstrate that DDB2 regulates negatively the constitutive expression of the SOD2 gene in breast cancer cells. We demonstrate that the binding of DDB2 was associated with the loss of acetylated H3 histones and the decrease in the binding of Sp1 but not AP-2? transcription factors to the SOD2 proximal promoter. In addition, we show that DDB2 exerts, at least in part, a control of breast cancer cell growth through its negative regulation of constitutive expression of the SOD2 gene. For the first time, these data give supporting evidence that DDB2 is a new transcriptional regulator, and they provide insight into the molecular function of breast cancer cell growth, which will have an important clinical interest.

Minig, Vanessa; Kattan, Zilal; van Beeumen, Josef; Brunner, Emilie; Becuwe, Philippe

2009-01-01

68

Antigen-Specific Monoclonal Antibodies Isolated from B Cells Expressing Constitutively Active STAT5  

PubMed Central

Background Fully human monoclonal antibodies directed against specific pathogens have a high therapeutic potential, but are difficult to generate. Methodology/Principal Findings Memory B cells were immortalized by expressing an inducible active mutant of the transcription factor Signal Transducer and Activator of Transcription 5 (STAT5). Active STAT5 inhibits the differentiation of B cells while increasing their replicative life span. We obtained cloned B cell lines, which produced antibodies in the presence of interleukin 21 after turning off STAT5. We used this method to obtain monoclonal antibodies against the model antigen tetanus toxin. Conclusions/Significance Here we describe a novel and relatively simple method of immortalizing antigen-specific human B cells for isolation of human monoclonal antibodies. These results show that STAT5 overexpression can be employed to isolate antigen specific antibodies from human memory B cells.

Scheeren, Ferenc A.; van Geelen, Caroline M. M.; Yasuda, Etsuko; Spits, Hergen; Beaumont, Tim

2011-01-01

69

CONSTITUTIVE AND STIMULATED MCP-1, GROA, B, AND Y EXPRESSION IN HUMAN A AIRWAY EPITHELIUM AND BRONCHOALVEOLAR MACROPHAGES  

EPA Science Inventory

Constitutive expression of mRNAs for GROa, GROB, GROY, and MCP-1, belonging to the chemokine family of 8-10 kD cytokines with chemotactic properties for granulocytes and monocytes, has been identified in freshly isolated human nasal and bronchial epithelium, and in bronchoalveola...

70

Brg-1 mediates the constitutive and fenretinide-induced expression of SPARC in mammary carcinoma cells via its interaction with transcription factor Sp1  

PubMed Central

Background Secreted protein, acidic and rich in cysteine (SPARC) is a matricellular protein that mediates cell-matrix interactions. It has been shown, depending on the type of cancer, to possess either pro- or anti-tumorigenic properties. The transcriptional regulation of the SPARC gene expression has not been fully elucidated and the effects of anti-cancer drugs on this process have not been explored. Results In the present study, we demonstrated that chromatin remodeling factor Brg-1 is recruited to the proximal SPARC promoter region (-130/-56) through an interaction with transcription factor Sp1. We identified Brg-1 as a critical regulator for the constitutive expression levels of SPARC mRNA and protein in mammary carcinoma cell lines and for SPARC secretion into culture media. Furthermore, we found that Brg-1 cooperates with Sp1 to enhance SPARC promoter activity. Interestingly, fenretinide [N-4(hydroxyphenyl) retinamide, 4-HPR], a synthetic retinoid with anti-cancer properties, was found to up-regulate the transcription, expression and secretion of SPARC via induction of the Brg-1 in a dose-dependent manner. Finally, our results demonstrated that fenretinide-induced expression of SPARC contributes significantly to a decreased invasion of mammary carcinoma cells. Conclusions Overall, our results reveal a novel cooperative role of Brg-1 and Sp1 in mediating the constitutive and fenretinide-induced expression of SPARC, and provide new insights for the understanding of the anti-cancer effects of fenretinide.

2010-01-01

71

Signal transducer and activator of transcription 1 negatively regulates constitutive gamma interferon-inducible lysosomal thiol reductase expression.  

PubMed

Gamma interferon-inducible lysosomal thiol reductase (GILT) is an enzyme that catalyzes thiol bond reduction and plays an important role in the early steps of antigen processing. The key factor involved in the regulation of GILT expression upon cell stimulation with interferon-? (IFN-?) is signal transducer and activator of transcription 1 (STAT1). In this study, we examined the role of STAT1 in regulating the constitutive expression of GILT. We showed that STAT1 interacts with the GILT promoter, even in the absence of IFN-?, and that STAT1 represses GILT expression. These results reveal an atypical negative regulatory role for STAT1 in the constitutive regulation of genes involved in antigen processing. PMID:21039465

Srinivasan, Priya; Maric, Maja

2011-02-01

72

Signal transducer and activator of transcription 1 negatively regulates constitutive gamma interferon-inducible lysosomal thiol reductase expression  

PubMed Central

Gamma interferon-inducible lysosomal thiol reductase (GILT) is an enzyme that catalyzes thiol bond reduction and plays an important role in the early steps of antigen processing. The key factor involved in the regulation of GILT expression upon cell stimulation with interferon-? (IFN-?) is signal transducer and activator of transcription 1 (STAT1). In this study, we examined the role of STAT1 in regulating the constitutive expression of GILT. We showed that STAT1 interacts with the GILT promoter, even in the absence of IFN-?, and that STAT1 represses GILT expression. These results reveal an atypical negative regulatory role for STAT1 in the constitutive regulation of genes involved in antigen processing.

Srinivasan, Priya; Maric, Maja

2011-01-01

73

New vectors for chromosomal integration enable high-level constitutive or inducible magnetosome expression of fusion proteins in Magnetospirillum gryphiswaldense.  

PubMed

The alphaproteobacterium Magnetospirillum gryphiswaldense biomineralizes magnetosomes, which consist of monocrystalline magnetite cores enveloped by a phospholipid bilayer containing specific proteins. Magnetosomes represent magnetic nanoparticles with unprecedented magnetic and physicochemical characteristics. These make them potentially useful in a number of biotechnological and biomedical applications. Further functionalization can be achieved by expression of foreign proteins via genetic fusion to magnetosome anchor peptides. However, the available genetic tool set for strong and controlled protein expression in magnetotactic bacteria is very limited. Here, we describe versatile vectors for either inducible or high-level constitutive expression of proteins in M. gryphiswaldense. The combination of an engineered native PmamDC promoter with a codon-optimized egfp gene (Mag-egfp) resulted in an 8-fold increase in constitutive expression and in brighter fluorescence. We further demonstrate that the widely used Ptet promoter is functional and tunable in M. gryphiswaldense. Stable and uniform expression of the EGFP and ?-glucuronidase (GusA) reporters was achieved by single-copy chromosomal insertion via Tn5-mediated transposition. In addition, gene duplication by Mag-EGFP-EGFP fusions to MamC resulted in further increased magnetosome expression and fluorescence. Between 80 and 210 (for single MamC-Mag-EGFP) and 200 and 520 (for MamC-Mag-EGFP-EGFP) GFP copies were estimated to be expressed per individual magnetosome particle. PMID:24532068

Borg, Sarah; Hofmann, Julia; Pollithy, Anna; Lang, Claus; Schüler, Dirk

2014-04-01

74

Field tolerance to fungal pathogens of Brassica napus constitutively expressing a chimeric chitinase gene  

SciTech Connect

Constitutive overexpression of a protein involved in plant defense mechanisms to disease is one of the strategies proposed to increase plant tolerance to fungal pathogens. A hybrid endochitinase gene under a constitutive promoter was introduced by Agrobacterium-mediated transformation into a winter-type oilseed rape (Brassica napus var. oleifera) inbred line. Progeny from transformed plants was challenged using three different fungal pathogens (Cylindrosporium concentricum, Phoma lingam, Sclerotinia sclerotiorum) in field trials at two different geographical locations. These plants exhibited an increased tolerance to disease as compared with the nontransgenic parental plants. 31 refs., 1 fig., 2 tabs.

Grison, R.; Grezes-Besset, B.; Lucante, N. [Rustica Prograin Genetique, Mondonville (France)] [and others] [Rustica Prograin Genetique, Mondonville (France); and others

1996-05-01

75

IFN-? Is Constitutively Expressed by Cells of the Reproductive Tract and Is Inefficiently Secreted by Fibroblasts and Cell Lines  

PubMed Central

Type-I interferons (IFNs) form a large family of cytokines that primarily act to control the early development of viral infections. Typical type-I IFN genes, such as those encoding IFN-? or IFN-? are upregulated by viral infection in many cell types. In contrast, the gene encoding IFN-? was reported to be constitutively expressed by cells of the female reproductive tract and to contribute to the protection against vaginal infections with herpes simplex virus 2 and Chlamydia muridarum. Our data confirm the lack of induction of IFN-? expression after viral infection and the constitutive expression of IFN-? by cells of the female but also of the male reproductive organs. Interestingly, when expressed from transfected expression plasmids in 293T, HeLa or Neuro2A cells, the mouse and human IFN-? precursors were inefficiently processed and secretion of IFN-? was minimal. Analysis of chimeric constructs produced between IFN-? and limitin (IFN-?) showed that both the signal peptide and the mature moiety of IFN-? contribute to poor processing of the precursor. Immunofluorescent detection of FLAG-tagged IFN-? in transfected cells suggested that IFN-? and chimeric proteins were defective for progression through the secretory pathway. IFN-? did not, however, act intracellularly and impart an antiviral state to producing cells. Given the constitutive expression of IFN-? in specialized cells and the poor processing of IFN-? precursor in fibroblasts and cell lines, we hypothesize that IFN-? secretion may require a co-factor specifically expressed in cells of the reproductive organs, that might secure the system against aberrant release of this IFN.

Hermant, Pascale; Francius, Cedric; Clotman, Frederic; Michiels, Thomas

2013-01-01

76

Hypoxia reduces constitutive and TNF-{alpha}-induced expression of monocyte chemoattractant protein-1 in human proximal renal tubular cells  

SciTech Connect

Chronic hypoxia has been reported to be associated with macrophage infiltration in progressive forms of kidney disease. Here, we investigated the regulatory effects of hypoxia on constitutive and TNF-{alpha}-stimulated expression of monocyte chemoattractant protein-1 (MCP-1) in cultured human proximal renal tubular cells (HPTECs). Hypoxia reduced constitutive MCP-1 expression at the mRNA and protein levels in a time-dependent fashion for up to 48 h. Hypoxia also inhibited MCP-1 up-regulation by TNF-{alpha}. Treatment with actinomycin D showed that hypoxic down-regulation of MCP-1 expression resulted mainly from a decrease in the transcription but not the mRNA stability. Immunoblot and immunofluorescence analyses revealed that treatment with hypoxia or an iron chelator, desferrioxamine, induced nuclear accumulation of hypoxia-inducible factor-1{alpha} (HIF-1{alpha}) in HPTECs. Desferrioxamine mimicked hypoxia in the reduction of MCP-1 expression. However, overexpression of a dominant negative form of HIF-1{alpha} did not abolish the hypoxia-induced reduction of MCP-1 expression in HPTECs. These results suggest that hypoxia is an important negative regulator of monocyte chemotaxis to the renal inflamed interstitium, by reducing MCP-1 expression partly via hypoxia-activated signals other than the HIF-1 pathway.

Li Xuan [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Kimura, Hideki [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan)]. E-mail: hkimura@fmsrsa.fukui-med.ac.jp; Hirota, Kiichi [Department of Anesthesia, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka (Japan); Department of Anesthesia, School of Medicine, Kyoto University, Kyoto (Japan); Sugimoto, Hidehiro [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Yoshida, Haruyoshi [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan)

2005-10-07

77

An insertion mutation associated with constitutive expression of repressible acid phosphatase in Saccharomyces cerevisiae  

Microsoft Academic Search

The PHO83 mutation in Saccharomyces cerevisiae, which had been detected on the basis of constitutive production of repressible acid phosphatase and mapped at the end of the PHO5 locus, was analysed by Southern hybridization with cloned DNA fragments of the PHO5 gene as probe. It was shown that this mutant has a DNA insertion of about 6 kilobase pairs, probably

Akio Toh-e; Yoshinobu Kaneko; Jirô Akimaru; Yasuji Oshima

1983-01-01

78

A Plasmodium berghei reference line that constitutively expresses GFP at a high level throughout the complete life cycle  

Microsoft Academic Search

Green fluorescent protein (GFP) is a well-established reporter protein for the examination of biological processes. This report describes a recombinant Plasmodium berghei, PbGFPCON, that constitutively expresses GFP in a growth responsive manner in its cytoplasm from a transgene that is integrated into the genome and controlled by the strong promoter from a P. berghei elongation factor-1? gene. All life cycle

Blandine Franke-Fayard; Holly Trueman; Jai Ramesar; Jacqui Mendoza; Maarten van der Keur; Reinier van der Linden; Robert E. Sinden; Andrew P. Waters; Chris J. Janse

2004-01-01

79

Repetitive myocardial stunning in pigs is associated with the increased expression of inducible and constitutive nitric oxide synthases  

Microsoft Academic Search

Objectives: Nitric oxide (NO) has complex effects on myocardial function particularly following ischaemia-reperfusion. The goal of this study was to examine the result of repetitive myocardial stunning on myocardial NO release and expression of inducible (iNOS) and constitutive (eNOS) NO synthases. Methods and results: Propofol anaesthetised pigs underwent ten, 2-min episodes of circumflex artery occlusion (n56) or acted as sham

Christopher S. R. Baker; Ornella Rimoldi; Paolo G. Camici; Edward Barnes; Matilde R. Chacon; Tanya Y. Huehns; Dorian O. Haskard; Julia M. Polak; Roger J. C. Hall

80

Constitutive Expression of a High-Affinity Sulfate Transporter in Indian Mustard Affects Metal Tolerance and Accumulation  

Microsoft Academic Search

The Stylosanthes hamata SHST1 gene encodes a high-affinity sulfate transporter located in the plasma membrane. In this study the S. hamata SHST1 gene was constitutively expressed in Indian mustard (Brassica juncea (L.) Czern.) to investigate its importance for toler- ance and accumulation of various oxyanions that may be transported by SHST1 and for cadmium, which is detoxified by sulfur-rich com-

Stormy Dawn Lindblom; Salah Abdel-Ghany; Brady R. Hanson; Seongbin Hwang; Norman Terry; Elizabeth A. H. Pilon-Smits

2006-01-01

81

Selection for low dormancy in annual ryegrass (Lolium rigidum) seeds results in high constitutive expression of a glucose-responsive ?-amylase isoform  

PubMed Central

Background and Aims ?-Amylase in grass caryopses (seeds) is usually expressed upon commencement of germination and is rarely seen in dry, mature seeds. A heat-stable ?-amylase activity was unexpectedly selected for expression in dry annual ryegrass (Lolium rigidum) seeds during targeted selection for low primary dormancy. The aim of this study was to characterize this constitutive activity biochemically and determine if its presence conferred insensitivity to the germination inhibitors abscisic acid and benzoxazolinone. Methods ?-Amylase activity in developing, mature and germinating seeds from the selected (low-dormancy) and a field-collected (dormant) population was characterized by native activity PAGE. The response of seed germination and ?-amylase activity to abscisic acid and benzoxazolinone was assessed. Using an alginate affinity matrix, ?-amylase was purified from dry and germinating seeds for analysis of its enzymatic properties. Key Results The constitutive ?-amylase activity appeared late during seed development and was mainly localized in the aleurone; in germinating seeds, this activity was responsive to both glucose and gibberellin. It migrated differently on native PAGE compared with the major activities in germinating seeds of the dormant population, but the enzymatic properties of ?-amylase purified from the low-dormancy and dormant seeds were largely indistinguishable. Seed imbibition on benzoxazolinone had little effect on the low-dormancy seeds but greatly inhibited germination and ?-amylase activity in the dormant population. Conclusions The constitutive ?-amylase activity in annual ryegrass seeds selected for low dormancy is electrophoretically different from that in germinating seeds and its presence confers insensitivity to benzoxazolinone. The concurrent selection of low dormancy and constitutive ?-amylase activity may help to enhance seedling establishment under competitive conditions.

Goggin, Danica E.; Powles, Stephen B.

2012-01-01

82

The diversity of inducible and constitutively expressed erm(C) genes and association to different replicon types in staphylococci plasmids  

PubMed Central

The aim of this study was to analyze the diversity of the macrolide resistance gene, erm(C) in relation to structural alterations affecting the gene expression. In addition, the association of erm(C) to mobile genetic elements (MGEs) in staphylococci mainly from Danish pigs was investigated. In total, 78 erythromycin-resistant isolates were screened for erm(C) by PCR. The erm(C) genes incl. the upstream regulatory region were sequenced and the expression types were characterized phenotypically (agar diffusion test) and genotypically (sequence analysis). Phylogenetic analysis of erm(C) was compared with structural alterations affecting the gene expression. Plasmids carrying erm(C) from seven selected isolates were fully or partially sequenced. Thirty-seven isolates were shown to be erm(C) positive and erm(C) from pigs were all constitutively expressed, mainly caused by different sized deletions (118, 111, 107, 70, 66, 16 and 3 bp) in the regulatory region. Duplication (63 bp) and substitutions were also found to cause a constitutive phenotype. Only one horse isolate had an inducible expression type. Phylogenetic analysis showed that structural alterations have happened in different erm(C) allele groups and not only in one group. Furthermore erm(C) was found mainly on plasmids (~2.4–8 kb) and gene sequence types correlated with plasmid replication (rep) gene types. One erm(C) type was linked to an IS257 element able to circularize. In conclusion, structural alterations giving rise to constitutive expression of erm(C) have happened several times in the evolution of erm(C). Interestingly, the diversity of erm(C) appears to be linked to the plasmid type or MGE carrying the gene.

de Vries, Lisbeth E.; Christensen, Henrik; Agers?, Yvonne

2012-01-01

83

Tyrosine kinase is essential for the constitutive expression of type I interleukin-1 receptor in human fibroblast cells.  

PubMed

The effect of genistein, an inhibitor of tyrosine kinase, on the constitutive expression of type I interleukin-1 receptor (IL-1RI) was examined in the human lung fibroblast cell line TIG-1, which has been shown to express only type I IL-1R. Genistein inhibited the 125I-labeled IL-1alpha binding to TIG-1 cells in both a time and dose dependent manner. Scatchard plot analysis revealed that the number of IL-1RI decreased with no change in binding affinity. Genistein did not affect the level of IL-1RI mRNA, and cycloheximide did not inhibit the down-regulatory effect of genistein. These results indicate that genistein inhibits IL-1RI expression, not at the transcriptional level, but at the post-translational level. IL-1RI expression, IL-1R associated kinase (IRAK) activity and IL-1-induced-IL-6 production were all down-regulated by pretreatment with genistein. These findings indicate that tyrosine kinase activity is essential for the constitutive expression of functional IL-1RI. PMID:10400830

Takii, T; Ito, A; Kawashima, S; Ninomiya, A; Matsumura, T; Hayashi, H; Onozaki, K

1999-06-01

84

Mechanism and biological significance of constitutive expression of MGSA/GRO chemokines in malignant melanoma tumor progression.  

PubMed

By reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry, MGSA-alpha, -beta, -gamma, and CXCR2 mRNA expression and proteins are detected in 7 out of 10 human melanoma lesions. The biological consequence of constitutive expression of the MGSA/GRO chemokine in immortalized melanocytes was tested in SCID and nude mouse models. Continuous expression of MGSA/GRO-alpha, -beta, or -gamma in immortalized melan-a mouse melanocytes results in nearly 100% tumor formation for each of the clones tested, whereas clones expressing only the neomycin resistance vector form tumors <10% of the time. Moreover, antibodies to the MGSA/GRO proteins slow or inhibit the formation of tumors in the SCID mouse model and block the angiogenic response to conditioned medium from the tumor-producing clones. Transcription of the MGSA/GRO chemokines is regulated by an enhancesome-like complex comprised of the nuclear factor-kappaB (NF-kappaB), HMG(I)Y, IUR, and Sp1 elements. In Hs294T melanoma cells the half life of the IKB protein is shortened in comparison to normal retinal epithelial cells, facilitating the endogenous nuclear localization of NF-kappaB. We propose that this endogenous nuclear NF-kappaB, working in concert with the 115-kDa IUR-binding factor, promotes constitutive expression of MGSA/GRO genes. PMID:9365113

Luan, J; Shattuck-Brandt, R; Haghnegahdar, H; Owen, J D; Strieter, R; Burdick, M; Nirodi, C; Beauchamp, D; Johnson, K N; Richmond, A

1997-11-01

85

Growth factor mRNA profiles in unstimulated human mononuclear cells: identification of genes which are constitutively and variably expressed.  

PubMed

Quiescent human mononuclear cells (MNC) as studied ex vivo express highly specific mRNA patterns of growth factors: We recently demonstrated that unstimulated MNC constitutively express the genes for the A and B chains of platelet-derived growth factor (PDGF). This expression was down-regulated by dietary omega-3 fatty acids. We now report that unstimulated human MNC express the genes for platelet-derived endothelial cell growth factor (PD-ECGF), insulin-like growth factor (IGF-1A, -1B) and transforming growth factor-beta 1 (TGF-beta 1). In contrast, acidic and basic fibroblast GF (FGFs), insulin-like GF-2 (IGF-2), transforming GF-alpha (TGF-alpha) and epidermal GF (EGF) were not expressed in MNC, nor were alpha- and beta- receptors for PDGF. Quantitatively, as measured over a period of six weeks, expression of PD-ECGF was constant, whereas TGF-beta 1, IGF-1A, and IGF-1B were expressed at varying levels and all independently of each other. Dietary omega-3 fatty acids had no effect on gene expression. Our results also indicate that down-regulation of PDGF gene expression represents a specific and possibly therapeutic effect of dietary fish oil supplementation. PMID:8216299

Jendraschak, E; Kaminski, W E; Hessel, F; Kiefl, R; von Schacky, C

1993-10-15

86

A Comparison of Constitutive Promoters for Expression of Transgenes in Alfalfa (Medicago Sativa)  

Microsoft Academic Search

The activity of constitutive promoters was compared in transgenic alfalfa plants using two marker genes. Three promoters, the 35S promoter from cauliflower mosaic virus (CaMV), the cassava vein mosaic virus (CsVMV) promoter, and the sugarcane bacilliform badnavirus (ScBV) promoter were each fused to the ß-glucuronidase (gusA) gene. The highest GUS enzyme activity was obtained using the CsVMV promoter and all

Deborah A. Samac; Mesfin Tesfaye; Melinda Dornbusch; Purev Saruul; Stephen J. Temple

2004-01-01

87

Constitutive expression of costimulatory molecules by human microglia and its relevance to CNS autoimmunity  

Microsoft Academic Search

Human microglia constitute the primary residential antigen presenting cells (APCs) in the central nervous system (CNS) and have the capacity of activating myelin reactive T-cells. T-cell activation requires two signals: first is the interaction of the T-cell receptor with the MHC-antigen complex and, secondly, contact of the CD28\\/CTLA4 T-cell surface molecules with the B7 family of costimulatory molecules on the

Fernando Dangond; Anja Windhagen; Christopher J Groves; David A Hafler

1997-01-01

88

Constitutive expression of a single antimicrobial peptide can restore wild-type resistance to infection in immunodeficient Drosophila mutants  

PubMed Central

One of the characteristics of the host defense of insects is the rapid synthesis of a variety of potent antibacterial and antifungal peptides. To date, seven types of inducible antimicrobial peptides (AMPs) have been characterized in Drosophila. The importance of these peptides in host defense is supported by the observation that flies deficient for the Toll or Immune deficiency (Imd) pathway, which affects AMP gene expression, are extremely susceptible to microbial infection. Here we have developed a genetic approach to address the functional relevance of a defined antifungal or antibacterial peptide in the host defense of Drosophila adults. We have expressed AMP genes via the control of the UAS/GAL4 system in imd; spätzle double mutants that do not express any known endogenous AMP gene. Our results clearly show that constitutive expression of a single peptide in some cases is sufficient to rescue imd; spätzle susceptibility to microbial infection, highlighting the important role of AMPs in Drosophila adult host defense.

Tzou, Phoebe; Reichhart, Jean-Marc; Lemaitre, Bruno

2002-01-01

89

Regulation of beta-glucuronidase synthesis in Escherichia coli K-12: constitutive mutants specifically derepressed for uidA expression.  

PubMed Central

All methyl-beta-D-galacturonide-positive mutants isolated from Escherichia coli K-12 carry constitutive mutations for beta-glucuronidase (UID) synthesis. Most of these mutants are specific for UID synthesis and are distributed in three classes according to the derepression level of UID. Each specific mutant carries a mutation(s) near uidA, the structural gene for UID, at min 30.5 of the E. coli K-12 linkage map. The expression of UID synthesis in F-merodiploid strains carrying these mutations permits discrimination between dominant and recessive constitutivity over the wild-type allele. The first kind of mutation (dominant) should affect the operator site uidO of the structural gene uidA; the second type of mutation (recessive) should affect a regulatory gene, uidR, operating through a negative control. The isolation of mutants bearing at this locus superrepressed mutations, which can revert to produce a constitutive phenotype, confirms the occurrence of such a regulatory gene. The partially derepressed uidR mutants of the first class are normally inducible and remain constitutive at low temperature; their UID has the same thermal sensitivity as in the wild-type strains. The occurrence of similar regulatory gene mutants has been recently described in the lactose system (Shineberg, 1974).

Novel, M; Novel, G

1976-01-01

90

Constitutive expression of Cry proteins in roots and border cells of transgenic cotton  

Microsoft Academic Search

Transgenic cotton plants expressing Cry1Ac and Cry2Ab, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control of certain lepidopteran pests, however, little is known about the proteins below ground expression.\\u000a We used ELISA to quantify in vitro expression of the Cry1Ac and Cry2Ab proteins in mucilage, root border cells and root tips in five transgenic cultivars of cotton compared

Oliver G. G. Knox; Vadakattu V. S. R. Gupta; David B. Nehl; Warwick N. Stiller

2007-01-01

91

Constitutive HIF-1? Expression Blunts the Beneficial Effects of Cardiosphere-Derived Cell Therapy in the Heart by Altering Paracrine Factor Balance  

Microsoft Academic Search

Hypoxia-inducible factor-1alpha (HIF-1?) expression promotes angiogenesis and can influence stem cell engraftment. We investigated\\u000a the effect of stable over-expression of constitutively active HIF-1? on cardiosphere-derived cell (CDC) engraftment and left\\u000a ventricular function. CDCs were transduced with a lentivirus expressing a constitutively active mutant of human HIF-1? (LVHIF-1?).\\u000a Two million male rat CDCs were injected into the infarct following ligation of

Michael Bonios; Connie Yachan Chang; John Terrovitis; Aurelio Pinheiro; Andreas Barth; Peihong Dong; Miguel Santaularia; D. Brian Foster; Venu Raman; Theodore P. Abraham; Maria Roselle Abraham

2011-01-01

92

A new series of vectors for constitutive, inducible or repressible gene expression in Candida guilliermondii.  

PubMed

The biotechnological potential of C. guilliermondii is now well established. This yeast species currently benefits from the availability of a convenient molecular toolbox including recipient strains, selectable markers and optimized transformation protocols. However, the number of expression systems for biotechnological applications in C. guilliermondii remains limited. We have therefore developed and characterized a new series of versatile controllable expression vectors for this yeast. While previous studies firmly demonstrated that knock-out systems represent efficient genetic strategies to interrupt yeast biochemical pathways at a specific step in C. guilliermondii, the set of expression plasmids described in this study will provide new powerful opportunities to boost homologous or heterologous biosynthetic routes by fine controlled over-expression approaches. PMID:24709398

Defosse, Tatiana A; Melin, Céline; Obando Montoya, Erika J; Lanoue, Arnaud; Foureau, Emilien; Glévarec, Gaëlle; Oudin, Audrey; Simkin, Andrew J; Crèche, Joël; Atehortùa, Lucia; Giglioli-Guivarc'h, Nathalie; Clastre, Marc; Courdavault, Vincent; Papon, Nicolas

2014-06-20

93

Efficient constitutive expression of thermostable 4-?-glucanotransferase in Bacillus subtilis using dual promoters  

Microsoft Academic Search

4-?-Glucanotransferases possess strong transglycosylation activity which has been used in various carbohydrate chemistry fields.\\u000a Due to safety issues of the recombinant enzymes we chose Bacillus subtilis as an expression host to produce a thermostable 4-?-glucanotransferase from Thermus scotoductus (TS?GT). The HpaII promoter in the Gram-positive bacterial vector pUB110 was used first to express TS?GT gene in B. subtilis. However, the

Hee-Kwon Kang; Jun-Hyuck Jang; Jae-Hoon Shim; Jong-Tae Park; Young-Wan Kim; Kwan-Hwa Park

2010-01-01

94

Identification of positive and negative regulators of disease resistance to rice blast fungus using constitutive gene expression patterns.  

PubMed

Elevated constitutive expression of components of the defence arsenal is associated with quantitative resistance to the rice blast fungus, a phenomenon called preformed defence. While the role of many disease regulators in inducible defence systems has been extensively studied, little attention has been paid so far to genes that regulate preformed defence. In this study, we show by microarray analysis across rice diversity that the preformed defence phenomenon impacts on a large number of defence-related genes without apparently affecting other biological processes. Using a guilt-by-association strategy, we identified two positive regulators that promote constitutive expression of known defence markers and partial resistance to rice blast. The HSF23 gene encodes for a putative member of the heat shock transcription factor family, while CaMBP encodes for a putative Calmodulin-binding protein. Both HSF23 and CaMBP strongly affect preformed defence and also plant growth. Additionally, we identified the OB-fold gene as a negative regulator of blast resistance, which could be involved in RNA stabilization. The OB-fold mutants do not suffer from obvious developmental defects. Taken together, our results prove that our strategy of combining analysis of gene expression diversity with guilt-by-association is a powerful way to identify disease resistance regulators in rice. PMID:22607456

Grand, Xavier; Espinoza, Rocio; Michel, Corinne; Cros, Sandrine; Chalvon, Véronique; Jacobs, John; Morel, Jean-Benoit

2012-09-01

95

Selective lignin downregulation leads to constitutive defense response expression in alfalfa (Medicago sativa L.).  

PubMed

• Downregulation of hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) in alfalfa (Medicago sativa) reduces lignin levels and improves forage quality and saccharification efficiency for bioethanol production. However, the plants have reduced stature. It was previously reported that HCT-down-regulated Arabidopsis have impaired auxin transport, but this has recently been disproved. • To address the basis for the phenotypes of lignin-modified alfalfa, we measured auxin transport, profiled a range of metabolites including flavonoids and hormones, and performed in depth transcriptome analyses. • Auxin transport is unaffected in HCT antisense alfalfa despite increased flavonoid biosynthesis. The plants show increased cytokinin and reduced auxin levels, and gibberellin levels and sensitivity are both reduced. Levels of salicylic, jasmonic and abscisic acids are elevated, associated with massive upregulation of pathogenesis and abiotic stress-related genes and enhanced tolerance to fungal infection and drought. • We suggest that HCT downregulated alfalfa plants exhibit constitutive activation of defense responses, triggered by release of bioactive cell wall fragments and production of hydrogen peroxide as a result of impaired secondary cell wall integrity. PMID:21251001

Gallego-Giraldo, Lina; Jikumaru, Yusuke; Kamiya, Yuji; Tang, Yuhong; Dixon, Richard A

2011-05-01

96

A constitutive PR-1::luciferase expression screen identifies Arabidopsis mutants with differential disease resistance to both biotrophic and necrotrophic pathogens.  

PubMed

SUMMARY A complex signal transduction network involving salicylic acid, jasmonic acid and ethylene underlies disease resistance in Arabidopsis. To understand this defence signalling network further, we identified mutants that expressed the marker gene PR-1::luciferase in the absence of pathogen infection. These cir mutants all display constitutive expression of a suite of defence-related genes but exhibit different disease resistance profiles to two biotrophic pathogens, Pseudomonas syringae pv. tomato and Peronospora parasitica NOCO2, and the necrotrophic pathogen Botrytis cinerea. We further characterized cir3, which displays enhanced resistance only to the necrotrophic pathogen. Cir3-mediated resistance to B. cinerea is dependent on accumulated salicylic acid and a functional EIN2 protein. PMID:20565636

Murray, Shane L; Adams, Nicolette; Kliebenstein, Daniel J; Loake, Gary J; Denby, Katherine J

2005-01-01

97

The Aspergillus niger annexin, anxC3.1 is constitutively expressed and is not essential for protein secretion.  

PubMed

An annexin, anxC3.1, was isolated and characterised from the industrially important filamentous fungus Aspergillus niger. anxC3.1 is a single copy gene encoding a 506 amino acid predicted protein which contains four annexin repeats. Disruption of the anxC3.1 gene did not lead to any visible changes in phenotype, nor in the levels of secreted protein, nor specifically in glucoamylase production, suggesting no major role in secretion. anxC3.1 expression was found to be unaltered under a variety of conditions such as increased secretion, altered nitrogen source, heat shock, and decreased Ca2+ levels, indicating that anxC3.1 is constitutively expressed. This is the first reported functional characterisation of a fungal annexin. PMID:15451115

Khalaj, Vahid; Hey, Peter; Smith, Lyndsay; Robson, Geoffrey D; Brookman, Jayne

2004-10-01

98

Constitutive TL1A expression under colitogenic conditions modulates the severity and location of gut mucosal inflammation and induces fibrostenosis.  

PubMed

Intestinal fibrostenosis is a hallmark of severe Crohn's disease and can lead to multiple surgeries. Patients with certain TNFSF15 variants overexpress TL1A. The aim of this study was to determine the effect of TL1A overexpression on intestinal inflammation and the development of fibrostenosis. We assessed the in vivo consequences of constitutive TL1A expression on gut mucosal inflammation and fibrostenosis using two murine models of chronic colitis. In the dextran sodium sulfate (DSS) and adoptive T-cell transfer models, there was proximal migration of colonic inflammation, worsened patchy intestinal inflammation, and long gross intestinal strictures in Tl1a transgenic compared to wild-type littermates. In the DSS model, myeloid- and T-cell-expressing Tl1a transgenic mice had increased T-cell activation markers and interleukin-17 expression compared to wild-type mice. In the T-cell transfer model, Rag1(-/-) mice receiving Tl1a transgenic T cells had increased interferon-? expression but reduced T-helper 17 cells and IL-17 production. Narrowed ureters with hydronephrosis were found only in the Tl1a transgenic mice in all chronic colitis models. In human translational studies, Crohn's disease patients with higher peripheral TL1A expression also exhibited intestinal fibrostenosis and worsened ileocecal inflammation with relative sparing of rectosigmoid inflammation. These data show that TL1A is an important cytokine that not only modulates the location and severity of mucosal inflammation, but also induces fibrostenosis. PMID:22138299

Barrett, Robert; Zhang, Xiaolan; Koon, Hon Wai; Vu, Michelle; Chang, Jyh-Yau; Yeager, Nicole; Nguyen, Mary Ann; Michelsen, Kathrin S; Berel, Dror; Pothoulakis, Charalabos; Targan, Stephan R; Shih, David Q

2012-02-01

99

Nuclear FactorB-dependent Gene Expression Profiling of Hodgkin's Disease Tumor Cells, Pathogenetic Significance, and Link to Constitutive Signal Transducer and Activator of Transcription 5a Activity  

Microsoft Academic Search

Constitutive nuclear nuclear factor (NF)- ? B activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF- ? B for Hodgkin and Reed- Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF- ? B target genes. We recognized 45 genes whose expression in

Michael Hinz; Petra Lemke; Ioannis Anagnostopoulos; Christine Hacker; Daniel Krappmann; Stephan Mathas; Bernd Dörken; Martin Zenke; Harald Stein; Claus Scheidereit

100

Nuclear Factor  B-dependent Gene Expression Profiling of Hodgkin's Disease Tumor Cells, Pathogenetic Significance, and Link to Constitutive Signal Transducer and Activator of Transcription 5a Activity  

Microsoft Academic Search

Constitutive nuclear nuclear factor (NF)- ? B activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF- ? B for Hodgkin and Reed- Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF- ? B target genes. We recognized 45 genes whose expression in

Michael Hinz; Petra Lemke; Ioannis Anagnostopoulos; Christine Hacker; Daniel Krappmann; Stephan Mathas; B. Dorken; Martin Zenke; Harald Stein; Claus Scheidereit

2002-01-01

101

Utility of temporally distinct baculovirus promoters for constitutive and baculovirus-inducible transgene expression in transformed insect cells  

PubMed Central

Genetically transformed lepidopteran insect cell lines have biotechnological applications as constitutive recombinant protein production platforms and improved hosts for baculovirus-mediated recombinant protein production. Insect cell transformation is often accomplished with a DNA construct(s) encoding a foreign protein(s) under the transcriptional control of a baculovirus immediate early promoter, such as the ie1 promoter. However, the potential utility of increasingly stronger promoters from later baculovirus gene classes, such as delayed early (39K), late (p6.9), and very late (polh), has not been systematically assessed. Hence, we produced DNA constructs encoding secreted alkaline phosphatase (SEAP) under the transcriptional control of each of the four temporally distinct classes of baculovirus promoters, used them to transform insect cells, and compared the levels of SEAP RNA and protein production obtained before and after baculovirus infection. The ie1 construct was the only one that supported SEAP protein production by transformed insect cells prior to baculovirus infection, confirming that only immediate early promoters can be used to isolate transformed insect cells for constitutive recombinant protein production. However, baculovirus infection activated transgene expression by all four classes of baculovirus promoters. After infection, cells transformed with the very late (polh) and late (p6.9) promoter constructs produced the highest levels of SEAP RNA, but only low levels of SEAP protein. Conversely, cells transformed with the immediate early (ie1) and delayed early (39K) promoter constructs produced lower levels of RNA, but equal or higher levels of SEAP protein. Unexpectedly, the 39K promoter construct provided tightly regulated, baculovirus-inducible protein production at higher levels than the later promoter constructs. Thus, this study demonstrated the utility of the 39K promoter for insect cell engineering, particularly when one requires higher levels of effector protein production than obtained with ie1 and/or when constitutive transgene expression adversely impacts host cell fitness and/or genetic stability.

Lin, Chi-Hung; Jarvis, Donald L.

2013-01-01

102

Higher constitutive IL15R? expression and lower IL-15 response threshold in coeliac disease patients  

PubMed Central

The IL-15 triggering effect of gliadin is not exclusive to coeliac disease (CD) patients, whereas the secondary response is CD specific. We have studied the expression of the IL-15 receptor, and the IL-15 response upon stimulation, in non-CD and CD patients, and the possible existence of a lower immunological threshold in the latter. Forty-two CD patients (20 on a gluten-containing diet, GCD, and 22 on gluten-free diet, GFD) and 24 non-CD healthy individuals were studied. IL15R? mRNA expression, and tissue characterization, were assayed in the duodenum. Biopsies from six CD patients on GFD and 10 non-CD individuals were studied in vitro using organ culture in basal conditions, as well as after IL-15 stimulation discarding basal IL-15 production. Secretion of immune mediators was measured in the culture supernatants. IL15R? mRNA expression was increased in CD patients, as compared with non-CD controls (on GFD P = 0·0334, on GCD P = 0·0062, respectively), and confirmed also by immunofluorescence. No differences were found between CD patients on GFD and on GCD. After in vitro IL-15 stimulation, IL15R? expression was only triggered in non-CD controls (P = 0·0313), though it remained increased in CD patients. Moreover, IL-15 induced a more intense immunological response in CD patients after triggering the production of both nitrites and IFN? (P = 0·0313, P = 0·0313, respectively). Gliadin-induced IL15 has a lower response threshold in CD patients, leading to the production of other immune mediators and the development of the intestinal lesion, and thus magnifying its effects within the CD intestine.

Bernardo, D; Garrote, J A; Allegretti, Y; Leon, A; Gomez, E; Bermejo-Martin, J F; Calvo, C; Riestra, S; Fernandez-Salazar, L; Blanco-Quiros, A; Chirdo, F; Arranz, E

2008-01-01

103

Construction of a constitutively expressed homo-fermentative pathway in Lactobacillus brevis.  

PubMed

Lactobacillus brevis is a promising lactic acid producing strain that simultaneously utilizes glucose and xylose from lignocellulosic hydrolysate without carbon catabolic repression and inhibition. The production of by-products acetic acid and ethanol has been the major drawback of this strain. Two genes, pfkA (fructose-6-phosphate kinase [PFK]) and fbaA (fructose-1,6-biphosphate aldolase [FBA]), that encode the key enzymes of the EMP/glycolytic pathway from Lactobacillus rhamnosus, were fused to the downstream of the strong promoter P32 and expressed in L. brevis s3f4 as a strategy to minimize the formation of by-products. By expressing the two enzymes, a homo-fermentative pathway for lactic acid production was constructed. The lactic acid yields achieved from glucose in the transformants were 1.12 and 1.16 mol/mol, which is higher than that of the native strain (0.74 mol/mol). However, the lactic acid yield from xylose in the transformants stayed the same as that of the native strain. Enzyme assay indicated that the activity of the foreign protein FBA in the transformants was much higher than that of the native strains, but was ten times lower than that in L. rhamnosus. This result was consistent with the metabolic flux analysis, which indicated that the conversion efficiency of the expressed PFK and FBA was somewhat low. Less than 20 % of the carbons accumulated in the form of fructose-6-phosphate were converted into glyceraldehyde-3-phosphate (GAP) by the expressed PFK and FBA. Metabolic flux analysis also indicated that the enzyme phosphoketolase (XPK) played an important role in splitting the carbon flow from the pentose phosphate pathway to the phosphoketolase pathway. This study suggested that the lactic acid yield of L. brevis could be improved by constructing a homo-fermentative pathway. PMID:24728715

Guo, Wei; He, Ronglin; Ma, Lijuan; Jia, Wendi; Li, Demao; Chen, Shulin

2014-08-01

104

Promoter Characterization and Constitutive Expression of the Escherichia coli gcvR Gene  

Microsoft Academic Search

The Escherichia coli glycine cleavage repressor protein (GcvR) negatively regulates expression of the glycine cleavage operon (gcv). In this study, the gcvR translational start site was determined by N-terminal amino acid sequence analysis of a GcvR-LacZ fusion protein. Primer extension analysis of the gcvR promoter region identified a primary transcription start site 27 bp upstream of the UUG translation start

ANGELA C. GHRIST; GEORGE V. STAUFFER

1998-01-01

105

Constitutive and LPS-regulated expression of interleukin-18 receptor beta variants in the mouse brain.  

PubMed

Interleukin (IL)-18 is a pro-inflammatory cytokine that is proposed to be involved in physiological as well as pathological conditions in the adult brain. IL-18 acts through a heterodimer receptor comprised of a subunit alpha (IL-18R?) required for binding, and a subunit beta (IL-18R?) necessary for activation of signal transduction. We recently demonstrated that the canonical alpha binding chain, and its putative decoy isoform, are expressed in the mouse central nervous system (CNS) suggesting that IL-18 may act on the brain by directly binding its receptor. Considering that the co-expression of the beta chain seems to be required to generate a functional receptor and, a short variant of this chain has been described in rat and human brain, in this study we have extended our investigation to IL-18R? in mouse. Using a multi-methodological approach we found that: (1) a short splice variant of IL-18R? was expressed in the CNS even if at lower levels compared to the full-length IL-18R? variants, (2) the canonical IL-18R? is expressed in the CNS particularly in areas and nuclei belonging to the limbic system as previously observed for IL-18R? and finally (3) we have also demonstrated that both IL-18R? isoforms are up-regulated in different brain areas three hours after a single lipopolysaccharide (LPS) injection suggesting that IL-18R? in the CNS might be involved in mediating the endocrine and behavioral effects of LPS. Our data highlight the considerable complexity of the IL-18 regulation activity in the mouse brain and further support an important central role for IL-18. PMID:21111041

Alboni, Silvia; Montanari, Claudia; Benatti, Cristina; Blom, Johanna M C; Simone, Maria Luisa; Brunello, Nicoletta; Caggia, Federica; Guidotti, Gianluigi; Marcondes, Maria Cecilia Garibaldi; Sanchez-Alavez, Manuel; Conti, Bruno; Tascedda, Fabio

2011-03-01

106

Constitutive expression of high-affinity sulfate transporter (HAST) gene in Indian mustard showed enhanced sulfur uptake and assimilation.  

PubMed

Lycopersicon esculantum sulfate transporter gene (LeST 1.1) encodes a high-affinity sulfate transporter (HAST) located in root epidermis. In this study, the LeST 1.1 gene was constitutively expressed in Indian mustard (Brassica juncea cv. Pusa Jai Kisan). Transgenic as well as untransformed plants were grown in sulfur-insufficient (25 and 50 ?M) and sulfur-sufficient (1,000 ?M) conditions for 30 days. Two-fold increase was noticed in the sulfate uptake rate of transgenic plants grown in both sulfur-insufficient and -sufficient conditions as compared to untransformed plants. The transgenic B. juncea plants were able to accumulate higher biomass and showed improved sulfur status even in sulfur-insufficient conditions when compared with untransformed plants. Chlorophyll content, ATP sulfurylase activity and protein content were also higher in transgenic plants than untranformed plants under sulfur-insufficient conditions. Our results, thus, clearly indicate that constitutive expression of LeST 1.1 gene in B. juncea had led to enhanced capacity of sulfur uptake and assimilation even in sulfur-insufficient conditions. This approach can also be used in other crops to enhance their sulfate uptake and assimilation potential under S-insufficient conditions. PMID:20938698

Abdin, M Z; Akmal, M; Ram, M; Nafis, T; Alam, P; Nadeem, M; Khan, M A; Ahmad, A

2011-07-01

107

Constitutive Expression of Interleukin (IL)-4 In Vivo Causes Autoimmune-type Disorders in Mice  

PubMed Central

The transgenic (tg) expression of interleukin (IL)-4 under the control of a major histocompatibility complex (MHC) class I promoter leads to B cell hyperactivity in mice, characterized by increased B cell surface MHC class II and CD23 expression, elevated responsiveness of the B cells to polyclonal ex vivo stimulation, and increased immunoglobulin (Ig)G1 and IgE serum levels. Tg mice develop anemia, glomerulonephritis with complement and immune deposition in the glomeruli, and show increased production of autoantibodies. Treatment of IL-4 tg mice with anti-IL-4 neutralizing antibodies protected the mice from disease development, showing that IL-4 was responsible for the observed disorders. Deletion of superantigen responsive autoreactive T cells in the IL-4 tg mice was normal and treatment of mutant mice with deleting anti-CD4 antibodies failed to ablate the onset of autoimmune-like disease, suggesting that CD4+T cells were not the primary cause of the disorders. Furthermore, the deletion of B cells reacting against MHC class I molecules was also normal in the IL-4 tg mice. Therefore the most likely explanation for the increased production of autoantibodies and the autoimmunelike disorders is that IL-4 acts directly on autoreactive B cells by expanding them in a polyclonal manner. Taken together our results show that inappropriate multi-organ expression of IL-4 in vivo leads to autoimmune-type disease in mice.

Erb, Klaus J.; Ruger, Beate; von Brevern, Maja; Ryffel, Bernhard; Schimpl, Annelise; Rivett, Karen

1997-01-01

108

Constitutive expression of ZmsHSP in Arabidopsis enhances their cytokinin sensitivity.  

PubMed

A small HSP gene, ZmsHSP, was isolated from Zea mays. Sequence analysis revealed that the open reading frame of ZmsHSP was 477 bp and that it encodes a protein composed of 159 amino acid residues with a calculated molecular mass of 18.17 kD and a predicated isoelectric point (pI) of 5.63. ZmsHSP contains a CS domain (p23-like domain) and shares similarity with the HSP90 co-chaperone p23. The expression level of ZmsHSP was different among various tissues with the highest expression in leaves and the lowest in silks. Results also showed that the expression of ZmsHSP in maize was significantly up-regulated by dehydration. Transgenic Arabidopsis plants overexpressing ZmsHSP under the control of the CaMV 35S promoter had lower endogenous cytokinin content and showed more sensitivity to cytokinin during the germination and early seedling stage than wild-type plants, suggesting that ZmsHSP might has a function in cytokinin response in Zea mays. PMID:19821154

Cao, Zuping; Jia, Zhiwei; Liu, Yongjun; Wang, Meng; Zhao, Jinfeng; Zheng, Jun; Wang, Guoying

2010-02-01

109

Constitutively active Akt1 expression in mouse pancreas requires S6 kinase 1 for insulinoma formation  

PubMed Central

Factors that promote pancreatic ? cell growth and function are potential therapeutic targets for diabetes mellitus. In mice, genetic experiments suggest that signaling cascades initiated by insulin and IGFs positively regulate ? cell mass and insulin secretion. Akt and S6 kinase (S6K) family members are activated as part of these signaling cascades, but how the interplay between these proteins controls ? cell growth and function has not been determined. Here, we found that although transgenic mice overexpressing the constitutively active form of Akt1 under the rat insulin promoter (RIP-MyrAkt1 mice) had enlarged ? cells and high plasma insulin levels, leading to improved glucose tolerance, a substantial proportion of the mice developed insulinomas later in life, which caused decreased viability. This oncogenic transformation tightly correlated with nuclear exclusion of the tumor suppressor PTEN. To address the role of the mammalian target of rapamycin (mTOR) substrate S6K1 in the MyrAkt1-mediated phenotype, we crossed RIP-MyrAkt1 and S6K1-deficient mice. The resulting mice displayed reduced insulinemia and glycemia compared with RIP-MyrAkt1 mice due to a combined effect of improved insulin secretion and insulin sensitivity. Importantly, although the increase in ? cell size in RIP-MyrAkt1 mice was not affected by S6K1 deficiency, the hyperplastic transformation required S6K1. Our results therefore identify S6K1 as a critical element for MyrAkt1-induced tumor formation and suggest that it may represent a useful target for anticancer therapy downstream of mTOR.

Alliouachene, Samira; Tuttle, Robyn L.; Boumard, Stephanie; Lapointe, Thomas; Berissi, Sophie; Germain, Stephane; Jaubert, Francis; Tosh, David; Birnbaum, Morris J.; Pende, Mario

2008-01-01

110

Characterization of constitutive promoters for piggyBac transposon-mediated stable transgene expression in mesenchymal stem cells (MSCs).  

PubMed

Multipotent mesenchymal stem cells (MSCs) can undergo self-renewal and give rise to multi-lineages under given differentiation cues. It is frequently desirable to achieve a stable and high level of transgene expression in MSCs in order to elucidate possible molecular mechanisms through which MSC self-renewal and lineage commitment are regulated. Retroviral or lentiviral vector-mediated gene expression in MSCs usually decreases over time. Here, we choose to use the piggyBac transposon system and conduct a systematic comparison of six commonly-used constitutive promoters for their abilities to drive RFP or firefly luciferase expression in somatic HEK-293 cells and MSC iMEF cells. The analyzed promoters include three viral promoters (CMV, CMV-IVS, and SV40), one housekeeping gene promoter (UbC), and two composite promoters of viral and housekeeping gene promoters (hEFH and CAG-hEFH). CMV-derived promoters are shown to drive the highest transgene expression in HEK-293 cells, which is however significantly reduced in MSCs. Conversely, the composite promoter hEFH exhibits the highest transgene expression in MSCs whereas its promoter activity is modest in HEK-293 cells. The reduced transgene expression driven by CMV promoters in MSCs may be at least in part caused by DNA methylation, or to a lesser extent histone deacetlyation. However, the hEFH promoter is not significantly affected by these epigenetic modifications. Taken together, our results demonstrate that the hEFH composite promoter may be an ideal promoter to drive long-term and high level transgene expression using the piggyBac transposon vector in progenitor cells such as MSCs. PMID:24714676

Wen, Sheng; Zhang, Hongmei; Li, Yasha; Wang, Ning; Zhang, Wenwen; Yang, Ke; Wu, Ningning; Chen, Xian; Deng, Fang; Liao, Zhan; Zhang, Junhui; Zhang, Qian; Yan, Zhengjian; Liu, Wei; Zhang, Zhonglin; Ye, Jixing; Deng, Youlin; Zhou, Guolin; Luu, Hue H; Haydon, Rex C; Shi, Lewis L; He, Tong-Chuan; Wei, Guanghui

2014-01-01

111

Characterization of Constitutive Promoters for piggyBac Transposon-Mediated Stable Transgene Expression in Mesenchymal Stem Cells (MSCs)  

PubMed Central

Multipotent mesenchymal stem cells (MSCs) can undergo self-renewal and give rise to multi-lineages under given differentiation cues. It is frequently desirable to achieve a stable and high level of transgene expression in MSCs in order to elucidate possible molecular mechanisms through which MSC self-renewal and lineage commitment are regulated. Retroviral or lentiviral vector-mediated gene expression in MSCs usually decreases over time. Here, we choose to use the piggyBac transposon system and conduct a systematic comparison of six commonly-used constitutive promoters for their abilities to drive RFP or firefly luciferase expression in somatic HEK-293 cells and MSC iMEF cells. The analyzed promoters include three viral promoters (CMV, CMV-IVS, and SV40), one housekeeping gene promoter (UbC), and two composite promoters of viral and housekeeping gene promoters (hEFH and CAG-hEFH). CMV-derived promoters are shown to drive the highest transgene expression in HEK-293 cells, which is however significantly reduced in MSCs. Conversely, the composite promoter hEFH exhibits the highest transgene expression in MSCs whereas its promoter activity is modest in HEK-293 cells. The reduced transgene expression driven by CMV promoters in MSCs may be at least in part caused by DNA methylation, or to a lesser extent histone deacetlyation. However, the hEFH promoter is not significantly affected by these epigenetic modifications. Taken together, our results demonstrate that the hEFH composite promoter may be an ideal promoter to drive long-term and high level transgene expression using the piggyBac transposon vector in progenitor cells such as MSCs.

Wen, Sheng; Zhang, Hongmei; Li, Yasha; Wang, Ning; Zhang, Wenwen; Yang, Ke; Wu, Ningning; Chen, Xian; Deng, Fang; Liao, Zhan; Zhang, Junhui; Zhang, Qian; Yan, Zhengjian; Liu, Wei; Zhang, Zhonglin; Ye, Jixing; Deng, Youlin; Zhou, Guolin; Luu, Hue H.; Haydon, Rex C.; Shi, Lewis L.; He, Tong-Chuan; Wei, Guanghui

2014-01-01

112

A constitutively expressed 36 kDa exochitinase from Bacillus thuringiensis HD-1.  

PubMed

A 36 kDa chitinase was purified by ion exchange and gel filtration chromatography from the culture supernatant of Bacillus thuringiensis HD-1. The chitinase production was independent of the presence of chitin in the growth medium and was produced even in the presence of glucose. The purified chitinase was active at acidic pH, had an optimal activity at pH 6.5, and showed maximum activity at 65 degrees C. Of the various substrates, the enzyme catalyzed the hydrolysis of the disaccharide 4-MU(GlnAc)(2) most efficiently and was therefore classified as an exochitinase. The sequence of the tryptic peptides showed extensive homology with Bacillus cereus 36 kDa exochitinase. The 1083 bp open reading frame encoding 36 kDa chitinase was amplified with primers based on the gene sequence of B. cereus 36 kDa exochitinase. The deduced amino-acid sequence showed that the protein contained an N-terminal signal peptide and consisted of a single catalytic domain. The two conserved signature sequences characteristic of family 18 chitinases were mapped at positions 105-109 and 138-145 of Chi36. The recombinant chitinase was expressed in a catalytically active form in Escherichia coli in the vector pQE-32. The expressed 36 kDa chitinase potentiated the insecticidal effect of the vegetative insecticidal protein (Vip) when used against neonate larvae of Spodoptera litura. PMID:12893268

Arora, Naresh; Ahmad, Tarannum; Rajagopal, R; Bhatnagar, Raj K

2003-08-01

113

The contributions of normal variation and genetic background to mammalian gene expression  

PubMed Central

Background Qualitative and quantitative variability in gene expression represents the substrate for external conditions to exert selective pressures for natural selection. Current technologies allow for some forms of genetic variation, such as DNA mutations and polymorphisms, to be determined accurately on a comprehensive scale. Other components of variability, such as stochastic events in cellular transcriptional and translational processes, are less well characterized. Although potentially important, the relative contributions of genomic versus epigenetic and stochastic factors to variation in gene expression have not been quantified in mammalian species. Results In this study we compared microarray-based measures of hepatic transcript abundance levels within and between five different strains of Mus musculus. Within each strain 23% to 44% of all genes exhibited statistically significant differences in expression between genetically identical individuals (positive false discovery rate of 10%). Genes functionally associated with cell growth, cytokine activity, amine metabolism, and ubiquitination were enriched in this group. Genetic divergence between individuals of different strains also contributed to transcript abundance level differences, but to a lesser extent than intra-strain variation, with approximately 3% of all genes exhibiting inter-strain expression differences. Conclusion These results indicate that although DNA sequence fixes boundaries for gene expression variability, there remain considerable latitudes of expression within these genome-defined limits that have the potential to influence phenotypes. The extent of normal or expected natural variability in gene expression may provide an additional level of phenotypic opportunity for natural selection.

Pritchard, Colin; Coil, David; Hawley, Sarah; Hsu, Li; Nelson, Peter S

2006-01-01

114

Cre recombinase-dependent expression of a constitutively active mutant allele of the catalytic subunit of protein kinase A.  

PubMed

Using the cre-loxP recombination system, we generated a line of mice expressing a constitutively active catalytic subunit of Protein Kinase A (PKA) in a temporally and spatially regulated fashion. In the absence of cre recombinase the modified catalytic subunit allele is functionally silent, but after recombination the mutant allele is expressed, resulting in enhanced PKA effects at basal cAMP levels. Mice expressing the modified protein in hepatocytes using albumin-cre transgenics show defects in glucose homeostasis, glycogen storage, fructose 2,6-bisphosphate levels, and induction of glucokinase mRNA during feeding. Similar to animals lacking glucokinase in the liver (Postic et al.: J Biol Chem 274:305-315, 1999), these mice also have defects in glucose-stimulated insulin secretion, a hallmark of Type II diabetes. The widespread expression of PKA and the involvement of this kinase in a myriad of signaling pathways suggest that these animals will provide critical tools for the study of PKA function in vivo. PMID:16155866

Niswender, Colleen M; Willis, Brandon S; Wallen, Angela; Sweet, Ian R; Jetton, Thomas L; Thompson, Brian R; Wu, Chaodong; Lange, Alex J; McKnight, G Stanley

2005-11-01

115

Memory for facial expression is influenced by the background music playing during study  

PubMed Central

The effect of the emotional quality of study-phase background music on subsequent recall for happy and sad facial expressions was investigated. Undergraduates (N = 48) viewed a series of line drawings depicting a happy or sad child in a variety of environments that were each accompanied by happy or sad music. Although memory for faces was very accurate, emotionally incongruent background music biased subsequent memory for facial expressions, increasing the likelihood that happy faces were recalled as sad when sad music was previously heard, and that sad faces were recalled as happy when happy music was previously heard. Overall, the results indicated that when recalling a scene, the emotional tone is set by an integration of stimulus features from several modalities.

Woloszyn, Michael R.; Ewert, Laura

2012-01-01

116

Plenary Perspective: The complexity of constitutive and inducible gene expression in mononuclear phagocytes  

PubMed Central

Monocytes and macrophages differentiate from progenitor cells under the influence of colony-stimulating factors. Genome-scale data have enabled the identification of the set of genes that distinguishes macrophages from other cell types and the ways in which thousands of genes are regulated in response to pathogen challenge. Although there has been a focus on a small subset of lineage-enriched transcription factors, such as PU.1, more than one-half of the transcription factors in the genome can be expressed in macrophage lineage cells under some state of activation, and they interact in a complex network. The network architecture is conserved across species, but many of the target genes evolve rapidly and differ between mouse and human. The data and publication deluge related to macrophage biology require the development of new analytical tools and ways of presenting information in an accessible form. The website www.macrophages.com is a community website that partly fills this niche.

Hume, David A.

2012-01-01

117

Comparative Expression Profiling of Leishmania: Modulation in Gene Expression between Species and in Different Host Genetic Backgrounds  

PubMed Central

Background Genome sequencing of Leishmania species that give rise to a range of disease phenotypes in the host has revealed highly conserved gene content and synteny across the genus. Only a small number of genes are differentially distributed between the three species sequenced to date, L. major, L. infantum and L. braziliensis. It is not yet known how many of these genes are expressed in the disease-promoting intracellular amastigotes of these species or whether genes conserved between the species are differentially expressed in the host. Methods/Principal Findings We have used customised oligonucleotide microarrays to confirm that all of the differentially distributed genes identified by genome comparisons are expressed in intracellular amastigotes, with only a few of these subject to regulation at the RNA level. In the first large-scale study of gene expression in L. braziliensis, we show that only ?9% of the genes analysed are regulated in their RNA expression during the L. braziliensis life cycle, a figure consistent with that observed in other Leishmania species. Comparing amastigote gene expression profiles between species confirms the proposal that Leishmania transcriptomes undergo little regulation but also identifies conserved genes that are regulated differently between species in the host. We have also investigated whether host immune competence influences parasite gene expression, by comparing RNA expression profiles in L. major amastigotes derived from either wild-type (BALB/c) or immunologically compromised (Rag2?/? ?c?/?) mice. While parasite dissemination from the site of infection is enhanced in the Rag2?/? ?c?/? genetic background, parasite RNA expression profiles are unperturbed. Conclusion/Significance These findings support the hypothesis that Leishmania amastigotes are pre-adapted for intracellular survival and undergo little dynamic modulation of gene expression at the RNA level. Species-specific parasite factors contributing to virulence and pathogenicity in the host may be limited to the products of a small number of differentially distributed genes or the differential regulation of conserved genes, either of which are subject to translational and/or post-translational controls.

Depledge, Daniel P.; Evans, Krystal J.; Ivens, Alasdair C.; Aziz, Naveed; Maroof, Asher; Kaye, Paul M.; Smith, Deborah F.

2009-01-01

118

Constitutive and dark-induced expression of Solanum tuberosum phosphoenolpyruvate carboxylase enhances stomatal opening and photosynthetic performance of Arabidopsis thaliana.  

PubMed

The effect of constitutive and dark-induced expression of Solanum tuberosum phosphoenolpyruvate carboxylase (PEPC) on the opening state of stomata and photosynthetic performance in Arabidopsis thaliana plants was studied. Transcript accumulation analyses of the A. thaliana dark-induced (Din10 and Din6) and the Pisum sativum asparagine synthetase 2 promoters (Asn2) in transiently transformed tobacco leaves showed that Din10 promoter induced more DsRed accumulation in the dark compared to the other din genes. Overexpression of PEPC under the control of the constitutive enhanced CaMV 35S (p35SS) and dark-induced Din10 promoter in stably transformed A. thaliana plants increased the number of opened stomata in dark adapted leaves. Gas exchange measurements using A. thaliana plants transgenic for p35SS-PEPC and Din10-PEPC revealed a marked increase in stomatal conductance, transpiration, and dark respiration rates measured in the dark compared to wild-type plants. Moreover, measurement of CO(2) assimilation rates at different external CO(2) concentrations (C(a) ) and different light intensities shows an increase in the CO(2) assimilation rates in transgenic Arabidopsis lines compared to wild-type plants. This is considered as first step towards transferring the aspects of Crassulacean acid metabolism-like photosynthetic mechanism into C3 plants. PMID:21960014

Kebeish, Rashad; Niessen, Markus; Oksaksin, Mehtap; Blume, Christian; Peterhaensel, Christoph

2012-02-01

119

Construction and Evaluation of Plasmid Vectors Optimized for Constitutive and Regulated Gene Expression in Burkholderia cepacia Complex Isolates  

PubMed Central

Genetic studies with Burkholderia cepacia complex isolates are hampered by the limited availability of cloning vectors and by the inherent resistance of these isolates to the most common antibiotics used for genetic selection. Also, some of the promoters widely employed for gene expression in Escherichia coli are inefficient in B. cepacia. In this study, we have utilized the backbone of the vector pME6000, a derivative of the pBBR1 plasmid that was originally isolated from Bordetella bronchiseptica, to construct a set of vectors useful for gene expression in B. cepacia. These vectors contain either the constitutive promoter of the S7 ribosomal protein gene from Burkholderia sp. strain LB400 or the arabinose-inducible PBAD promoter from E. coli. Promoter sequences were placed immediately upstream of multiple cloning sites in combination with the minimal sequence of pME6000 required for plasmid maintenance and mobilization. The functionality of both vectors was assessed by cloning the enhanced green fluorescent protein gene (e-gfp) and determining the levels of enhanced green fluorescent protein expression and fluorescence emission for a variety of clinical and environmental isolates of the B. cepacia complex. We also demonstrate that B. cepacia carrying these constructs can readily be detected intracellularly by fluorescence microscopy following the infection of Acanthamoeba polyphaga.

Lefebre, Matthew D.; Valvano, Miguel A.

2002-01-01

120

Postnatal expression in hyaline cartilage of constitutively active human collagenase-3 (MMP-13) induces osteoarthritis in mice  

PubMed Central

It has been suggested that increased collagenase-3 (MMP-13) activity plays a pivotal role in the pathogenesis of osteoarthritis (OA). We have used tetracycline-regulated transcription in conjunction with a cartilage-specific promoter to target a constitutively active human MMP-13 to the hyaline cartilages and joints of transgenic mice. Postnatal expression of this transgene resulted in pathological changes in articular cartilage of the mouse joints similar to those observed in human OA. These included characteristic erosion of the articular cartilage associated with loss of proteoglycan and excessive cleavage of type II collagen by collagenase, as well as synovial hyperplasia. These results demonstrate that excessive MMP-13 activity can result in articular cartilage degradation and joint pathology of the kind observed in OA, suggesting that excessive activity of this proteinase can lead to this disease.

Neuhold, Lisa A.; Killar, Loran; Zhao, Weiguang; Sung, Mei-Li A.; Warner, Linda; Kulik, John; Turner, James; Wu, William; Billinghurst, C.; Meijers, T.; Poole, A. Robin; Babij, Philip; DeGennaro, Louis J.

2001-01-01

121

Myocardial expression of a constitutively active alpha 1B-adrenergic receptor in transgenic mice induces cardiac hypertrophy.  

PubMed Central

Transgenic mice were generated by using the alpha-myosin heavy chain promoter coupled to the coding sequence of a constitutively active mutant alpha 1B-adrenergic receptor (AR). These transgenic animals demonstrated cardiac-specific expression of this alpha 1-AR with resultant activation of phospholipase C as shown by increased myocardial diacylglycerol content. A phenotype consistent with cardiac hypertrophy developed in adult transgenic mice with increased heart/body weight ratios, myocyte cross-sectional areas, and ventricular atrial natriuretic factor mRNA levels relative to nontransgenic controls. These transgenic animals may provide insight into the biochemical triggers that induce hypertrophy in cardiac disease and serve as a convenient experimental model for studies of this condition. Images

Milano, C A; Dolber, P C; Rockman, H A; Bond, R A; Venable, M E; Allen, L F; Lefkowitz, R J

1994-01-01

122

Resistance to influenza virus infection of Mx transgenic mice expressing Mx protein under the control of two constitutive promoters.  

PubMed Central

Transgenic mice constitutively expressing in the brain the influenza virus resistance protein Mx1 controlled by the HMG (3-hydroxy-3-methylglutaryl coenzyme A reductase) promoter showed specific resistance against the neurotropic influenza A virus strain NWS. Control mice of the A2G strain express Mx1 protein in all organs, but only after induction by interferon type I upon or without viral infection. The extent of specific resistance in transgenic mice of the best-expressing line reached about two-thirds that of controls, most likely because of considerably less total-body Mx protein activity in the transgenic mice. Thus, the theoretical advantage in these mice of the continuous presence of Mx protein with early inhibitory potential to viral replication was apparently offset by restricted organ expression. Strong evidence that the Mx1 protein on its own is a specific anti-influenza A virus agent and that its efficiency in the experimental setting is independent of interferon actions could be derived from the treatment of experimental and control mice with anti-interferon antibodies at the time of virus tests. Whereas in A2G mice, Mx1 mRNA and Mx1 protein synthesis were abolished and viral resistance was markedly reduced or abolished, resistance in the transgenic mice persisted to almost the same degree. Transgenic mice generated with a mouse albumin/Mx1 cDNA construct showed liver-specific expression. However, in two expressing transgenic lines, Mx1 protein synthesis was suppressed after a few months. The mechanism of suppression could not be elucidated, but increasing methylation of the transgene's coding region was not the cause. It is possible that continuous Mx1 protein expression in the liver is less well tolerated than that in the brain. Whether this partial suppression and, with the HMG promoter, restricted organ expression are the organism's responses to interference of Mx1 with normal cellular activities such as nucleocytoplasmic transport of RNA and proteins cannot be determined until the molecular mechanisms of antiviral activity of Mx1 protein are understood. Images

Kolb, E; Laine, E; Strehler, D; Staeheli, P

1992-01-01

123

Metformin represses drug-induced expression of CYP2B6 by modulating the constitutive androstane receptor signaling.  

PubMed

Metformin is currently the most widely used drug for the treatment of type 2 diabetes. Mechanistically, metformin interacts with many protein kinases and transcription factors that alter the expression of numerous downstream target genes governing lipid metabolism, cell proliferation, and drug metabolism. The constitutive androstane receptor (CAR, NR1i3), a known xenobiotic sensor, has recently been recognized as a novel signaling molecule, in that its activation could be regulated by protein kinases in addition to the traditional ligand binding. We show that metformin could suppress drug-induced expression of CYP2B6 (a typical target gene of CAR) by modulating the phosphorylation status of CAR. In human hepatocytes, metformin robustly suppressed the expression of CYP2B6 induced by both indirect (phenobarbital) and direct CITCO [6-(4-chlorophenyl)imidazo[2,1-b]1,3thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime] activators of human CAR. Mechanistic investigation revealed that metformin specifically enhanced the phosphorylation of threonine-38 of CAR, which blocks CAR nuclear translocation and activation. Moreover, we showed that phosphorylation of CAR by metformin was primarily an AMP-activated protein kinase- and extracellular signal-regulated kinase 1/2-dependent event. Additional two-hybrid and coimmunoprecipitation assays demonstrated that metformin could also disrupt CITCO-mediated interaction between CAR and the steroid receptor coactivator 1 or the glucocorticoid receptor-interacting protein 1. Our results suggest that metformin is a potent repressor of drug-induced CYP2B6 expression through specific inhibition of human CAR activation. Thus, metformin may affect the metabolism and clearance of drugs that are CYP2B6 substrates. PMID:24252946

Yang, Hui; Garzel, Brandy; Heyward, Scott; Moeller, Timothy; Shapiro, Paul; Wang, Hongbing

2014-02-01

124

Expression of v-src in a murine T-cell hybridoma results in constitutive T-cell receptor phosphorylation and interleukin 2 production.  

PubMed Central

Ligand binding to the T-cell antigen receptor results in phosphatidylinositol hydrolysis and the resultant activation of protein kinase C, as well as the activation of a receptor-coupled protein-tyrosine kinase. As a model for tyrosine kinase activation in T cells, we used retroviral gene transfer to express the v-src oncogene in an antigen-specific murine T-cell hybridoma. Clones that expressed v-src mRNA demonstrated constitutive tyrosine phosphorylation of several cellular substrates, including the zeta chain of the T-cell receptor, and constitutive interleukin 2 production. Thus, expression of a constitutively active protein-tyrosine kinase such as pp60v-src appears to be sufficient to induce the expression of at least one gene critical to the process of T-cell activation. Images

O'Shea, J J; Ashwell, J D; Bailey, T L; Cross, S L; Samelson, L E; Klausner, R D

1991-01-01

125

Identification of centrarchid hepcidins and evidence that 17?-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)  

USGS Publications Warehouse

Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormone. Both hepcidins are predominately expressed in the liver of largemouth bass, similar to other fish and mammals. Experimental exposure of pond-raised largemouth bass to 17?-estradiol and/or the bacteria Edwardsiella ictaluri led to distinct changes in expression of hep-1 and hep-2. Estradiol reduced the constitutive expression of hep-1 in the liver. Bacterial exposure induced expression of hep-2, suggesting that hepcidin-2 may have an antimicrobial function, and this induction was abolished by estradiol. To our knowledge, this is the first report of the regulation of hepcidin expression by estradiol in either fish or mammals.

Robertson, L. S.; Iwanowicz, L. R.; Marranca, J. M.

2009-01-01

126

Compensatory increase in lipogenic gene expression in adipose tissue of transgenic mice expressing constitutively active AMP-activated protein kinase-alpha1 in liver.  

PubMed

We previously described a line of transgenic mice selectively expressing constitutively active AMPK-?1 under the control of liver-specific human apoE promoter with the hepatic control region sequence. In the short-term activation, the CA-AMPK-?1 transgenic mice at age 10-12weeks exhibited normal hepatic triglyceride content as compared to wild-type mice due to compensatory increase in mRNA expression of genes in the cholesterol and fatty acid synthesis pathways. But it was not known whether the lipogenic gene expression in white adipose tissue also changed. Here we characterized mRNA expression profile of main lipogenic genes in the cholesterol and fatty acid biosynthesis pathway in white adipose tissue. The data show that short-term chronic activation of AMPK in liver caused marked compensatory increase in lipogenic gene expression both in liver due to induction of Srebp-2 and in white adipose tissue due to upregulation of Srebp-1c. These results support the notion that in addition to its well-recognized function for fat storage adipose tissue can play an adaptive role in fatty acid synthesis when fatty acid synthesis is severely reduced in liver, the main lipogenic organ in mammals. PMID:21820413

Knowles, Christi; Liu, Zhi-Mei; Yang, Jian

2011-08-26

127

Effects of inactivation and constitutive expression of the unfolded- protein response pathway on protein production in the yeast Saccharomyces cerevisiae.  

PubMed

One strategy to obtain better yields of secreted proteins has been overexpression of single endoplasmic reticulum-resident foldases or chaperones. We report here that manipulation of the unfolded-protein response (UPR) pathway regulator, HAC1, affects production of both native and foreign proteins in the yeast Saccharomyces cerevisiae. The effects of HAC1 deletion and overexpression on the production of a native protein, invertase, and two foreign proteins, Bacillus amyloliquefaciens alpha-amylase and Trichoderma reesei endoglucanase EGI, were studied. Disruption of HAC1 caused decreases in the secretion of both alpha-amylase (70 to 75% reduction) and EGI (40 to 50% reduction) compared to the secretion by the parental strain. Constitutive overexpression of HAC1 caused a 70% increase in alpha-amylase secretion but had no effect on EGI secretion. The invertase levels were twofold higher in the strain overexpressing HAC1. Also, the effect of the active form of T. reesei hac1 was tested in S. cerevisiae. hac1 expression caused a 2.4-fold increase in the secretion of alpha-amylase in S. cerevisiae and also slight increases in invertase and total protein production. Overexpression of both S. cerevisiae HAC1 and T. reesei hac1 caused an increase in the expression of the known UPR target gene KAR2 at early time points during cultivation. PMID:12676684

Valkonen, Mari; Penttilä, Merja; Saloheimo, Markku

2003-04-01

128

Effects of Inactivation and Constitutive Expression of the Unfolded- Protein Response Pathway on Protein Production in the Yeast Saccharomyces cerevisiae  

PubMed Central

One strategy to obtain better yields of secreted proteins has been overexpression of single endoplasmic reticulum-resident foldases or chaperones. We report here that manipulation of the unfolded-protein response (UPR) pathway regulator, HAC1, affects production of both native and foreign proteins in the yeast Saccharomyces cerevisiae. The effects of HAC1 deletion and overexpression on the production of a native protein, invertase, and two foreign proteins, Bacillus amyloliquefaciens ?-amylase and Trichoderma reesei endoglucanase EGI, were studied. Disruption of HAC1 caused decreases in the secretion of both ?-amylase (70 to 75% reduction) and EGI (40 to 50% reduction) compared to the secretion by the parental strain. Constitutive overexpression of HAC1 caused a 70% increase in ?-amylase secretion but had no effect on EGI secretion. The invertase levels were twofold higher in the strain overexpressing HAC1. Also, the effect of the active form of T. reesei hac1 was tested in S. cerevisiae. hac1 expression caused a 2.4-fold increase in the secretion of ?-amylase in S. cerevisiae and also slight increases in invertase and total protein production. Overexpression of both S. cerevisiae HAC1 and T. reesei hac1 caused an increase in the expression of the known UPR target gene KAR2 at early time points during cultivation.

Valkonen, Mari; Penttila, Merja; Saloheimo, Markku

2003-01-01

129

The constitutive expression of Arabidopsis plasmodesmal-associated class 1 reversibly glycosylated polypeptide impairs plant development and virus spread  

PubMed Central

Arabidopsis class 1 reversibly glycosylated polypeptides (C1RGPs) were shown to be plasmodesmal-associated proteins. Transgenic tobacco (Nicotiana tabacum) plants constitutively expressing GFP tagged AtRGP2 under the control of the CaMV 35S promoter are stunted, have a rosette-like growth pattern, and in source leaves exhibit strong chlorosis, increased photoassimilate retention and starch accumulation that results in elevated leaf specific fresh and dry weights. Basal callose levels around plasmodesmata (Pd) of leaf epidermal cells in transgenic plants are higher than in WT. Such a phenotype is characteristic of virus-infected plants and some transgenic plants expressing Pd-associated viral movement proteins (MP). The local spread of Tobacco mosaic virus (TMV) is inhibited in AtRGP2:GFP transgenics compared to WT. Taken together these observations suggest that overexpression of the AtRGP2:GFP leads to a reduction in Pd permeability to photoassimilate, thus lowering the normal rate of translocation from source leaves to sink organs. Such a reduction may also inhibit the local cell-to-cell spread of viruses in transgenic plants. The observed reduction in Pd permeability could be due to a partial Pd occlusion caused either by the accumulation of AtRGP2:GFP fusion in Pd, and/or by constriction of Pd by the excessive callose accumulation.

Zavaliev, Raul; Sagi, Guy; Gera, Abed; Epel, Bernard L.

2010-01-01

130

Molecular characterization of the constitutive expression of the plasma platelet-activating factor acetylhydrolase gene in macrophages.  

PubMed Central

Plasma platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase that inactivates platelet-activating factor (PAF) and PAF-like lipids to generate products with little or no biological activity. The levels of circulating PAF-AH correlate with several disease syndromes. We previously reported that mediators of inflammation regulate the expression of the human PAF-AH gene at the transcriptional level. In the present paper, we characterize the constitutive expression of plasma PAF-AH using the mouse gene as a model system, and we report comparative results obtained using human and mouse promoter constructs. We first cloned, sequenced and analysed the promoter region of the murine plasma PAF-AH (mPAF-AH) gene and found that this gene lacks a canonical TATA box. We demonstrated that the cis -elements required for basal transcription are localized within the -316 to -68 bp region. In vitro band-shift and supershift assays showed that Sp1 and Sp3 transcription factors from RAW264.7 and J774A.1 macrophage nuclear extracts bound strongly to a distal GC-rich site within -278/-243 [specificity protein (Sp-A)] and to a proximal TC-rich motif within -150/-114 (Sp-B). In addition, we observed weak binding to a GA-rich site within -110/-82 (Sp-C). The regions containing Sp-B and Sp-C are highly conserved between the human and mouse genes. Forced expression of Sp1 or Sp3 in Sp-lacking Drosophila SL2 cells induced markedly the activity of the exogenous mPAF-AH promoter in a dose-dependent manner, and this induction was dependent on the presence of intact Sp-A and Sp-B. Interestingly, we found that the Sp1- and Sp3-associated DNA-binding activities increased during the maturation of primary human monocytes into macrophages in cell culture. These results demonstrate that Sp1 and Sp3 are key factors that contribute to the basal, constitutive transcription of the plasma PAF-AH gene in macrophages.

Wu, Xiaoqing; McIntyre, Thomas M; Zimmerman, Guy A; Prescott, Stephen M; Stafforini, Diana M

2003-01-01

131

Genetic Background Modulates Gene Expression Profile Induced by Skin Irradiation in Ptch1 Mice  

SciTech Connect

Purpose: Ptch1 germ-line mutations in mice predispose to radiation-induced basal cell carcinoma of the skin, with tumor incidence modulated by the genetic background. Here, we examined the possible mechanisms underlying skin response to radiation in F1 progeny of Ptch1{sup neo67/+} mice crossed with either skin tumor-susceptible (Car-S) or -resistant (Car-R) mice and X-irradiated (3 Gy) at 2 days of age or left untreated. Methods and Materials: We conducted a gene expression profile analysis in mRNA samples extracted from the skin of irradiated or control mice, using Affymetrix whole mouse genome expression array. Confirmation of the results was done using real-time reverse-transcriptase polymerase chain reaction. Results: Analysis of the gene expression profile of normal skin of F1 mice at 4 weeks of age revealed a similar basal profile in the nonirradiated mice, but alterations in levels of 71 transcripts in irradiated Ptch1{sup neo67/+} mice of the Car-R cross and modulation of only eight genes in irradiated Ptch1{sup neo67/+} mice of the Car-S cross. Conclusions: These results indicate that neonatal irradiation causes a persistent change in the gene expression profile of the skin. The tendency of mice genetically resistant to skin tumorigenesis to show a more complex pattern of transcriptional response to radiation than do genetically susceptible mice suggests a role for this response in genetic resistance to basal cell tumorigenesis.

Galvan, Antonella; Noci, Sara [Department of Experimental Oncology and Laboratories, Fondazione IRCCS Istituto Nazionale Tumori, Milan (Italy); Mancuso, Mariateresa; Pazzaglia, Simonetta; Saran, Anna [ENEA Laboratories, Rome (Italy); Dragani, Tommaso A. [Department of Experimental Oncology and Laboratories, Fondazione IRCCS Istituto Nazionale Tumori, Milan (Italy)], E-mail: tommaso.dragani@istitutotumori.mi.it

2008-12-01

132

Ortho-aminoazotoluene activates mouse constitutive androstane receptor (mCAR) and increases expression of mCAR target genes.  

PubMed

2'-3-dimethyl-4-aminoazobenzene (ortho-aminoazotoluene, OAT) is an azo dye and a rodent carcinogen that has been evaluated by the International Agency for Research on Cancer (IARC) as a possible (class 2B) human carcinogen. Its mechanism of action remains unclear. We examined the role of the xenobiotic receptor Constitutive Androstane Receptor (CAR, NR1I3) as a mediator of the effects of OAT. We found that OAT increases mouse CAR (mCAR) transactivation in a dose-dependent manner. This effect is specific because another closely related azo dye, 3'-methyl-4-dimethyl-aminoazobenzene (3'MeDAB), did not activate mCAR. Real-time Q-PCR analysis in wild-type C57BL/6 mice revealed that OAT induces the hepatic mRNA expression of the following CAR target genes: Cyp2b10, Cyp2c29, Cyp3a11, Ugt1a1, Mrp4, Mrp2 and c-Myc. CAR-null (Car(-/-)) mice showed no increased expression of these genes following OAT treatment, demonstrating that CAR is required for their OAT dependent induction. The OAT-induced CAR-dependent increase of Cyp2b10 and c-Myc expression was confirmed by Western blotting. Immunohistochemistry analysis of wild-type and Car(-/-) livers showed that OAT did not acutely induce hepatocyte proliferation, but at much later time points showed an unexpected CAR-dependent proliferative response. These studies demonstrate that mCAR is an OAT xenosensor, and indicate that at least some of the biological effects of this compound are mediated by this nuclear receptor. PMID:21672546

Smetanina, Mariya A; Pakharukova, Mariya Y; Kurinna, Svitlana M; Dong, Bingning; Hernandez, Juan P; Moore, David D; Merkulova, Tatyana I

2011-08-15

133

Constitutive expression of ectopic c-Myc delays glucocorticoid-evoked apoptosis of human leukemic CEM-C7 cells  

PubMed Central

Sensitivity to glucocorticoid (GC)-evoked apoptosis in lymphoid cell lines correlates closely with GC-mediated suppression of c-Myc expression. To establish a functional role for c-Myc in GC-mediated apoptosis, we have stably expressed MycER™, the human c-Myc protein fused to the modified ligand-binding domain of the murine estrogen receptor ?, in GC-sensitive CEM-C7-14 cells. In CEM-C7-14 cells, MycER™ constitutively imparts c-Myc functions. Cells expressing MycER™ (C7-MycER™) exhibited a marked reduction in cell death after 72 h in 100 nM dexamethasone (Dex), with 10 – 20-fold more viable cells when compared to the parental CEM-C7-14 clone. General GC responsiveness was not compromised, as evidenced by Dex-mediated suppression of endogenous c-Myc and cyclin D3, and induction of c-Jun and the glucocorticoid receptor. MycER™ also blunted Dex-mediated upregulation of p27kip1 and suppression of the Myc target p53. In comparison to parental CEM-C7-14 cells, Dex-evoked DNA strand breaks were negligible and caspase activation was delayed, but the extent of G1 cell cycle arrest was similar in C7-MycER™ cells. Myc-ER™ did not result in permanent, complete resistance to GC however, and the GC-treated cells eventually died, indicative of redundant or interactive mechanisms in the GC-evoked lytic response of lymphoid cells. Our results emphasize the importance of c-Myc suppression in GC-evoked apoptosis of CEM-C7-14 cells.

Medh, Rheem D; Wang, Aixia; Zhou, Feng; Thompson, E Brad

2009-01-01

134

Constitutive expression of growth regulated oncogene ( gro ) in human colon carcinoma cells with different metastatic potential and its role in regulating their metastatic phenotype  

Microsoft Academic Search

The purpose of this study was to examine the expression and functional significance of the growth-regulated oncogene (gro) family in human colon carcinoma growth and metastasis. We examined constitutive expression of CXCL1 (gro-?), CXCL2 (gro-?), CXCL3 (gro-?) and their receptor, CXCR2 in human colon carcinoma cells with different metastatic potentials. Non-metastatic and low metastatic cells expressed lower levels of CXCL1

Aihua Li; Michelle L. Varney; Rakesh K. Singh

2005-01-01

135

Human memory FOXP3+ Tregs secrete IL17 ex vivo and constitutively express the TH17 lineage-specific transcription factor RORgammat  

Microsoft Academic Search

Recent studies have suggested a close relationship between CD4+FOXP3+ regulatory T cells (Tregs) and proinflammatory IL-17-producing T helper cells (TH17) expressing the lineage-specific transcription factor RORgammat. We report here the unexpected finding that human memory Tregs secrete IL-17 ex vivo and constitutively express RORgammat. IL-17-secreting Tregs share some phenotypic and functional features with conventional TH17 cells, expressing high levels of

Maha Ayyoub; Florence Deknuydt; Isabelle Raimbaud; Christelle Dousset; Lucie Leveque; Gilles Bioley; Danila Valmori

2009-01-01

136

Destabilizing protein polymorphisms in the genetic background direct phenotypic expression of mutant SOD1 toxicity.  

PubMed

Genetic background exerts a strong modulatory effect on the toxicity of aggregation-prone proteins in conformational diseases. In addition to influencing the misfolding and aggregation behavior of the mutant proteins, polymorphisms in putative modifier genes may affect the molecular processes leading to the disease phenotype. Mutations in SOD1 in a subset of familial amyotrophic lateral sclerosis (ALS) cases confer dominant but clinically variable toxicity, thought to be mediated by misfolding and aggregation of mutant SOD1 protein. While the mechanism of toxicity remains unknown, both the nature of the SOD1 mutation and the genetic background in which it is expressed appear important. To address this, we established a Caenorhabditis elegans model to systematically examine the aggregation behavior and genetic interactions of mutant forms of SOD1. Expression of three structurally distinct SOD1 mutants in C. elegans muscle cells resulted in the appearance of heterogeneous populations of aggregates and was associated with only mild cellular dysfunction. However, introduction of destabilizing temperature-sensitive mutations into the genetic background strongly enhanced the toxicity of SOD1 mutants, resulting in exposure of several deleterious phenotypes at permissive conditions in a manner dependent on the specific SOD1 mutation. The nature of the observed phenotype was dependent on the temperature-sensitive mutation present, while its penetrance reflected the specific combination of temperature-sensitive and SOD1 mutations. Thus, the specific toxic phenotypes of conformational disease may not be simply due to misfolding/aggregation toxicity of the causative mutant proteins, but may be defined by their genetic interactions with cellular pathways harboring mildly destabilizing missense alleles. PMID:19266020

Gidalevitz, Tali; Krupinski, Thomas; Garcia, Susana; Morimoto, Richard I

2009-03-01

137

Constitutive expression of fluorescent protein by Aspergillus var. niger and Aspergillus carbonarius to monitor fungal colonization in maize plants.  

PubMed

Aspergillus niger and Aspergillus carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspergilli produce important mycotoxins, ochratoxins A, and the fumonisins. To facilitate the study of the black aspergilli-maize interactions with maize during the early stages of infections, we developed a method that used the enhanced yellow fluorescent protein (eYFP) and the monomeric red fluorescent protein (mRFP1) to transform A. niger and A. carbonarius, respectively. The results were constitutive expressions of the fluorescent genes that were stable in the cytoplasms of hyphae and conidia under natural environmental conditions. The hyphal in planta distribution in 21-day-old seedlings of maize were similar wild type and transformants of A. niger and A. carbonarius. The in planta studies indicated that both wild type and transformants internally colonized leaf, stem and root tissues of maize seedlings, without any visible disease symptoms. Yellow and red fluorescent strains were capable of invading epidermal cells of maize roots intercellularly within the first 3 days after inoculation, but intracellular hyphal growth was more evident after 7 days of inoculation. We also tested the capacity of fluorescent transformants to produce ochratoxin A and the results with A. carbonarius showed that this transgenic strain produced similar concentrations of this secondary metabolite. This is the first report on the in planta expression of fluorescent proteins that should be useful to study the internal plant colonization patterns of two ochratoxigenic species in the Aspergillus section Nigri. PMID:23899775

Palencia, Edwin Rene; Glenn, Anthony Elbie; Hinton, Dorothy Mae; Bacon, Charles Wilson

2013-09-01

138

Constitutive expression of a high-affinity sulfate transporter in Indian mustard affects metal tolerance and accumulation.  

PubMed

The Stylosanthes hamata SHST1 gene encodes a high-affinity sulfate transporter located in the plasma membrane. In this study the S. hamata SHST1 gene was constitutively expressed in Indian mustard [Brassica juncea (L.) Czern.] to investigate its importance for tolerance and accumulation of various oxyanions that may be transported by SHST1 and for cadmium, which is detoxified by sulfur-rich compounds. The transgenic SHST1 lines SHST1-12C and SHST1-4C were compared with wild-type Indian mustard for tolerance and accumulation of arsenate, chromate, tungstate, vanadate, and cadmium. As seedlings the SHST1 plants accumulated significantly more Cd and W, and somewhat more Cr and V. The SHST1 seedlings were less tolerant to Cd, Mo, and V compared to wild-type plants. Mature SHST1 plants were less tolerant than wild-type plants to Cd and Cr. SHST1 plants accumulated significantly more Cd, Cr, and W in their roots than wild-type plants. In their shoots they accumulated significantly more Cr and somewhat more V and W. Shoot Cd accumulation was significantly lower than in wild-type, and As levels were somewhat reduced. Compared to wild-type plants, sulfur accumulation was enhanced in roots of SHST1 plants but not in shoots. Together these results suggest that SHST1 can facilitate uptake of other oxyanions in addition to sulfate and that SHST1 mediates uptake in roots rather than root-to-shoot translocation. Since SHST1 overexpression led to enhanced accumulation of Cr, Cd, V, and W, this approach shows some potential for phytoremediation, especially if it could be combined with the expression of a gene that confers enhanced metal translocation or tolerance. PMID:16585614

Lindblom, Stormy Dawn; Abdel-Ghany, Salah; Hanson, Brady R; Hwang, Seongbin; Terry, Norman; Pilon-Smits, Elizabeth A H

2006-01-01

139

Constitutive androstane receptor activation by 2,4,6-triphenyldioxane-1,3 suppresses the expression of the gluconeogenic genes.  

PubMed

The constitutive androstane receptor (CAR, NR1I3) has a central role in detoxification processes, regulating the expression of a set of genes involved in metabolism. The dual role of NR1I3 as both a xenosensor and as a regulator of endogenous energy metabolism has recently been accepted. Here, we investigated the mechanism of transcriptional regulation of the glucose metabolising genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) by the cis isomer of 2,4,6-triphenyldioxane-1,3 (cisTPD), a highly effective NR1I3 activator in rat liver. It was shown that expression of the gluconeogenic genes PEPCK and G6Pase was repressed by cisTPD treatment under fasting conditions. Western-blot analysis demonstrated a clear reduction in the intensity of PEPCK and G6Pase immunobands from the livers of cisTPD-treated animals relative to bands from the livers of control animals. Chromatin immunoprecipitation assays demonstrated that cisTPD prevents the binding of FOXO1 to the insulin response sequences in the PEPCK and G6Pase gene promoters in rat liver. Moreover, cisTPD-activated NR1I3 inhibited NR2A1 (HNF-4) transactivation by competing with NR2A1 for binding to the NR2A1-binding element (DR1-site) in the gluconeogenic gene promoters. Thus, our results are consistent with the hypothesis that the cisTPD-activated NR1I3 participates in the regulation of the gluconeogenic genes PEPCK and G6Pase. PMID:22296760

Kachaylo, Ekaterina M; Yarushkin, Andrei A; Pustylnyak, Vladimir O

2012-03-15

140

Tobacco Transgenic Lines That Express Fenugreek Galactomannan Galactosyltransferase Constitutively Have Structurally Altered Galactomannans in Their Seed Endosperm Cell Walls1  

PubMed Central

Galactomannans [(1?6)-?-d-galactose (Gal)-substituted (1?4)-?-d-mannans] are major cell wall storage polysaccharides in the endosperms of some seeds, notably the legumes. Their biosynthesis in developing legume seeds involves the functional interaction of two membrane-bound glycosyltransferases, mannan synthase (MS) and galactomannan galactosyltransferase (GMGT). MS catalyzes the elongation of the mannan backbone, whereas GMGT action determines the distribution and amount of Gal substitution. Fenugreek (Trigonella foenum-graecum) forms a galactomannan with a very high degree of Gal substitution (Man/Gal = 1.1), and its GMGT has been characterized. We now report that the endosperm cell walls of the tobacco (Nicotiana tabacum) seed are rich in a galactomannan with a very low degree of Gal substitution (Man/Gal about 20) and that its depositional time course is closely correlated with membrane-bound MS and GMGT activities. Furthermore, we demonstrate that seeds from transgenic tobacco lines that express fenugreek GMGT constitutively in membrane-bound form have endosperm galactomannans with increased average degrees of Gal substitution (Man/Gal about 10 in T1 generation seeds and about 7.5 in T2 generation seeds). Membrane-bound enzyme systems from transgenic seed endosperms form galactomannans in vitro that are more highly Gal substituted than those formed by controls under identical conditions. To our knowledge, this is the first report of structural manipulation of a plant cell wall polysaccharide in transgenic plants via a biosynthetic membrane-bound glycosyltransferase.

Reid, J.S. Grant; Edwards, Mary E.; Dickson, Cathryn A.; Scott, Catherine; Gidley, Michael J.

2003-01-01

141

Constitutive S-adenosylmethionine decarboxylase gene expression increases drought tolerance through inhibition of reactive oxygen species accumulation in Arabidopsis.  

PubMed

Using subtractive hybridization analysis, the S-adenosylmethionine decarboxylase (SAMDC) gene from Capsicum annuum was isolated and renamed CaSAMDC. We generated independent transgenic Arabidopsis (Arabidopsis thaliana) lines constitutively expressing a 35S::CaSAMDC construct. Drought tolerance was significantly enhanced in Arabidopsis T4 transgenic homozygous lines as compared to wild-type (WT) plants. The levels of main polyamines (PAs) were more significantly increased in CaSAMDC-overexpressing transgenic plants after 6 h of drought stress as compared to stressed WT plants. Basal transcription of polyamine oxidase (PAO) showed at a much higher level in unstressed-transgenic plants as compared to unstressed WT plants. However, the difference in PAO transcription level between WT and transgenic plants was reduced after drought stress. Cellular accumulation of reactive oxygen species (ROS) was significantly reduced following drought stress in transgenic Arabidopsis plants as compared to WT plants. These results were in agreement with additional observations that stress-induced ROS generation, as determined by qRT-PCR analysis of NADPH oxidase (RbohD and RbohF), was significantly suppressed while transcription of ROS-detoxifying enzymes was notably elevated in transgenic lines in response to drought stress. Further, ROS-induced transcription of the metacaspase II gene was remarkably inhibited in transgenic plants. Collectively, these results suggest that drought stress tolerance due to reduction of ROS production and enhancement of ROS detoxification can be attributed to elevation of PAs. PMID:24477528

Wi, Soo Jin; Kim, Soo Jin; Kim, Woo Taek; Park, Ky Young

2014-05-01

142

Characterization and constitutive expression of a novel endo-1,4-?-D-xylanohydrolase from Aspergillus niger in Pichia pastoris.  

PubMed

A putative endo-1,4-?-D-xylanohydrolase gene xyl10 from Aspergillus niger, encoding a 308-residue mature xylanase belonging to glycosyl hydrolase family 10, was constitutively expressed in Pichia pastoris. The recombinant Xyl10 exhibited optimal activity at pH 5.0 and 60 °C with more than 50 % of the maximum activity from 40 to 70 °C. It retained more than 90 % of the original activity after incubation at 60 °C (pH 5.0) for 30 min and more than 74 % after incubation at pH 3.0-13.0 for 2 h (25 °C). The specific activity, K m and V max values for purified Xyl10 were, respectively, 3.2 × 10(3) U mg(-1), 3.6 mg ml(-1) and 5.4 × 10(3) ?mol min(-1 )mg(-1) towards beechwood xylan. The enzyme degraded xylan to a series of xylooligosaccharides and xylose. The recombinant enzyme with these properties has the potential for various industrial applications. PMID:23690032

Zheng, Jia; Guo, Ning; Wu, Lishuang; Tian, Jian; Zhou, Hongbo

2013-09-01

143

Constitutive migration and expression of three protease systems define in vitro the malignant phenotype of Ha-ras transformed rat liver epithelial cells.  

PubMed

The analysis of migration and gene expression patterns of normal and Ha-ras transformed rat liver epithelial cells revealed differences of diagnostic relevance. The normal cells are induced to migrate by EGF/TGF alpha and to express a set of secreted proteins including fibronectin, EIP-1/PAI-1, and MEP cathepsin L, which the malignant, constitutively migratory cells express constitutively. Only the transformed cells produce proteins of Mr 58/60,000 identified by peptide sequencing as stromelysin-1. The constitutively migratory cells produce invasive tumors and, after intravenous injection, metastatic colonies in the lung ('experimental metastasis'). The results demonstrate specific differences between the migration/invasion of normal and malignant epithelial cells, with PAI-1 as a general biochemical marker for migration/invasion. Constitutive migration and the described gene expression pattern are proposed as in vitro indicators of an invasive phenotype. EGF inducibility of the transformed cells to maximal migration and to an increased expression of stromelysin indicates susceptibility to a paracrine stimulation of malignancy. PMID:21544365

Zoller, J; Bauhofer, A; Crabb, J; Seebacher, T; Geimer, P; Schramke, H; Bade, E

1996-02-01

144

Constitutive expression of pathogenesis-related proteins PR-1, GRP, and PR-S in tobacco has no effect on virus infection.  

PubMed Central

Samsun NN tobacco cells were transformed with chimeric genes for pathogenesis-related (PR) proteins derived from genomic (PR-1a, GRP) or cDNA (PR-S) clones under the transcriptional control of the cauliflower mosaic virus 35S promoter. Regenerated plants were assayed by RNA and protein gel blotting, and plants showing high specific expression of the inserted genes were selected for self-pollination and seed formation. Inspection of second generation transformants showed that constitutive expression of PR-1a, GRP, and PR-S in tobacco in general does not have an effect on the phenotypic appearance of the plants or the expression of other endogenous PR genes. Furthermore, constitutive expression of the above genes does not affect the susceptibility of the plants to infection with tobacco mosaic virus or alfalfa mosaic virus.

Linthorst, H J; Meuwissen, R L; Kauffmann, S; Bol, J F

1989-01-01

145

Constitutive Expression of Soybean Ferritin cDNA Intransgenic Wheat and Rice Results in Increased Iron Levels in Vegetative Tissues but not in Seeds  

Microsoft Academic Search

We used particle bombardment to produce transgenic wheat and rice plants expressing recombinant soybean ferritin, a protein that can store large amounts of iron. The cDNA sequence was isolated from soybean by RT-PCR and expressed using the constitutive maize ubiquitin-1 promoter. The presence of ferritin mRNA and protein was confirmed in the vegetative tissues and seeds of transgenic wheat and

Georgia Drakakaki; Paul Christou; Eva Stöger

2000-01-01

146

Constitutive Expression of Tert in Thymocytes Leads to Increased Incidence and Dissemination of T-Cell Lymphoma in Lck-Tert Mice  

PubMed Central

Here we describe a new mouse model with constitutive expression of the catalytic subunit of telomerase (Tert) targeted to thymocytes and peripheral T cells (Lck-Tert mice). Two independent Lck-Tert mouse lines showed higher incidences of spontaneous T-cell lymphoma than the corresponding age-matched wild-type controls, indicating that constitutive expression of Tert promotes lymphoma. Interestingly, T-cell lymphomas in Lck-Tert mice were more disseminated than those in wild-type controls and affected both lymphoid and nonlymphoid tissues, while nonlymphoid tissues were never affected with lymphoma in age-matched wild-type controls. Importantly, these roles of Tert constitutive expression in promoting tumor progression and dissemination were independent of the role of telomerase in telomere length maintenance, since telomere length distributions on a single-cell basis were identical in Lck-Tert and wild-type thymocytes. Finally, Tert constitutive expression did not interfere with telomere capping in Lck-Tert primary thymocytes, although it resulted in greater chromosomal instability upon gamma irradiation in Lck-Tert primary lymphocytes than in controls, suggesting that Tert overexpression may interfere with the cellular response to DNA damage.

Canela, Andres; Martin-Caballero, Juan; Flores, Juana M.; Blasco, Maria A.

2004-01-01

147

Constitutive high-level expression of a codon-optimized ?-fructosidase gene from the hyperthermophile Thermotoga maritima in Pichia pastoris.  

PubMed

Enzymes for use in the sugar industry are preferred to be thermotolerant. In this study, a synthetic codon-optimized gene encoding a highly thermostable ?-fructosidase (BfrA, EC 3.2.1.26) from the bacterium Thermotoga maritima was expressed in the yeast Pichia pastoris. The gradual increase of the transgene dosage from one to four copies under the control of the constitutive glyceraldehyde 3-phosphate dehydrogenase promoter had an additive effect on BfrA yield without causing cell toxicity. Maximal values of cell biomass (115 g/l, dry weight) and overall invertase activity (241 U/ml) were reached at 72 h in fed-batch fermentations using cane sugar as the main carbon source for growth. Secretion driven by the Saccharomyces cerevisiae ?-factor signal peptide resulted in periplasmic retention (44 %) and extracellular release (56 %) of BfrA. The presence of N-linked oligosaccharides did not influence the optimal activity, thermal stability, kinetic properties, substrate specificity, and exo-type action mode of the yeast-secreted BfrA in comparison to the native unglycosylated enzyme. Complete inversion of cane sugar at initial concentration of 60 % (w/v) was achieved by periplasmic BfrA in undisrupted cells reacting at pH 5.5 and 70 °C, with average productivity of 4.4 g of substrate hydrolyzed per grams of biomass (wet weight) per hour. The high yield of fully active glycosylated BfrA here attained by recombinant P. pastoris in a low-cost fermentation process appears to be attractive for the large-scale production of this thermostable enzyme useful for the manufacture of inverted sugar syrup. PMID:22821437

Menéndez, Carmen; Martínez, Duniesky; Trujillo, Luis E; Mazola, Yuliet; González, Ernesto; Pérez, Enrique R; Hernández, Lázaro

2013-02-01

148

Up-regulation of phosphoinositide metabolism in tobacco cells constitutively expressing the human type I inositol polyphosphate 5-phosphatase  

NASA Technical Reports Server (NTRS)

To evaluate the impact of suppressing inositol 1,4,5-trisphosphate (InsP(3)) in plants, tobacco (Nicotiana tabacum) cells were transformed with the human type I inositol polyphosphate 5-phosphatase (InsP 5-ptase), an enzyme which specifically hydrolyzes InsP(3). The transgenic cell lines showed a 12- to 25-fold increase in InsP 5-ptase activity in vitro and a 60% to 80% reduction in basal InsP(3) compared with wild-type cells. Stimulation with Mas-7, a synthetic analog of the wasp venom peptide mastoparan, resulted in an approximately 2-fold increase in InsP(3) in both wild-type and transgenic cells. However, even with stimulation, InsP(3) levels in the transgenic cells did not reach wild-type basal values, suggesting that InsP(3) signaling is compromised. Analysis of whole-cell lipids indicated that phosphatidylinositol 4,5-bisphosphate (PtdInsP(2)), the lipid precursor of InsP(3), was greatly reduced in the transgenic cells. In vitro assays of enzymes involved in PtdInsP(2) metabolism showed that the activity of the PtdInsP(2)-hydrolyzing enzyme phospholipase C was not significantly altered in the transgenic cells. In contrast, the activity of the plasma membrane PtdInsP 5 kinase was increased by approximately 3-fold in the transgenic cells. In vivo labeling studies revealed a greater incorporation of (32)P into PtdInsP(2) in the transgenic cells compared with the wild type, indicating that the rate of PtdInsP(2) synthesis was increased. These studies show that the constitutive expression of the human type I InsP 5-ptase in tobacco cells leads to an up-regulation of the phosphoinositide pathway and highlight the importance of PtdInsP(2) synthesis as a regulatory step in this system.

Perera, Imara Y.; Love, John; Heilmann, Ingo; Thompson, William F.; Boss, Wendy F.; Brown, C. S. (Principal Investigator)

2002-01-01

149

Constitutive activation of signal transducer and activator of transcription 3 regulates expression of vascular endothelial growth factor in human meningioma differentiation  

PubMed Central

Purpose Janus tyrosine kinases (JAKs) and signal transducer and activator of transcription factors (STATs), especially STAT3, are constitutively activated in human cancers. The function of STAT3 in the pathogenesis of meningioma remains unknown. In this study, we investigated the role of JAK1/STAT3 regulating vascular endothelial growth factor (VEGF) expression in the occurrence and progression of human meningioma. Methods We detected the expression of JAK1, p-JAK1, STAT3, p-STAT3, and VEGF in human meningioma and normal dura tissues by RT–PCR, Western blot analysis, and immunohistochemistry. Results JAK1, p-JAK1, STAT3, p-STAT3, and VEGF showed high expression in grade I and grade II meningioma. The level of STAT3 activation was associated with VEGF expression; all meningioma tumors that expressed p-STAT3 also expressed VEGF. Both frequency of positivity and expression were enhanced with increasing tumor grade; high frequencies and levels were found in grade II tumors, with no expression detected in normal dura tissues (P < 0.05). Conclusions VEGF is directly regulated by constitutive STAT3 activity and associated with meningioma differentiation. STAT3 has an important role in the occurrence and development of human meningioma by regulating VEGF expression.

Zhang, Mao Xiu; Zhao, Xu; Wang, Zhi Gang

2010-01-01

150

Constitution Daily  

NSDL National Science Digital Library

Everyone could use a bit of the Constitution added to their daily lives, and this website more than delivers on its promise to deliver "smart conversation about the Constitution". Constitution Daily is an experimental blog edited by the National Constitution Center (NCC) in Philadelphia, and commentary here can include conversations about student privacy rights, the Second Amendment, and the activities of Congress. Visitors can click on the "Issues" section to dive into topic areas that include civility and privacy. After looking at each topic area, visitors can look at an interactive timeline that arranges comments, posts, and discussion on the subject. The site also contains some nice polls, and information about upcoming events at the NCC.

151

Valsartan ameliorates the constitutive adipokine expression pattern in mature adipocytes: a role for inverse agonism of the angiotensin II type 1 receptor in obesity.  

PubMed

Angiotensin (Ang) II receptor blockers (ARBs) alleviate obesity-related insulin resistance, which suggests an important role for the Ang II type 1 receptor (AT1R) in the regulation of adipocytokines. Therefore, we treated mature 3T3-L1 adipocytes with 50??mol?l(-1) of valsartan, a selective AT1R blocker without direct agonism to peroxisome proliferator-activated receptor (PPAR)-?. In the absence of effective concentrations of Ang II, unstimulated mature adipocytes expressed and secreted high levels of interleukin (IL)-6. This constitutive proinflammatory activity was attenuated by the suppression of extracellular signal-regulated kinase phosphorylation by valsartan but was unaffected by the Ang II type 2 receptor blocker PD123319. COS7 cells co-transfected with AT1R and IL-6, which expressed NF-?B but lacked PPAR-?, showed no constitutive but substantial ligand-dependent IL-6 reporter activity, which was counteracted by valsartan. Valsartan preserved cytosolic I?B-? and subsequently reduced nuclear NF-?B1 protein expression in mature adipocytes. Interestingly, valsartan did not increase PPAR-? messenger RNA expression per se but enhanced the transcriptional activity of PPAR-? in mature adipocytes; this enhancement was accompanied by upregulation of the PPAR coactivator (PGC)-1?. Moreover, T0090907, a PPAR-? inhibitor, increased IL-6 expression, and this increase was attenuated by valsartan. Indeed, addition of valsartan without direct PPAR-? agonism increased adiponectin production in mature adipocytes. Together, the findings indicate that valsartan blocks the constitutive AT1R activity involving the NF-?B pathway that limits PPAR-? activity in mature adipocytes. Thus, inverse agonism of AT1R attenuates the spontaneous proinflammatory response and enhances the constitutive insulin-sensitizing activities of mature adipocytes, which may underlie the beneficial metabolic impacts of ARBs. PMID:24599011

Hasan, Arif U; Ohmori, Koji; Hashimoto, Takeshi; Kamitori, Kazuyo; Yamaguchi, Fuminori; Ishihara, Yasuhiro; Ishihara, Naoko; Noma, Takahisa; Tokuda, Masaaki; Kohno, Masakazu

2014-07-01

152

Construction and properties of a cell line constitutively expressing the herpes simplex virus glycoprotein B dependent on functional alpha 4 protein synthesis.  

PubMed Central

We report the construction of a cell line constitutively expressing the glycoprotein B (gB) of herpes simplex virus (HSV) 1. The cell line was constructed in two steps. In the first, a baby hamster kidney cell line was transfected with the DNA of a plasmid containing the neomycin phosphotransferase gene that confers resistance to the antibiotic G418 and the gene specifying a temperature-sensitive (ts-) alpha 4 protein of HSV-1, the major viral regulatory protein. A clonal cell line, alpha 4/c113, selected for resistance to the antibiotic G418, expressed high levels of alpha 4 protein constitutively. Superinfection of these cells with HSV-2 resulted in twofold induction of the resident HSV-1 alpha 4 gene. In the second step, alpha 4/c113 cells were transfected with the DNA of a plasmid carrying the gB gene and the mouse methotrexate resistance dihydrofolate reductase gene. A clonal cell line, alpha 4/c113/gB, selected for methotrexate resistance expressed gB constitutively. Expression of both gB and alpha 4 continued unabated for at least 32 serial passages. Cells passaged serially in medium containing both methotrexate and G418 after passage 10 contained a higher copy number of the alpha 4 gene and produced larger amounts of both gB and alpha 4 proteins than did cells maintained in medium containing methotrexate alone. Expression of gB was dependent on the presence of functional alpha 4 protein inasmuch as expression of gB ceased on shift up to nonpermissive temperatures, when shifted to permissive temperatures, the cell line reinitiated expression of gB after a delay commensurate with the length of incubation at the nonpermissive temperature, and the cell-resident HSV-1 gB gene was expressed at the nonpermissive temperature in cells infected with a recombinant expressing a ts+ alpha 4 protein and an HSV-2 gB. The properties of the alpha 4/c113 cell line suggest that it may express other viral genes induced by alpha 4 protein constitutively, provided that the product is not toxic to the cells. Images

Arsenakis, M; Hubenthal-Voss, J; Campadelli-Fiume, G; Pereira, L; Roizman, B

1986-01-01

153

Constitutively active erythropoietin receptor expression in breast cancer cells promotes cellular proliferation and migration through a MAP-kinase dependent pathway  

SciTech Connect

The role of erythropoietin receptor (EpoR) expression in tumor cells and the potential of EpoR-mediated signaling to contribute to cellular proliferation and invasiveness require further characterization. To determine whether EpoR expression and activation in tumor cells modulates intracellular signal transduction to promote cellular proliferation and migration, we employed a novel experimental model using human breast cancer cells engineered to stably express a constitutively active EpoR-R129C variant. EpoR-R129C expression resulted in increased cellular proliferation and migration of breast cancer cells and these effects were associated with significantly increased Epo-induced phosphorylation of ERK1/2, AKT and c-Jun-NH2-kinase (SAPK/JNK) proteins. Expression of the constitutively active EpoR-R129C receptor promoted the proliferation and migration of breast cancer cells via activation of ERK- and SAPK/JNK-dependent signaling pathways, respectively. These findings suggest that EpoR over-expression and activation in breast cancer cells has the potential to contribute to tumor progression by promoting the proliferation and invasiveness of the neoplastic cells.

Fu Ping; Jiang Xiaohong [Department of Medicine, Hematology-Medical Oncology, Duke University Medical Center, DUMC Box 3912, Durham, NC 27710 (United States); Arcasoy, Murat O. [Department of Medicine, Hematology-Medical Oncology, Duke University Medical Center, DUMC Box 3912, Durham, NC 27710 (United States)], E-mail: arcas001@mc.duke.edu

2009-02-13

154

STAT3 is constitutively activated and supports cell survival in association with survivin expression in gastric cancer cells  

Microsoft Academic Search

Signal transduction and activator of transcription 3(STAT3) signaling is constitutively activated in various tumors, and is involved in cell survival and proliferation during oncogenesis. There are few reports, however, on the role of STAT3 signaling in gastric cancer. The aim of the present study was to clarify the role of STAT3 signaling in apoptosis and cellular proliferation in gastric cancer.

Naoki Kanda; Hiroshi Seno; Yoshitaka Konda; Hiroyuki Marusawa; Masashi Kanai; Toshio Nakajima; Tomoko Kawashima; Apichart Nanakin; Tateo Sawabu; Yoshito Uenoyama; Akira Sekikawa; Mayumi Kawada; Katsumasa Suzuki; Takahisa Kayahara; Hirokazu Fukui; Mitsutaka Sawada; Tsutomu Chiba; H Seno

2004-01-01

155

Constitution Annotated  

NSDL National Science Digital Library

What exactly does the United States Constitution mean? It is subject, of course, to ongoing meditation, debate, argument, and interpretation. This useful site provides one lens of interpretation of the Constitution, based primarily on Supreme Court case law and legal analysis. Visitors can look over each section of the Constitution individually, including all of the articles and amendments. Additionally, the site contains a complete table of Supreme Court cases, along with those cases that have been overruled as well as proposed amendments that have not been ratified. Additionally, the site contains a gallery of significant primary source documents from American history. Interested users should not forget to download the helpful app that is also included here.

2013-06-26

156

Constitutive and Regulated Membrane Expression of Aquaporin 1 and Aquaporin 2 Water Channels in Stably Transfected LLC-PK_1 Epithelial Cells  

Microsoft Academic Search

The aquaporins (AQPs) are a family of homologous water-channel proteins that can be inserted into epithelial cell plasma membranes either constitutively (AQP1) or by regulated exocytosis following vasopressin stimulation (AQP2). LLC-PK_1 porcine renal epithelial cells were stably transfected with cDNA encoding AQP2 (tagged with a C-terminal c-Myc epitope) or rat kidney AQP1 cDNA in an expression vector containing a cytomegalovirus

Toshiya Katsura; Jean-Marc Verbavatz; Javier Farinas; Tonghui Ma; Dennis A. Ausiello; A. S. Verkman; Dennis Brown

1995-01-01

157

Constitutive expression of a fungal glucose oxidase gene in transgenic tobacco confers chilling tolerance through the activation of antioxidative defence system  

Microsoft Academic Search

Scientific evidences in the literature have shown that plants treated exogenously with micromole concentration of hydrogen\\u000a peroxide (H2O2) acquire abiotic stress tolerance potential, without substantial disturbances in the endogenous H2O2 pool. In this study, we enhanced the endogenous H2O2 content of tobacco (Nicotiana tabaccum L. cv. SR1) plants by the constitutive expression of a glucose oxidase (GO; EC 1.1.3.4) gene

Subbiyan Maruthasalam; Yi Lun Liu; Ching Mei Sun; Pei Ying Chen; Chih Wen Yu; Pei Fang Lee; Chin Ho Lin

2010-01-01

158

Targeted Knockout of Cyp1a1 Gene Does Not Alter Hepatic Constitutive Expression of Other Genes in the Mouse [ Ah] Battery  

Microsoft Academic Search

Using the Cre-lox system, we have generated a cytochrome P450 1A1 Cyp1a1(?\\/?) knockout mouse by deletion of the translated portions of the Cyp1a1 gene. These mice are viable and demonstrate no obvious phenotype, compared with wild-type littermates. As a first step toward characterizing genes that might be expected to compensate for loss of CYP1A1, constitutive expression of [Ah] gene battery

Timothy P. Dalton; Matthew Z. Dieter; Robin S. Matlib; Nicole L. Childs; Howard G. Shertzer; Mary Beth Genter; Daniel W. Nebert

2000-01-01

159

Constitutive systemic expression of IL1Ra or soluble TNF receptor by genetically modified hematopoietic cells suppresses LPS induction of IL6 and IL10  

Microsoft Academic Search

We have been developing both local and systemic gene therapy approaches to treat inflammatory and autoimmune diseases. To determine if systemic, constitutive expression of biologically active anti-inflammatory agents is therapeutic and\\/or has associated toxicity, mouse hematopoietic stem cells were infected with retroviral vectors carrying the genes for human IL-1 receptor antagonist (IL-1Ra), human soluble TNF receptor p75 (sTNFR), or the

LA Doughty; KD Patrene; CH Evans; SS Boggs; PD Robbins

1997-01-01

160

Constitutive expression and localization of cytochrome P-450 1A1 in rat and human brain: presence of a splice variant form in human brain1  

Microsoft Academic Search

Cytochrome P-450 function as mono-oxygenases and meta- bolize xenobiotics. CYP1A1, a cytochrome P-450 enzyme, bioactivates polycyclic aromatic hydrocarbons to reactive metabolite(s) that bind to DNA and initiate carcinogenesis. Northern and immunoblot analyses revealed constitutive expression of Cyp1a1 and CYP1A1 in rat and human brain, respectively. CYP1A1 mRNA and protein were localized pre- dominantly in neurons of cerebral cortex, Purkinje and

Shankar J. Chinta; Reddy P. Kommaddi; Cheri M. Turman; Henry W. Strobel; Vijayalakshmi Ravindranath

2005-01-01

161

Constitutive Expression of Human Ribosomal Protein L7 Arrests the Cell Cycle in G 1and Induces Apoptosis in Jurkat T-Lymphoma Cells  

Microsoft Academic Search

Protein L7 is involved in translational control in eucaryotic cells as indicated by its association with ribosomes, its capability to inhibit specifically the cell-free translation of distinct mRNAs, and its interference with the synthesis of two major nucleus-associated proteins in L7 cDNA-transfected Jurkat T-lymphoma cells [F. Neumannet al.(1995)Nucleic Acids Res.23, 195]. In this report we show that the constitutive expression

Frank Neumann; Ulrich Krawinkel

1997-01-01

162

Bone-marrow derived hematopoietic stem\\/progenitor cells express multiple isoforms of NADPH oxidase and produce constitutively reactive oxygen species  

Microsoft Academic Search

Consolidated evidence highlights the importance of redox signalling in poising the balance between self-renewal and differentiation in adult stem cells. The present study shows that human hematopoietic stem\\/progenitor cells (HSCs) constitutively generate low levels of hydrogen peroxide whose production is inhibited by DPI, apocynin, catalase, and LY294002 and scarcely stimulated by PMA. Moreover, it is shown that HSCs express at

Claudia Piccoli; Annamaria D’Aprile; Maria Ripoli; Rosella Scrima; Lucia Lecce; Domenico Boffoli; Antonio Tabilio; Nazzareno Capitanio

2007-01-01

163

Constitutive expression of a cowpea trypsin inhibitor gene, CpTi , in transgenic rice plants confers resistance to two major rice insect pests  

Microsoft Academic Search

The gene encoding a cowpea trypsin inhibitor (CpTI), which confers insect resistance in trangenic tobacco, was introduced into rice. Expression of the CpTi gene driven by the constitutively active promoter of the rice actin 1 gene (Act1) leads to high-level accumulation of the CpTI protein in transgenic rice plants. Protein extracts from transgenic rice plants exhibit a strong inhibitory activity

Deping Xu; Qingzhong Xue; David McElroy; Yogesh Mawal; Vaughan A. Hilder; Ray Wu

1996-01-01

164

Constitutive IDO expression in human cancer is sustained by an autocrine signaling loop involving IL-6, STAT3 and the AHR  

PubMed Central

Indoleamine-2,3-dioxygenase (IDO) inhibitors have entered clinical trials based on their ability to restore anti-tumor immunity in preclinical studies. However, the mechanisms leading to constitutive expression of IDO in human tumors are largely unknown. Here we analyzed the pathways mediating constitutive IDO expression in human cancer. IDO-positive tumor cells and tissues showed basal phosphorylation and acetylation of STAT3 as evidenced by western blotting and immunoprecipitation. Inhibition of IL-6 or STAT3 using siRNA and/or pharmacological inhibitors reduced IDO mRNA and protein expression as well as kynurenine formation. In turn, IDO enzymatic activity activated the AHR as shown by the induction of AHR target genes. IDO-mediated AHR activation induced IL-6 expression, while inhibition or knockdown of the AHR reduced IL-6 expression. IDO activity thus sustains its own expression via an autocrine AHR–IL-6–STAT3 signaling loop. Inhibition of the AHR–IL-6–STAT3 signaling loop restored T-cell proliferation in mixed leukocyte reactions performed in the presence of IDO-expressing human cancer cells. Identification of the IDO-AHR-IL-6-STAT3 signaling loop maintaining IDO expression in human cancers reveals novel therapeutic targets for the inhibition of this core pathway promoting immunosuppression of human cancers. The relevance of the IDO-AHR-IL-6-STAT3 transcriptional circuit is underscored by the finding that high expression of its members IDO, STAT3 and the AHR target gene CYP1B1 is associated with reduced relapse-free survival in lung cancer patients.

Sahm, Felix; Rauschenbach, Katharina J.; Trump, Saskia; Winter, Marcus; Ott, Martina; Ochs, Katharina; Lutz, Christian; Liu, Xiangdong; Anastasov, Natasa; Lehmann, Irina; Hofer, Thomas; von Deimling, Andreas; Wick, Wolfgang; Platten, Michael

2014-01-01

165

Analysis of mouse keratin 6a regulatory sequences in transgenic mice reveals constitutive, tissue-specific expression by a keratin 6a minigene.  

PubMed

The analysis of keratin 6 expression is complicated by the presence of multiple isoforms that are expressed constitutively in a number of internal stratified epithelia, in palmoplantar epidermis, and in the companion cell layer of the hair follicle. In addition, keratin 6 expression is inducible in interfollicular epidermis and the outer root sheath of the follicle, in response to wounding stimuli, phorbol esters, or retinoic acid. In order to establish the critical regions involved in the regulation of keratin 6a (the dominant isoform in mice), we generated transgenic mice with two different-sized mouse keratin 6a constructs containing either 1.3 kb or 0.12 kb of 5' flanking sequence linked to the lacZ reporter gene. Both constructs also contained the first intron and the 3' flanking sequence of mouse keratin 6a. Ectopic expression of either transgene was not observed. Double-label immunofluorescence analyses demonstrated expression of the reporter gene in keratin 6 expressing tissues, including the hair follicle, tongue, footpad, and nail bed, showing that both transgenes retained keratinocyte-specific expression. Quantitative analysis of beta-galactosidase activity verified that both the 1.3 and 0.12 kb keratin 6a promoter constructs produced similar levels of the reporter. Notably, both constructs were constitutively expressed in the outer root sheath and interfollicular epidermis in the absence of any activating stimulus, suggesting that they lack the regulatory elements that normally silence transcription in these cells. This study has revealed that a keratin 6a minigene contains critical cis elements that mediate tissue-specific expression and that the elements regulating keratin 6 induction lie distal to the 1.3 kb promoter region. PMID:11069616

Mahony, D; Karunaratne, S; Cam, G; Rothnagel, J A

2000-11-01

166

Constitutional Conservatism  

ERIC Educational Resources Information Center

After their dismal performance in election 2008, conservatives are taking stock. As they examine the causes that have driven them into the political wilderness and as they explore paths out, they should also take heart. After all, election 2008 shows that America's constitutional order is working as designed. Indeed, while sorting out their errors…

Berkowitz, Peter

2009-01-01

167

Ortho-aminoazotoluene activates mouse constitutive androstane receptor (mCAR) and increases expression of mCAR target genes  

Microsoft Academic Search

2?-3-dimethyl-4-aminoazobenzene (ortho-aminoazotoluene, OAT) is an azo dye and a rodent carcinogen that has been evaluated by the International Agency for Research on Cancer (IARC) as a possible (class 2B) human carcinogen. Its mechanism of action remains unclear. We examined the role of the xenobiotic receptor Constitutive Androstane Receptor (CAR, NR1I3) as a mediator of the effects of OAT. We found

Mariya A. Smetanina; Mariya Y. Pakharukova; Svitlana M. Kurinna; Bingning Dong; Juan P. Hernandez; David D. Moore; Tatyana I. Merkulova

2011-01-01

168

Sorting of neutrophil-specific granule protein human cathelicidin, hCAP-18, when constitutively expressed in myeloid cells  

Microsoft Academic Search

Neutrophil granulocytes carry storage organelles, e.g., azurophil and specific granules. Poorly understood are the mechanisms for re- trieval from constitutive secretion followed by sort- ing for storage. Therefore, we asked whether the specific granule protein human cathelicidin (hCAP- 18) could be sorted for storage in other granules when the biosynthetic window is widened to allow this. We observed that hCAP-18

Elinor Bulow; Niklas Bengtsson; Jero Calafat; Urban Gullberg; Inge Olsson

169

Sex Differences in the Constitutive Gene Expression of Sulfotransferases and UDP-glucuronosyltransferases in the Pig Liver: Androgen-mediated Regulation.  

PubMed

  Using two breeds (Meishan and Landrace) of pigs and their crossbred offspring (ML, Meishan × Landrace; LM, Landrace × Meishan), of which males have genetically different serum androgen levels, we examined whether or not serum androgen plays a crucial role in the constitutive gene expression of hepatic sulfotransferases (SULTs) and UDP-glucuronosyltransferases (UGTs). Real-time RT-PCR analyses showed that in Meishan, ML, and LM pigs, SULT1A1 and SULT2A1 mRNA levels were lower in males having high levels of serum androgen (>38 ng/ml) than in females, whereas those of UGT1A1, UGT1A6, and UGT2B31 were just the opposite. In Landrace pigs having low levels of serum androgen (<22 ng/ml), no such sex differences in expression levels were observed. Moreover, castration of male Meishan pigs altered the gene expression patterns of SULTs and UGTs to female levels. Testosterone-treatment to the castrated males and intact females of either pig breed resulted in decreased SULT1A1 and SULT2A1 and increased UGT1A1, UGT1A6, and UGT2B31 mRNA levels. These findings demonstrate that androgen is one of the physiological factors that determine sexual dimorphism on the constitutive gene expression of SULTs and UGTs in the pig liver. PMID:24172717

Kojima, Misaki; Degawa, Masakuni

2014-04-25

170

Constitutive Gs activation using a single-construct tetracycline-inducible expression system in embryonic stem cells and mice  

PubMed Central

Introduction The controlled expression of many genes, including G-protein coupled receptors (GPCRs), is important for delineating gene functions in complex model systems. Binary systems for inducible regulation of transgene expression are widely used in mice. One system is the tTA/TRE expression system, composed of a tetracycline-dependent DNA binding factor and a separate tetracycline operon. However, the requirement for two separate transgenes (one for each tTA or TRE component) makes this system less amenable to models requiring directed cell targeting, increases the risk of multiple transgene integration sites, and requires extensive screening for appropriately-functioning clones. Methods We developed a single, polycistronic tetracycline-inducible expression platform to control the expression of multiple cistrons in mammalian cells. This platform has three basic constructs: regulator, responder, and destination vectors. The modular platform is compatible with both the TetOff (tTA) and TetOn (rtTA) systems. The modular Gateway recombineering-compatible components facilitate rapidly generating vectors to genetically modify mammalian cells. We apply this system to use the elongation factor 1? (EF1?) promoter to drive doxycycline-regulated expression of both the fluorescent marker mCherry and an engineered Gs-coupled GPCR "Rs1" separated by a 2A ribosomal skip site. Results We show that our combined expression construct drives expression of both the mCherry and Rs1 transgenes in a doxycycline-dependent manner. We successfully target the expression construct into the Rosa26 locus of mouse embryonic stem (ES) cells. Rs1 expression in mouse ES cells increases cAMP accumulation via both basal and ligand-induced Gs mechanisms and is associated with increased embryoid body size. Heterozygous mice carrying the Rs1 expression construct showed normal growth and weight, and developed small increases in bone formation that could be observed in the calvaria. Conclusions Our results demonstrate the feasibility of a single-vector strategy that combines both the tTA and TRE tetracycline-regulated components for use in cells and mouse models. Although the EF1? promoter is useful for driving expression in pluripotent cells, a single copy of the EF1? promoter did not drive high levels of mCherry and Rs1 expression in the differentiated tissues of adult mice. These findings indicate that promoter selection is an important factor when developing transgene expression models.

2011-01-01

171

Cis- and trans-acting elements required for constitutive and cytokine-regulated expression of the mouse complement C3 gene.  

PubMed Central

The third component of complement (C3) is an important mediator of inflammation. Murine and human genomic cosmid clones were isolated, characterized and sequenced 5' to the complement C3 gene transcriptional initiation sites to determine cis elements that participate in constitutive and regulated C3 gene expression. The murine and human 5' flanking regions are 51% identical overall, with positions -36 to -1 and -146 to -68 showing 80% identity. Four TATA boxes were identified upstream of the murine transcriptional initiation site, but deletion and transfection analysis using reporter gene constructs in HepG2 cells indicated that only the TATA element at position -30, together with sequences -395 to -111, are essential for constitutive expression of murine C3 in hepatocytes. Deletion analysis also suggested that sequences between -1457 and -800 contain regulatory elements that are involved in suppressing basal expression. Sequences between -90 to -41 confer both enhancer activity and interleukin-1/-6 (IL-1/IL-6)-responsiveness. Mutation analyses showed that both sequences between -88 and -83 and -77 to -72 are essential for enhancer activity and responsiveness to IL-1, but only sequences between -88 and -83 are necessary for IL-6-responsiveness. A gel-retardation assay showed that several nucleoproteins, perhaps of the C/EBP family, from HepG2 cells bound to sequences between -88 to -83. Collectively, these results localize cis-acting elements involved in constitutive and IL-1/IL-6-regulated murine C3 gene expression and provide evidence for specific transacting factors. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5.

Kawamura, N; Singer, L; Wetsel, R A; Colten, H R

1992-01-01

172

Differential expression of a C-terminal splice variant of phosphatidylinositol transfer protein ? lacking the constitutive-phosphorylated Ser262 that localizes to the Golgi compartment  

PubMed Central

Mammalian PITP? (phosphatidylinositol transfer protein ?) is a 272-amino-acid polypeptide capable of transferring PtdIns, PtdCho and SM (sphingomyelin) between membrane bilayers. It has been reported that Ser262 present in the C-terminus of PITP? is constitutively phosphorylated and determines Golgi localization. We provide evidence for the expression of an sp (splice) variant of PITP? (PITP?-sp2) where the C-terminal 15 amino acids of PITP?-sp1 are replaced by an alternative C-terminus of 16 amino acids. PITP?-sp1 is the product of the first 11 exons, whereas PITP?-sp2 is a product of the first 10 exons followed by the twelfth exon – exon 11 being ‘skipped’. Both splice variants are capable of PtdIns and PtdCho transfer, with PITP?-sp2 being unable to transport SM. PITP? is ubiquitously expressed, with the highest amounts of PITP? found in HL60 cells and in rat liver; HL60 cells express only PITP?-sp1, whereas rat liver expresses both sp variants in similar amounts. In both cell types, PITP?-sp1 is constitutively phosphorylated and both the PtdIns and PtdCho forms of PITP?-sp1 are present. In contrast, PITP?-sp2 lacks the constitutively phosphorylated Ser262 (replaced with glutamine). Nonetheless, both PITP? variants localize to the Golgi and, moreover, dephosphorylation of Ser262 of PITP?-sp1 does not affect its Golgi localization. The presence of PITP? sp variants adds an extra level of proteome complexity and, in rat liver, the single gene for PITP? gives rise to seven distinct protein species that can be resolved on the basis of their charge differences.

Morgan, Clive P.; Allen-Baume, Victoria; Radulovic, Marko; Li, Michelle; Skippen, Alison; Cockcroft, Shamshad

2006-01-01

173

The Constitution: Perspectives on Contemporary American Democracy.  

ERIC Educational Resources Information Center

Four articles expressing the views of nine prominent United States citizens about the Constitution provide a context for reflecting on the meaning of the Constitution in present-day America. In "Why Has the Constitution Endured So Long?" Don Edwards, chairman of the House Civil and Constitutional Rights Subcommittee, discusses why the Constitution

Close Up Foundation, Arlington, VA.

174

Constitutive expression of CD26/dipeptidylpeptidase IV on peripheral blood B lymphocytes of patients with B chronic lymphocytic leukaemia  

PubMed Central

We have investigated the expression of the ectoenzyme dipeptidylpeptidase IV (DPP IV)/CD26 on lymphocytes obtained from patients with B chronic lymphocytic leukaemia (B-CLL) and compared it with healthy subjects. Using two-colour immunofluorescence analysis with CD26 and CD20 or CD23 monoclonal antibodies, CD26 was found undetectable on peripheral resting B-cells (CD20+ CD23?) from normal donors whereas it was expressed on B-cells activated in vitro with interleukin (IL)-4 and Staphylococcus aureus strain cowan I (CD20+ CD23+). The expression of CD26 on leukaemic B-cells (CD20+ CD23+) was clearly induced in 22 out of 25 patients examined. Consequently, induced levels of CD26 cell surface expression on either normal activated and malignant B-cells coincided with the enhancement of DPP IV activity detected on the surface of these cells. Reverse transcription polymerase chain reaction analyses showed that the transcript levels of the CD26 gene was higher in normal activated B-cells and B-CLL cells than in resting B-cells, suggesting that CD26 was expressed at the level of transcriptional activation. These observations provide evidence of the abnormal expression of DPPIV/CD26 in B-CLL which, therefore, may be considered as a novel marker for B-CLL. Further investigation in relation to CD26 expression and other B malignancies needs to be defined. © 1999 Cancer Research Campaign

Bauvois, B; Meester, I De; Dumont, J; Rouillard, D; Zhao, H X; Bosmans, E

1999-01-01

175

IRF-1 and p65 mediate upregulation of constitutive HLA-A antigen expression by hepatocellular carcinoma cells  

PubMed Central

Malignant transformation of hepatocytes is frequently associated with upregulation of HLA-A expression. Currently there is no information available regarding the mechanisms underlying this phenotypic change. We investigated HLA-A expression in 165 paraffin embedded tissues and 21 fresh tissues from liver cancer patients. Utilizing truncated HLA-A promoter–reporter constructs and gel-shift assay we had identified the regulatory elements and transcription factors required for HLA-A upregulation. 54% of the paraffin embedded tissues showed increased HLA-A expression in their cancerous part. 43% of the fresh liver cancer tissues had increased HLA-A complex expression with the HLA-A heavy chain gene demonstrating the highest level of upregulation (62%). Enhanced HLA-A expression in the liver cell lines QGY7701 and BEL7402 was found to be mediated by binding of interferon regulatory factor 1 (IRF-1) to interferon stimulated response element, and of nuclear transcription factor p65 binding to enhancer A element in the HLA-A promoter of these cell lines. The in vivo relevance of these findings was indicated by the association of the enhanced expression of IRF-1 and accumulation of nuclear p65 with HLA-A upregulation in 8 of the 21 liver cancer lesions investigated. Our results indicated that HLA-A upregulation in liver cancer was mediated by both increased nuclear aggregation of transcription factor p65 and upregulation of transcription factor IRF-1.

Shen, Yuqing; Xia, Mei; Zhang, Jianqiong; Xu, Lianhong; Yang, Jin; Chen, Aiqin; Miao, Fengqin; Ferrone, Soldano; Xie, Wei

2012-01-01

176

Genetic background influences adaptation to cardiac hypertrophy and Ca(2+) handling gene expression.  

PubMed

Genetic variability has a profound effect on the development of cardiac hypertrophy in response to stress. Consequently, using a variety of inbred mouse strains with known genetic profiles may be powerful models for studying the response to cardiovascular stress. To explore this approach we looked at male C57BL/6J and 129/SvJ mice. Hemodynamic analyses of left ventricular pressures (LVPs) indicated significant differences in 129/SvJ and C57BL/6J mice that implied altered Ca(2+) handling. Specifically, 129/SvJ mice demonstrated reduced rates of relaxation and insensitivity to dobutamine (Db). We hypothesized that altered expression of genes controlling the influx and efflux of Ca(2+) from the sarcoplasmic reticulum (SR) was responsible and investigated the expression of several genes involved in maintaining the intracellular and sarcoluminal Ca(2+) concentration using quantitative real-time PCR analyses (qRT-PCR). We observed significant differences in baseline gene expression as well as different responses in expression to isoproterenol (ISO) challenge. In untreated control animals, 129/SvJ mice expressed 1.68× more ryanodine receptor 2(Ryr2) mRNA than C57BL/6J mice but only 0.37× as much calsequestrin 2 (Casq2). After treatment with ISO, sarco(endo)plasmic reticulum Ca(2+)-ATPase(Serca2) expression was reduced nearly two-fold in 129/SvJ while expression in C57BL/6J was stable. Interestingly, ? (1) adrenergic receptor(Adrb1) expression was lower in 129/SvJ compared to C57BL/6J at baseline and lower in both strains after treatment. Metabolically, the brain isoform of creatine kinase (Ckb) was up-regulated in response to ISO in C57BL/6J but not in 129/SvJ. These data suggest that the two strains of mice regulate Ca(2+) homeostasis via different mechanisms and may be useful in developing personalized therapies in human patients. PMID:23508205

Waters, Steve B; Diak, Douglass M; Zuckermann, Matthew; Goldspink, Paul H; Leoni, Lara; Roman, Brian B

2013-01-01

177

An ATF/CREB binding motif is required for aberrant constitutive expression of the MHC class II DR alpha promoter and activation by SV40 T-antigen.  

PubMed Central

Constitutive expression of major histocompatibility complex class II (MHC II) antigens normally occurs in B-lymphocytes and antigen presenting cells of the monocyte/macrophage lineage. However, many malignant tumours and transformed cells express these proteins aberrantly. We demonstrate here that the MHC II DR alpha promoter is constitutively active both in the SV40 large T antigen transformed cell line, COS, and in CV1 cells from which they are derived. As an approach to understanding the molecular mechanisms underlying aberrant DR alpha expression we have examined the cis- and trans-acting requirements for DR alpha transcription in these cell types. Electrophoretic mobility shift assays showed that the region immediately 3' to the X-box was bound by a member of the ATF/CREB family of transcription factors. Using deletions and point mutations in the DR alpha promoter we demonstrate that, in contrast to B-cells, the octamer motif and conserved X- and Y-boxes make only a minor contribution to promoter function while single point mutations in the ATF/CREB motif reduced transcription up to 20-fold. In addition, we show that the DR alpha promoter is activated by SV40 large T-antigen and that activation requires an intact ATF/CREB motif. Similar data were obtained using B16 melanoma cells. These results suggest that the ATF/CREB motif may be a target for transcription deregulation in several transformed cell types. Images

Cox, P M; Goding, C R

1992-01-01

178

Uropathic observations in mice expressing a constitutively active point mutation in the 5-HT3A receptor subunit.  

PubMed

Mutant mice with a hypersensitive serotonin (5-HT)3A receptor were generated through targeted exon replacement. A valine to serine mutation (V13'S) in the channel-lining M2 domain of the 5-HT3A receptor subunit rendered the 5-HT3 receptor 70-fold more sensitive to serotonin and produced constitutive activity when combined with the 5-HT3B subunit. Mice homozygous for the mutant allele (5-HT3Avs/vs) had decreased levels of 5-HT3A mRNA. Measurements on sympathetic ganglion cells in these mice showed that whole-cell serotonin responses were reduced, and that the remaining 5-HT3 receptors were hypersensitive. Male 5-HT3Avs/vs mice died at 2-3 months of age, and heterozygous (5-HT3Avs/+) males and homozygous mutant females died at 4-6 months of age from an obstructive uropathy. Both male and female 5-HT3A mutant mice had urinary bladder mucosal and smooth muscle hyperplasia and hypertrophy, whereas male mutant mice had additional prostatic smooth muscle and urethral hyperplasia. 5-HT3A mutant mice had marked voiding dysfunction characterized by a loss of micturition contractions with overflow incontinence. Detrusor strips from 5-HT3Avs/vs mice failed to contract to neurogenic stimulation, despite overall normal responses to a cholinergic agonist, suggestive of altered neuronal signaling in mutant mouse bladders. Consistent with this hypothesis, decreased nerve fiber immunoreactivity was observed in the urinary bladders of 5-HT3Avs/vs compared with 5-HT3A wild-type (5-HT3A+/+) mice. These data suggest that persistent activation of the hypersensitive and constitutively active 5-HT3A receptor in vivo may lead to excitotoxic neuronal cell death and functional changes in the urinary bladder, resulting in bladder hyperdistension, urinary retention, and overflow incontinence. PMID:15201326

Bhattacharya, Anindya; Dang, Hong; Zhu, Quan-Ming; Schnegelsberg, Birthe; Rozengurt, Nora; Cain, Gary; Prantil, Rachelle; Vorp, David A; Guy, Nicholas; Julius, David; Ford, Anthony P D W; Lester, Henry A; Cockayne, Debra A

2004-06-16

179

Constitutive over-expression of two wheat pathogenesis-related genes enhances resistance of tobacco plants to Phytophthora nicotianae  

Microsoft Academic Search

The potential role in plant defence of the two wheat pathogenesis-related proteins of class 4 Wheatwin1 and Wheatwin2, possessing\\u000a high in vitro antimicrobial activity against several pathogens, was investigated through over-expression of their encoding\\u000a genes wPR4a and wPR4b in transgenic tobacco plants. Several independent transformants were obtained, expressing high levels of either transgene\\u000a when analysed by northern and western blotting. Accumulation

Floriana Fiocchetti; Rosalinda D’Amore; Monica De Palma; Laura Bertini; Carla Caruso; Carlo Caporale; Antonino Testa; Gennaro Cristinzio; Francesco Saccardo; Marina Tucci

2008-01-01

180

Rat lymphoid cell lines producing human T cell leukemia virus. II. Constitutive expression of rat interleukin 2 receptor  

PubMed Central

Three rat lymphoid cell lines (TARS-1, TARL-2, and TART-1) (12) transformed by human T cell leukemia/lymphoma virus I (HTLV-I) had rearrangement of the beta chain gene of the T cell antigen receptor, and had integrated proviral DNA from HTLV-I in their genomes. As is the case with adult T cell leukemia (ATL)-derived human T cell lines transformed by HTLV-I, these rat cell lines unequivocally expressed interleukin 2 (IL-2) receptor, as determined by radiolabeled IL-2 binding. By Scatchard plot analysis, one of the cell lines, TART-1, proved to have high affinity receptors (Ka = 1.3 X 10(11)/M and 8.8 X 10(9)/M). Rat IL-2 receptor, not human IL-2 receptor, was expressed on HTLV+ rat cell lines, as demonstrated by the fact that they expressed antigens reactive with monoclonal antibodies (ART-18) against rat IL-2 receptor, but not with anti-Tac antibodies. The collective evidence indicates that the endogenous IL-2 receptor gene is activated in human and rat lymphoid cell lines with HTLV-I production. The mechanism of abnormal IL-2 receptor expression in HTLV infection is discussed.

1985-01-01

181

Dysmegakaryopoiesis of FPD/AML pedigrees with constitutional RUNX1 mutations is linked to myosin II deregulated expression.  

PubMed

FPD/AML is a familial platelet disorder characterized by platelet defects, predisposition to acute myelogenous leukemia (AML) and germ-line heterozygous RUNX1 alterations. Here we studied the in vitro megakaryopoiesis of 3 FPD/AML pedigrees. A 60% to 80% decrease in the output of megakaryocytes (MKs) from CD34(+) was observed. MK ploidy level was low and mature MKs displayed a major defect in proplatelet formation. To explain these defects, we focused on myosin II expression as RUNX1 has been shown to regulate MYL9 and MYH10 in an inverse way. In FPD/AML MKs, expression of MYL9 and MYH9 was decreased, whereas MYH10 expression was increased and the MYH10 protein was still present in the cytoplasm of mature MKs. Myosin II activity inhibition by blebbistatin rescued the ploidy defect of FPD/AML MKs. Finally, we demonstrate that MYH9 is a direct target of RUNX1 by chromatin immunoprecipitation and luciferase assays and we identified new RUNX1 binding sites in the MYL9 promoter region. Together, these results demonstrate that the defects in megakaryopoiesis observed in FPD/AML are, in part, related to a deregulation of myosin IIA and IIB expression leading to both a defect in ploidization and proplatelet formation. PMID:22898599

Bluteau, Dominique; Glembotsky, Ana C; Raimbault, Anna; Balayn, Nathalie; Gilles, Laure; Rameau, Philippe; Nurden, Paquita; Alessi, Marie Christine; Debili, Najet; Vainchenker, William; Heller, Paula G; Favier, Remi; Raslova, Hana

2012-09-27

182

Sensorimotor functions in transgenic mice expressing the neurofilament\\/heavy-LacZ fusion protein on two genetic backgrounds  

Microsoft Academic Search

NFH-LacZ transgenic mice are characterized by expression of a non-endogenous fusion protein between a truncated form of mouse NFH (neurofilament of heavy molecular weight) and the complete Escherichia coli ?-galactosidase protein. These transgenic mice were compared to their respective controls on two background strains (C3H and FVB) in several sensorimotor tests. NFH-LacZ mice were deficient in tests requiring balance and

M. Dubois; C. Strazielle; J. Eyer; R. Lalonde

2002-01-01

183

ALK1 signalling analysis identifies angiogenesis related genes and reveals disparity between TGF-? and constitutively active receptor induced gene expression  

Microsoft Academic Search

BACKGROUND: TGF-?1 is an important angiogenic factor involved in the different aspects of angiogenesis and vessel maintenance. TGF-? signalling is mediated by the T?RII\\/ALK5 receptor complex activating the Smad2\\/Smad3 pathway. In endothelial cells TGF-? utilizes a second type I receptor, ALK1, activating the Smad1\\/Smad5 pathway. Consequently, a perturbance of ALK1, ALK5 or T?RII activity leads to vascular defects. Mutations in

Andreas Lux; Fiona Salway; Holly K Dressman; Gabriele Kröner-Lux; Mathias Hafner; Philip JR Day; Douglas A Marchuk; John Garland

2006-01-01

184

Constitutive expression of the xylanase inhibitor TAXI-III delays Fusarium head blight symptoms in durum wheat transgenic plants.  

PubMed

Cereals contain xylanase inhibitor (XI) proteins which inhibit microbial xylanases and are considered part of the defense mechanisms to counteract microbial pathogens. Nevertheless, in planta evidence for this role has not been reported yet. Therefore, we produced a number of transgenic plants constitutively overexpressing TAXI-III, a member of the TAXI type XI that is induced by pathogen infection. Results showed that TAXI-III endows the transgenic wheat with new inhibition capacities. We also showed that TAXI-III is correctly secreted into the apoplast and possesses the expected inhibition parameters against microbial xylanases. The new inhibition properties of the transgenic plants correlate with a significant delay of Fusarium head blight disease symptoms caused by Fusarium graminearum but do not significantly influence leaf spot symptoms caused by Bipolaris sorokiniana. We showed that this contrasting result can be due to the different capacity of TAXI-III to inhibit the xylanase activity of these two fungal pathogens. These results provide, for the first time, clear evidence in planta that XI are involved in plant defense against fungal pathogens and show the potential to manipulate TAXI-III accumulation to improve wheat resistance against F. graminearum. PMID:23945000

Moscetti, Ilaria; Tundo, Silvio; Janni, Michela; Sella, Luca; Gazzetti, Katia; Tauzin, Alexandra; Giardina, Thierry; Masci, Stefania; Favaron, Francesco; D'Ovidio, Renato

2013-12-01

185

Constitutive expression of the GIGANTEA ortholog affects circadian rhythms and suppresses one-shot induction of flowering in Pharbitis nil, a typical short-day plant.  

PubMed

GIGANTEA (GI) is a key regulator of flowering time, which is closely related to the circadian clock function in Arabidopsis. Mutations in the GI gene cause photoperiod-insensitive flowering and altered circadian rhythms. We isolated the GI ortholog PnGI from Pharbitis (Ipomoea) nil, an absolute short-day (SD) plant. PnGI mRNA expression showed diurnal rhythms that peaked at dusk under SD and long-day (LD) conditions, and also showed robust circadian rhythms under continuous dark (DD) and continuous light (LL) conditions. Short irradiation with red light during the flower-inductive dark period did not change PnGI expression levels, suggesting that such a night break does not abolish flowering by affecting the expression of PnGI. In Pharbitis, although a single dusk signal is sufficient to induce expression of the ortholog of FLOWERING LOCUS T (PnFT1), PnGI mRNA expression was not reset by single lights-off signals. Constitutive expression of PnGI (PnGI-OX) in transgenic plants altered period length in leaf-movement rhythms under LL and affected circadian rhythms of PnFT mRNA expression under DD. PnGI-OX plants formed fewer flower buds than the wild type when one-shot darkness was given. In PnGI-OX plants, expression of PnFT1 was down-regulated, suggesting that PnGI functions as a suppressor of flowering, possibly in part through down-regulation of PnFT1. PMID:21382978

Higuchi, Yohei; Sage-Ono, Kimiyo; Sasaki, Ryuta; Ohtsuki, Namie; Hoshino, Atsushi; Iida, Shigeru; Kamada, Hiroshi; Ono, Michiyuki

2011-04-01

186

Development of Non-Antibiotic-Resistant, Chromosomally Based, Constitutive and Inducible Expression Systems for aroA-Attenuated Salmonella enterica Serovar Typhimurium ?  

PubMed Central

Live-vaccine delivery systems expressing two model antigens from Mycoplasma hyopneumoniae, F2P97 (Adh) and NrdF, were constructed using Salmonella enterica serovar Typhimurium aroA (STM-1), and immunogenicity in mice was evaluated. Recombinant plasmid-based expression (PBE) and chromosomally based expression (CBE) systems were constructed. The PBE system was formed by cloning both antigen genes into pJLA507 to create an operon downstream of temperature-inducible promoters. Constitutive CBE was achieved using a promoter-trapping technique whereby the promoterless operon was stably integrated into the chromosome of STM-1, and the expression of antigens was assessed. The chromosomal position of the operon was mapped in four clones. Inducible CBE was obtained by using the in vivo-induced sspA promoter and recombining the expression construct into aroD. Dual expression of the antigens was detected in all systems, with PBE producing much larger quantities of both antigens. The stability of antigen expression after in vivo passage was 100% for all CBE strains recovered. PBE and CBE strains were selected for comparison in a vaccination trial. The vaccine strains were delivered orally into mice, and significant systemic immunoglobulin M (IgM) and IgG responses against both antigens were detected among all CBE groups. No significant immune response was detected using PBE strains. Expression of recombinant antigens in S. enterica serovar Typhimurium aroA from chromosomally located strong promoters without the use of antibiotic resistance markers is a reliable and effective method of inducing a significant immune response.

Matic, Jake N.; Terry, Tamsin D.; Van Bockel, David; Maddocks, Tracy; Tinworth, David; Jennings, Michael P.; Djordjevic, Steven P.; Walker, Mark J.

2009-01-01

187

Constitutive expression of human immunodeficiency virus (HIV) nef protein in human astrocytes does not influence basal or induced HIV long terminal repeat activity.  

PubMed Central

Since human immunodeficiency virus (HIV) nef has been suggested to exert regulatory effects on HIV long terminal repeat (LTR) activity, we transiently transfected HIV LTR chloramphenicol acetyltransferase or luciferase expression vectors into a human astrocytoma clone (U-373nef) that constitutively expresses the HIV nef gene. In these cells, basal HIV LTR activity, as well as tumor necrosis factor-induced or tat-driven activity, was similar to that in control cells. Lack of any detectable effect of HIV nef on LTR activity was not the result of mutations in integrated nef DNA, as was shown by polymerase chain reaction. These data suggest that the role of nef in HIV genome transcription does not necessarily involve a direct influence on HIV LTR activity. Images

Bachelerie, F; Alcami, J; Hazan, U; Israel, N; Goud, B; Arenzana-Seisdedos, F; Virelizier, J L

1990-01-01

188

An inducible 70 kDa-class heat shock protein is constitutively expressed during early development and diapause in the annual killifish Austrofundulus limnaeus  

PubMed Central

The annual killifish Austrofundulus limnaeus inhabits ephemeral ponds in regions of northern South America, where they survive the periodic drying of their habitat as diapausing embryos. These diapausing embryos are highly resistant to a number of environmental insults such as high temperature, dehydration, anoxia, and increased salinity. Molecular chaperones are known to play a role in stabilizing protein structure and function during events of cellular stress. Relative levels of heat shock protein (Hsp)70 were measured in developing and diapausing embryos of A. limnaeus using quantitative Western blots. An inducible or embryo-specific form of Hsp70 is expressed during embryonic development in A. limnaeus and is elevated during diapause II in this species. Constitutive expression of Hsp70 during development may afford these embryos protection from environmental stresses during development more quickly than relying on the induction of a classic heat shock response.

Podrabsky, Jason E.; Somero, George N.

2007-01-01

189

Molecular cloning and characterization of PtrLAR3, a gene encoding leucoanthocyanidin reductase from Populus trichocarpa, and its constitutive expression enhances fungal resistance in transgenic plants  

PubMed Central

The flavonoid-derived proanthocyanidins (PAs) are one class of the major defence phenolics in poplar leaves. Transcriptional activation of PA biosynthetic genes, resulting in PA accumulation in leaves, was detected following infection by the fungal Marssonina brunnea f.sp. multigermtubi using digital gene expression analysis. In order to study PA biosynthesis and its induction by fungi, a putative leucoanthocyanidin reductase gene, PtrLAR3, was isolated from Populus trichocarpa. Sequence comparison of PtrLAR3 with other known leucoanthocyanidin reductase proteins revealed high amino acid sequence similarity. Semi-quantitative reverse-transcription (RT) PCR and quantitative real-time PCR analysis demonstrated that PtrLAR3 was expressed in various tissues and the highest level of expression was observed in roots. Overexpression of PtrLAR3 in Chinese white poplar (Populus tomentosa Carr.) led to a significant plant-wide increase in PA levels. In vitro assays showed that crude leaf extracts from 35S:PtrLAR3 transformants were able to inhibit significantly the hyphal growth of M. brunnea f.sp. multigermtubi compared to the extracts from control plants. The transgenic 35S:PtrLAR3 poplar plants displayed a significant (P < 0.05) reduction in their disease symptoms compared with the control. RT-PCR analysis showed that PtrLAR3 expression was up-regulated in all transformants. These results suggested that constitutive expression of endogenous PtrLAR3 could be exploited to improve resistance to fungal pathogens in poplar.

Yuan, Li; Wang, Lijun; Han, Zujing; Jiang, Yuanzhong; Zhao, Lili; Liu, Hong; Yang, Li; Luo, Keming

2012-01-01

190

Constitutive expression of mustard annexin, AnnBj1 enhances abiotic stress tolerance and fiber quality in cotton under stress  

Microsoft Academic Search

Annexins belong to a multigene family of Ca2+ dependent, phospholipid and cytoskeleton binding proteins. They have been shown to be upregulated under various stress conditions.\\u000a We generated transgenic cotton plants expressing mustard annexin (AnnBj1), which showed enhanced tolerance towards different abiotic stress treatments like sodium chloride, mannitol, polyethylene\\u000a glycol and hydrogen peroxide. The tolerance to these treatments was associated with

Kesanakurti Divya; S. K. Jami; P. B. Kirti

2010-01-01

191

Patterns of constitutive and IFN-? inducible expression of HLA class II molecules in human melanoma cell lines  

Microsoft Academic Search

Major histocompatibility complex (MHC) class II proteins (HLA-DR, HLA-DP and HLA-DQ) play a fundamental role in the regulation\\u000a of the immune response. The level of expression of human leukocyte antigen (HLA) class II antigens is regulated by interferon-?\\u000a (IFN-?) and depends on the status of class II trans-activator protein (CIITA), a co-activator of the MHC class II gene promoter.\\u000a In

T. Rodríguez; R. Méndez; A. Del Campo; N. Aptsiauri; J. Martín; G. Orozco; G. Pawelec; D. Schadendorf; F. Ruiz-Cabello; F. Garrido

2007-01-01

192

Cytochrome P450 2A5 constitutive expression and induction by heavy metals is dependent on redox-sensitive transcription factor Nrf2 in liver.  

PubMed

Mouse cytochrome P450 2A5 (CYP2A5) is upregulated in various pathophysiological liver diseases and induced by structurally variable hepatotoxic chemicals. A putative common feature for all of these conditions is altered cellular redox status. Nuclear factor erythroid 2-like 2 (Nrf2) is a transcription factor that is post-translationally regulated by oxidative stress and controls the transcription of numerous protective target genes. In the present study, we have extensively characterized the regulation of Cyp2a5 by Nrf2 and compared it to a well-characterized target gene Hmox1. The treatment of mouse primary hepatocytes with lead chloride, methylmercury chloride, or phenethyl isothiocyanate all leads to nuclear accumulation of Nrf2. Both CYP2A5 and HMOX1 were induced by all three compounds; however, HMOX1 responded more rapidly and transiently as compared to CYP2A5. Experiments in Nrf2(-/-) primary hepatocytes showed that Nrf2 is crucial for CYP2A5 induction but not for elevation of HMOX1. Both CYP2A5 and HMOX1 were upregulated by Nrf2 overexpression and downregulated by Keap1 or Bach1 overexpression. However, in all cases, CYP2A5 responded much more potently. Results in Nrf2-deficient animals showed that CYP2A5 expression is significantly attenuated in the absence of Nrf2, while expression of HMOX1 was unaffected. Therefore, Cyp2a5 joins the group of genes constitutively regulated by Nrf2. Our current results unequivocally show that expression of CYP2A5 is tightly controlled by Nrf2 in liver. Nrf2 is needed for constitutive expression of CYP2A5, and CYP2A5 is also sensitively upregulated by an increased level of Nrf2 protein. Therefore, CYP2A5 upregulation could be a useful indicator for hepatic activation of the Nrf2 pathway. PMID:20402460

Lämsä, Virpi; Levonen, Anna-Liisa; Leinonen, Hanna; Ylä-Herttuala, Seppo; Yamamoto, Masayuki; Hakkola, Jukka

2010-05-17

193

Sp1 and Sp3 control constitutive expression of the human NHE2 promoter by interactions with the proximal promoter and the transcription initiation site  

PubMed Central

We have previously cloned the human Na+/H+ exchanger NHE2 gene and its promoter region. In the present study, the regulatory elements responsible for the constitutive expression of NHE2 were studied. Transient transfection assays revealed that the ?40/+150 promoter region contains the core promoter responsible for the optimal promoter activity. A smaller fragment, ?10/+40, containing the TIS (transcription initiation site) showed minimal activity. We identified a palindrome that overlaps the TIS and binds to the transcription factors Sp1 and Sp3. Mutations in the 5? flank of the palindrome abolished the Sp1/Sp3 interaction and reduced promoter activity by approx. 45%. In addition, a conserved GC-box centered at ?25 was found to play a critical role in basal promoter activity and also interacted with Sp1 and Sp3. An internal deletion in the GC-box severely reduced the promoter activity. Sp1/Sp3 binding to these elements was established using gel-mobility shift assays, confirmed by chromatin immunoprecipitation and co-transfections in Drosophila SL2 cells. Furthermore, we identified two positive regulatory elements in the DNA region corresponding to the 5?-UTR (5?-untranslated region). The results in the present study indicate that Sp1 and Sp3 are required for constitutive NHE2 expression and that the positive regulatory elements of the 5?-UTR may co-operate with the 5?-flanking region to achieve the optimal promoter activity.

Pearse, Ian; Zhu, Ying X.; Murray, Eleanor J.; Dudeja, Pradeep K.; Ramaswamy, Krishnamurthy; Malakooti, Jaleh

2007-01-01

194

Constitutive Smad signaling and Smad-dependent collagen gene expression in mouse embryonic fibroblasts lacking peroxisome proliferator-activated receptor-{gamma}  

SciTech Connect

Transforming growth factor-{beta} (TGF-{beta}), a potent inducer of collagen synthesis, is implicated in pathological fibrosis. Peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) is a nuclear hormone receptor that regulates adipogenesis and numerous other biological processes. Here, we demonstrate that collagen gene expression was markedly elevated in mouse embryonic fibroblasts (MEFs) lacking PPAR-{gamma} compared to heterozygous control MEFs. Treatment with the PPAR-{gamma} ligand 15d-PGJ{sub 2} failed to down-regulate collagen gene expression in PPAR-{gamma} null MEFs, whereas reconstitution of these cells with ectopic PPAR-{gamma} resulted in their normalization. Compared to control MEFs, PPAR-{gamma} null MEFs displayed elevated levels of the Type I TGF-{beta} receptor (T{beta}RI), and secreted more TGF-{beta}1 into the media. Furthermore, PPAR-{gamma} null MEFs showed constitutive phosphorylation of cellular Smad2 and Smad3, even in the absence of exogenous TGF-{beta}, which was abrogated by the ALK5 inhibitor SB431542. Constitutive Smad2/3 phosphorylation in PPAR-{gamma} null MEFs was associated with Smad3 binding to its cognate DNA recognition sequences, and interaction with coactivator p300 previously implicated in TGF-{beta} responses. Taken together, these results indicate that loss of PPAR-{gamma} in MEFs is associated with upregulation of collagen synthesis, and activation of intracellular Smad signal transduction, due, at least in part, to autocrine TGF-{beta} stimulation.

Ghosh, Asish K [Northwestern University Feinberg School of Medicine, Division of Rheumatology, 240 East Huron Street, Chicago, IL 60611 (United States)], E-mail: a-ghosh2@northwestern.edu; Wei, Jun; Wu, Minghua [Northwestern University Feinberg School of Medicine, Division of Rheumatology, 240 East Huron Street, Chicago, IL 60611 (United States); Varga, John [Northwestern University Feinberg School of Medicine, Division of Rheumatology, 240 East Huron Street, Chicago, IL 60611 (United States)], E-mail: j-varga@northwestern.edu

2008-09-19

195

Biochemical and Morphological Consequences of Human ?-Synuclein Expression in a Mouse ?-Synuclein Null Background  

PubMed Central

A consensus about the functions of human wild-type or mutated ?-synuclein (?SYN) is lacking. Both forms of ?SYN are implicated in Parkinson’s disease, whereas the wild-type form is implicated in substance abuse. Interactions with other cellular proteins and organelles may meditate its functions. We developed a series of congenic mouse lines containing various allele doses or combinations of the human wild type ?SYN (hw?SYN) or a doubly mutated (A30P*A53T) ?SYN (hm2?SYN) in a C57Bl/6J line spontaneously deleted in mouse ?SYN (C57BL/6JOla). Both transgenes had a functional role in the nigrostriatal system, demonstrated by significant elevations in striatal catecholamines, metabolites, and the enzyme tyrosine hydroxylase compared to null-mice without a transgene. Consequences occurred when the transgenes were expressed at a fraction of the endogenous level. Hemizygous congenic mice did not exhibit any change in the number or size of dopaminergic neurons in the ventral midbrain at nine months of age. Human ?SYN was predominantly located in neuronal cell bodies, neurites, synapses, and in intraneuronal/intraneuritic aggregates. The hm2?SYN transgene resulted in more aggregates and dystrophic neurites than did the hw5 transgene. The hw?SYN transgene resulted in higher expression of two striatal proteins, synaptogamin 7 and UCHL1, compared to the levels of the hm2?SYN transgene. These observations suggest that mutations in ?SYN may impair specific functional domains, leaving others intact. These lines may also be useful for exploring interactions between h?SYN and environmental or genetic risk factors in dopamine-related disorders using a mouse model.

Prasad, Kavita; Tarasewicz, Elizabeth; Strickland, Pamela A. Ohman; O'Neill, Michael; Mitchell, Stephen N.; Merchant, Kalpana; Tep, Samnang; Hilton, Kathryn; Datwani, Akash; Buttini, Manuel; Mueller-Steiner, Sarah; Richfield, Eric K.

2011-01-01

196

Expression of a Constitutively Active Calcineurin Encoded by an Intron-Retaining mRNA in Follicular Keratinocytes  

PubMed Central

Hair growth is a highly regulated cyclical process. Immunosuppressive immunophilin ligands such as cyclosporin A (CsA) and FK506 are known as potent hair growth modulatory agents in rodents and humans that induce active hair growth and inhibit hair follicle regression. The immunosuppressive effectiveness of these drugs has been generally attributed to inhibition of T cell activation through well-characterized pathways. Specifically, CsA and FK506 bind to intracellular proteins, principally cyclophilin A and FKBP12, respectively, and thereby inhibit the phosphatase calcineurin (Cn). The calcineurin (Cn)/NFAT pathway has an important, but poorly understood, role in the regulation of hair follicle development. Here we show that a novel-splicing variant of calcineurin Aß CnAß-FK, which is encoded by an intron-retaining mRNA and is deficient in the autoinhibitory domain, is predominantly expressed in mature follicular keratinocytes but not in the proliferating keratinocytes of rodents. CnAß-FK was weakly sensitive to Ca2+ and dephosphorylated NFATc2 under low Ca2+ levels in keratinocytes. Inhibition of Cn/NFAT induced hair growth in nude mice. Cyclin G2 was identified as a novel target of the Cn/NFATc2 pathway and its expression in follicular keratinocytes was reduced by inhibition of Cn/NFAT. Overexpression of cyclin G2 arrested the cell cycle in follicular keratinocytes in vitro and the Cn inhibitor, cyclosporin A, inhibited nuclear localization of NFATc2, resulting in decreased cyclin G2 expression in follicular keratinocytes of rats in vivo. We therefore suggest that the calcineurin/NFAT pathway has a unique regulatory role in hair follicle development.

Fujimura, Atsushi; Michiue, Hiroyuki; Nishiki, Tei-ichi; Ohmori, Iori; Wei, Fan-Yan; Matsui, Hideki; Tomizawa, Kazuhito

2011-01-01

197

Function of plastid sigma factors in higher plants: regulation of gene expression or just preservation of constitutive transcription?  

Microsoft Academic Search

Plastid gene expression is rather complex. Transcription is performed by three different RNA polymerases, two of them are\\u000a nucleus-encoded, monomeric, of the phage-type (named RPOTp and RPOTmp) and one of them is plastid-encoded, multimeric, of\\u000a the eubacterial-type (named PEP). The activity of the eubacterial-type RNA polymerase is regulated by up to six nucleus-encoded\\u000a transcription initiation factors of the sigma-type. This

Silva Lerbs-Mache

2011-01-01

198

Apoptosis is inversely related to necrosis and determines net growth in tumors bearing constitutively expressed myc, ras, and HPV oncogenes.  

PubMed Central

Immortalized rat fibroblasts were transfected with expression plasmids containing a mutated human Ha-ras (T24) oncogene, human c-myc, HPV 16 or 18 genomes, or combinations of these. Cell proliferation rates in vitro of the resulting 13 transformed lines were closely similar but apoptotic rates in vitro varied over a 60-fold range and correlated inversely with rates of population expansion in culture. To determine whether such differences in susceptibility to apoptosis affected the pattern of tumor growth in vivo, the transfected lines were injected subcutaneously into immunesuppressed mice producing fibrosarcomas in which prevalence of apoptosis and mitosis, extent of necrosis, and net growth rate were measured. Cell lines with high apoptotic rates in vitro tended to generate slowly growing tumors with high ratios of apoptosis to mitosis and little necrosis. The three most extreme examples of this phenotype all resulted from single transfections with c-myc. Lines with low apoptotic rates in vitro generated rapidly expanding tumors with high mitotic rates, extensive necrosis, and little apoptosis relative to mitosis, even in the compromised zone at the edge of necrotic regions. The four fastest-growing tumors all contained a T24-ras oncogene. The results suggest that oncogene expression determines intrinsic apoptotic rates and in this way may significantly influence the net growth rate and extent of necrosis in tumors. Images Figure 1 Figure 5

Arends, M. J.; McGregor, A. H.; Wyllie, A. H.

1994-01-01

199

Constitutive expression of mustard annexin, AnnBj1 enhances abiotic stress tolerance and fiber quality in cotton under stress.  

PubMed

Annexins belong to a multigene family of Ca(2+) dependent, phospholipid and cytoskeleton binding proteins. They have been shown to be upregulated under various stress conditions. We generated transgenic cotton plants expressing mustard annexin (AnnBj1), which showed enhanced tolerance towards different abiotic stress treatments like sodium chloride, mannitol, polyethylene glycol and hydrogen peroxide. The tolerance to these treatments was associated with decreased hydrogen peroxide levels and enhanced total peroxidase activity, enhanced content of osmoprotectants- proline and sucrose in transgenic plants. They showed higher retention of total chlorophyll and reduced TBARS in leaf disc assays with stress treatments, and decreased hydrogen peroxide accumulation in the stomatal guard cells when compared to their wild type counterparts. They also showed significantly enhanced fresh weight, relative water content, dry weight under stress. Treatment with sodium chloride resulted in enhanced expression of genes for Delta-pyrroline-5-carboxylase synthetase in leaves, and sucrose phosphate synthase, sucrose synthase and cellulose synthase A in the leaves and fibers of transgenic plants. The transgenic plants maintained normal seed development, fiber quality and cellulose content under stress. PMID:20148350

Divya, Kesanakurti; Jami, S K; Kirti, P B

2010-06-01

200

High-efficiency transformation and selective tolerance against biotic and abiotic stress in mulberry, Morus indica cv. K2, by constitutive and inducible expression of tobacco osmotin.  

PubMed

Osmotin and osmotin-like proteins are stress proteins belonging to the plant PR-5 group of proteins induced in several plant species in response to various types of biotic and abiotic stresses. We report here the overexpression of tobacco osmotin in transgenic mulberry plants under the control of a constitutive promoter (CaMV 35S) as well as a stress-inducible rd29A promoter. Southern analysis of the transgenic plants revealed the stable integration of the introduced genes in the transformants. Real-time PCR analysis provided evidence for the expression of osmotin in the transgenic plants under both the constitutive and stress-inducible promoters. Transgenic plants with the stress-inducible promoter were observed to better tolerate salt and drought stress than those with the constitutive promoter. Transgenic plants when subjected to simulated salinity and drought stress conditions showed better cellular membrane stability (CMS) and photosynthetic yield than non-transgenic plants under conditions of both salinity and drought stress. Proline levels were very high in transgenic plants with the constitutive promoter relative to those with the stress-inducible promoter. Fungal challenge undertaken with three fungal species known to cause serious losses to mulberry cultivation, namely, Fusarium pallidoroseum, Colletotrichum gloeosporioides and Colletotrichum dematium, revealed that transgenic plants with osmotin under control of the constitutive promoter had a better resistance than those with osmotin under the control of the stress-inducible promoter. Evaluation in next generation was undertaken by studying bud break in transgenic and non-transgenic plants under simulated drought (2% polyethylene glycol) and salt stress (200 mM NaCl) conditions. The axillary buds of the selected transgenic lines had a better bud break percentage under stressed conditions than buds from non-transgenic mulberry lines. A biotic assay with Bombyx mori indicated that osmotin protein had no undesirable effect on silkworm rearing and feeding. We therefore conclude that 35S transgenic plants are better suited for both abiotic stress also biotic challenges (fungal), while the rd29A transgenic plants are more responsive to drought. PMID:20549349

Das, Manaswini; Chauhan, Harsh; Chhibbar, Anju; Rizwanul Haq, Qazi Mohd; Khurana, Paramjit

2011-04-01

201

Constitutive Inositol Phosphate Formation in Cytomegalovirus-Infected Human Fibroblasts Is due to Expression of the Chemokine Receptor Homologue pUS28  

PubMed Central

An open reading frame (ORF), US28, with homology to mammalian chemokine receptors has been identified in the genome of human cytomegalovirus (HCMV). Its protein product, pUS28, has been shown to bind several human CC chemokines, including RANTES, MCP-1, and MIP-1?, and the CX3C chemokine fractalkine with high affinity. Addition of CC chemokines to cells expressing pUS28 was reported to cause a pertussis toxin-sensitive increase in the concentration of cytosolic free Ca2+. Recently, pUS28 was shown to mediate constitutive, ligand-independent, and pertussis toxin-insensitive activation of phospholipase C via Gq/11-dependent signaling pathways in transiently transfected COS-7 cells. Since these findings are not easily reconciled with the former observations, we analyzed the role of pUS28 in mediating CC chemokine activation of pertussis toxin-sensitive G proteins in cell membranes and phospholipase C in intact cells. The transmembrane signaling functions of pUS28 were studied in HCMV-infected cells rather than in cDNA-transfected cells. Since DNA sequence analysis of ORF US28 of different laboratory and clinical strains had revealed amino acid sequence differences in the amino-terminal portion of pUS28, we compared two laboratory HCMV strains, AD169 and Toledo, and one clinical strain, TB40/E. The results showed that infection of human fibroblasts with all three HCMV strains led to a vigorous, constitutively enhanced formation of inositol phosphates which was insensitive to pertussis toxin. This effect was critically dependent on the presence of the US28 ORF in the HCMV genome but was independent of the amino acid sequence divergence of the three HCMV strains investigated. The constitutive activity of pUS28 is not explained by expression of pUS28 at high density in HCMV-infected cells. The pUS28 ligands RANTES and MCP-1 failed to stimulate binding of guanosine 5?-O-(3-[35S]thiotriphosphate to membranes of HCMV-infected cells and did not enhance constitutive activation of phospholipase C in intact HCMV-infected cells. These findings raise the possibility that the effects of CC chemokines and pertussis toxin on G protein-mediated transmembrane signaling previously observed in HCMV-infected cells are either independent of or not directly mediated by the protein product of ORF US28.

Minisini, Rosalba; Tulone, Calogero; Luske, Anke; Michel, Detlef; Mertens, Thomas; Gierschik, Peter; Moepps, Barbara

2003-01-01

202

Constitutive expression in gal7 mutants of Kluyveromyces lactis is due to internal production of galactose as an inducer of the Gal/Lac regulon.  

PubMed

The induction process of the galactose regulon has been intensively studied, but until now the nature of the inducer has remained unknown. We have analyzed a delta gal7 mutant of the yeast Kluyveromyces lactis, which lacks the galactotransferase activity and is able to express the genes of the Gal/Lac regulon also in the absence of galactose. We found that this expression is semiconstitutive and undergoes a strong induction during the stationary phase. The gal1-209 mutant, which has a reduced kinase activity but retains its positive regulatory function, also shows a constitutive expression of beta-galactosidase, suggesting that galactose is the inducer. A gal10 deletion in delta gal7 or gal1-209 mutants reduces the expression to under wild-type levels. The presence of the inducer could be demonstrated in both delta gal7 crude extracts and culture medium by means of a bioassay using the induction in gal1-209 cells. A mutation in the transporter gene LAC12 decreases the level of induction in gal7 cells, indicating that galactose is partly released into the medium and then retransported into the cells. Nuclear magnetic resonance analysis of crude extracts from delta gal7 cells revealed the presence of 50 microM galactose. We conclude that galactose is the inducer of the Gal/Lac regulon and is produced via UDP-galactose through a yet-unknown pathway. PMID:9032299

Cardinali, G; Vollenbroich, V; Jeon, M S; de Graaf, A A; Hollenberg, C P

1997-03-01

203

Establishment of stably transfected cells constitutively expressing the full-length and truncated antigenic proteins of two genetically distinct mink astroviruses.  

PubMed

Astroviruses are becoming a growing concern in veterinary and public health. To date there are no registered vaccines against astrovirus-induced disease, mostly due to the difficulty to cultivate astroviruses to high titer for vaccine development using conventional techniques. As means to circumvent this drawback, we have developed stably transfected mink fetal cells and BHK21 cells constitutively expressing the full-length and truncated capsid proteins of two distinct genotypes of mink astrovirus. Protein expression in these stably transfected cells was demonstrated by strong signals as evaluated by in-situ PLA and IFA, and confirmed by Western blotting. The recombinant full-length and truncated proteins induced a high level of antibodies in mink, evaluated by ELISA, demonstrating their immunogenicity. In a challenge experiment in mink, a reduction in presentation clinical signs and virus shedding was observed in mink kits born from immunized females. The gene integration and protein expression were sustained through cell passage, showing that the used approach is robust and reliable for expression of functional capsid proteins for vaccine and diagnostic applications. PMID:24376619

Bidokhti, Mehdi R M; Ullman, Karin; Jensen, Trine H; Chriél, Mariann; Mottahedin, Amin; Munir, Muhammad; Andersson, Anna Maria; Detournay, Olivier; Hammer, Anne Sofie; Baule, Claudia

2013-01-01

204

Establishment of Stably Transfected Cells Constitutively Expressing the Full-Length and Truncated Antigenic Proteins of Two Genetically Distinct Mink Astroviruses  

PubMed Central

Astroviruses are becoming a growing concern in veterinary and public health. To date there are no registered vaccines against astrovirus-induced disease, mostly due to the difficulty to cultivate astroviruses to high titer for vaccine development using conventional techniques. As means to circumvent this drawback, we have developed stably transfected mink fetal cells and BHK21 cells constitutively expressing the full-length and truncated capsid proteins of two distinct genotypes of mink astrovirus. Protein expression in these stably transfected cells was demonstrated by strong signals as evaluated by in-situ PLA and IFA, and confirmed by Western blotting. The recombinant full-length and truncated proteins induced a high level of antibodies in mink, evaluated by ELISA, demonstrating their immunogenicity. In a challenge experiment in mink, a reduction in presentation clinical signs and virus shedding was observed in mink kits born from immunized females. The gene integration and protein expression were sustained through cell passage, showing that the used approach is robust and reliable for expression of functional capsid proteins for vaccine and diagnostic applications.

Bidokhti, Mehdi R. M.; Ullman, Karin; Jensen, Trine H.; Chriel, Mariann; Mottahedin, Amin; Munir, Muhammad; Andersson, Anna Maria; Detournay, Olivier; Hammer, Anne Sofie; Baule, Claudia

2013-01-01

205

Regional changes in constitutive, but not inducible NOS expression in the brains of mice infected with the LP-BM5 leukemia virus.  

PubMed

Potential neurotoxins such as nitric oxide have been implicated in the pathogenesis of acquired immunodeficiency syndrome (AIDS) dementia complex. The LP-BM5 murine leukemia-infected mice, which develop immunological and cognitive deficits reminiscent of human HIV-1 infection, were employed to investigate the changes in brain constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) expression. Cerebellar and striatal cNOS enzymatic activity increased approximately 70% as early as 2 weeks after infection, declining to control levels by 12-16 weeks. In contrast, cNOS protein expression in the striatum and cerebellum was decreased 30% at 4 weeks, declining to 50% of control levels by 16 weeks post-infection. Staining intensity for cNOS, but not neuron number was reduced in the cerebral cortex, striatum, ventromedial hypothalamic nucleus and amygdala. Although iNOS protein expression was elevated in splenic monocytes, neither iNOS activity, mRNA nor protein was detected in the brains of mice 12 weeks after infection. These results indicate that neurons decrease cNOS protein expression to compensate for chronic cNOS activation, probably resulting from glutamatergic stimulation. The cNOS activation is contemporaneous with microglial activation in LP-BM5-infected mice, and precedes the development of cognitive deficits. Moreover, the lack of iNOS induction in either infected macrophages or glial elements suggests that iNOS is not necessary for the development of these cognitive deficits. PMID:9106446

Li, Y; Kustova, Y; Sei, Y; Basile, A S

1997-03-28

206

Increased Na+/Ca2+ Exchanger Expression/Activity Constitutes a Point of Inflection in the Progression to Heart Failure of Hypertensive Rats  

PubMed Central

Spontaneously hypertensive rat (SHR) constitutes a genetic model widely used to study the natural evolution of hypertensive heart disease. Ca2+-handling alterations are known to occur in SHR. However, the putative modifications of Ca2+-handling proteins during the progression to heart failure (HF) are not well established. Moreover, the role of apoptosis in SHR is controversial. We investigated intracellular Ca2+, Ca2+-handling proteins and apoptosis in SHR vs. control Wistar rats (W) from 3 to 15 months (mo). Changes associated with the transition to HF (i.e. lung edema and decrease in midwall fractional shortening), occurred at 15 mo in 38% of SHR (SHRF). In SHRF, twitch and caffeine-induced Ca2+ transients, significantly decreased relative to 6/9 mo and 15 mo without HF signs. This decrease occurred in association with a decrease in the time constant of caffeine-Ca2+ transient decay and an increase in Na+/Ca2+ exchanger (NCX) abundance (p<0.05) with no changes in SERCA2a expression/activity. An increased Ca2+-calmodulin-kinase II activity, associated with an enhancement of apoptosis (TUNEL and Bax/Bcl2) was observed in SHR relative to W from 3 to 15 mo. Conclusions: 1. Apoptosis is an early and persistent event that may contribute to hypertrophic remodeling but would not participate in the contractile impairment of SHRF. 2. The increase in NCX expression/activity, associated with an increase in Ca2+ efflux from the cell, constitutes a primary alteration of Ca2+-handling proteins in the evolution to HF. 3. No changes in SERCA2a expression/activity are observed when HF signs become evident.

Rodriguez, Jesica S.; Velez Rueda, J. Omar; Salas, Margarita; Becerra, Romina; Di Carlo, Mariano N.; Said, Matilde; Vittone, Leticia; Rinaldi, Gustavo; Portiansky, Enrique L.; Mundina-Weilenmann, Cecilia; Palomeque, Julieta; Mattiazzi, Alicia

2014-01-01

207

Constitutive Expression of the Cytochrome P450 EthABCD Monooxygenase System Enables Degradation of Synthetic Dialkyl Ethers in Aquincola tertiaricarbonis L108  

PubMed Central

In Rhodococcus ruber IFP 2001, Rhodococcus zopfii IFP 2005, and Gordonia sp. strain IFP 2009, the cytochrome P450 monooxygenase EthABCD catalyzes hydroxylation of methoxy and ethoxy residues in the fuel oxygenates methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). The expression of the IS3-type transposase-flanked eth genes is ETBE dependent and controlled by the regulator EthR (C. Malandain et al., FEMS Microbiol. Ecol. 72:289–296, 2010). In contrast, we demonstrated by reverse transcription-quantitative PCR (RT-qPCR) that the betaproteobacterium Aquincola tertiaricarbonis L108, which possesses the ethABCD genes but lacks ethR, constitutively expresses the P450 system at high levels even when growing on nonether substrates, such as glucose. The mutant strain A. tertiaricarbonis L10, which is unable to degrade dialkyl ethers, resulted from a transposition event mediated by a rolling-circle IS91-type element flanking the eth gene cluster in the wild-type strain L108. The constitutive expression of Eth monooxygenase is likely initiated by the housekeeping sigma factor ?70, as indicated by the presence in strain L108 of characteristic ?10 and ?35 binding sites upstream of ethA which are lacking in strain IFP 2001. This enables efficient degradation of diethyl ether, diisopropyl ether, MTBE, ETBE, TAME, and tert-amyl ethyl ether (TAEE) without any lag phase in strain L108. However, ethers with larger residues, n-hexyl methyl ether, tetrahydrofuran, and alkyl aryl ethers, were not attacked by the Eth system at significant rates in resting-cell experiments, indicating that the residue in the ether molecule which is not hydroxylated also contributes to the determination of substrate specificity.

Schuster, Judith; Purswani, Jessica; Breuer, Uta; Pozo, Clementina; Harms, Hauke; Muller, Roland H.

2013-01-01

208

Liver Phospholipid transfer protein (PLTP) Expression with a PLTP-null Background Promotes Very Low Density Lipoprotein Production  

PubMed Central

It is known that plasma phospholipid transfer protein (PLTP) activity influences lipoprotein metabolism. The liver is one of the major sites of lipoprotein production and degradation, as well as of PLTP expression. To address the impact of liver-expressed PLTP on lipoprotein metabolism, we created a mouse model that expresses PLTP in the liver acutely and specifically, with a PLTP-null background. This approach in mouse model preparation can also be used universally for evaluating the function of many other genes in the liver. We found that liver PLTP expression dramatically increases plasma levels of non-HDL-cholesterol (2.7-fold, P<0.0001), non-HDL-phospholipid (2.5-fold, P<0.001), and triglyceride (51%, P<0.01), but has no significant influence on plasma HDL-lipids, as compared with controls. Plasma apoB levels were also significantly increased in the PLTP-expressed mice (2.2-fold, P<0.001), but those of apoA-I were not. To explore the mechanism involved, we examined the lipidation and secretion of nascent VLDL, finding that liver PLTP expression significantly increases VLDL lipidation in hepatocyte microsomal lumen, and also VLDL secretion into the plasma. In conclusion, it is possible to prepare a mouse model that expresses the gene of interest only in the liver, but not in other tissues. Our results suggest, for the first time, that the major function of liver PLTP is to drive VLDL production and makes a small contribution to plasma PLTP activity, thus has marginal effect on plasma HDL levels.

Yazdanyar, Amirfarbod; Jiang, Xian-Cheng

2012-01-01

209

Constitutive expression and inducibility of O6-methylguanine-DNA methyltransferase and N-methylpurine-DNA glycosylase in rat liver cells exhibiting different status of differentiation.  

PubMed

We have analyzed the expression of the DNA repair genes O6-methylguanine-DNA methyltransferase (MGMT) and N-methylpurine-DNA glycosylase (MPG) at RNA and protein activity level in primary rat hepatocytes in vitro and various rat hepatoma cell lines exhibiting different status of differentiation. The basal level of MGMT mRNA and activity correlated well with the degree of differentiation, as measured by tyrosine aminotransferase (TAT) mRNA expression. Induction of MGMT mRNA and protein activity by X-ray and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) treatment was most pronounced in the well-differentiated hepatocytes and in various differentiated hepatoma cell lines (up to 6-fold). There was virtually no induction in H5 hepatoma cells which exhibited the lowest degree of differentiation and expressed only low amounts of MGMT. For the other hepatoma cell lines tested, MGMT induction did not clearly correlate with TAT expression. Thus, Fao cells which exhibited a high degree of differentiation responded only very weakly with respect to induction. The results indicate that the basal level of MGMT mRNA expression is dependent on liver-specific regulatory factors, whereas the inducibility is a more complex phenomenon not solely dependent on them. Contrary to MGMT, MPG was constitutively expressed at relatively high amounts in all cell lines tested and no correlation was apparent with the degree of differentiation. MPG activity was significantly induced by mutagen treatment only in H4IIE cells. The tumor promoter phenobarbital induced MGMT, but not MPG mRNA in hepatocytes. The results indicate that MGMT and MPG are not co-regulated. Hepatoma cells with low MGMT level were most sensitive to MNNG-induced cytotoxicity. On the other hand, no correlation was apparent between MPG activity and sensitivity of the cell lines to methylating agents indicating that the MPG level is not predictive for alkylating drug resistance. PMID:7827137

Grombacher, T; Kaina, B

1995-01-25

210

Constitutive Expression of the Maltoporin LamB in the Absence of OmpR Damages the Cell Envelope? †  

PubMed Central

Cells experience multiple environmental stimuli simultaneously. To survive, they must respond accordingly. Unfortunately, the proper response to one stress easily could make the cell more susceptible to a second coexistent stress. To deal with such a problem, a cell must possess a mechanism that balances the need to respond simultaneously to both stresses. Our recent studies of ompR malT(Con) double mutants show that elevated expression of LamB, the outer membrane porin responsible for maltose uptake, causes cell death when the osmoregulator OmpR is disabled. To obtain insight into the nature of the death experienced by ompR malT(Con) mutants, we described the death process. On the basis of microscopic and biochemical approaches, we conclude that death results from a loss of membrane integrity. On the basis of an unbiased genome-wide search for suppressor mutations, we conclude that this loss of membrane integrity results from a LamB-induced envelope stress that the cells do not sufficiently perceive and thus do not adequately accommodate. Finally, we conclude that this envelope stress involves an imbalance in the lipopolysaccharide/porin composition of the outer membrane and an increased requirement for inorganic phosphate.

Reimann, Sylvia A.; Wolfe, Alan J.

2011-01-01

211

Biotic and abiotic stress tolerance in transgenic tomatoes by constitutive expression of S-adenosylmethionine decarboxylase gene.  

PubMed

Recent findings have implicated the role of polyamines (putrescine, spermidine and spermine) in stress tolerance. Therefore, the present work was carried out with the goal of generating transgenic tomato plants with human S-adenosylmethionine decarboxylase (samdc) gene, a key gene involved in biosynthesis of polyamines, viz. spermidine and spermine and evaluating the transgenic plants for tolerance to both biotic and abiotic stresses. Several putative transgenic tomato plants with normal phenotype were obtained, and the transgene integration and expression was validated by PCR, Southern blot analysis and RT-PCR analysis, respectively. The transgenic plants exhibited high levels of polyamines as compared to the untransformed control plants. They also showed increased resistance against two important fungal pathogens of tomato, the wilt causing Fusarium oxysporum and the early blight causing Alternaria solani and tolerance to multiple abiotic stresses such as salinity, drought, cold and high temperature. These results suggest that engineering polyamine accumulation can confer tolerance to both biotic and abiotic stresses in plants. PMID:23573001

Hazarika, Pranjal; Rajam, Manchikatla Venkat

2011-04-01

212

Thyroglobulin Repression of Thyroid Transcription Factor 1 (TTF-1) Gene Expression Is Mediated by Decreased DNA Binding of Nuclear Factor I Proteins Which Control Constitutive TTF-1 Expression  

Microsoft Academic Search

Follicular thyroglobulin (TG) selectively suppresses the expression of thyroid-restricted transcription fac- tors, thereby altering the expression of thyroid-specific proteins. In this study, we investigated the molecular mechanism by which TG suppresses the prototypic thyroid-restricted transcription factor, thyroid transcrip- tion factor 1 (TTF-1), in rat FRTL-5 thyrocytes. We show that the region between bp 2264 and 2153 on the TTF-1 promoter

MINORU NAKAZATO; HYUN-KYUNG CHUNG; LUCA ULIANICH; ANTONINO GRASSADONIA; KOICHI SUZUKI; LEONARD D. KOHN

2000-01-01

213

The nuclear receptors pregnane X receptor and constitutive androstane receptor contribute to the impact of fipronil on hepatic gene expression linked to thyroid hormone metabolism.  

PubMed

Fipronil is described as a thyroid disruptor in rat. Based on the hypothesis that this results from a perturbation of hepatic thyroid hormone metabolism, our goal was to investigate the pathways involved in fipronil-induced liver gene expression regulations. First, we performed a microarray screening in the liver of rats treated with fipronil or vehicle. Fipronil treatment led to the upregulation of several genes involved in the metabolism of xenobiotics, including the cytochrome P450 Cyp2b1, Cyp2b2 and Cyp3a1, the carboxylesterases Ces2 and Ces6, the phase II enzymes Ugt1a1, Sult1b1 and Gsta2, and the membrane transporters Abcc2, Abcc3, Abcg5, Abcg8, Slco1a1 and Slco1a4. Based on a large overlap with the target genes of constitutive androstane receptor (CAR) and pregnane X receptor (PXR), we postulated that these two nuclear receptors are involved in mediating the effects of fipronil on liver gene expression in rodents. We controlled that liver gene expression changes induced by fipronil were generally reproduced in mice, and then studied the effects of fipronil in wild-type, CAR- and PXR-deficient mice. For most of the genes studied, the gene expression modulations were abolished in the liver of PXR-deficient mice and were reduced in the liver of CAR-deficient mice. However, CAR and PXR activation in mouse liver was not associated with a marked increase of thyroid hormone clearance, as observed in rat. Nevertheless, our data clearly indicate that PXR and CAR are key modulators of the hepatic gene expression profile following fipronil treatment which, in rats, may contribute to increase thyroid hormone clearance. PMID:23962444

Roques, Béatrice B; Leghait, Julien; Lacroix, Marlène Z; Lasserre, Frédéric; Pineau, Thierry; Viguié, Catherine; Martin, Pascal G P

2013-10-01

214

Constitutive expression of RyhB regulates the heme biosynthesis pathway and increases the 5-aminolevulinic acid accumulation in Escherichia coli.  

PubMed

In the current study, the small RNA ryhB, which regulates the metabolism of iron in Escherichia coli, was constitutively expressed in engineered E. coli DALA. The resulting strain E. coli DALRA produced 16% more 5-aminolevulinic acid (ALA) than the parent strain E. coli DALA in batch fermentation. Meanwhile, we found that addition of iron in the medium increased heme formation and reduced ALA yield, whereas the presence of iron chelator in the medium decreased heme concentration and increased the ALA production efficiency (ALA yield per OD600). The qRT-PCR analysis showed that the mRNA levels of hemB and hemH were also decreased as well as the known RyhB target genes of acnAB, sdhAB, fumA, and cydAB in E. coli DALRA. These results indicated that small RNA can be used as a tool for regulating ALA accumulation in E. coli. PMID:24188714

Li, Fangfang; Wang, Yang; Gong, Kai; Wang, Qian; Liang, Quanfeng; Qi, Qingsheng

2014-01-01

215

Constitutive expression of the c-H-ras oncogene inhibits doxorubicin-induced apoptosis and promotes cell survival in a rhabdomyosarcoma cell line.  

PubMed Central

Drugs used in anti-cancer chemotherapy are thought to exert their cytotoxic action by induction of apoptosis. Genes have been identified which can mediate or modulate this drug-induced apoptosis, among which are c-myc, p53 and bcl-2. Since expression of oncogenic ras genes is a frequent observation in human cancer, we investigated the effects of the c-H-ras oncogene on anti-cancer drug-induced apoptosis. Apoptosis induced by a 2 h doxorubicin exposure was measured by in situ nick translation and flow cytometry in a rat cell line (R2T24) stably transfected with the c-H-ras oncogene and in a control cell line (R2NEO) transfected only with the antibiotic resistance gene neo. Both cell lines (R2T24 and R2NEO) had nearly identical growth characteristics, including cell doubling time, distribution over the cell cycle phases and plating efficiency in soft agar. Doxorubicin exposure of the R2NEO cells led to massive induction of apoptosis. In contrast, R2T24 cells, expressing the c-H-ras oncogene, showed significantly less apoptosis after doxorubicin incubation. Doxorubicin induced approximately 3- to 5-fold less cytotoxicity in the R2T24 cells than in the R2NEO cells, as determined by clonogenic assay in soft agar. No difference was observed in intracellular doxorubicin accumulation between the two cell lines, indicating that the classical, P-glycoprotein-mediated multidrug resistance phenotype is not involved in the observed differences in drug sensitivity. In conclusion, our data show that constitutive expression of the c-H-ras oncogene suppresses doxorubicin-induced apoptosis and promotes cell survival, suggesting that human tumours with ras oncogene expression might be less susceptible to doxorubicin treatment.

Nooter, K.; Boersma, A. W.; Oostrum, R. G.; Burger, H.; Jochemsen, A. G.; Stoter, G.

1995-01-01

216

Constitutive heterologous expression of avrXa27 in rice containing the R gene Xa27 confers enhanced resistance to compatible Xanthomonas oryzae strains.  

PubMed

The vascular pathogen Xanthomonas oryzae pv. oryzae (Xoo) and nonvascular pathogen Xanthomonas oryzae pv. oryzicola (Xoc) cause bacterial blight (BB) and bacterial leaf streak (BLS) diseases of rice, respectively. We have previously identified the avirulence gene avrXa27 from Xoo PXO99(A), which specifically induces the expression of the rice resistance gene Xa27, ultimately leading to resistance against BB disease in rice. In this study, we have generated a transgenic rice line (L24) that expresses avrXa27 constitutively under the control of the PR1 promoter, and have examined its role in the host-pathogen interaction. L24 is not more susceptible to BB, indicating that avrXa27 does not contribute to virulence. AvrXa27 retains avirulence activity in L24 and, after crossing with a line containing Xa27, progeny display phenotypic changes including inhibition of tillering, delay in flowering, stiff leaves, early leaf senescence and activation of pathogenesis-related (PR) genes. On challenge with a variety of compatible strains of Xoo and Xoc strain L8, lines with both avrXa27 and Xa27 also show enhanced resistance to bacterial infection. The induction of Xa27 and subsequent inhibition of Xoc growth in Xa27 plants are observed on inoculation with Xoc L8 harbouring avrXa27. Our results indicate that the heterologous expression of avrXa27 in rice containing Xa27 triggers R gene-specific resistance and, at the same time, confers enhanced resistance to compatible strains of Xoo and Xoc. The expression of AvrXa27 and related proteins in plants has the potential to generate broad resistance in plants. PMID:19161350

Tian, Dongsheng; Yin, Zhongchao

2009-01-01

217

Constitutive expression of the pea ABA-responsive 17 (ABR17) cDNA confers multiple stress tolerance in Arabidopsis thaliana.  

PubMed

The constitutive expression of the pea ABR17 (abscisic acid-responsive 17) cDNA, which is a member of the group 10 family of pathogenesis-related proteins (PR 10), in Arabidopsis thaliana is reported. The presence of ABR17 transcripts and the protein in the three transgenic lines is demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) and two-dimensional electrophoresis followed by tandem mass spectrometry, respectively. Three independently derived transgenic lines containing ABR17 germinated better in the presence of salt, cold temperature or both. Furthermore, the transgenic plants also exhibited enhanced tolerance to freezing temperature, suggesting the potential utility of the ABR17 gene to engineer multiple stress tolerance. In order to obtain insights into the mechanism underlying ABR17-mediated stress tolerance, we have compared the proteome of a transgenic line with that of its wild-type counterpart. Several proteins were observed to be significantly altered in the transgenic line, including some with a role(s) in photosynthesis, stress tolerance and the regulation of gene expression. Our findings are discussed within the context of available genes to engineer multiple stress tolerance as well as the biological activities of the ABR17 protein. PMID:17309728

Srivastava, Sanjeeva; Rahman, Muhammad H; Shah, Salehuzzaman; Kav, Nat N V

2006-09-01

218

Interleukin-22 binding protein (IL-22BP) is constitutively expressed by a subset of conventional dendritic cells and is strongly induced by retinoic acid.  

PubMed

Interleukin-22 (IL-22) is mainly produced at barrier surfaces by T cells and innate lymphoid cells and is crucial to maintain epithelial integrity. However, dysregulated IL-22 action leads to deleterious inflammation and is involved in diseases such as psoriasis, intestinal inflammation, and cancer. IL-22 binding protein (IL-22BP) is a soluble inhibitory IL-22 receptor and may represent a crucial regulator of IL-22. We show both in rats and mice that, in the steady state, the main source of IL-22BP is constituted by a subset of conventional dendritic cells (DCs) in lymphoid and non-lymphoid tissues. In mouse intestine, IL-22BP was specifically expressed in lamina propria CD103(+)CD11b(+) DC. In humans, IL-22BP was expressed in immature monocyte-derived DC and strongly induced by retinoic acid but dramatically reduced upon maturation. Our data suggest that a subset of immature DCs may actively participate in the regulation of IL-22 activity in the gut by producing high levels of IL-22BP. PMID:23653115

Martin, J C J; Bériou, G; Heslan, M; Chauvin, C; Utriainen, L; Aumeunier, A; Scott, C L; Mowat, A; Cerovic, V; Houston, S A; Leboeuf, M; Hubert, F X; Hémont, C; Merad, M; Milling, S; Josien, R

2014-01-01

219

Bone-marrow derived hematopoietic stem/progenitor cells express multiple isoforms of NADPH oxidase and produce constitutively reactive oxygen species.  

PubMed

Consolidated evidence highlights the importance of redox signalling in poising the balance between self-renewal and differentiation in adult stem cells. The present study shows that human hematopoietic stem/progenitor cells (HSCs) constitutively generate low levels of hydrogen peroxide whose production is inhibited by DPI, apocynin, catalase, and LY294002 and scarcely stimulated by PMA. Moreover, it is shown that HSCs express at the mRNA and protein levels the catalytic subunits of NOX1, NOX2, and NOX4 isoforms of the NADPH oxidase family along with the complete battery of the regulatory subunits p22, p40, p47, p67, rac1, rac2, NOXO1, and NOXA1 as well as the splicing variant NOX2s and that the three NOX isoforms are largely co-expressed in the same HSC. These findings are interpreted in terms of a positive feed-back mechanism of NOXs activation enabling a fine tuning of the ROS level to be possibly used in redox-mediated signalling for growth and differentiation of HSCs. PMID:17204244

Piccoli, Claudia; D'Aprile, Annamaria; Ripoli, Maria; Scrima, Rosella; Lecce, Lucia; Boffoli, Domenico; Tabilio, Antonio; Capitanio, Nazzareno

2007-02-23

220

Reduced expression of IL-12 p35 by SJL/J macrophages responding to Theiler's virus infection is associated with constitutive activation of IRF-3  

SciTech Connect

Macrophages responding to viral infections may contribute to autoimmune demyelinating diseases (ADD). Macrophages from ADD-susceptible SJL/J mice responding to Theiler's Virus (TMEV) infection, the TLR7 agonist loxoribine, or the TLR4 agonist-LPS expressed less IL-12 p35 but more IL-12/23 p40 and IFN-{beta} than macrophages from ADD-resistant B10.S mice. While expression of IRF-1 and -7 was similar between B10.S and SJL/J TMEV-infected macrophages, SJL/J but not B10.S macrophages exhibited constitutively active IRF-3. In contrast to overexpressed IRF-1, IRF-5, and IRF-7, which stimulated p35 promoter reporter activity, overexpressed IRF-3 repressed p35 promoter activity in response to TMEV infection, loxoribine, IFN-{gamma}/LPS, but not IFN-{gamma} alone. IRF-3 lessened but did not eliminate IRF-1-stimulated p35 promoter activity. Repression by IRF-3 required bp -172 to -122 of the p35 promoter. The data suggest that pre-activated IRF-3 is a major factor in the differences in IL-12 production between B10.S and SJL/J macrophages responding to TMEV.

Dahlberg, Angela [Department of Oral Biology and Nebraska Center for Virology, University of Nebraska Medical Center, 40th and Holdrege Sts., Lincoln, NE 68583-0740 (United States); Auble, Mark R. [Department of Oral Biology and Nebraska Center for Virology, University of Nebraska Medical Center, 40th and Holdrege Sts., Lincoln, NE 68583-0740 (United States); Petro, Thomas M. [Department of Oral Biology and Nebraska Center for Virology, University of Nebraska Medical Center, 40th and Holdrege Sts., Lincoln, NE 68583-0740 (United States)]. E-mail: tpetro@unmc.edu

2006-09-30

221

Quantitative expression profiling of G-protein-coupled receptors (GPCRs) in metastatic melanoma: the constitutively active orphan GPCR GPR18 as novel drug target.  

PubMed

G-protein-coupled receptors (GPCRs) have been implicated in the tumorigenesis and metastasis of human cancers and are considered amongst the most desirable targets for drug development. Utilizing a robust quantitative PCR array, we quantified expression of 94 human GPCRs, including 75 orphan GPCRs and 19 chemokine receptors, and 36 chemokine ligands, in 40 melanoma metastases from different individuals and benign nevi. Inter-metastatic site comparison revealed that orphan GPR174 and CCL28 are statistically significantly overexpressed in subcutaneous metastases, while P2RY5 is overexpressed in brain metastases. Comparison between metastases (all three metastatic sites) and benign nevi revealed that 16 genes, including six orphan receptors (GPR18, GPR34, GPR119, GPR160, GPR183 and P2RY10) and chemokine receptors CCR5, CXCR4, and CXCR6, were statistically significantly differentially expressed. Subsequent functional experiments in yeast and melanoma cells indicate that GPR18, the most abundantly overexpressed orphan GPCR in all melanoma metastases, is constitutively active and inhibits apoptosis, indicating an important role for GPR18 in tumor cell survival. GPR18 and five other orphan GPCRs with yet unknown biological function may be considered potential novel anticancer targets in metastatic melanoma. PMID:20880198

Qin, Y; Verdegaal, E M E; Siderius, M; Bebelman, J P; Smit, M J; Leurs, R; Willemze, R; Tensen, C P; Osanto, S

2011-02-01

222

Abundant constitutive expression of the immediate-early 94K protein from cytomegalovirus (Colburn) in a DNA-transfected mouse cell line.  

PubMed Central

A 94-kilodalton phosphoprotein known as IE94 is the only viral polypeptide synthesized in abundance under immediate-early conditions after infection by cytomegalovirus (CMV) strain Colburn in either permissive primate or nonpermissive rodent cells. The IE94 gene, which maps at coordinates 0.71 to 0.73 in the viral genome, contains a large intron in the 5' leader sequence, and its promoter regulatory region contains novel, multiple-palindromic, repeated elements. Two recombinant plasmids (pTJ148 and pTJ198) containing the 10.5-kilobase-pair HindIII-H DNA fragment from CMV (Colburn) were transfected into mouse Ltk- cells, by either linked or unlinked coselection in hypoxanthine-aminopterin-thymidine medium, together with herpes simplex virus thymidine kinase genes. With both procedures, constitutive synthesis of the IE94 immediate-early protein was detected in pools of Ltk+ cells by immunoprecipitation. Subsequently, we isolated a clonal Ltk+ cell line which expressed the [35S]methionine-labeled IE94 polypeptide in sufficient abundance to be visualized directly in autoradiographs after gel electrophoresis of total-cell-culture protein extracts. The IE94 polypeptide synthesized in the transfected cells was indistinguishable in size and overall net charge from that produced in virus-infected cells. In addition, the IE94 protein expressed in LH2p198-3 cells was phosphorylated (presumably by a cellular protein kinase) and generated similar phosphopeptide patterns after partial tryptic digestion to those obtained with the CMV IE94 protein from infected cells. The cell line contained two to four stably integrated copies of the IE94 gene and synthesized a single virus-specific mRNA of 2.5 kilobases detectable on Northern blots. A new antigen, detectable by indirect anticomplement immunofluorescence with monoclonal antibody against the human CMV IE68 protein, was present in the nuclei of more than 95% of the LH2p198-3 cells. This evidence suggests that (unlike most herpesvirus genes) the CMV IE94 gene, together with its complex promoter and spliced mRNA structure, may contain all of the regulatory elements necessary for strong constitutive expression in mammalian cells in the absence of other viral factors. Images

Jeang, K T; Cho, M S; Hayward, G S

1984-01-01

223

Cell surface expression of bacterial esterase A by Saccharomyces cerevisiae and its enhancement by constitutive activation of the cellular unfolded protein response.  

PubMed

Yeast cell surface display is a powerful tool for expression and immobilization of biocatalytically active proteins on a unicellular eukaryote. Here bacterial carboxylesterase EstA from Burkholderia gladioli was covalently anchored into the cell wall of Saccharomyces cerevisiae by in-frame fusion to the endogenous yeast proteins Kre1p, Cwp2p, and Flo1p. When p-nitrophenyl acetate was used as a substrate, the esterase specific activities of yeast expressing the protein fusions were 103 mU mg(-1) protein for Kre1/EstA/Cwp2p and 72 mU mg(-1) protein for Kre1/EstA/Flo1p. In vivo cell wall targeting was confirmed by esterase solubilization after laminarinase treatment and immunofluorescence microscopy. EstA expression resulted in cell wall-associated esterase activities of 2.72 U mg(-1) protein for Kre1/EstA/Cwp2p and 1.27 U mg(-1) protein for Kre1/EstA/Flo1p. Furthermore, esterase display on the yeast cell surface enabled the cells to effectively grow on the esterase-dependent carbon source glycerol triacetate (Triacetin). In the case of Kre1/EstA/Flo1p, in vivo maturation within the yeast secretory pathway and final incorporation into the wall were further enhanced when there was constitutive activation of the unfolded protein response pathway. Our results demonstrate that esterase cell surface display in yeast, which, as shown here, is remarkably more effective than EstA surface display in Escherichia coli, can be further optimized by activating the protein folding machinery in the eukaryotic secretion pathway. PMID:16980424

Breinig, Frank; Diehl, Björn; Rau, Sabrina; Zimmer, Christian; Schwab, Helmut; Schmitt, Manfred J

2006-11-01

224

Constitutive expression of a COOH-terminal leucine mutant of lysosome-associated membrane protein-1 causes its exclusive localization in low density intracellular vesicles.  

PubMed

Lysosome-associated membrane protein-1 (LAMP-1) is a type I transmembrane protein with a short cytoplasmic tail that possesses a lysosome-targeting signal of GYQTI(382)-COOH. Wild-type (WT)-LAMP-1 was exclusively localized in high density lysosomes, and efficiency of LAMP-1's transport to lysosomes depends on its COOH-terminal amino acid residue. Among many different COOH-terminal amino acid substitution mutants of LAMP-1, a leucine-substituted mutant (I382L) displays the most efficient targeting to late endosomes and lysosomes [Akasaki et al. (2010) J. Biochem. 148: , 669-679]. In this study, we generated two human hepatoma cell lines (HepG2 cell lines) that stably express WT-LAMP-1 and I382L, and compared their intracellular distributions. The subcellular fractionation study using Percoll density gradient centrifugation revealed that WT-LAMP-1 had preferential localization in the high density secondary lysosomes where endogenous human LAMP-1 was enriched. In contrast, a major portion of I382L was located in a low density fraction. The low density fraction also contained approximately 80% of endogenous human LAMP-1 and significant amounts of endogenous ?-glucuronidase and LAMP-2, which probably represents occurrence of low density lysosomes in the I382L-expressing cells. Double immunofluorescence microscopic analyses distinguished I382L-containing intracellular vesicles from endogenous LAMP-1-containing lysosomes and early endosomes. Altogether, constitutive expression of I382L causes its aberrant intracellular localization and generation of low density lysosomes, indicating that the COOH-terminal isoleucine is critical for normal localization of LAMP-1 in the dense lysosomes. PMID:24695761

Akasaki, Kenji; Shiotsu, Keiko; Michihara, Akihiro; Ide, Norie; Wada, Ikuo

2014-07-01

225

Incomplete transfer of accessory loci influencing SbMATE expression underlies genetic background effects for aluminum tolerance in sorghum.  

PubMed

Impaired root development caused by aluminum (Al) toxicity is a major cause of grain yield reduction in crops cultivated on acid soils, which are widespread worldwide. In sorghum, the major Al-tolerance locus, Alt(SB) , is due to the function of SbMATE, which is an Al-activated root citrate transporter. Here we performed a molecular and physiological characterization of various Alt(SB) donors and near-isogenic lines harboring various Alt(SB) alleles. We observed a partial transfer of Al tolerance from the parents to the near-isogenic lines that was consistent across donor alleles, emphasizing the occurrence of strong genetic background effects related to Alt(SB) . This reduction in tolerance was variable, with a 20% reduction being observed when highly Al-tolerant lines were the Alt(SB) donors, and a reduction as great as 70% when other Alt(SB) alleles were introgressed. This reduction in Al tolerance was closely correlated with a reduction in SbMATE expression in near-isogenic lines, suggesting incomplete transfer of loci acting in trans on SbMATE. Nevertheless, Alt(SB) alleles from the highly Al-tolerant sources SC283 and SC566 were found to retain high SbMATE expression, presumably via elements present within or near the Alt(SB) locus, resulting in significant transfer of the Al-tolerance phenotype to the derived near-isogenic lines. Allelic effects could not be explained by coding region polymorphisms, although occasional mutations may affect Al tolerance. Finally, we report on the extensive occurrence of alternative splicing for SbMATE, which may be an important component regulating SbMATE expression in sorghum by means of the nonsense-mediated RNA decay pathway. PMID:22989115

Melo, Janaina O; Lana, Ubiraci G P; Piñeros, Miguel A; Alves, Vera M C; Guimarães, Claudia T; Liu, Jiping; Zheng, Yi; Zhong, Silin; Fei, Zhangjun; Maron, Lyza G; Schaffert, Robert E; Kochian, Leon V; Magalhaes, Jurandir V

2012-09-18

226

A Constitutive Expressed Phosphate Transporter, OsPht1;1, Modulates Phosphate Uptake and Translocation in Phosphate-Replete Rice1[W][OA  

PubMed Central

A number of phosphate (Pi) starvation- or mycorrhiza-regulated Pi transporters belonging to the Pht1 family have been functionally characterized in several plant species, whereas functions of the Pi transporters that are not regulated by changes in Pi supply are lacking. In this study, we show that rice (Oryza sativa) Pht1;1 (OsPT1), one of the 13 Pht1 Pi transporters in rice, was expressed abundantly and constitutively in various cell types of both roots and shoots. OsPT1 was able to complement the proton-coupled Pi transporter activities in a yeast mutant defective in Pi uptake. Transgenic plants of OsPT1 overexpression lines and RNA interference knockdown lines contained significantly higher and lower phosphorus concentrations, respectively, compared with the wild-type control in Pi-sufficient shoots. These responses of the transgenic plants to Pi supply were further confirmed by the changes in depolarization of root cell membrane potential, root hair occurrence, 33P uptake rate and transportation, as well as phosphorus accumulation in young leaves at Pi-sufficient levels. Furthermore, OsPT1 expression was strongly enhanced by the mutation of Phosphate Overaccumulator2 (OsPHO2) but not by Phosphate Starvation Response2, indicating that OsPT1 is involved in the OsPHO2-regulated Pi pathway. These results indicate that OsPT1 is a key member of the Pht1 family involved in Pi uptake and translocation in rice under Pi-replete conditions.

Sun, Shubin; Gu, Mian; Cao, Yue; Huang, Xinpeng; Zhang, Xiao; Ai, Penghui; Zhao, Jianning; Fan, Xiaorong; Xu, Guohua

2012-01-01

227

Constitutive expression of mouse mast cell protease-1 in normal BALB/c mice and its up-regulation during intestinal nematode infection.  

PubMed Central

Rodent intestinal mucosal mast cells (IMMC) store and secrete soluble granule serine proteases, the beta-chymases, which may promote epithelial permeability during intestinal hypersensitivity reactions. The beta-chymase mouse mast cell protease-1 (mMCP-1) is generally considered to be expressed late in the in vitro differentiation of mast cells. The purpose of this study was to determine the kinetics of mMCP-1 transcription and expression in vivo during nematode-induced IMMC hyperplasia. Concentrations of mMCP-1 in blood and jejunum of BALB/c mice were quantified by enzyme-linked immunosorbent assay before and at various stages after infection with the intestinal nematode Nippostronglyus brasilliensis. Mature mMCP-1 enzyme was detected in jejunal homogenate (194 ng/mg soluble protein) and in blood (8.3 ng/ml serum) from normal uninfected BALB/c mice. Maximal IMMC hyperplasia occurred 7-14 days post infection and was significantly correlated with increased levels of mMCP-1 in jejunum (r = 0.58, P < 0.001) and with raised concentrations of mMCP-1 in serum (r = 0.66, P < 0.001). Transcription of the mMCP-1 gene was detected by RNA blotting in normal, uninfected jejunum, but transcription was up-regulated after infection with maximal transcription occurring on days 7 and 14. In conclusion, mMCP-1 transcription, storage and secretion occur constitutively in normal BALB/c jejunum but this basal secretion is up-regulated during nematode infection, suggesting both a physiological and pathological function for this protease. Images Figure 4

Wastling, J M; Scudamore, C L; Thornton, E M; Newlands, G F; Miller, H R

1997-01-01

228

Altered methylation and expression of ER-associated degradation factors in long-term alcohol and constitutive ER stress-induced murine hepatic tumors.  

PubMed

Mortality from liver cancer in humans is increasingly attributable to heavy or long-term alcohol consumption. The mechanisms by which alcohol exerts its carcinogenic effect are not well understood. In this study, the role of alcohol-induced endoplasmic reticulum (ER) stress response in liver cancer development was investigated using an animal model with a liver knockout (KO) of the chaperone BiP and under constitutive hepatic ER stress. Long-term alcohol and high fat diet feeding resulted in higher levels of serum alanine aminotransferase, impaired ER stress response, and higher incidence of liver tumor in older (aged 16 months) KO females than in either middle-aged (6 months) KOs or older (aged 16 months) wild type females. In the older KO females, stronger effects of the alcohol on methylation of CpG islands at promoter regions of genes involved in the ER-associated degradation (ERAD) were also detected. Altered expression of ERAD factors including derlin 3, Creld2 (cysteine-rich with epidermal growth factor-like domains 2), Herpud1 (homocysteine-inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member), Wfs1 (Wolfram syndrome gene), and Yod1 (deubiquitinating enzyme 1) was co-present with decreased proteasome activities, increased estrogen receptor ? variant (ER?36), and enhanced phosphorylations of ERK1/2 (extracellular signal-regulated protein kinases 1 and 2) and STAT3 (the signal transducers and activators of transcription) in the older KO female fed alcohol. Our results suggest that long-term alcohol consumption and aging may promote liver tumorigenesis in females through interfering with DNA methylation and expression of genes involved in the ERAD. PMID:24198826

Han, Hui; Hu, Jay; Lau, Mo Y; Feng, Min; Petrovic, Lydia M; Ji, Cheng

2013-01-01

229

Double-negative T cells from MRL-lpr/lpr mice mediate cytolytic activity when triggered through adhesion molecules and constitutively express perforin gene  

PubMed Central

The lpr gene induces in mice, accumulation of large numbers of CD4-CD8- (double negative [DN]) T lymphocytes which bear adhesion molecules not characteristic of normal resting T cells. These cells fail to acquire interleukin 2 (IL-2) receptors, produce IL-2, and proliferate when activated with mitogens or monoclonal antibodies (mAbs) against the T cell receptor (TCR). Because of these poor functions in vitro, the nature and significance of DN T cells in the autoimmune disease process is not clear. In the current study, we describe a surprising finding that mAbs against CD3-TCR-alpha/beta complex can strongly trigger the lytic activity of the DN T cells to induce redirected lysis of Fc receptor-positive targets. Similar redirected lysis was also inducible using mAbs against CD44 and gp90MEL-14, molecules involved in the binding of lymphocytes to endothelial cells. The spontaneous cytotoxic potential of the DN T cells was further corroborated by demonstrating that the lpr DN T cells constitutively transcribed perforin gene but failed to express granzyme A. The current study suggests that DN T cells are capable of mediating lysis of autologous cells bearing the specific ligands for adhesion molecules involved in the signaling of cytotoxicity. These findings provide a novel insight into the functional significance of DN T cells in lpr mice and their potential role in the pathogenesis of autoimmune disease.

1993-01-01

230

Generation of a permanent cell line that supports efficient growth of Marek's disease virus (MDV) by constitutive expression of MDV glycoprotein E.  

PubMed

A recombinant cell line (SOgE) was established, which was derived from the permanent quail muscle cell line QM7 and constitutively expressed the glycoprotein E (gE) gene of Marek's disease virus serotype 1 (MDV-1). The SOgE cell line supported growth of virulent (RB-1B) and vaccine (CVI988, 584Ap80C) MDV-1 strains at a level comparable with that of primary chicken embryo cells (CEC). The SOgE cell line was used to produce a vaccine against Marek's disease. Chickens were immunized at 1 day old with 10(3) p.f.u. CVI988 produced on either CEC or SOgE cells. Challenge infection was performed at day 12 with hypervirulent Italian MDV-1 strain EU1. Whereas 7/7 or 6/6 animals, respectively, immunized with SOgE or QM7 cells alone developed Marek's disease, only 1/8 animals from both CVI988-immunized groups exhibited signs of disease, suggesting that SOgE cells are a valuable permanent cell culture system for MDV-1 vaccine production. PMID:12124462

Schumacher, Daniel; Tischer, B Karsten; Teifke, Jens-Peter; Wink, Kerstin; Osterrieder, Nikolaus

2002-08-01

231

Characterization and constitutive expression of an acidic mesophilic endo-1,4-?-D-xylanohydrolase with high thermotolerance and catalytic efficiency in Pichia pastoris.  

PubMed

A putative endo-1,4-?-D-xylanohydrolase gene xyl11 from Aspergillus niger, encoding a 188-residue xylanase of glycosyl hydrolase family 11, was constitutively expressed in Pichia pastoris. The recombinant Xyl11 exhibited optimal activity at pH 5.0 and 50 °C, and displayed more than 68 % of the maximum activity over the temperature range 35-65 °C and 33 % over the pH range 2.2-7.0. It maintained more than 40 % of the original activity after incubation at 90 °C (pH 5.0) for 10 min and more than 75 % of the original activity after incubation at pH 2.2-11.0 (room temperature) for 2 h. The specific activity, K m and V max of purified Xyl11 were 22,253 U mg(-1), 6.57 mg ml(-1) and 51,546.4 ?mol min(-1) mg(-1). It could degrade xylan to a series of xylooligosaccharides and no xylose was detected. The recombinant enzyme with high stability and catalytic efficiency could work over wide ranges of pH and temperature and thus has the potential for various industrial applications. PMID:23670313

Guo, Ning; Zheng, Jia; Tian, Jian; Wu, Lishuang; Zhou, Hongbo

2013-11-01

232

Modulation of constitutive nitric oxide synthase, bcl-2 and Fas expression in cultured human coronary endothelial cells exposed to anoxia-reoxygenation and angiotensin II: role of AT1 receptor activation  

Microsoft Academic Search

Background: Angiotensin II (Ang II) plays a critical role in the pathophysiology of myocardial ischemia-reperfusion injury. We have recently shown that reoxygenation following a period of anoxia causes apoptosis of cultured human coronary artery endothelial cells (HCAECs). Ang II further enhances apoptosis of HCAECs via Ang II type 1 receptor (AT1R) activation. Recent studies suggest an important role of constitutive

Dayuan Li; Kathleen Tomson; Baichun Yang; Paulette Mehta; Byron P. Croker; Jawahar L. Mehta

233

Different strategies for reducing intestinal background radioactivity associated with imaging HSV1-tk expression using established radionucleoside probes.  

PubMed

One limitation of HSV1-tk reporter positron emission tomography (PET) with nucleoside analogues is the high background radioactivity in the intestine. We hypothesized that endogenous expression of thymidine kinase in bacterial flora could phosphorylate and trap such radiotracers, contributing to the high radioactivity levels in the bowel, and therefore explored different strategies to increase fecal elimination of radiotracer. Intestinal radioactivity was assessed by in vivo microPET imaging and ex vivo tissue sampling following intravenous injection of 18F-FEAU, 124I-FIAU, or 18F-FHBG in a germ-free mouse strain. We also explored the use of an osmotic laxative agent and/or a 100% enzymatically hydrolyzed liquid diet. No significant differences in intestinal radioactivity were observed between germ-free and normal mice. 18F-FHBG-derived intestinal radioactivity levels were higher than those of 18F-FEAU and 124I-FIAU; the intestine to blood ratio was more than 20-fold higher for 18F-FHBG than for 18F-FEAU and 124I-FIAU. The combination of Peptamen and Nulytely lowered intestinal radioactivity levels and increased (2.2-fold) the HSV1-tk transduced xenograft to intestine ratio for 18F-FEAU. Intestinal bacteria in germ-free mice do not contribute to the high intestinal levels of radioactivity following injection of radionucleoside analogues. The combination of Peptamen and Nulytely increased radiotracer elimination by increasing bowel motility without inducing dehydration. PMID:20128998

Ruggiero, Alessandro; Brader, Peter; Serganova, Inna; Zanzonico, Pat; Cai, Shangde; Lipman, Neil S; Hricak, Hedvig; Blasberg, Ronald G

2010-02-01

234

Different strategies for reducing intestinal background radioactivity associated with imaging HSV1-tk expression using established radionucleoside probes  

PubMed Central

One limitation of HSV1-tk reporter PET imaging with nucleoside analogues is the high background radioactivity in the intestine. We hypothesized that endogenous expression of thymidine kinase in bacterial flora could phosphorylate and trap such radiotracers, contributing to the high radioactivity levels in the bowel and therefore explored different strategies to increase fecal elimination of radiotracer. Methods Intestinal radioactivity was assessed by in vivo microPET imaging and ex vivo tissue sampling following intravenous injection of 18F-FEAU, 124I-FIAU or 18F-FHBG in a germ-free mouse strain. We also explored the use of an osmotic laxative agent and/or a 100% enzymatically hydrolyzed liquid diet. Results No significant differences in intestinal radioactivity were observed between germ-free and normal mice. 18F-FHBG-derived intestinal radioactivity levels were higher than those of 18F-FEAU and 124I-FIAU; the intestine-to-blood ratio was more than 20-fold higher for 18F-FHBG than for 18F-FEAU and 124I-FIAU. The combination of Peptamen and Nulytely lowered intestinal radioactivity levels and increased (2.2-fold) the HSV1-tk transduced xenograft-to-intestine ratio for 18F-FEAU. Conclusions Intestinal bacteria in germ-free mice do not contribute to the high intestinal levels of radioactivity following injection of radionucleoside analogs. The combination of Peptamen and Nulytely increased radiotracer elimination by increasing bowel motility without inducing dehydration.

Ruggiero, Alessandro; Brader, Peter; Serganova, Inna; Zanzonico, Pat; Cai, Shangde; Lipman, Neil S.; Hricak, Hedvig; Blasberg, Ronald G.

2011-01-01

235

Constitutive expression of an inducible ?-1,3-glucanase in alfalfa reduces disease severity caused by the oomycete pathogen Phytophthora megasperma f. sp medicaginis , but does not reduce disease severity of chitin-containing fungi  

Microsoft Academic Search

cDNA sequences coding for an acidic glucanase (Aglul) that is expressed in elicited alfalfa cell suspension cultures, and a rice basic chitinase (RCH10) that is induced by elicitor and wounding, were placed into constitutive expression cassettes under control of the cauliflower mosaic virus 35S promoter or 35S enhancer sequences, and introduced in alfalfa plants of the regenerable cultivar Regen SY

Sameer A. Masoud; Qun Zhu; Chris Lamb; Richard A. Dixon

1996-01-01

236

Only the promoter region of the constitutively expressed normal and amplified human dihydrofolate reductase gene is DNase I hypersensitive and undermethylated.  

PubMed

The human dihydrofolate reductase (DHFR) gene was found to be undermethylated only in its 5' promoter region; the remaining CCGG residues in the 30-kilobase (kb) DHFR gene were insensitive to digestion by HpaII. Each of 27 CpG residues that were part of an HpaII or HhaI cutting site within a 1.1-kb segment of the DHFR gene promoter region were found to be unmethylated. All 80 copies of the DHFR gene in methotrexate-resistant HeLa cell line exhibited this pattern of undermethylation of only the promoter region. This same region was shown to be DNase I hypersensitive in chromatin from normal cells and from those cells in which the DHFR gene was amplified. Again, all copies of the amplified gene exhibited DNase I hypersensitivity of the promoter region. The remainder of the 30-kb DHFR gene is both completely methylated and insensitive to DNase I digestion. Detailed mapping of the DNase I-hypersensitive region revealed four strong cutting sites within a 500-base pair segment immediately upstream from the DHFR coding sequence and a weak cutting site within intron I. Two of the strong DNase I cutting sites in chromatin were also sensitive to S1 nuclease nicking when this DNA fragment was part of supercoiled plasmid DNA. Promoter undermethylation and DNase I hypersensitivity, features previously shown for specialized and inducible genes, have now been shown to be characteristic of the constitutively expressed DHFR gene. That these features characterize all copies of the amplified DHFR gene in a methotrexate-resistant cell line suggest that all gene copies are transcriptionally active. PMID:2982820

Shimada, T; Nienhuis, A W

1985-02-25

237

Constitutive expression of a salinity-induced wheat WRKY transcription factor enhances salinity and ionic stress tolerance in transgenic Arabidopsis thaliana  

SciTech Connect

Highlights: •A class II WRKY transcription factor, TaWRKY79 was isolated and characterized. •TaWRKY79 was induced by NaCl or abscisic acid. •843 bp regulatory segment was sufficient to respond to ABA or NaCl treatment. •TaWRKY79 enhanced salinity and ionic tolerance while reduced sensitivity to ABA. •TaWRKY79 increased salinity and ionic tolerance in an ABA-dependent pathway. -- Abstract: The isolation and characterization of TaWRKY79, a wheat class II WRKY transcription factor, is described. Its 1297 bp coding region includes a 987 bp long open reading frame. TaWRKY79 was induced by stressing seedlings with either NaCl or abscisic acid (ABA). When a fusion between an 843 bp segment upstream of the TaWRKY79 coding sequence and GUS was introduced into Arabidopsis thaliana, GUS staining indicated that this upstream segment captured the sequence(s) required to respond to ABA or NaCl treatment. When TaWRKY79 was constitutively expressed as a transgene in A. thaliana, the transgenic plants showed an improved capacity to extend their primary root in the presence of either 100 mM NaCl, 10 mM LiCl or 2 ?M ABA. The inference was that TaWRKY79 enhanced the level of tolerance to both salinity and ionic stress, while reducing the level of sensitivity to ABA. The ABA-related genes ABA1, ABA2 ABI1 and ABI5 were all up-regulated in the TaWRKY79 transgenic plants, suggesting that the transcription factor operates in an ABA-dependent pathway.

Qin, Yuxiang, E-mail: yuxiangqin@126.com [Department of Biotechnology, University of Jinan, Jinan 250022 (China)] [Department of Biotechnology, University of Jinan, Jinan 250022 (China); Tian, Yanchen [The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan 250100 (China)] [The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan 250100 (China); Han, Lu; Yang, Xinchao [Department of Biotechnology, University of Jinan, Jinan 250022 (China)] [Department of Biotechnology, University of Jinan, Jinan 250022 (China)

2013-11-15

238

A Constitutively Expressed, Truncated umuDC Operon Regulates the recA-Dependent DNA Damage Induction of a Gene in Acinetobacter baylyi Strain ADP1  

PubMed Central

In response to environmentally caused DNA damage, SOS genes are up-regulated due to RecA-mediated relief of LexA repression. In Escherichia coli, the SOS umuDC operon is required for DNA damage checkpoint functions and for replicating damaged DNA in the error-prone process called SOS mutagenesis. In the model soil bacterium Acinetobacter baylyi strain ADP1, however, the content, regulation, and function of the umuDC operon are unusual. The umuC gene is incomplete, and a remnant of an ISEhe3-like transposase has replaced the middle 57% of the umuC coding region. The umuD open reading frame is intact, but it is 1.5 times the size of other umuD genes and has an extra 5? region that lacks homology to known umuD genes. Analysis of a umuD::lacZ fusion showed that umuD was expressed at very high levels in both the absence and presence of mitomycin C and that this expression was not affected in a recA-deficient background. The umuD mutation did not affect the growth rate or survival after UV-induced DNA damage. However, the UmuD-like protein found in ADP1 (UmuDAb) was required for induction of an adjacent DNA damage-inducible gene, ddrR. The umuD mutation specifically reduced the DNA damage induction of the RecA-dependent DNA damage-inducible ddrR locus by 83% (from 12.9-fold to 2.3-fold induction), but it did not affect the 33.9-fold induction of benA, an unrelated benzoate degradation gene. These data suggest that the response of the ADP1 umuDC operon to DNA damage is unusual and that UmuDAb specifically regulates the expression of at least one DNA damage-inducible gene.

Hare, Janelle M.; Perkins, Sara N.; Gregg-Jolly, Leslie A.

2006-01-01

239

The Constitutional Amendment Process  

ERIC Educational Resources Information Center

This article discusses the constitutional amendment process. Although the process is not described in great detail, Article V of the United States Constitution allows for and provides instruction on amending the Constitution. While the amendment process currently consists of six steps, the Constitution is nevertheless quite difficult to change.…

Chism, Kahlil

2005-01-01

240

The interaction with Sp1 and reduction in the activity of histone deacetylase 1 are critical for the constitutive gene expression of IL1 in human melanoma cells  

Microsoft Academic Search

A375-6 human melanoma cells are sen- sitive to the antiproliferative effect of IL-1. After a long period of culturing, we have obtained cells resistant to IL-1. The resistant clone A375-R8 constitutively produced IL-1. In this study, we identified a sequence, CGCC, located at -48 to -45 upstream of the transcription start site, to be essential for the constitutive IL-1 gene

Kazuaki Enya; Hidetoshi Hayashi; Takemasa Takii; Nobumichi Ohoka; Shinya Kanata; Takashi Okamoto; Kikuo Onozaki

2008-01-01

241

Overexpression of chicken interferon regulatory factor-1 (Ch-IRF-1) induces constitutive expression of MHC class I antigens but does not confer virus resistance to a permanent chicken fibroblast cell line.  

PubMed

The chicken fibroblast cell line C32 has been transfected with the chicken homolog (Ch-IRF-1) of the mammalian transcription factor IRF-1. Stable transfectants were generated, constitutively overexpressing Ch-IRF-1 mRNA and protein. Cells overexpressing Ch-IRF-1 showed enhanced constitutive expression of MHC class I (B-F, beta-microglobulin) antigens. With increasing number of passages cells with normal B-F IV surface antigen expression accumulated. In the revertants, the amount of Ch-IRF-1 mRNA was reduced. Overexpression of Ch-IRF-1 had no effect on the constitutive expression and the induction by chicken interferon type-I and type-II (Ch-IFN) of guanylate-binding protein (GBP). Susceptibility to vesicular stomatitis virus, sindbis virus, Newcastle disease virus and vaccinia virus was not altered by overexpression of Ch-IRF-1. An antiviral state could be induced against all viruses tested by similar amounts of Ch-IFN type I in clone 20-18 expressing Ch-IRF-1 and cells transfected with empty vector. PMID:9831662

Zoeller, B; Popp, M; Walter, A; Redmann-Müller, I; Lodemann, E; Jungwirth, C

1998-11-19

242

Constitutive nuclear factor kappaB activity is required to elicit interferon-gamma-induced expression of chemokine CXC ligand 9 (CXCL9) and CXCL10 in human tumour cell lines.  

PubMed Central

CXC ligand 10 (CXCL10) and CXCL9 are chemoattractants for activated T cells and possess angiostatic activity. Both CXCL9 and CXCL10 have been considered as important components for the anti-tumour activities of interferon-gamma (IFNgamma) and interleukin-12 in animal models. In this article we show that the CXCL9 and CXCL10 genes in some types of human tumour cell lines are not inducible by IFNgamma and we describe experiments designed to explore the molecular mechanisms involved in this impaired induction. The human oral squamous carcinoma line Ca9-22 and the glioma line A172 failed to express CXCL9 and CXCL10 mRNAs in response to IFNgamma, whereas other carcinoma lines including HSC-2 did express these mRNAs. Production of these chemokine proteins was also impaired in Ca9-22 cells. The impaired expression was not due to any deficiency in the IFNgamma/signal transducer and activator of transcription 1 (STAT1)-dependent signalling pathway. Instead, analysis of nuclear factor kappaB (NF-kappaB) activity revealed that the constitutive low level of NF-kappaB activity, which is seen in cells that express these chemokines, was absent in Ca9-22 and A172 cells. Activation of NF-kappaB in Ca9-22 cells restored the expression of IFNgamma-stimulated CXCL9 and CXCL10 mRNAs. In contrast, inhibition of the constitutive NF-kappaB in HSC-2 cells by adenovirus-mediated gene transfer of a dominant-negative IkappaBalpha suppressed the IFNgamma-induced expression of the CXCL9 and CXCL10 mRNAs. These results indicate that constitutive NF-kappaB activity, which is often associated with tumour development, is required for the induced expression of CXCL9 and CXCL10 genes in human tumour cell lines in response to IFNgamma.

Hiroi, Miki; Ohmori, Yoshihiro

2003-01-01

243

Cloning of a novel constitutively expressed pectate lyase gene pelB from Fusarium solani f. sp. pisi (Nectria haematococca, mating type VI) and characterization of the gene product expressed in Pichia pastoris.  

PubMed Central

Since plant-pathogenic fungi must penetrate through pectinaceous layers of the host cell wall, pectin-degrading enzymes are thought to be important for pathogenesis. Antibodies prepared against a pectin-inducible pectate lyase (pectate lyase A [PLA]) produced by a phytopathogenic fungus, Fusarium solani f. sp. pisi (Nectria haematococca, mating type VI), was previously found to protect the host from infection. The gene (pelA) and its cDNA were cloned and sequenced. Here we report the isolation of a new pectate lyase gene, pelB, from a genomic library of F. solani f. sp. pisi with the pelA cDNA as the probe. A 2.6-kb DNA fragment containing pelB and its flanking regions was sequenced. The coding region of pelB was amplified by reverse transcription-mediated PCR, using total RNA isolated from F. solani pisi culture grown in the presence of glucose as the sole carbon source. The predicted open reading frame of pelB would encode a 25.6-kDa protein of 244 amino acids which has 65% amino acid sequence identity with PLA from F. solani f. sp. pisi but no significant homology with other pectinolytic enzymes. The first 16 amino acid residues at the N terminus appeared to be a signal peptide. The pelB cDNA was expressed in Pichia pastoris, yielding a pectate lyase B (PLB) which was found to be a glycoprotein of 29 kDa. PLB was purified to homogeneity by using a two-step procedure involving ammonium sulfate precipitation followed by Superdex G75 gel filtration chromatography. Purified PLB showed optimal lyase activity at pH 10.0. A rapid drop in the viscosity of the substrate and Mono Q anion-exchange chromatography of the products generated by the lyase showed that PLB cleaved polygalacturonate chains in an endo fashion. Western blotting (immunoblotting) with antibodies raised against PLA showed that PLB and PLA are immunologically related to each other. The 5' flanking regions of both pelA and pelB were translationally fused to the beta-glucuronidase gene and introduced into F. solani f. sp. pisi, and beta-glucuronidase activities of the transformants were measured. Expression of the marker gene by the transformants showed that pelA expression is induced by pectin and repressed by glucose, whereas expression of pelB is constitutive and is not subject to glucose repression. Reverse transcription-mediated PCR showed that both pelA and pelB are expressed when F. solani f. sp. pisi infects pea epicotyl.

Guo, W; Gonzalez-Candelas, L; Kolattukudy, P E

1995-01-01

244

Expression of green fluorescent protein in Bacillus brevis under the control of a novel constitutive promoter F1 and insertion mutagenesis of F1 in Escherichia coli DH5alpha.  

PubMed

The constitutive expression vector pHY300-F1gfp was constructed to test the function of a promoter, F1, cloned from the rice epiphyte Bacillus brevis strain DX01. The DX01 cells harboring the plasmid pHY300-F1gfp were shown to produce bright green fluorescence. The results were confirmed by Western blot analysis and fluorescence-activated cell sorting. Expression of the F1 promoter was constitutive. To improve the activity of F1, insertion mutagenesis of F1 based on in vitro transposition reaction was performed. Seven mutants with enhanced transcription activity in Escherichia coli DH5alpha were obtained. The enhanced promoters showed similar high activities in B. brevis strain DX01. PMID:14659550

Chen, Yunpeng; Yan, Jian; Yang, Mingjie; Wang, Jingwen; Shen, Daleng

2003-12-01

245

Survival and Degradative Capacity of 'Pseudomonas putida' Induced or Constitutively Expressing Plasmid-Mediated Degradation of 2,4-Dichlorophenoxyacetate (TFD) in Soil.  

National Technical Information Service (NTIS)

The survival of genetically altered Pseudomonas putida strains harboring an inducible plasmid, pR0101, or a constitutive plasmid, pR0103, was compared. These plasmids encode for the degradation of 2,4-dichlorophenoxyacetate (TFD) to 2-chloromaleylacetate,...

K. A. Short R. J. Seidler R. H. Olsen

1990-01-01

246

America's Lived Constitution  

Microsoft Academic Search

This Feature is an adaptation of chapter 3 of a forthcoming book, America's Unwritten Constitution, which in turn is a sequel to a 2005 book, America's Constitution: A Biography. The 2005 book explores America's written Constitution in considerable detail, taking readers on a journey that begins with the Preamble and proceeds through the document, Article by Article and Amendment by

Akhil R Amar

2011-01-01

247

Non-competitive antagonism of beta(2)-agonist-mediated cyclic AMP accumulation by ICI 118551 in BC3H1 cells endogenously expressing constitutively active beta(2)-adrenoceptors.  

PubMed

Constitutive activity of the beta(2)-adrenoceptor, which is sensitive to inhibition by an inverse agonist such as ICI 118551, has been readily demonstrated in recombinant systems expressing constitutively-active mutant receptors or over-expressing the wild-type beta(2)-adrenoceptor. Here we demonstrate the presence of constitutive beta(2)-adrenoceptor activity in BC3H1 cells which endogenously express this receptor. In BC3H1 cells, only ICI 118551 behaved as an inverse agonist at beta(2)-adrenoceptors, while propranolol, ICI 118551, atenolol and, to a lesser extent, alprenolol exhibited inverse agonism in CHO-beta(2)4 cells transfected with cDNA for the human beta(2)-adrenoceptor (310 fmol. mg protein(-1)). The level of expression of beta2-adrenoceptors in BC3H1 cells was not high (78 fmol.mg protein-1) and the efficiency of receptor - effector coupling in this cell line was much lower than in the recombinant CHO-beta(2)4 cells (as judged by the partial agonist nature of both salbutamol and clenbuterol). ICI 118551 (log K(D)-9.73+/-0.07) and propranolol (log K(D)-9.25+/-0.12) both behaved as conventional competitive antagonists of isoprenaline-stimulated cyclic AMP accumulation in high expressing CHO-beta(2)4 cells. In contrast, ICI 118551 appeared to act as a non-competitive antagonist in BC3H1 cells and in low expressing CHO-beta(2)6 cells (50 fmol.mg protein(-1)). This non-competitive effect of ICI 118551 in BC3H1 cells was also observed when either salbutamol was used as agonist, or the incubation period with isoprenaline was extended to 30 min. The possibility that these effects of ICI 118551 are due to an interaction with different affinity states (R, R* and R') of the receptor is discussed. PMID:10960078

Hopkinson, H E; Latif, M L; Hill, S J

2000-09-01

248

Constitutive and tissue-specific differential expression of the cryIA(b) gene in transgenic rice plants conferring resistance to rice insect pest  

Microsoft Academic Search

The truncated chimeric Bt gene, cryIA(b) of Bacillus thuringiensis, driven by two constitutive promoters, 35S from CaMV and Actin-1 from rice, and two tissue-specific promoters, pith tissue\\u000a and pepcarboxylase (PEPC) for green tissue from maize, was introduced into several varieties of rice (indica and japonica)\\u000a by microprojectile bombardment and protoplast systems. A total of 1800 putative transgenic Bt rice plants

K. Datta; A. Vasquez; J. Tu; L. Torrizo; M. F. Alam; N. Oliva; E. Abrigo; G. S. Khush; S. K. Datta

1998-01-01

249

Constitutive Activation of Nuclear Factor-E2-Related Factor 2 Induces Biotransformation Enzyme and Transporter Expression in Livers of Mice With Hepatocyte-Specific Deletion of Kelch-like ECH-associated protein 1  

PubMed Central

Chemicals that activate nuclear factor-E2-related factor-2 (Nrf2) often increase multidrug resistance-associated protein expression in liver. Hepatocyte-specific deletion of Kelch-like ECH-associated protein 1 (Keap1) activates Nrf2. Use of hepatocyte-specific Keap1 deletion represents a non-pharmacological method to determine whether constitutive Nrf2 activation upregulates liver transporter expression in vivo. The mRNA, protein expression and localization of several biotransformation and transporters was determined in livers of wild-type and hepatocyte-specific Keap1-null mice. Sulfotransferase 2a1/2, NADP(H):quinone oxidoreductase 1, Cytochrome P450 2b10, 3a11, and glutamate-cysteine ligase catalytic subunit expression was increased in livers of Keap1-null mice. Oatp1a1 expression was nearly abolished, as compared to that detected in livers of wild-type mice. By contrast, Mrp 1-5 mRNA and protein levels were increased in Keap1-null mouse livers, with Mrp4 expression being more than 15-fold higher than wild-types. In summary, Nrf2 has a significant role in affecting expression of Oatp and Mrp expression.

Cheng, Qiuqiong; Taguchi, Keiko; Aleksunes, Lauren M.; Manautou, Jose E.; Cherrington, Nathan J.; Yamamoto, Masayuki; Slitt, Angela L.

2013-01-01

250

Expression of Drosophila mushroom body mutations in alternative genetic backgrounds: a case study of the mushroom body miniature gene (mbm).  

PubMed Central

Mutations in 12 genes regulating Drosophila melanogaster mushroom body (MB) development were each studied in two genetic backgrounds. In all cases, brain structure was qualitatively or quantitatively different after replacement of the "original" genetic background with that of the Canton Special wild-type strain. The mushroom body miniature gene (mbm) was investigated in detail. mbm supports the maintenance of MB Kenyon cell fibers in third instar larvae and their regrowth during metamorphosis. Adult mbm1 mutant females are lacking many or most Kenyon cell fibers and are impaired in MB-mediated associative odor learning. We show here that structural defects in mbm1 are apparent only in combination with an X-linked, dosage-dependent modifier (or modifiers). In the Canton Special genetic background, the mbm1 anatomical phenotype is suppressed, and MBs develop to a normal size. However, the olfactory learning phenotype is not fully restored, suggesting that submicroscopic defects persist in the MBs. Mutant mbm1 flies with full-sized MBs have normal retention but show a specific acquisition deficit that cannot be attributed to reductions in odor avoidance, shock reactivity, or locomotor behavior. We propose that polymorphic gene interactions (in addition to ontogenetic factors) determine MB size and, concomitantly, the ability to recognize and learn odors. Images Fig. 1 Fig. 2 Fig. 3

de Belle, J S; Heisenberg, M

1996-01-01

251

Sex Differences in Constitutive Autophagy  

PubMed Central

Sex bias has been described nowadays in biomedical research on animal models, although sexual dimorphism has been confirmed widely under pathological and physiological conditions. The main objective of our work was to study the sex differences in constitutive autophagy in spinal cord and skeletal muscle tissue from wild type mice. To examine the influence of sex on autophagy, mRNA and proteins were extracted from male and female mice tissues. The expressions of microtubule-associated protein 1 light chain 3 (LC3) and sequestosome 1 (p62), markers to monitor autophagy, were analyzed at 40, 60, 90, and 120 days of age. We found significant sex differences in the expression of LC3 and p62 in both tissues at these ages. The results indicated that sex and tissue specific differences exist in constitutive autophagy. These data underlined the need to include both sexes in the experimental groups to minimize any sex bias.

Olivan, Sara; Calvo, Ana Cristina; Manzano, Raquel; Zaragoza, Pilar

2014-01-01

252

Role of p53 in Regulating Constitutive and X-Radiation-Inducible CD95 Expression and Function in Carcinoma Cells1  

Microsoft Academic Search

The p53 tumor suppressor protein is known to regulate the expression of the CD95 (Fas\\/APO-1) death receptor in a small subset of normal cell types as well as in many cancer cell types. However, whether p53-depend- ent regulation of CD95 expression is consistently associated with increased susceptibility to CD95-mediated cell death is poorly understood. To ad- dress this issue, we

Michael A. Sheard; Stjepan Uldrijan; Borivoj Vojtesek

253

Expression of v-src in a Murine T-Cell Hybridoma Results in Constitutive T-Cell Receptor Phosphorylation and Interleukin 2 Production  

Microsoft Academic Search

Ligand binding to the T-cell antigen receptor results in phosphatidylinositol hydrolysis and the resultant activation of protein kinase C, as well as the activation of a receptor-coupled protein-tyrosine kinase. As a model for tyrosine kinase activation in T cells, we used retroviral gene transfer to express the v-src oncogene in an antigen-specific murine T-cell hybridoma. Clones that expressed v-src mRNA

John J. O'Shea; Jonathan D. Ashwell; Trevor L. Bailey; Sharon L. Cross; Lawrence E. Samelson; Richard D. Klausner

1991-01-01

254

Are Vouchers Constitutional?  

ERIC Educational Resources Information Center

Reviews the Supreme Court's decisions regarding aid to students in religious schools. Reveals two distinct constitutionality theories as basis for the decisions. Regarding the constitutionality of voucher programs, the decisive issue is "how," not "what," public aid is directed to religious institutions. (MMU)

Lewin, Nathan

1999-01-01

255

Interpreting the Constitution.  

ERIC Educational Resources Information Center

Discusses constitutional interpretations relating to capital punishment and protection of human dignity. Points out the document's effectiveness in creating a new society by adapting its principles to current problems and needs. Considers two views of the Constitution that lead to controversy over the legitimacy of judicial decisions. (PS)

Brennan, William J., Jr.

1987-01-01

256

Constitution of the AFT.  

ERIC Educational Resources Information Center

This document contains the constitution and the bylaws of the American Federation of Teachers. The constitution is comprised of 12 articles which deal with the name and objectives of the organization, membership, chartering of state and local units, federation officers, the Executive Council, conventions, representation of state and local units at…

American Federation of Teachers, Washington, DC.

257

Cloning, expression, purification and preliminary X--ray analysis of the protein kinase domain of constitutive triple response 1 (CTR1) from Arabidopsis thaliana  

PubMed Central

Ethylene, a gaseous plant hormone, is perceived by a group of membrane-bound receptors. Constitutive triple response 1 (CTR1) from Arabidopsis thaliana directly interacts with ethylene receptors and thus links signal reception to the intracellular signalling pathway. The C-terminal protein kinase domain of CTR1 has been crystallized in its wild-type form and as a kinase-dead mutant. The wild-type crystals diffracted X-ray radiation to 3?Å resolution and the crystals of the kinase-dead mutant diffacted to 2.5?Å resolution. The crystals belonged to space groups P41212 and P42212, respectively, with two molecules per asymmetric unit in both cases.

Mayerhofer, Hubert; Mueller-Dieckmann, Christoph; Mueller-Dieckmann, Jochen

2011-01-01

258

Cloning, expression, purification and preliminary X-ray analysis of the protein kinase domain of constitutive triple response 1 (CTR1) from Arabidopsis thaliana.  

PubMed

Ethylene, a gaseous plant hormone, is perceived by a group of membrane-bound receptors. Constitutive triple response 1 (CTR1) from Arabidopsis thaliana directly interacts with ethylene receptors and thus links signal reception to the intracellular signalling pathway. The C-terminal protein kinase domain of CTR1 has been crystallized in its wild-type form and as a kinase-dead mutant. The wild-type crystals diffracted X-ray radiation to 3?Å resolution and the crystals of the kinase-dead mutant diffacted to 2.5?Å resolution. The crystals belonged to space groups P4(1)2(1)2 and P4(2)2(1)2, respectively, with two molecules per asymmetric unit in both cases. PMID:21206040

Mayerhofer, Hubert; Mueller-Dieckmann, Christoph; Mueller-Dieckmann, Jochen

2011-01-01

259

Depletion of endogenous serotonin synthesis with p-CPA attenuates upregulation of constitutive isoform of heme oxygenase-2 expression, edema formation and cell injury following a focal trauma to the rat spinal cord.  

PubMed

The possibility that the upregulation of hemeoxygenase (HO) enzyme responsible for carbon monoxide (CO) formation in the spinal cord following trauma is involved in edema formation and cell damage was examined in a rat model. A focal trauma to the rat spinal cord by making an incision into the right dorsal horn of the T10-11 segment resulted in profound upregulation of HO-2 (the constitutive isoform of the enzyme) expression in the T9 and T12 segments 5 h after injury. In these segments a marked increase in edema formation, nerve cell damage, and expression of heat shock protein (HSP 72) were observed. Pretreatment with p-chlorophenylalanine (p-CPA, a serotonin synthesis inhibitor) significantly attenuated the trauma induced edema formation, cell injury, and HSP expression. Upregulation of HO-2 in p-CPA treated traumatised rats was considerably reduced. These observations suggest that (i) spinal cord injury has the capacity to induce an upregulation of HO-2 and HSP expression, (ii) abnormal production of CO as reflected by HO-2 expression is injurious to the cord, and (iii) that endogenous serotonin is involved in HO-2 expression in the cord. PMID:14753474

Sharma, H S; Westman, J

2003-01-01

260

Stromal-Derived Factor-1 and Its Receptor, CXCR4, Are Constitutively Expressed by Mouse Liver Sinusoidal Endothelial Cells: Implications for the Regulation of Hematopoietic Cell Migration to the Liver During Extramedullary Hematopoiesis  

PubMed Central

Stromal-derived factor (SDF)-1 is the main regulating factor for trafficking/homing of hematopoietic stem cells (HSC) to the bone marrow (BM). It is possible that this chemokine may also play a fundamental role in regulating the migration of HSC to several organs during extramedullary hematopoiesis. Because liver sinusoidal endothelial cells (LSEC) constitute an extramedullary niche for HSC, it is possible that these cells represent one of the main cellular sources of SDF-1 at the liver. Here, we show that LSEC express SDF-1 at the mRNA and protein level. Biological assays showed that conditioned medium from LSEC (LSEC-CM) stimulated the migration of BM progenitor lineage-negative (BM/Lin?) cells. This effect was significantly reduced by AMD3100, indicating that the SDF-1/CXCR4 axis is involved in the stimulatory migrating effect induced by LSEC-CM. Early localization of HSC in SDF-1–expressing LSEC microenvironment together with increased levels of this chemokine in hepatic homogenates was found in an experimental model of liver extramedullary hematopoiesis. Flow cytometry studies showed that LSEC express the CXCR4 receptor. Functional assays showed that activation of this receptor by SDF-1 stimulated the migration of LSEC and increased the expression of PECAM-1. Our findings suggest that LSEC through the production of SDF-1 may constitute a fundamental niche for regulation of HSC migration to the liver. To our knowledge, this is the first report showing that LSEC not only express and secrete SDF-1, but also its receptor CXCR4.

Mendt, Mayela

2012-01-01

261

Matrix metalloproteinase 28, a novel matrix metalloproteinase, is constitutively expressed in human intervertebral disc tissue and is present in matrix of more degenerated discs  

PubMed Central

Introduction The regulation and elevation in expression of the catabolic matrix metalloproteinases (MMPs) is of high importance in the human intervertebral disc since upregulation of these matrix-degrading enzymes results in matrix destruction associated with disc degeneration. MMP28 (epilysin) is a newly discovered MMP believed to play a role in matrix composition and turnover in skin. It is present in basal keratinocytes where its expression is upregulated with wound repair, and in cartilage and synovium where it is upregulated in osteoarthritis. Recent work has shown that mechanical compression can act to modulate expression of MMP28. The expression of MMP28 is unexplored in the intervertebral disc. Methods Following approval by our human subjects institutional review board, we employed microarray analyses to evaluate in vivo expression of MMP28 and the MMP28 precursor in human disc tissue, and utilized immunohistochemistry to determine cellular and extracellular matrix localization of MMP28 in 35 human disc tissue specimens. The percentage of cells positive for MMP28 immunocytochemical localization was also determined. Results The present work documents the expression and presence of MMP28 in cells and extracellular matrix (ECM) of the human intervertebral disc. Gene expression levels in human disc tissue were detectable for both MMP28 and the MMP28 precursor. MMP28 cytoplasmic localization was present in cells of the outer annulus; it was also present in some, but not all, cells of the inner annulus and nucleus. MMP28 was not found in the ECM of healthier Grade I to II discs, but was identified in the ECM of 61% of the more degenerated Grade III to V discs (P = 0.0018). There was a significant difference in cellular MMP28 distribution in the disc (P = 0.008): the outer annulus showed the largest percentage of cells positive for MMP28 immunolocalization, followed by the inner annulus and then the nucleus. Herniated discs showed a significantly greater proportion of MMP28-positive cells compared with nonherniated discs (P = 0.034). Conclusions Findings presented here show the first documentation of intervertebral disc expression and production of MMP28. MMP28 was found in both disc cell cytoplasm and in the ECM of more degenerated specimens, with greater cellular localization in the outer annulus and in herniated disc specimens. These findings are important because of the key role of MMPs in disc turnover and homeostasis, and previous indications of a role for this MMP in matrix repair and matrix turnover in other tissues. Our data, which show the presence of MMP28 in human disc tissue, suggest that MMP28 may have a potentially important role in ECM modulation in the healthy and degenerating disc.

2009-01-01

262

Constitutive Expression Exposes Functional Redundancy between the Arabidopsis Histone H2A Gene HTA1 and Other H2A Gene Family Members[OA  

PubMed Central

The Arabidopsis thaliana histone H2A gene HTA1 is essential for efficient transformation of Arabidopsis roots by Agrobacterium tumefaciens. Disruption of this gene in the rat5 mutant results in decreased transformation. In Arabidopsis, histone H2A proteins are encoded by a 13-member gene family. RNA encoded by these genes accumulates to differing levels in roots and whole plants; HTA1 transcripts accumulate to levels up to 1000-fold lower than do transcripts of other HTA genes. We examined the extent to which other HTA genes or cDNAs could compensate for loss of HTA1 activity when overexpressed in rat5 mutant plants. Overexpression of all tested HTA cDNAs restored transformation competence to the rat5 mutant. However, only the HTA1 gene, but not other HTA genes, could phenotypically complement rat5 mutant plants when expressed from their native promoters. Expression analysis of HTA promoters indicated that they had distinct but somewhat overlapping patterns of expression in mature plants. However, only the HTA1 promoter was induced by wounding or by Agrobacterium infection of root segments. Our data suggest that, with respect to Agrobacterium-mediated transformation, all tested histone H2A proteins are functionally redundant. However, this functional redundancy is not normally evidenced because of the different expression patterns of the HTA genes.

Yi, HoChul; Sardesai, Nagesh; Fujinuma, Toshinori; Chan, Chien-Wei; Veena; Gelvin, Stanton B.

2006-01-01

263

Transcriptome analysis of Hpa1Xoo transformed cotton revealed constitutive expression of genes in multiple signalling pathways related to disease resistance  

PubMed Central

The transcriptome profile in leaves and roots of the transgenic cotton line T-34 expressing hpa1Xoo from Xanthomonas oryzae pv. oryzae was analysed using a customized 12k cotton cDNA microarray. A total of 530 cDNA transcripts involved in 34 pathways were differentially expressed in the transgenic line T-34, in which 123 differentially expressed genes were related to the cotton defence responses including the hypersensitive reaction, defence responses associated with the recognition of pathogen-derived elicitors, and defence signalling pathways mediated by salicylic acid, jasmonic acid, ethylene, auxin, abscicic acid, and Ca2+. Furthermore, transcripts encoding various leucine-rich protein kinases and mitogen-activated protein kinases were up-regulated in the transgenic line T-34 and expression of transcripts related to the energy producing and consuming pathway was also increased, which suggested that the enhanced metabolism related to the host defence response in the transgenic line T-34 imposed an increased energy demand on the transgenic plant.

Miao, Weiguo; Song, Congfeng; Wang, Yu; Ren, Yonghong; Wang, Jinsheng

2010-01-01

264

Transposon-Mediated Alteration of TaMATE1B Expression in Wheat Confers Constitutive Citrate Efflux from Root Apices[W  

PubMed Central

The TaMATE1B gene (for multidrug and toxic compound extrusion) from wheat (Triticum aestivum) was isolated and shown to encode a citrate transporter that is located on the plasma membrane. TaMATE1B expression in roots was induced by iron deficiency but not by phosphorus deficiency or aluminum treatment. The coding region of TaMATE1B was identical in a genotype showing citrate efflux from root apices (cv Carazinho) to one that lacked citrate efflux (cv Egret). However, sequence upstream of the coding region differed between these two genotypes in two ways. The first difference was a single-nucleotide polymorphism located approximately 2 kb upstream from the start codon in cv Egret. The second difference was an 11.1-kb transposon-like element located 25 bp upstream of the start codon in cv Carazinho that was absent from cv Egret. The influence of these polymorphisms on TaMATE1B expression was investigated using fusions to green fluorescent protein expressed in transgenic lines of rice (Oryza sativa). Fluorescence measurements in roots of rice indicated that 1.5- and 2.3-kb regions upstream of TaMATE1B in cv Carazinho (which incorporated 3? regions of the transposon-like element) generated 20-fold greater expression in the apical 1 mm of root compared with the native promoter in cv Egret. By contrast, fluorescence in more mature tissues was similar in both cultivars. The presence of the single-nucleotide polymorphism alone consistently generated 2-fold greater fluorescence than the cv Egret promoter. We conclude that the transposon-like element in cv Carazinho extends TaMATE1B expression to the root apex, where it confers citrate efflux and enhanced aluminum tolerance.

Tovkach, Andriy; Ryan, Peter R.; Richardson, Alan E.; Lewis, David C.; Rathjen, Tina M.; Ramesh, Sunita; Tyerman, Stephen D.; Delhaize, Emmanuel

2013-01-01

265

Constitutive expression of the Wilms' tumor gene (WT1) in the leukemic cell line U937 blocks parts of the differentiation program  

Microsoft Academic Search

The Wilms tumor gene, WT1, encodes a zinc-finger DNA binding protein which is thought to function as a tissue specific transcription factor, regulating cell growth and differentiation. High expression of WT1 has been detected in a range of acute leukemias. To elucidate a role for WT1 in leukemogenesis, we transfected the monoblastic cell line U937, which lacks detectable levels of

Helena Svedberg; Kristina Chylicki; Bo Baldetorp; Frank J Rauscher; Urban Gullberg

1998-01-01

266

Expression and characterization of constitutive heat shock protein 70.1 (HSPA-1A) gene in in vitro produced and in vivo-derived buffalo (Bubalus bubalis) embryos.  

PubMed

Cells are blessed with a group of stress protector molecules known as heat shock proteins (HSPs), amongst them HSP70, encoded by HSPA-1A gene, is most abundant and highly conserved protein. Variety of stresses hampers the developmental competence of embryos under in vivo and in vitro conditions. Present work was designed to study the quantitative expression of HSPA-1A mRNA in immature oocytes (IMO), matured oocytes (MO), in vitro produced (IVP) and in vivo-derived (IVD) buffalo embryos to assess the level of stress to which embryos are exposed under in vivo and in vitro culture conditions. Further, HSPA-1A gene sequence was analysed to determine its homology with other mammalian sequences. The mRNA expression analysis was carried out on 72 oocytes (40 IMO; 32 MO), 76 IVP and 55 IVD buffalo embryos. Expression of HSPA-1A was found in oocytes and throughout the developmental stages of embryos examined irrespective of the embryo source; however, higher (p < 0.05) expression was observed in 8-16 cell, morula and blastocyst stages of IVP embryos as compared to IVD embryos. Phylogenetic analysis of bubaline HSPA-1A revealed that it shares 91-98% identity with other mammalian sequences. It can be concluded that higher level of HSPA-1A mRNA in IVP embryos in comparison with in vivo-derived embryos is an indicator of cellular stress in IVP system. This study suggests need for further optimization of in vitro culture system in which HSPA-1A gene could be used as a stress biomarker during pre-implantation development. PMID:22463675

Sharma, G T; Nath, A; Prasad, S; Singhal, S; Singh, N; Gade, N E; Dubey, P K; Saikumar, G

2012-12-01

267

Constitutive Expression of Bcl2 in B Cells Causes a Lethal Form of Lupuslike Autoimmune Disease After Induction of Neonatal Tolerance to H-2 b Alloantigens  

Microsoft Academic Search

Summary The bd-2 protooncogene has been shown to provide a survival signal to self-reactive B ceils, but it fails to override their developmental arrest after encounter with antigen. Furthermore, con- stitutive expression of bcl-2 in B cells does not promote the development of autoimmune disease in most strains of mice, indicating that signals other than those conferred by bcl-2 are

Roberto Carri; Shozo Izui; Jesfis Merino; M. Valdecilla

268

A Novel Mutation within the Central Listeria monocytogenes Regulator PrfA That Results in Constitutive Expression of Virulence Gene Products  

Microsoft Academic Search

The PrfA protein of Listeria monocytogenes functions as a key regulatory factor for the coordinated expression of many virulence genes during bacterial infection of host cells. PrfA activity is controlled by multiple regulatory mechanisms, including an apparent requirement for either the presence of a cofactor or some form of posttranslational modification that regulates the activation of PrfA. In this study,

Kendy K. Y. Wong; Nancy E. Freitag

2004-01-01

269

Silencing Sl-EBF1 and Sl-EBF2 expression causes constitutive ethylene response phenotype, accelerated plant senescence, and fruit ripening in tomato.  

PubMed

The hormone ethylene regulates a wide range of plant developmental processes and EBF (EIN3-binding F-box) proteins were shown to negatively regulate the ethylene signalling pathway via mediating the degradation of EIN3/EIL proteins. The present study reports on the identification of two tomato F-box genes, Sl-EBF1 and Sl-EBF2 from the EBF subfamily. The two genes display contrasting expression patterns in reproductive and vegetative tissues and in response to ethylene and auxin treatment. Sl-EBF1 and Sl-EBF2 genes are actively regulated at crucial stages in the development of the reproductive organs. Their dynamic expression in flowers during bud-to-anthesis and anthesis-to-post-anthesis transitions, and at the onset of fruit ripening, suggests their role in situations where ethylene is required for stimulating flower opening and triggering fruit ripening. VIGS-mediated silencing of a single tomato EBF gene uncovered a compensation mechanism that tends to maintain a threshold level of Sl-EBF expression via enhancing the expression of the second Sl-EBF gene. In line with this compensation, tomato plants silenced for either of the Sl-EBF genes were indistinguishable from control plants, indicating functional redundancy among Sl-EBF genes. By contrast, co-silencing of both Sl-EBFs resulted in ethylene-associated phenotypes. While reports on EBF genes to date have focused on their role in modulating ethylene responses in Arabidopsis, the present study uncovered their role in regulating crucial stages of flower and fruit development in tomato. The data support the hypothesis that protein degradation via the ubiquitin/26S proteasome pathway is a control point of fruit ripening and open new leads for engineering fruit quality. PMID:19903730

Yang, Yingwu; Wu, Yu; Pirrello, Julien; Regad, Farid; Bouzayen, Mondher; Deng, Wei; Li, Zhengguo

2010-03-01

270

Triple synergism of human T-lymphotropic virus type 1-encoded tax, GATA-binding protein, and AP-1 is required for constitutive expression of the interleukin-5 gene in adult T-cell leukemia cells.  

PubMed Central

Accumulated evidence demonstrates that adult T-cell leukemia (ATL) is frequently associated with eosinophilia, and human T-lymphotropic virus type 1 (HTLV-1)-infected cells frequently express interleukin-5 (IL-5). However, the molecular mechanism of constitutive IL-5 expression in HTLV-1-infected cells remains unclear. To clarify the mechanism of aberrant IL-5 expression in HTLV-1-infected cells, we investigated the response of the human IL-5 promoter to the HTLV-1-encoded protein Tax. Cotransfection experiments using Jurkat cells revealed that Tax is incapable of activating the IL-5 promoter by itself but that it synergistically transactivates the promoter with GATA-binding protein (GATA-4) and 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation. By introducing a series of mutations within the IL-5 promoter, we found that conserved lymphokine element 0 (CLE0) is responsible for mediating the signal induced by Tax-TPA. A deletion construct of the promoter indicated that the -75 GATA element and CLE0 are sufficient to mediate synergistic activation of the IL-5 promoter. Electrophoretic mobility shift assays using Jurkat cell nuclear extracts demonstrated that TPA induces a transcription factor to bind CLE0, and an experiment using JPX-9 cell nuclear extracts showed that Tax enhances this binding activity. An antibody supershift experiment revealed that this band consists of c-Jun and JunD. However, among the Jun family members, only c-Jun is able to cooperate with Tax and GATA-4 to activate the IL-5 promoter. We have determined the minimum factors required for IL-5 gene activation by reconstituting the IL-5 promoter activity in F9 cells. This is the first report to demonstrate the functional involvement of Tax protein in IL-5 gene regulation and to suggest the functional triple synergism among Tax, GATA-4, and AP-1, which disrupts regulated control of the gene and leads to constitutive expression of the IL-5 gene.

Yamagata, T; Mitani, K; Ueno, H; Kanda, Y; Yazaki, Y; Hirai, H

1997-01-01

271

p53 StatusAffectsthe Rate of the Onsetbut not the Overall Extentof Doxorubicin induced Cell Death in Rat-i Fibroblasts Constitutively Expressing c-Myc  

Microsoft Academic Search

To betterunderstandthe effectsof p53 on the processof DNAdamage induced cell death, weexaminedthe influenceof p53 status on the rate of the onset and the overall extent of cell death induced by doxorubicin. We per formed this study with Rat-I fibroblasts, with Rat-Ilmyc cells which consti tutlvely express c-Myc, and with kat-Ilmyc\\/pS3Hisl75 cells derived from Rat-1\\/myccells,which,Inaddition,expressthefUll-length dominant-negative pS3Hisl7S mutant gene. The pS3Hisl7S

Jia-wen Han; Cheryl A. Dionne; Nancy L. Kedersha; Victor S. Goidmacher

272

Constitutive and Induced IL18 Receptor Expression by Various Peripheral Blood Cell Subsets as Determined by Anti-hIL18R Monoclonal Antibody  

Microsoft Academic Search

Interleukin-18 (IL-18) was identified as a molecule that induces IFN-? production and enhances NK cell cytotoxicity. Characterization of the receptor for human IL-18 (hIL-18R) is important for investigating the physiological role of IL-18 in nature. In the present study, we describe a monoclonal antibody (mAb) against hIL-18R (mAb No. 117-10C). This mAb inhibited the binding of125I-labeled hIL-18 to IL-18R-expressing L428

Toshio Kunikata; Kakuji Torigoe; Shimpei Ushio; Takanori Okura; Chie Ushio; Hiroshi Yamauchi; Masao Ikeda; Hakuo Ikegami; Masashi Kurimoto

1998-01-01

273

A Continuous Bovine Kidney Cell Line Constitutively Expressing Bovine ?V?6 Integrin Has Increased Susceptibility to Foot-and-Mouth Disease Virus  

PubMed Central

Foot-and-mouth disease (FMD) is a worldwide problem limiting the trade of animals and their products from affected countries. The rapid isolation, serotyping, and vaccine matching of FMD virus from disease outbreaks is critical for enabling the implementation of effective vaccination programs and to stop the spread of infection during outbreaks. Some primary cells have been shown to be highly susceptible to most strains of FMD virus (FMDV) but are difficult and expensive to prepare and maintain. Since the ?V?6 integrin is a principal receptor for FMDV, we transduced a bovine kidney cell line to stably express both the ?V and ?6 bovine integrin subunits. This stable cell line (LFBK-?V?6) showed ?6 expression and enhanced susceptibility to FMDV infection for ?100 cell passages. LFBK-?V?6 cells were highly sensitive for detecting all serotypes of FMDV from experimentally infected animals, including the porcinophilic FMDV strain O/TAW/97. In comparison to other cell types that are currently used for virus isolation, LFBK-?V?6 cells were more effective at detecting FMDV in clinical samples, supporting their use as a more sensitive tool for virus isolation.

LaRocco, Michael; Kramer, Ed; Ahmed, Zaheer; Pacheco, Juan M.; Duque, Hernando; Baxt, Barry; Rodriguez, Luis L.

2013-01-01

274

The Cap'n'Collar basic leucine zipper transcription factor Nrf2 (NF-E2 p45-related factor 2) controls both constitutive and inducible expression of intestinal detoxification and glutathione biosynthetic enzymes.  

PubMed

Northern blotting has shown that mouse small intestine contains relatively large amounts of the nuclear factor-E2 p45-related factor (Nrf) 2 transcription factor but relatively little Nrf1. Regulation of intestinal antioxidant and detoxication enzymes by Nrf2 has been assessed using a mouse line bearing a targeted disruption of the gene encoding this factor. Both Nrf2-/- and Nrf2+/+ mice were fed a control diet or one supplemented with either synthetic cancer chemopreventive agents [butylated hydroxyanisole (BHA), ethoxyquin (EQ), or oltipraz] or phytochemicals [indole-3-carbinol, cafestol and kahweol palmitate, sulforaphane, coumarin (CMRN), or alpha-angelicalactone]. The constitutive level of NAD(P)H:quinone oxidoreductase (NQO) and glutathione S-transferase (GST) enzyme activities in cytosols from small intestine was typically found to be between 30% and 70% lower in samples prepared from Nrf2 mutant mice fed a control diet than in equivalent samples from Nrf2+/+ mice. Most of the chemopreventive agents included in this study induced NQO and GST enzyme activities in the small intestine of Nrf2+/+ mice. Increases of between 2.7- and 6.2-fold were observed in wild-type animals fed diets supplemented with BHA or EQ; increases of about 2-fold were observed with a mixture of cafestol and kahweol palmitate, CMRN, or alpha-angelicalactone; and increases of 1.5-fold were measured with sulforaphane. Immunoblotting confirmed that in the small intestine, the constitutive level of NQO1 is lower in the Nrf2-/- mouse, and it also showed that induction of the oxidoreductase was substantially diminished in the mutant mouse. Immunoblotting class-alpha and class-mu GST showed that constitutive expression of most transferase subunits is also reduced in the small intestine of Nrf2 mutant mice. Significantly, induction of class-alpha and class-mu GST by EQ, BHA, or CMRN is apparent in the gene knockout animal. No consistent change in the constitutive levels of the catalytic heavy subunit of gamma-glutamylcysteinyl synthetase (GCS(h)) was observed in the small intestine of Nrf2-/- mice. However, although the expression of GCS(h) was found to be increased dramatically in the small intestine of Nrf2+/+ mice by dietary BHA or EQ, this induction was essentially abolished in the knockout mice. It is apparent that Nrf2 influences both constitutive and inducible expression of intestinal antioxidant and detoxication proteins in a gene-specific fashion. Immunohistochemistry revealed that induction of NQO1, class-alpha GST, and GCS(h) occurs primarily in epithelial cells of the small intestine. This suggests that the variation in inducibility of NQO1, Gsta1/2, and GCS(h) in the mutant mouse is not attributable to the expression of the enzymes in distinct cell types but rather to differences in the dependency of these genes on Nrf2 for induction. PMID:11309284

McMahon, M; Itoh, K; Yamamoto, M; Chanas, S A; Henderson, C J; McLellan, L I; Wolf, C R; Cavin, C; Hayes, J D

2001-04-15

275

The Effect of High Concentrations of Glufosinate Ammonium on the Yield Components of Transgenic Spring Wheat (Triticum aestivum L.) Constitutively Expressing the bar Gene  

PubMed Central

We present an experiment done on a bar+ wheat line treated with 14 different concentrations of glufosinate ammonium—an effective component of nonselective herbicides—during seed germination in a closed experimental system. Yield components as number of spikes per plant, number of grains per spike, thousand kernel weight, and yield per plant were thoroughly analysed and statistically evaluated after harvesting. We found that a concentration of glufosinate ammonium 5000 times the lethal dose was not enough to inhibit the germination of transgenic plants expressing the bar gene. Extremely high concentrations of glufosinate ammonium caused a bushy phenotype, significantly lower numbers of grains per spike, and thousand kernel weights. Concerning the productivity, we observed that concentrations of glufosinate ammonium 64 times the lethal dose did not lead to yield depression. Our results draw attention to the possibilities implied in the transgenic approaches.

Ay, Zoltan; Mihaly, Robert; Cserhati, Matyas; Kotai, Eva; Pauk, Janos

2012-01-01

276

Constitutive expression of a miR319 gene alters plant development and enhances salt and drought tolerance in transgenic creeping bentgrass.  

PubMed

MicroRNA319 (miR319) is one of the first characterized and conserved microRNA families in plants and has been demonstrated to target TCP (for TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTORS [PCF]) genes encoding plant-specific transcription factors. MiR319 expression is regulated by environmental stimuli, suggesting its involvement in plant stress response, although experimental evidence is lacking and the underlying mechanism remains elusive. This study investigates the role that miR319 plays in the plant response to abiotic stress using transgenic creeping bentgrass (Agrostis stolonifera) overexpressing a rice (Oryza sativa) miR319 gene, Osa-miR319a. We found that transgenic plants overexpressing Osa-miR319a displayed morphological changes and exhibited enhanced drought and salt tolerance associated with increased leaf wax content and water retention but reduced sodium uptake. Gene expression analysis indicated that at least four putative miR319 target genes, AsPCF5, AsPCF6, AsPCF8, and AsTCP14, and a homolog of the rice NAC domain gene AsNAC60 were down-regulated in transgenic plants. Our results demonstrate that miR319 controls plant responses to drought and salinity stress. The enhanced abiotic stress tolerance in transgenic plants is related to significant down-regulation of miR319 target genes, implying their potential for use in the development of novel molecular strategies to genetically engineer crop species for enhanced resistance to environmental stress. PMID:23292790

Zhou, Man; Li, Dayong; Li, Zhigang; Hu, Qian; Yang, Chunhua; Zhu, Lihuang; Luo, Hong

2013-03-01

277

Constitutive expression of the proteorhodopsin gene by a flavobacterium strain representative of the proteorhodopsin-producing microbial community in the North Sea.  

PubMed

Proteorhodopsin (PR), a photoactive proton pump containing retinal, is present in approximately half of all bacteria in the ocean, but its physiological role is still unclear, since very few strains carrying the PR gene have been cultured. The aim of this work was to characterize PR diversity in a North Sea water sample, cultivate a strain representative of North Sea PR clusters, and study the effects of light and carbon concentration on the expression of the PR gene. A total of 117 PR sequences, of which 101 were unique, were obtained from a clone library of PCR-amplified PR gene fragments. Of the North Sea PRs, 97% were green light absorbing, as inferred from the amino acid at position 105; 67% of the PR protein fragments showed closest similarity to PRs from Alphaproteobacteria, 4% showed closest similarity to PRs from Gammaproteobacteria, and 29% showed closest similarity to PRs from "Bacteroidetes"/Flavobacteria. The dominant PR cluster (comprising 18% of all PRs) showed a high degree of similarity to the PR from the cultivated Roseobacter strain HTCC2255. The relative abundances of the North Sea PR clusters were confirmed by quantitative PCR. They were detected in metagenomic fragments from coastal oceans worldwide with various degrees of abundance. Several hundred bacterial strains from the North Sea water sample were cultivated on oligocarbophilic media. By screening with degenerate primers, two strains carrying the PR gene were identified. Their 16S rRNA gene sequences were identical and affiliated with a Bacteroidetes subcluster from the North Sea. The PR sequence of isolate PRO95 was completed by chromosomal walking. It was 76% identical to that of Dokdonia donghaensis MED134 and was functional, as indicated by the signature amino acids. PRO95 expressed its PR gene in liquid media containing between 9.7 and 121 mM carbon, both in the light and in the dark. Growth was not enhanced by light. Thus, the detection of the physiological role of PR may require more sensitive methods. PMID:20305030

Riedel, Thomas; Tomasch, Jürgen; Buchholz, Ina; Jacobs, Jenny; Kollenberg, Mario; Gerdts, Gunnar; Wichels, Antje; Brinkhoff, Thorsten; Cypionka, Heribert; Wagner-Döbler, Irene

2010-05-01

278

The Trypanosoma brucei DNA polymerase alpha core subunit gene is developmentally regulated and linked to a constitutively expressed open reading frame.  

PubMed Central

As an initial step towards the characterization of replicative DNA polymerases of trypanosomes, we have cloned, sequenced and examined the expression of the Trypanosoma (Trypanozoon) brucei brucei gene that encodes the DNA polymerase alpha catalytic core (pol alpha). The protein sequence contains the six conserved regions that have been recognized previously in eukaryotic and viral replicative DNA polymerases. In addition, we have identified a seventh region which appears to be conserved primarily in alpha-type DNA polymerases. The T.brucei DNA pol alpha core N-terminus is 123 and 129 amino acids smaller than that of the human and yeast homologue, respectively. The gene is separated by 386 bp from an upstream open reading frame (ORF) of 442 codons. Stable transcripts of the upstream sequence are detected in both dividing and non-dividing forms, while pol alpha transcripts are detected principally in dividing forms. Allelic copies of the T.brucei pol alpha region exhibit restriction site polymorphisms; one such sequence polymorphism affects the amino acid sequence of the T.brucei DNA pol alpha core. The T.brucei pol alpha region cross-hybridizes weakly with that of T.(Nannomonas) congolense and T.(Duttonella) vivax. Images

Leegwater, P A; Strating, M; Murphy, N B; Kooy, R F; van der Vliet, P C; Overdulve, J P

1991-01-01

279

The Constitutional Heritage.  

ERIC Educational Resources Information Center

Changing political, social, economic, and intellectual conditions over the past two hundred years have demanded innovation and adjustment of legal doctrine, thus giving the United States Constitution a character which the framers of the document could not have predicted. Historically, one must not only understand developments since 1787 but also…

Baxter, Maurice

280

Crushed Salt Constitutive Model  

SciTech Connect

The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

Callahan, G.D.

1999-02-01

281

South Africa's Constitutional Change.  

ERIC Educational Resources Information Center

Describes the striking dichotomy of South Africa's beauty and the squalor resulting from the apartheid policies of the government. Reviews reactions of black South Africans to recent constitutional changes and details efforts to secure more sweeping reform. Includes stories of several individuals who have taken actions which oppose the system of…

Getman, Thomas

1987-01-01

282

Sexuality and the Constitution.  

ERIC Educational Resources Information Center

Argues for abortion rights and protection of intimate decisions and relationships. Describes the role and position of women in eighteenth century American society as a means of exposing the fallacy of the anti-abortion movement's insistence on adherence to constitutional text. Discusses the recent attempts to overturn the Roe v. Wade ruling. (PS)

Copelon, Rhonda

1987-01-01

283

Cytochrome P450 1C1 complementary DNA cloning, sequence analysis and constitutive expression induced by benzo-a-pyrene in Nile tilapia (Oreochromis niloticus).  

PubMed

CYP1C is the newest member of the CYP1 family of P450s; however, its physiological significance, inducers, and metabolic functions are unknown. In this study, a new complementary DNA of the CYP1C subfamily encoding CYP1C1 was isolated from Nile tilapia (Oreochromis niloticus) liver after intracoelomic injection with benzo-a-pyrene (BaP). The full-length cDNA was 2223 base pair (bp) long and contained an open reading frame of 1581 bp encoding a protein of 526 amino acids and a stop codon. The sequence exhibited 3' non-coding region of 642 bp. The deduced amino acid sequence of O. niloticus CYP1C1 shows similarities of 86, 82.5, 79.7, 78.7, 77.8, 75.5, 69.6 and 61.3% with scup CYP1C1, killifish CYP1C1,1C2, Japanese eel CYP1C1, zebra fish CYP1C1, common carp CYP1C1, scup CYP1C2, common carp CYP1C2 and zebra fish CYP1C2, respectively. Phylogenetic tree based on the amino acids sequences clearly shows tilapia CYP1C1 and scup CYP1C1 to be more closely related to each other than to CYP1C genes from other species. Furthermore, for measuring BaP induction of CYP1C1 mRNA in different organs of tilapia (O. niloticus), ?-actin gene as internal control was selected based on previous studies to assess their expression variability. Real time RCR results revealed that there was a large increase in CYP1C1 mRNA in liver (43.1), intestine (5.1) and muscle (2.4). PMID:22204985

Hassanin, Abeer A I; Kaminishi, Yoshino; Funahashi, Aki; Itakura, Takao

2012-03-01

284

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host  

PubMed Central

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis.

Alaish, Samuel M.; Smith, Alexis D.; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P.; Cross, Alan S

2013-01-01

285

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host.  

PubMed

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis. PMID:23652772

Alaish, Samuel M; Smith, Alexis D; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P; Cross, Alan

2013-01-01

286

Production of a Marfan cellular phenotype by expressing a mutant human fibrillin allele on a normal human or murine genetic background  

SciTech Connect

The Marfan Syndrome (MFS) is a heritable disorder of connective tissue caused by defects in fibrillin (FBN1), a 350 kD glycoprotein and principal component of the extracellular microfibril. Previous correlations of mutant transcript level and disease severity suggested a dominant negative model of MFS pathogenesis. To address this hypothesis we assembled an expression construct containing the mutant allele from a patient with severe MFS. This mutation causes skipping of FBN1 exon 2 and a frame shift, leading to a premature termination codon in exon 4. The predicted peptide would thus consist of 55 wild type and 45 missense amino acids. The construct was stably transfected into cultured human and mouse fibroblasts, and several clonal cell populations were established. Human and mouse cells expressing the truncated peptide exhibited markedly diminished fibrillin deposition and disorganized microfibrillar architecture by immunofluorescence. Pulse-chase analysis of these cells demonstrated normal levels of fibrillin synthesis but substantially decreased fibrillin deposition into the extracellular matrix. These data illustrate that expression of a mutant FBN1 allele, on a background of two normal alleles, is sufficient to disrupt normal fibrillin aggregation and reproduce the MFS cellular phenotype. This provides confirmation of a dominant negative model of MFS pathogenesis and may offer mutant allele knockout as a strategy for gene therapy. In addition, these data underscore the importance of the FBN1 amino-terminus in normal multimer formation and suggest that expression of the human extreme 5{prime} FBN1 coding sequence may be sufficient, in isolation, to produce an animal model of MFS. Indeed, transgenic mice harboring this mutant allele have been produced, and phenotype analysis is currently in progress.

Eldadah, Z.A.; Dietz, H.C. [Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States); Brenn, T. [Stanford Univ. Medical Center, CA (United States)] [and others

1994-09-01

287

The Na+/H+ exchanger NHE1, but not the Na+, HCO3(-) cotransporter NBCn1, regulates motility of MCF7 breast cancer cells expressing constitutively active ErbB2.  

PubMed

We and others have shown central roles of the Na(+)/H(+) exchanger NHE1 in cell motility. The aim of this study was to determine the roles of NHE1 and of the Na(+), HCO(3)(-) cotransporter NBCn1 in motility of serum-starved MCF-7 breast cancer cells expressing constitutively active ErbB2 (?NErbB2). ?NErbB2 expression elicited NBCn1 upregulation, Ser(703)-phosphorylation of NHE1, and NHE1-inhibitor (EIPA)-sensitive pericellular acidification, in conjunction with increased expression of ?1 integrin and ERM proteins. Active ERM proteins and NHE1 colocalized strongly to invadopodial rosettes, the diameter of which was increased by ?NErbB2. Adhesion and migration on collagen-I were augmented by ?NErbB2, unaffected by the NBC inhibitor S0859, and further stimulated by EIPA in a manner potentiated by PI3K-Akt-inhibition. These findings demonstrate that NHE1 inhibition can enhance cancer cell motility, adding an important facet to the understanding of NHE1 in cancer. PMID:22120673

Lauritzen, Gitte; Stock, Christian-Martin; Lemaire, Justine; Lund, Stine F; Jensen, Mie Frid; Damsgaard, Britt; Petersen, Katrine Seide; Wiwel, Maria; Rønnov-Jessen, Lone; Schwab, Albrecht; Pedersen, Stine Falsig

2012-04-28

288

GLUT2 surface expression and intracellular transport via the constitutive pathway in pancreatic beta cells and insulinoma: evidence for a block in trans-Golgi network exit by brefeldin A.  

PubMed

The biosynthesis, intracellular transport, and surface expression of the beta cell glucose transporter GLUT2 was investigated in isolated islets and insulinoma cells. Using a trypsin sensitivity assay to measure cell surface expression, we determined that: (a) greater than 95% of GLUT2 was expressed on the plasma membrane; (b) GLUT2 did not recycle in intracellular vesicles; and (c) after trypsin treatment, reexpression of the intact transporter occurred with a t1/2 of approximately 7 h. Kinetics of intracellular transport of GLUT2 was investigated in pulse-labeling experiments combined with glycosidase treatment and the trypsin sensitivity assay. We determined that transport from the endoplasmic reticulum to the trans-Golgi network (TGN) occurred with a t1/2 of 15 min and that transport from the TGN to the plasma membrane required a similar half-time. When added at the start of a pulse-labeling experiment, brefeldin A prevented exit of GLUT2 from the endoplasmic reticulum. When the transporter was first accumulated in the TGN during a 15-min period of chase, but not following a low temperature (22 degrees C) incubation, addition of brefeldin A (BFA) prevented subsequent surface expression of the transporter. This indicated that brefeldin A prevented GLUT2 exit from the TGN by acting at a site proximal to the 22 degrees C block. Together, these data demonstrate that GLUT2 surface expression in beta cells is via the constitutive pathway, that transport can be blocked by BFA at two distinct steps and that once on the surface, GLUT2 does not recycle in intracellular vesicles. PMID:8276890

Thorens, B; Gérard, N; Dériaz, N

1993-12-01

289

Characterization of stable, constitutively expressed, chromosomal green and red fluorescent transcriptional fusions in the select agent bacterium, Francisella tularensis Schu S4 and the surrogate type B live vaccine strain (LVS).  

PubMed

Here, we constructed stable, constitutively expressed, chromosomal green (GFP) and red fluorescent (RFP) reporters in the genome of the surrogate strain, Francisella tularensis spp. holarctica LVS (herein LVS), and the select agent, F. tularensis Schu S4. A bioinformatic approach was used to identify constitutively expressed genes. Two promoter regions upstream of the FTT1794 and rpsF(FTT1062) genes were selected and fused with GFP and RFP reporter genes in pMP815, respectively. While the LVS strains with chromosomally integrated reporter fusions exhibited fluorescence, we were unable to deliver the same fusions into Schu S4. Neither a temperature-sensitive Francisella replicon nor a pBBR replicon in the modified pMP815 derivatives facilitated integration. However, a mini-Tn7 integration system was successful at integrating the reporter fusions into the Schu S4 genome. Finally, fluorescent F. tularensis LVS and a mutant lacking MglA were assessed for growth in monocyte-derived macrophages (MDMs). As expected, when compared to wild-type bacteria, replication of an mglA mutant was significantly diminished, and the overall level of fluorescence dramatically decreased with infection time. The utility of the fluorescent Schu S4 strain was also examined within infected MDMs treated with clarithromycin and enrofloxacin. Taken together, this study describes the development of an important reagent for F. tularensis research, especially since the likelihood of engineered antibiotic resistant strains will emerge with time. Such strains will be extremely useful in high-throughput screens for novel compounds that could interfere with critical virulence processes in this important bioweapons agent and during infection of alveolar macrophages. PMID:23852642

Su, Shengchang; Saldanha, Roland; Pemberton, Adin; Bangar, Hansraj; Kawamoto, Steven A; Aronow, Bruce; Hassett, Daniel J; Lamkin, Thomas J

2013-10-01

290

Purification from rat liver of a novel constitutively expressed member of the aldo-keto reductase 7 family that is widely distributed in extrahepatic tissues.  

PubMed

Antiserum raised against human aflatoxin B(1) aldehyde reductase 1 (hAFAR1) has been used to identify a previously unrecognized rat aldo-keto reductase (AKR). This novel enzyme is designated rat aflatoxin B(1) aldehyde reductase 2 (rAFAR2) and it characteristically migrates faster during SDS/PAGE than does the archetypal ethoxyquin-inducible rAFAR protein (now called rAFAR1). Significantly, rAFAR2 is essentially unreactive with polyclonal antibodies raised against rAFAR1. Besides its distinct electrophoretic and immunochemical properties, rAFAR2 appears to be regulated differently from rAFAR1 as it is expressed in most rat tissues and does not appear to be induced by ethoxyquin. Multiple forms of rAFAR2 have been identified. Anion-exchange chromatography on Q-Sepharose, followed by adsorption chromatography on columns of Matrex Orange A and Cibacron Blue, have been employed to purify rAFAR2 from rat liver cytosol. The Q-Sepharose chromatography step resulted in the resolution of rAFAR2 into three peaks of AKR activity, two of which were purified and shown to be capable of catalysing the reduction of 2-carboxybenzaldehyde, succinic semialdehyde, 4-nitrobenzaldehyde and 9,10-phenathrenequinone. The two most highly purified rAFAR2-containing preparations eluted from the Cibacron Blue column were 91 and 98% homogeneous. Analysis of these by SDS/PAGE indicated that the least anionic (peak CBA5) comprised a polypeptide of 37.0 kDa, whereas the most anionic (peak CBA6) contained two closely migrating polypeptides of 36.8 and 37.0 kDa; by contrast, in the present study, rAFAR1 was estimated by SDS/PAGE to be composed of 38.0 kDa subunits. Final purification of the 37 kDa polypeptide in CBA5 and CBA6 was accomplished by reversed-phase HPLC. Partial proteolysis of the two preparations of the 37 kDa polypeptide with Staphylococcus aureus V8 protease yielded fragments of identical size, suggesting that they represent the product of a single gene. Furthermore, the peptide maps from CBA5 and CBA6 differed substantially from that yielded by rAFAR1, indicating that they are genetically distinct from the inducible reductase. A peptide generated by CNBr digestion of the 37 kDa polypeptide from CBA6 was shown by Edman degradation to share 88% sequence identity with residues Tyr(168)-Leu(183) of rAFAR1. This provides evidence that the rat protein identified by its cross-reactivity with anti-hAFAR1 serum is an additional member of the AKR7 family. PMID:10816434

Kelly, V P; Ireland, L S; Ellis, E M; Hayes, J D

2000-06-01

291

Constitutive modeling and thermoviscoplasticity  

NASA Technical Reports Server (NTRS)

Development and solution of coupled thermomechanical equations at elevated temperature and/or high strain rates are discussed. Three main considerations are presented: development of the coupled thermomechanical equations by means of the rational theory of thermodynamics, development of a thermoviscoplastic constitutive equation which is congruous with the developed coupled equations, and the applicability of the developed equations to the treatment by the finite element method.

Hetnarski, Richard B.; Ghoneim, Hany; Paul, Donald B.

1988-01-01

292

A new mouse model for marfan syndrome presents phenotypic variability associated with the genetic background and overall levels of Fbn1 expression.  

PubMed

Marfan syndrome is an autosomal dominant disease of connective tissue caused by mutations in the fibrillin-1 encoding gene FBN1. Patients present cardiovascular, ocular and skeletal manifestations, and although being fully penetrant, MFS is characterized by a wide clinical variability both within and between families. Here we describe a new mouse model of MFS that recapitulates the clinical heterogeneity of the syndrome in humans. Heterozygotes for the mutant Fbn1 allele mg?loxPneo, carrying the same internal deletion of exons 19-24 as the mg? mouse model, present defective microfibrillar deposition, emphysema, deterioration of aortic wall and kyphosis. However, the onset of a clinical phenotypes is earlier in the 129/Sv than in C57BL/6 background, indicating the existence of genetic modifiers of MFS between these two mouse strains. In addition, we characterized a wide clinical variability within the 129/Sv congenic heterozygotes, suggesting involvement of epigenetic factors in disease severity. Finally, we show a strong negative correlation between overall levels of Fbn1 expression and the severity of the phenotypes, corroborating the suggested protective role of normal fibrillin-1 in MFS pathogenesis, and supporting the development of therapies based on increasing Fbn1 expression. PMID:21152435

Lima, Bruno L; Santos, Enrico J C; Fernandes, Gustavo R; Merkel, Christian; Mello, Marco R B; Gomes, Juliana P A; Soukoyan, Marina; Kerkis, Alexandre; Massironi, Silvia M G; Visintin, José A; Pereira, Lygia V

2010-01-01

293

Thomas Jefferson and the Constitution.  

ERIC Educational Resources Information Center

Examines Thomas Jefferson's role in the making and interpretation of the United States Constitution. Discusses the dominant features of Jefferson's constitutional theory; the character of Jefferson's presidency; and Jefferson's ongoing concern about constitutional preservation and change. Lists important dates in the history of the constitution.…

Peterson, Merrill D.

1987-01-01

294

The Constitution in Other Lands.  

ERIC Educational Resources Information Center

Designed for classroom teaching, this document contains articles on the new constitutions of Japan, South Korea, and the Philippine Islands which were modeled in part on the U.S. Constitution. These countries' experiences with constitutional government are examined, and whether or not the U.S. Constitution can be a suitable model for other…

Bill of Rights in Action, 1987

1987-01-01

295

Six novel constitutive promoters for metabolic engineering of Aspergillus niger.  

PubMed

Genetic tools for the fine-tuning of gene expression levels are a prerequisite for rational strain optimization through metabolic engineering. While Aspergillus niger is an industrially important fungus, widely used for production of organic acids and heterologous proteins, the available genetic tool box for this organism is still rather limited. Here, we characterize six novel constitutive promoters of A. niger providing different expression levels. The selection of the promoters was based on published transcription data of A. niger. The promoter strength was determined with the ?-glucuronidase (gusA) reporter gene of Escherichia coli. The six promoters covered a GUS activity range of two to three orders of magnitude depending on the strain background. In order to demonstrate the power of the newly characterized promoters for metabolic engineering, they were used for heterologous expression of the cis-aconitate decarboxylase (cad1) gene of Aspergillus terreus, allowing the production of the building block chemical itaconic acid with A. niger. The CAD activity, dependent on the choice of promoter, showed a positive correlation with the specific productivity of itaconic acid. Product titers from the detection limit to up to 570 mg/L proved that the set of constitutive promoters is a powerful tool for the fine-tuning of metabolic pathways for the improvement of industrial production processes. PMID:22707054

Blumhoff, Marzena; Steiger, Matthias G; Marx, Hans; Mattanovich, Diethard; Sauer, Michael

2013-01-01

296

A constitutively expressed serum amyloid A protein gene (SAA4) is closely linked to, and shares structural similarities with, an acute-phase serum amyloid A protein gene (SAA2)  

SciTech Connect

The acute-phase reactant serum amyloid A (SAA) is a polymorphic apolipoprotein encoded by a family of highly homologous and closely linked genes: SAA1, SAA2, and SAA3. The authors have isolated a human genomic cosmid clone containing the gene encoding a fourth, constitutively expressed member of the human SAA superfamily, C-SAA, together with an SAA2*2 (SAA2{beta}) gene. The gene encoding C-SAA shares the same 5{prime} to 3{prime} orientation as SAA2*2 and has the characteristic four-exon structure of the other members of the SAA superfamily. The exons of the gene encoding C-SAA share only limited sequence identity with those of SAA1, SAA2, and SAA3; they specify an mRNA, represented by the CS-1 cDNA reported previously, which is expressed at low levels (relative to the acute-phase SAAs) in normal and acute-phase liver. The gene encoding C-SAA is located 9 kb downstream of SAA2*2 and therefore occupies the locus that has been identified as containing the SAA4 gene. 35 refs., 3 figs., 1 tab.

Steel, D.M.; Sellar, G.C.; Uhlar, C.M.; Whitehead, A.S. [Univ. of Dublin (Ireland)] [Univ. of Dublin (Ireland); Simon, S. [Center for Blood Research, Boston, MA (United States)] [Center for Blood Research, Boston, MA (United States); DeBeer, F.C. [Univ. of Kentucky Medical Center, Lexington, KY (United States)] [Univ. of Kentucky Medical Center, Lexington, KY (United States)

1993-05-01

297

Constitutive activity of neural melanocortin receptors.  

PubMed

The two neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), are G protein-coupled receptors expressed primarily in the brain that regulate different aspects of energy homeostasis. The MCRs are unique in having endogenous antagonists, agouti and agouti-related protein (AgRP). These antagonists were later shown to be inverse agonists. The MC3R has little or no constitutive activity, whereas the MC4R has significant constitutive activity that can easily be detected. We describe herein methods for detecting constitutive activities in these receptors and small molecule ligands as inverse agonists. AgRP is an inverse agonist for both MC3R and MC4R. We also provide models for the constitutively active MC4R mutants. PMID:21036237

Tao, Ya-Xiong; Huang, Hui; Wang, Zhi-Qiang; Yang, Fan; Williams, Jessica N; Nikiforovich, Gregory V

2010-01-01

298

Computational analysis and modeling of cleavage by the immunoproteasome and the constitutive proteasome  

Microsoft Academic Search

BACKGROUND: Proteasomes play a central role in the major histocompatibility class I (MHCI) antigen processing pathway. They conduct the proteolytic degradation of proteins in the cytosol, generating the C-terminus of CD8 T cell epitopes and MHCI-peptide ligands (P1 residue of cleavage site). There are two types of proteasomes, the constitutive form, expressed in most cell types, and the immunoproteasome, which

Carmen M. Diez-Rivero; Esther M. Lafuente; Pedro A. Reche

2010-01-01

299

Conscience and the Constitution  

NSDL National Science Digital Library

This companion site to the PBS national broadcast December 2000, of "Conscience and the Constitution" examines the historical and moral issues surrounding the decision of a handful of Japanese to refuse to be drafted from their location in an American concentration camp in 1944. The site also looks at the history of the Japanese American Citizens League (JACL), an organization of first generation Japanese-Americans that not only supported the efforts of the US military to apprehend and relocate Japanese citizens, but opposed all efforts of individual Japanese-Americans to challenge the constitutionality of the government's actions. In addition to the thoughtful narration of the history and the controversy it continues to generate, the Website provides access to original documents of the parties involved, including letters and statements from the draft resisters, who eventually served more than two years hard labor, the columns of the journalist who supported their civil disobedience, and public statements and correspondence of the JACL. Some video portions of the broadcast are also available here in RealPlayer.

300

Controlled expression of functional miR122 with a ligand inducible expression system  

Microsoft Academic Search

BACKGROUND: To study the biological function of miRNAs, and to achieve sustained or conditional gene silencing with siRNAs, systems that allow controlled expression of these small RNAs are desirable. Methods for cell delivery of siRNAs include transient transfection of synthetic siRNAs and expression of siRNAs in the form of short hairpins using constitutive RNA polymerase III promoters. Systems employing constitutive

Cathy M Shea; George Tzertzinis

2010-01-01

301

Courts over Constitutions Revisited: Unwritten Constitutionalism in the States  

Microsoft Academic Search

A good deal of modern debate in constitutional law has concerned the appropriate methods for construing constitutional rights. But the focus on “individual rights” has sometimes prompted us to pay too little attention to the “right” deemed most fundamental by those who brought us the state and federal constitutions: the right of the people collectively to make determinations about how

Thomas B. McAffee; Nathan N. Frost; Rachel Beth Klein-Levine

2004-01-01

302

The influence of ethylene perception on sex expression in melon ( Cucumis melo L.) as assessed by expression of the mutant ethylene receptor, At-etr1-1 , under the control of constitutive and floral targeted promoters  

Microsoft Academic Search

Sexual diversity expressed by Curcurbitaceae species is a primary example of developmental plasticity in plants. Ethylene,\\u000a which promotes femaleness (carpel development), plays a key role in sex determination. We sought to determine the critical\\u000a location for ethylene perception in developing floral primodia. The dominant negative Arabidopsis ethylene response mutant\\u000a gene, etr1-1, was introduced into melon (Cucumis melo L.) plants under

Holly A. Little; Ekaterina Papadopoulou; Sue A. Hammar; Rebecca Grumet

2007-01-01

303

Identification and characterization of a constitutively T-loop phosphorylated and active recombinant S6K1: expression, purification, and enzymatic studies in a high capacity non-radioactive TR-FRET Lance assay.  

PubMed

The p70 S6 ribosomal protein kinase 1 (S6K) is a substrate and effector of the mammalian target of rapamycin (mTOR). The mTOR/S6K pathway is implicated in cancer and metabolic disorders. To study the molecular regulation of S6K and identify specific inhibitors, availability of active recombinant S6K and robust enzyme assays are critically needed. To date, however, expression of active recombinant S6K has not been feasible as S6K activation requires a cascade of phosphorylation events. We have compared several engineered S6K enzymes. Expression of the Flag-S6KDeltaCT(T389E) in HEK293 cells resulted in a highly active S6K that was constitutively phosphorylated on T229 in the activation-loop (T-loop). The active enzyme was readily purified in large scale by anti-Flag affinity chromatography achieving a high purity. We developed a high capacity homogeneous time-resolved fluorescence resonance energy transfer. Lance assay for measurement of substrate phosphorylation and analysis of kinetic parameters. The Michaelis constant (Km) values of S6K for ATP and the Biotin-S6 substrate peptide were determined to be 21.4+/-0.29 and 0.9+/-0.48 microM, respectively. The Lance assay was further validated with a diverse panel of literature inhibitors, in which the PKC inhibitors staurosporine, Ro-318220, and the PKA inhibitor Balanol potently inhibited S6K. Dose-response and inhibition mechanism by these inhibitors were also studied. Our data provide a new simplified strategy to achieve rapid production of active S6K and demonstrate utility of the Lance assay for S6K enzyme screen in searching for specific inhibitors. PMID:16213157

Zhang, Wei-Guo; Shor, Boris; Yu, Ker

2006-04-01

304

Bioactive terpenoids and flavonoids from ginkgo biloba extract induce the expression of hepatic drug-metabolizing enzymes through Pregnane X receptor, Constitutive androstane receptor, and Aryl hydrocarbon receptor-mediated pathways  

PubMed Central

Purpose The objective of the current study is to investigate the hypothesis that bioactive terpenoids and flavonoids of Ginkgo biloba extract (GBE) induce human hepatic drug metabolizing enzymes (DMEs) and transporters through the selective activation of pregnane X receptor (PXR), constitutive androstane receptor (CAR), and aryl hydrocarbon receptor (AhR). Methods Human primary hepatocyte (HPH), and HepG2 cells are used as in vitro models for enzyme induction and nuclear receptor activation studies. A combination of real-time RT-PCR, transient transfection, and cell-based reporter assays were employed. Results In human primary hepatocytes, real-time PCR analysis showed induction of CYP2B6, CYP3A4, UGT1A1, MDR1, and MRP2 by EGb 761, ginkgolide A (GA) and ginkgolide B (GB), but not by bilobalide (BB) or the flavonoids (quercetin, kaempferol and tamarixetin) of GBE. Cell-based reporter assays in HepG2 revealed that GA and GB are potent activators of PXR; quercetin and kaempferol activate PXR, CAR, and AhR, whereas BB exerts no effects on these xenobiotic receptors. Notably, the flavonoids induced the expression of UGT1A1 and CYP1A2 in HepG2 cells but not in HPH. Conclusion Our results indicate that terpenoids and flavonoids of GBE exhibit differential induction of DMEs through the selective activation of PXR, CAR, and AhR.

Li, Linhao; Stanton, Joseph D; Tolson, Antonia H; Luo, Yuan; Wang, Hongbing

2008-01-01

305

Schwann cells express NDF and SMDF/n-ARIA mRNAs, secrete neuregulin, and show constitutive activation of erbB3 receptors: evidence for a neuregulin autocrine loop.  

PubMed

Cultured Schwann cells secreted low levels (30 pg/ml/1.5 x 10(6) cells) of a 45-kDa neuregulin protein and showed constitutive activation of a neuregulin receptor, Erb-B3, suggesting the existence of an autocrine loop involving neuregulins in Schwann cells. RT-PCR analyses indicated that Schwann cells and fibroblasts in culture produced SMDF/n-ARIA and NDF but not GGF neuregulin messages. Schwann cell and fibroblast neuregulin messages encoded both beta and alpha domains; Schwann cell transcripts encoded only transmembrane neuregulin forms while fibroblast messages encoded transmembrane and secreted forms. SMDF/n-ARIA and NDF messages were also expressed in early postnatal rat sciatic nerve, suggesting a role for neuregulins in peripheral nerve development. An anti-neuregulin antibody inhibited the mitogenic response of Schwann cells to cultured neurons and to extracts of cultured neurons or embryonic brain, consistent with the accepted paracrine role of neuregulins on Schwann cells. Surprisingly, the same antibody inhibited Schwann cell proliferation stimulated by several unrelated mitogens including bFGF, HGF, and TGF-beta1. These data implicate both paracrine and autocrine pathways involving neuregulin form(s) in Schwann cell mitogenic responses. PMID:9417836

Rosenbaum, C; Karyala, S; Marchionni, M A; Kim, H A; Krasnoselsky, A L; Happel, B; Isaacs, I; Brackenbury, R; Ratner, N

1997-12-01

306

Constitutive Tensors for Bianisotropic Media.  

National Technical Information Service (NTIS)

We consider one of the key problems of bianisotropic materials for electromagnetic applications- constitutive relations. The discussion will be restricted to macroscopic level of the tensor description. We will discuss the constitutive tensors under the f...

V. Dmitriev

2000-01-01

307

Polity.org: Constitutional Matters  

NSDL National Science Digital Library

Full text of the new South African Constitution, adopted by the Constitutional Assembly on May 8, 1996, and the full text of President Nelson Mandela's address to the Constitutional Assembly upon its adoption, are available via the Web. The constitution is available as a single file, and as plain text, WordPerfect 5.1, 6.1 and Microsoft Word 6.0 .zip files.

1996-01-01

308

How Capitalistic Is the Constitution?  

ERIC Educational Resources Information Center

Second in a three-part series designed to help prepare the nation for a thoughtful observance of the Constitutional bicentennial, this publication contains seven essays on the topic of capitalism and the Constitution. "American Democracy and the Acquisitive Spirit" (Marc F. Plattner) supports the argument that the framers of the Constitution

Goldwin, Robert A., Ed.; Schambra, William A., Ed.

309

This Constitution: A Bicentennial Chronicle.  

ERIC Educational Resources Information Center

Providing a link between constitutional scholars and the planners of school and public programs observing the Bicentennial of the United States Constitution, this series of the Bicentennial Chronicles features articles that provide a link between scholars of the Constitution and the people who will be planning programs for the public and for the…

This Constitution, 1986

1986-01-01

310

Constitutive models in LAME.  

SciTech Connect

The Library of Advanced Materials for Engineering (LAME) provides a common repository for constitutive models that can be used in computational solid mechanics codes. A number of models including both hypoelastic (rate) and hyperelastic (total strain) constitutive forms have been implemented in LAME. The structure and testing of LAME is described in Scherzinger and Hammerand ([3] and [4]). The purpose of the present report is to describe the material models which have already been implemented into LAME. The descriptions are designed to give useful information to both analysts and code developers. Thus far, 33 non-ITAR/non-CRADA protected material models have been incorporated. These include everything from the simple isotropic linear elastic models to a number of elastic-plastic models for metals to models for honeycomb, foams, potting epoxies and rubber. A complete description of each model is outside the scope of the current report. Rather, the aim here is to delineate the properties, state variables, functions, and methods for each model. However, a brief description of some of the constitutive details is provided for a number of the material models. Where appropriate, the SAND reports available for each model have been cited. Many models have state variable aliases for some or all of their state variables. These alias names can be used for outputting desired quantities. The state variable aliases available for results output have been listed in this report. However, not all models use these aliases. For those models, no state variable names are listed. Nevertheless, the number of state variables employed by each model is always given. Currently, there are four possible functions for a material model. This report lists which of these four methods are employed in each material model. As far as analysts are concerned, this information is included only for the awareness purposes. The analyst can take confidence in the fact that model has been properly implemented and the methods necessary for achieving accurate and efficient solutions have been incorporated. The most important method is the getStress function where the actual material model evaluation takes place. Obviously, all material models incorporate this function. The initialize function is included in most material models. The initialize function is called once at the beginning of an analysis and its primary purpose is to initialize the material state variables associated with the model. Many times, there is some information which can be set once per load step. For instance, we may have temperature dependent material properties in an analysis where temperature is prescribed. Instead of setting those parameters at each iteration in a time step, it is much more efficient to set them once per time step at the beginning of the step. These types of load step initializations are performed in the loadStepInit method. The final function used by many models is the pcElasticModuli method which changes the moduli that are to be used by the elastic preconditioner in Adagio. The moduli for the elastic preconditioner are set during the initialization of Adagio. Sometimes, better convergence can be achieved by changing these moduli for the elastic preconditioner. For instance, it typically helps to modify the preconditioner when the material model has temperature dependent moduli. For many material models, it is not necessary to change the values of the moduli that are set initially in the code. Hence, those models do not have pcElasticModuli functions. All four of these methods receive information from the matParams structure as described by Scherzinger and Hammerand.

Hammerand, Daniel Carl; Scherzinger, William Mark

2007-09-01

311

Conversations on the Constitution  

NSDL National Science Digital Library

Perhaps the United States might be a better place if at the dinner table one interested party might ask the question, "Hey Mom, can we talk about the establishment clause tonight?" Until such topics spontaneously arrive in a pre-prandial setting like the one just mentioned, there will still be great interest in this lovely website created by the American Bar Association. As its mission statement declares, "This project is designed to further dialogue in schools and in the workplace about American constitutional principles and values." Within the site, visitors can peruse a list of topics, such as war powers, the establishment of religion, and cruel and unusual punishment. Each area has a brief overview of each topic, and then three "starter" questions. These starter questions feature a list of specific queries, accompanied by brief illustrations (such as political cartoons and the like) that can be used at the dinner table, the boardroom table, or just about any table. Finally, interested parties can also take a few interactive tests on such areas as Supreme Court rulings and students' rights in the classroom.

312

The Constitution Project  

NSDL National Science Digital Library

Recently, The Constitution Project (TCP) started the bipartisan Task Force on Detainee Treatment. The purpose of TCP is to "bring the American people a comprehensive understanding of what is known and what may still be unknown about the past and current treatment of detainees by the U.S. government, as part of the counterterrorism policies of the Obama, Bush, and Clinton administrations." Visitors to their site can learn about their efforts to shed light on these various activities, and it is a good idea to take a quick look over their "Headline News" area to get started. Users should not miss the report "Principles for Government Data Mining", which can be found near the bottom of the homepage. This section is dedicated to looking into the threats to civil liberties posed by government data mining programs and recommends a series of reforms. Along with reading the report here, users can watch a webcast that features a panel of experts discussing the report's findings and future directions.

313

Amendment to the Constitution.  

PubMed

This Amendment rewrites Clause 4 of Article 10 of the Chinese Constitution to permit the right of land use to be transferred by lease in accordance with the law. In December 1988, the Government also enacted legislation amending the Land Management Law so as to allow for the transfer of Land. See Renmin Ribao (Beijing), 31 December 1988, p. 4; Foreign Broadcast Information Service, FBIS-CHI-89-003, 5 January 1989, pp. 38-39. Provisional Regulations on the Land Use Tax in Urban Areas were promulgated on 27 September 1988. See Xinhua Domestic Service (Beijing), 4 October 1988, Foreign Broadcast Information Service, FBIS-CHI-88-197, 12 October 1988, pp. 26-27, and Xinhua (Beijing), 4 October 1988, FBIS-CHI-88-193, 5 October 1988, pp. 20. Provisional Tax Regulations on Farmland Occupation and Use were proclaimed on 1 April 1987. See Xinhua Domestic Service (Beijing), 19 April 1987; Joint Publications Research Service, China, 22 April 1987, pp. K33-K35. PMID:12289449

1988-01-01

314

Creep constitutive equations for damaged materials  

SciTech Connect

The object of the present paper is to combine knowledge of microscopic mechanisms with experimental observations to obtain constitutive equations for damaged materials. The initial focus is on the mechanisms of failure in creeping materials. A general structure for the constitutive equations is obtained which gives a framework for the development of constitute equations for particular materials. In the present paper this is attempted for copper and an aluminum alloy. A section of the paper is devoted to the application of the material models to structural problems. It is found that when the rate of increase of damage is mathematically separable in expressions for stress and damage that it is possible to obtain upper bounds for the life of a component. 35 refs., 17 figs.

Cocks, A.C.F.; Leckie, F.A. (Univ. of Illinois, Urbana, IL (United States))

1987-01-01

315

Comparison of Efficacy of the Disease-Specific LOX1- and Constitutive Cytomegalovirus-Promoters in Expressing Interleukin 10 through Adeno-Associated Virus 2/8 Delivery in Atherosclerotic Mice  

PubMed Central

The development of gene therapy vectors for treating diseases of the cardiovascular system continues at a steady pace. Moreover, in the field of gene therapy the utility of “disease-specific promoters” has strong appeal. Many therapeutic genes, including transforming growth factor beta 1 or interleukin 10, are associated to adverse effects. The use of a disease-specific promoter might minimize toxicity. The lectin-like oxidized low density lipoprotein receptor 1 is a marker of cardiovascular disease and a potential therapeutic target. The lectin-like oxidized low density lipoprotein receptor 1 is known to be up-regulated early during disease onset in a number of cell types at the sites where the disease will be clinically evident. In this study an adeno-associated virus-2 DNA vector (AAV2) using the AAV8 capsid, and containing the full length The lectin-like oxidized low density lipoprotein receptor 1 promoter, was generated and assayed for its ability to express human interleukin 10 in low density lipoprotein receptor knockout mice on high cholesterol diet. The cytomegalovirus early promoter was used for comparison in a similarly structured vector. The two promoters were found to have equal efficacy in reducing atherogenesis as measured by aortic systolic blood velocity, aortic cross sectional area, and aortic wall thickness. This is the first head-to-head comparison of a constitutive with a disease-specific promoter in a therapeutic context. These data strongly suggest that the use of a disease-specific promoter is appropriate for therapeutic gene delivery.

Zhu, Hongqing; Cao, Maohua; Mirandola, Leonardo; Figueroa, Jose A.; Cobos, Everardo; Chiriva-Internati, Maurizio; Hermonat, Paul L.

2014-01-01

316

New Constitutive Vectors: Useful Genetic Engineering Tools for Biocatalysis  

PubMed Central

Constitutive vectors are useful tools for genetic engineering. Two constitutive vectors with high levels of expression and broad host ranges were developed and used in a range of Pseudomonas hosts. The vectors showed superior characteristics compared to the inducible vectors as well as the potential to be used as improved genetic tools for biocatalysis.

Xu, Youqiang; Tao, Fei; Xu, Ping

2013-01-01

317

Expression of background potassium channels in rat DRG is cell-specific and down-regulated in a neuropathic pain model.  

PubMed

Neuropathic pain is associated with hyperexcitability of DRG neurons. Despite the importance of leakage potassium channels for neuronal excitability, little is known about their cell-specific expression in DRGs and possible modulation in neuropathic pain. Multiple leakage channels are expressed in DRG neurons, including TASK1, TASK3, TRESK, TRAAK, TWIK1, TREK1 and TREK2 but little is known about their distribution among different cell types. Our immunohistochemical studies show robust TWIK1 expression in large and medium size neurons, without overlap with TRPV1 or IB4 staining. TASK1 and TASK3, on the contrary, are selectively expressed in small cells; TASK1 expression closely overlaps TRPV1-positive cells, while TASK3 is expressed in TRPV1- and IB4-negative cells. We also studied mRNA expression of these channels in L4-L5 DRGs in control conditions and up to 4 weeks after spared nerve injury lesion. We found that TWIK1 expression is much higher than TASK1 and TASK3 and is strongly decreased 1, 2 and 4 weeks after neuropathic injury. TASK3 expression, on the other hand, decreases 1 week after surgery but reverts to baseline by 2weeks; TASK1 shows no significant change at any time point. These data suggest an involvement of TWIK1 in the maintenance of the pain condition. PMID:23994814

Pollema-Mays, Sarah L; Centeno, Maria Virginia; Ashford, Crystle J; Apkarian, A Vania; Martina, Marco

2013-11-01

318

The Texas Constitutions Digitization Project  

NSDL National Science Digital Library

Presented by the Tarlton Law Library at the University of Texas School of law, this site offers digital copies of the twelve constitutions of the State (and Republic) of Texas drafted between 1824 and 1876. Both transcriptions and digital images of the original documents are provided, along with a bibliography of printings, a supplemental bibliography, and a link to the relevant Handbook of Texas article. A Spanish version is also available for a few of the constitutions. An internal search engine, an annotated bibliography on the constitutions, a bibliography on Texas constitutional history, and a collection of related links are also provided.

319

Constitutive Activity of Neural Melanocortin Receptors  

Microsoft Academic Search

The two neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), are G protein-coupled receptors expressed primarily in the brain that regulate different aspects of energy homeostasis. The MCRs are unique in having endogenous antagonists, agouti and agouti-related protein (AgRP). These antagonists were later shown to be inverse agonists. The MC3R has little or no constitutive activity, whereas

Ya-Xiong Tao; Hui Huang; Zhi-Qiang Wang; Fan Yang; Jessica N. Williams; Gregory V. Nikiforovich

2010-01-01

320

Constitutive Somatostatin Receptor Activity Determines Tonic Pituitary Cell Response  

PubMed Central

Somatostatin (SRIF) binds G protein-coupled SRIF receptor subtypes (SST1, -2, -3, -4, and -5) to regulate cell secretion and proliferation. Hypothalamic SRIF inhibits pituitary growth hormone, thyroid stimulating hormone, and ACTH secretion. We tested SRIF-independent constitutive SST activity in AtT20 mouse pituitary corticotroph cells in which ACTH secretion is highly sensitive to SRIF action. Stable transfectants expressing SST2 or SST5 were sensitized to selective agonist action, and constitutive SST receptor activity was demonstrated by forskolin and pertussis toxin cAMP cell responses. Persistent constitutive SST activity decreased cell ACTH responses to CRH through decreased expression of CRH receptor subtype 1. Decreased dopamine receptor type 1 expression was associated with attenuated dopamine agonist action, whereas responses to isoproterenol were enhanced through increased ?2-adrenoreceptor expression. Thus, integrated pituitary cell ACTH regulation is determined both by phasic SRIF action, as well as by tonic constitutive SST activity, independently of SRIF.

Ben-Shlomo, Anat; Zhou, Cuiqi; Pichurin, Oxana; Chesnokova, Vera; Liu, Ning-Ai; Culler, Michael D.; Melmed, Shlomo

2009-01-01

321

Operators and Fractional Derivatives for Viscoelastic Constitutive Equations.  

National Technical Information Service (NTIS)

The operator form of the constitutive equation containing fractional derivatives leads to an expression for the complex modulus which is a ratio of polynomials of fractional order in reduced frequency. A ratio of factored polynomials is developed by use o...

L. Rogers

1984-01-01

322

Constitutive equations of ageing polymeric materials  

NASA Technical Reports Server (NTRS)

The constitutive equation for the relaxation behavior of time-dependent, chemically unstable materials developed by Valanis and Peng (1983), which used the irreversible thermodynamics of internal variables in Eyring's absolute reaction theory and yielded a theoretical expression for the effect of chemical crosslink density on the relaxation rate, is presently applied to the creep behavior of a network polymer which is undergoing a scission process. In particular, two equations are derived which may for the first time show the relations between mechanical models and internal variables in the creep expressions, using a three-element model with a Maxwell element.

Peng, S. T. J.

1985-01-01

323

The Judgment of Constitutional Morality  

Microsoft Academic Search

This thesis examines a novel claim that judicial review of legislation is democratically justified because judges can have access to their community's constitutional morality and base their judgments on those grounds. A constitutional morality is a complex intersubjective agreement where citizens have agreed to entrench certain rights in law. It is often claimed both in preambles and in theoretical defenses

Scott Wisdom

2008-01-01

324

Constitutional Rights of Government Employees.  

National Technical Information Service (NTIS)

The intent of this research paper is to study the evolution of the constitutional rights of government employees. There is a perception by many young and old citizens that one must give up some constitutional rights to work for the federal government. Is ...

L. L. Thomas

2001-01-01

325

Constitutional Change: A Case Study.  

ERIC Educational Resources Information Center

Presents a lesson for secondary students which teaches that the U.S. Constitution has changed in a variety of ways and that it has a direct effect upon the lives of citizens. Provides a worksheet and a lecture outline covering three methods of constitutional change and Supreme Court cases such as Dred Scott and Brown vs. Board of Education. (GEA)

Christofferson, Walter D.; Pergande, Donald J.

1987-01-01

326

Developing Standards for Constitutional Change.  

ERIC Educational Resources Information Center

Maintains that the principle of self-restraint that has marked the amending practices since the creation of the U.S. Constitution may be in danger of being forgone. Offers eight standards developed by the Citizens for the Constitution that are designed to weigh the desirability of proposed amendments. (CMK)

Update on Law-Related Education, 1998

1998-01-01

327

Contributions of Sasang Constitutional Medicine  

Microsoft Academic Search

Sasang Constitutional Medicine (SCM), also referred to as 'integrative medicine', constitutes a unique contribu- tion to the growing field of complementary and alterna- tive medicine. Like all other ancient cultures—including those from India, (Ayurveda) China (TCM), Japan (Kampo), Korea (TKM) and the Mediterranean (TAIM)—there is an emerging fascination with, and indeed use of, these approaches as adjuncts to Western medicine

Edwin L. Cooper

2009-01-01

328

Microplane constitutive model for porous isotropic rocks  

NASA Astrophysics Data System (ADS)

The paper deals with constitutive modelling of contiguous rock located between rock joints. A fully explicit kinematically constrained microplane-type constitutive model for hardening and softening non-linear triaxial behaviour of isotropic porous rock is developed. The microplane framework, in which the constitutive relation is expressed in terms of stress and strain vectors rather than tensors, makes it possible to model various microstructural physical mechanisms associated with oriented internal surfaces, such as cracking, slip, friction and splitting of a particular orientation. Formulation of the constitutive relation is facilitated by the fact that it is decoupled from the tensorial invariance restrictions, which are satisfied automatically. In its basic features, the present model is similar to the recently developed microplane model M4 for concrete, but there are significant improvements and modifications. They include a realistic simulation of (1) the effects of pore collapse on the volume changes during triaxial loading and on the reduction of frictional strength, (2) recovery of frictional strength during shearing, and (3) the shear-enhanced compaction in triaxial tests, manifested by a deviation from the hydrostatic stress-strain curve. The model is calibrated by optimal fitting of extensive triaxial test data for Salem limestone, and good fits are demonstrated. Although these data do not cover the entire range of behaviour, credence in broad capabilities of the model is lend by its similarity to model M4 for concrete - an artificial rock. The model is intended for large explicit finite-element programs.

Baant, Zdenk P.; Zi, Goangseup

2003-01-01

329

Remarks on turbulent constitutive relations  

NASA Technical Reports Server (NTRS)

The paper demonstrates that the concept of turbulent constitutive relations can be used to construct general models for various turbulent correlations. Some of the Generalized Cayley-Hamilton formulas for relating tensor products of higher extension to tensor products of lower extension are introduced. The combination of dimensional analysis and invariant theory can lead to 'turbulent constitutive relations' (or general turbulence models) for, in principle, any turbulent correlations. As examples, the constitutive relations for Reynolds stresses and scalar fluxes are derived. The results are consistent with ones from Renormalization Group (RNG) theory and two-scale Direct-Interaction Approximation (DIA) method, but with a more general form.

Shih, Tsan-Hsing; Lumley, John L.

1993-01-01

330

Cleanup liability and the Constitution  

SciTech Connect

It was observed in the July 1992 issue of this Journal that a plain reading of the Constitution's prohibition on [open quotes][ital ex post facto][close quotes] suggests that some environmental statutes such as the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA or Superfund) and the Resource Conservation and Recovery Act of 1976 (RCRA) conflict with Constitutional principles. Like many Constitutional principles, however, the Supreme Court's interpretation of the Constitution's bar on [ital ex post facto] laws has a long history. The Court has consistently interpreted this clause as limited to criminal or penal statutes. This article discusses the history of the [ital ex post facto] clause, the retroactive application of CERCLA and RCRA, the decision that retroactive application of CERCLA and RCRA does not violate the [ital ex post facto] clause, and laws, regulations, and guidance. 27 refs.

Friedland, D.M.; Hagen, P.E. (Beveridge Diamond, Washington, DC (United States))

1992-12-01

331

GLUT2 Surface Expression and Intracellular Transport via the Constitutive Pathway in Pancreatic # Cells and Insulinoma: Evidence for a Block in Trans-Golgi Network Exit by Brefeldin A  

Microsoft Academic Search

The biosynthesis, intracellular transport, and surface expression of the\\/3 cell glucose trans- porter GLUI2 was investigated in isolated islets and insulinoma cells. Using a trypsin sensitivity assay to measure cell surface expression, we determined that: (a) greater than 95 % of GLUT2 was expressed on the plasma membrane; (b) GLUT2 did not recycle in in- tracellular vesicles; and (c) after

Bernard Thorens; Nathalie D

332

Cells transformed by ODC, c-Ha-ras and v-src exhibit MAP kinase\\/Erk-independent constitutive phosphorylation of Sos, Raf and c-Jun activation domain, and reduced PDGF receptor expression  

Microsoft Academic Search

While it is known that the constitutive activity of a variety of signal transduction molecules leads to cell transformation, a key unresolved question is whether these wirings converge to a common intermediate(s) that dictates transformation. In this study, we investigated whether NIH3T3 and Rat-1 cells transformed by human ornithine decarboxylase (ODC), c-Ha-rasVal12 and temperature-sensitive v-src oncogene display common alteration(s) in

Aino Paasinen-Sohns; Erkki Hölttä

1997-01-01

333

Schwann Cells Express NDF and SMDF\\/n-ARIA mRNAs, Secrete Neuregulin, and Show Constitutive Activation of erbB3 Receptors: Evidence for a Neuregulin Autocrine Loop  

Microsoft Academic Search

Cultured Schwann cells secreted low levels (30 pg\\/ml\\/1.5×106cells) of a 45-kDa neuregulin protein and showed constitutive activation of a neuregulin receptor, Erb-B3, suggesting the existence of an autocrine loop involving neuregulins in Schwann cells. RT-PCR analyses indicated that Schwann cells and fibroblasts in culture produced SMDF\\/n-ARIA and NDF but not GGF neuregulin messages. Schwann cell and fibroblast neuregulin messages encoded

Claudia Rosenbaum; Saikumar Karyala; Mark A. Marchionni; Haesun A. Kim; Alexei L. Krasnoselsky; Beth Happel; Indu Isaacs; Robert Brackenbury; Nancy Ratner

1997-01-01

334

Development of test panel of beta-lactamases expressed in a common Escherichia coli host background for evaluation of new beta-lactam antibiotics.  

PubMed Central

A test panel of 35 different beta-lactamases expressed in a common Escherichia coli host was created to compare the effect that each beta-lactamase had on susceptibility to various beta-lactam antibiotics. A comparison of the MICs obtained with this panel generally reflected differences in the substrate profiles of the various beta-lactamases examined. In addition, several strains of the panel were subjected to selection with porin-specific bacteriophages to obtain mutants lacking either the OmpC or OmpF porin protein. A mutation in either OmpC or OmpF did change the susceptibilities of certain strains expressing beta-lactamase to certain beta-lactam antibiotics. However, the loss of a single porin did not predictably alter susceptibility to any given beta-lactam drug. This panel of strains producing various beta-lactamases was found to be a useful tool for comparing the effects of different beta-lactamases and outer membrane permeability upon susceptibility to beta-lactam drugs.

Bradford, P A; Sanders, C C

1995-01-01

335

Liberty Library of Constitutional Classics  

NSDL National Science Digital Library

The Liberty Library of Constitutional Classics is a treasure trove of political primary documents that have influenced the U.S. government as well as many other countries with Republican forms of government around the world. The site makes available documents online it a variety of formats, each format is given a symbol the user can then choose which format (html, pdf, word, etc) they would prefer. The primary documents range from the Code of Hammurabi (c.1780 BCE), to Civil Disobedience by Henry David Thoreau (1849). The documents are arranged chronologically to make searching simple. Students will find this site especially useful and perhaps even a cost effective way of accessing documents for class readings or research. Instructors will also enjoy the easy access to these sources. The site also contains links to other collections including, U.S. State Constitutions, National Constitutions (from around the world), and Landmark Court Decisions.

Roland, Jon

2006-11-23

336

Hanford Site background: Part 3, Groundwater background.  

National Technical Information Service (NTIS)

This report presents and interprets groundwater background data collected from the unconfined aquifer beneath the Hanford Site, a U.S. Department of Energy complex located near Richland, Washington. Characterization of background composition is an importa...

1997-01-01

337

Psychology's influence on constitutional interpretation  

Microsoft Academic Search

When organized psychology files amicus briefs with the Supreme Court and other courts, it does so for a variety of reasons and seeks to advance a number of policy objectives. The thesis of this article is that pursuit of some of those objectives is improper and that their pursuit threatens to defeat other objectives. Psychology's expertise is not in constitutional

Thomas Grisso; Michael J. Sakst

1991-01-01

338

Constitutive Modeling for Isotropic Materials.  

National Technical Information Service (NTIS)

The third and fourth years of a 4-year research program, part of the NASA HOST Program, are described. The program goals were: (1) to develop and validate unified constitutive models for isotropic materials, and (2) to demonstrate their usefulness for str...

K. S. Chan U. S. Lindholm S. R. Bodner

1988-01-01

339

Constitutional Reform of School Finance.  

ERIC Educational Resources Information Center

This book contains conference papers by experts in educational administration, law, and economics. Six of the papers are devoted to a legal analysis of fiscal inequality among school attendance units, school districts, and States. These contributions are: (1) K. Forbis Jordan and Kern Alexander, "Constitutional Methods of Financing Public…

Alexander, Kern, Ed.; Jordan, K. Forbis, Ed.

340

A Venture in Constitutional Law.  

ERIC Educational Resources Information Center

Senior high girls and boys from two single-sex schools undertook a study of a Supreme Court case that provided insight not only into constitutional law and history but also into how men and women can work together and relate in other ways than dating. (DS)

Cole, W. Graham; Dillon, Dorothy H.

1980-01-01

341

Constitutive relations of ferroelectric ceramics  

Microsoft Academic Search

The objective of this thesis is to obtain a better understanding on the fundamental constitutive behavior of ferroelectric ceramics based on the physics of phase transition, micromechanics of heterogeneous materials, and principles of irreversible thermodynamics. Within this framework, a self-consistent model is developed to investigate the electromechanical responses of ferroelectric polycrystals under temperature change and electromechanical loading. Cooling of a

Yu Su

2003-01-01

342

Take Advantage of Constitution Day  

ERIC Educational Resources Information Center

The announcement of the mandate for Constitution and Citizenship Day shortly before September, 2005, probably led to groans of dismay. Not another "must-do" for teachers and schools already stressed by federal and state requirements for standardized tests, increasingly rigid curricula, and scrutiny from the public and officials. But the idea and…

McCune, Bonnie F.

2008-01-01

343

Assessing the language skills of children from culturally and linguistically diverse backgrounds: the expressive vocabulary performance of Singaporean English-Mandarin bilingual pre-schoolers.  

PubMed

Standardized language assessments such as the Clinical Evaluation of Language Fundamentals Pre-school 2 United Kingdom (CELF Preschool 2 UK) are often used in speech-language pathology clinics to determine if a child is at risk of language difficulties. Many of these assessments are designed and standardized for use with monolingual Standard English-speaking children. It is thus recommended that these assessments should only be used with the populations they were designed for; if not test bias might result. However, such tests are still selected and used in the clinics of many multicultural and multilinguistic communities (e.g., Singapore). This research aimed to explore the performance of 79 Singaporean English-Mandarin pre-school children on the Expressive Vocabulary (EV) sub-test of the CELF Preschool 2 UK and to determine if their performance on the EV sub-test accurately reflected their language abilities by comparing their performance on a local screening language assessment tool, the Singapore English Action Picture Test (SEAPT). Results showed that local children performed poorly as compared to their UK counterparts. Two plausible reasons for the findings are: (1) the sub-test elicited only a single measure in English which ignored the language abilities of these bilingual children in their second language; and (2) the presence of culturally and linguistically biased test items. PMID:22335605

Teoh, Wei Qin; Brebner, Chris; McCormack, Paul

2012-06-01

344

President Mandela Address to Constitutional Assembly  

NSDL National Science Digital Library

Full text of the new South African Constitution, adopted by the Constitutional Assembly on May 8, 1996, and the full text of President Nelson Mandela's address to the Constitutional Assembly upon its adoption, are available via the Web.

Mandela, Nelson, 1918-.

1996-01-01

345

Nongeometric fluxes as supergravity backgrounds  

NASA Astrophysics Data System (ADS)

We consider examples of D=4 string theory vacua which, although globally nongeometric, admit a local description in terms of D=10 supergravity backgrounds. We analyze such backgrounds and find that the supersymmetry spinors vary nontrivially along the internal manifold, reproducing the interpolating supergravity solutions found by Frey and Graña. Finally, we propose a simple, local expression for nongeometric fluxes in terms of the internal spinors of the compactification.

Marchesano, Fernando; Schulgin, Waldemar

2007-08-01

346

Nongeometric fluxes as supergravity backgrounds  

SciTech Connect

We consider examples of D=4 string theory vacua which, although globally nongeometric, admit a local description in terms of D=10 supergravity backgrounds. We analyze such backgrounds and find that the supersymmetry spinors vary nontrivially along the internal manifold, reproducing the interpolating supergravity solutions found by Frey and Grana. Finally, we propose a simple, local expression for nongeometric fluxes in terms of the internal spinors of the compactification.

Marchesano, Fernando [ASC, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Schulgin, Waldemar [Max Planck Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

2007-08-15

347

Constitutive modeling for isotropic materials  

NASA Technical Reports Server (NTRS)

The third and fourth years of a 4-year research program, part of the NASA HOST Program, are described. The program goals were: (1) to develop and validate unified constitutive models for isotropic materials, and (2) to demonstrate their usefulness for structural analysis of hot section components of gas turbine engines. The unified models selected for development and evaluation were those of Bodner-Partom and of Walker. The unified approach for elastic-viscoplastic constitutive equations is a viable method for representing and predicting material response characteristics in the range where strain rate and temperature dependent inelastic deformations are experienced. This conclusion is reached by extensive comparison of model calculations against the experimental results of a test program of two high temperature Ni-base alloys, B1900+Hf and Mar-M247, over a wide temperature range for a variety of deformation and thermal histories including uniaxial, multiaxial, and thermomechanical loading paths. The applicability of the Bodner-Partom and the Walker models for structural applications has been demonstrated by implementing these models into the MARC finite element code and by performing a number of analyses including thermomechanical histories on components of hot sections of gas turbine engines and benchmark notch tensile specimens. The results of the 4-year program have been published in four annual reports. The results of the base program are summarized in this report. The tasks covered include: (1) development of material test procedures, (2) thermal history effects, and (3) verification of the constitutive model for an alternative material.

Chan, K. S.; Lindholm, U. S.; Bodner, S. R.

1988-01-01

348

Constitutive Expression of the AP-1 Transcription Factors c-jun, junD, junB, and c-fos and the Marginal Zone B-Cell Transcription Factor Notch2 in Splenic Marginal Zone Lymphoma  

PubMed Central

Splenic marginal zone lymphoma (SMZL) is a lymphoma type of putative marginal zone B-cell origin. No specific genetic alterations have yet been demonstrated in SMZL. Clinically, SMZL is a low-grade B-cell non-Hodgkin lymphoma. However, the presence of p53 mutation, 7q22–7q32 deletion or the absence of somatic hypermutations of immunoglobulin genes has been correlated with a worse prognosis. In this study, we analyzed genome-wide gene expression of 24 cases of SMZL using the microarray technique. The AP-1 transcription factors c-jun, junD, junB, and c-fos as well as Notch2 were found to be specifically up-regulated. These data were confirmed by real-time PCR and immunohistochemical staining of tissue sections. The absence of concordant high expression of the MAP kinases, the signaling cascade leading to AP-1 up-regulation, suggests autoregulation of the AP-1 transcription factors and an important role in SMZL oncogenesis. High expression of Notch2, a transcription factor that induces marginal zone B-cell differentiation, is highly suggestive for a marginal zone B-cell origin of SMZL. In addition, SMZL with the 7q deletion showed high expression of TGF-?1 and low expression of the DNA helicase XPB, a crucial part of the nucleotide excision repair complex, possibly explaining the more aggressive clinical course of those cases.

Tr?en, Gunhild; Nygaard, Vigdis; Jenssen, Tor-Kristian; Ikonomou, Ida Munster; Tierens, Anne; Matutes, Estella; Gruszka-Westwood, Alicja; Catovsky, Daniel; Myklebost, Ola; Lauritzsen, Grete; Hovig, Eivind; Delabie, Jan

2004-01-01

349

Constitutional political economy in the European Union  

Microsoft Academic Search

This article surveys recent research in constitutional political economy in Europe. Although not all of the works discussed necessarily focus only on European constitutional issues or are written by Europeans, European constitutional issues figure importantly in each area surveyed. The article examines the literatures linking constitutional institutions to economic growth, government size, government deficits and corruption, bicameralism, direct democracy and

Dennis C. Mueller

2005-01-01

350

Constitution-Writing in Central Europe.  

ERIC Educational Resources Information Center

Remarks on experiences as a participant at a conference on constitution-writing that linked Czech and Slovak constitution writers with U.S. lawyers. Argues cultural traditions must be respected when advising how to write constitutions. Examines challenges facing Czech and Slovak constitution writers, including structuring the government; the…

Troy, Daniel E.

1990-01-01

351

Impact of constitutional copy number variants on biological pathway evolution  

PubMed Central

Background Inherited Copy Number Variants (CNVs) can modulate the expression levels of individual genes. However, little is known about how CNVs alter biological pathways and how this varies across different populations. To trace potential evolutionary changes of well-described biological pathways, we jointly queried the genomes and the transcriptomes of a collection of individuals with Caucasian, Asian or Yoruban descent combining high-resolution array and sequencing data. Results We implemented an enrichment analysis of pathways accounting for CNVs and genes sizes and detected significant enrichment not only in signal transduction and extracellular biological processes, but also in metabolism pathways. Upon the estimation of CNV population differentiation (CNVs with different polymorphism frequencies across populations), we evaluated that 22% of the pathways contain at least one gene that is proximal to a CNV (CNV-gene pair) that shows significant population differentiation. The majority of these CNV-gene pairs belong to signal transduction pathways and 6% of the CNV-gene pairs show statistical association between the copy number states and the transcript levels. Conclusions The analysis suggested possible examples of positive selection within individual populations including NF-kB, MAPK signaling pathways, and Alu/L1 retrotransposition factors. Altogether, our results suggest that constitutional CNVs may modulate subtle pathway changes through specific pathway enzymes, which may become fixed in some populations.

2013-01-01

352

Foundations of Our Constitution. Reflecting on September 11.  

ERIC Educational Resources Information Center

This lesson plan provides background on six significant historical documents: (1) "Meeting at Runnymede--The Story of King John and the Magna Carta"; (2) "The Mayflower Compact"; (3) "The Declaration of Independence and Natural Rights"; (4) "The Federalist Papers"; (5) "Aristotle: In Search of the Best Constitution"; and (6) "The Pledge of…

Constitutional Rights Foundation, Los Angeles, CA.

353

Constitutive expression of catABC genes in the aniline-assimilating bacterium Rhodococcus species AN-22: production, purification, characterization and gene analysis of CatA, CatB and CatC  

PubMed Central

The aniline-assimilating bacterium Rhodococcus sp. AN-22 was found to constitutively synthesize CatB (cis,cis-muconate cycloisomerase) and CatC (muconolactone isomerase) in its cells growing on non-aromatic substrates, in addition to the previously reported CatA (catechol 1,2-dioxygenase). The bacterium maintained the specific activity of the three enzymes at an almost equal level during cultivation on succinate. CatB and CatC were purified to homogeneity and characterized. CatB was a monomer with a molecular mass of 44 kDa. The enzyme was activated by Mn2+, Co2+ and Mg2+. Native CatC was a homo-octamer with a molecular mass of 100 kDa. The enzyme was stable between pH 7.0 and 10.5 and was resistant to heating up to 90 °C. Genes coding for CatA, CatB and CatC were cloned and named catA, catB and catC respectively. The catABC genes were transcribed as one operon. The deduced amino acid sequences of CatA, CatB and CatC showed high identities with those from other Gram-positive micro-organisms. A regulator gene such as catR encoding a regulatory protein was not observed around the cat gene cluster of Rhodococcus sp. AN-22, but a possible relic of catR was found in the upstream region of catA. Reverse transcriptase-PCR and primer extension analyses showed that the transcriptional start site of the cat gene cluster was located 891 bp upstream of the catA initiation codon in the AN-22 strain growing on both aniline and succinate. Based on these data, we concluded that the bacterium constitutively transcribed the catABC genes and translated its mRNA into CatA, CatB and CatC.

Matsumura, Eitaro; Sakai, Masashi; Hayashi, Katsuaki; Murakami, Shuichiro; Takenaka, Shinji; Aoki, Kenji

2005-01-01

354

Is the tobacco settlement constitutional?  

PubMed

In August 2005, the Competitive Enterprise Institute (CEI), a conservative advocacy organization, filed a lawsuit in Louisiana challenging the legality of the 1998 Master Settlement Agreement (MSA). The suit alleges that the MSA, under which the states receive monetary payments and the four major tobacco companies are insulated from price competition, violates the Compact Clause and other provisions of the U.S. Constitution. This lawsuit threatens to unravel of one of the most significant opportunities to improve public health in United States history. We consider the merits of the lawsuit, the problems with the MSA that it highlights, and the potential consequences of the suit for public health. PMID:17199817

Rajkumar, Rahul; Gross, Cary P; Forman, Howard P

2006-01-01

355

Background level care.  

PubMed

The framework enabled by the International Caries Detection and Assessment System to allow appropriate, patient-centred caries management includes a frequently encountered scenario in which a comprehensive assessment of the teeth and the patient reveals no lesions in need of active preventive or operative care. The issue addressed here is: what background care is appropriate for patients attending a dental practice for routine caries care who, at present, appear to have no active or progressing caries lesions? It is proposed that, in addition to the use of criteria for lesion extent, treatment planning systems should also express the results of lesion assessments in terms of background level care (BLC), preventive treatment options and operative treatment options. The specific treatment options recommended for specific lesions and patients will depend upon a variety of other factors, including lesion activity, monitoring lesion behaviour over time and a range of other prognostic factors. Over recent decades, there has been comparatively little focus on appropriate BLC in a general practice setting. There are a range of issues around the need to support caries prevention and health maintenance from a behavioural and patient-focussed perspective. Even if a patient is deemed to be at low risk of future caries at a particular examination, there is a need for maintenance care. Intrinsic issues which need to be managed for both patients and their caries lesions in this patient group are: (1) the possibility of a change in caries risk status and (2) the impact of incorrect lesion assessments/diagnoses. PMID:19494681

Pitts, N B

2009-01-01

356

A combination of transcriptomics and metabolomics uncovers enhanced bile acid biosynthesis in HepG2 cells expressing CCAAT/enhancer-binding protein ? (C/EBP?), hepatocyte nuclear factor 4? (HNF4?), and constitutive androstane receptor (CAR).  

PubMed

The development of hepatoma-based in vitro models to study hepatocyte physiology is an invaluable tool for both industry and academia. Here, we develop an in vitro model based on the HepG2 cell line that produces chenodeoxycholic acid, the main bile acid in humans, in amounts comparable to human hepatocytes. A combination of adenoviral transfections for CCAAT/enhancer-binding protein ? (C/EBP?), hepatocyte nuclear factor 4? (HNF4?), and constitutive androstane receptor (CAR) decreased intracellular glutamate, succinate, leucine, and valine levels in HepG2 cells, suggestive of a switch to catabolism to increase lipogenic acetyl CoA and increased anaplerosis to replenish the tricarboxylic acid cycle. Transcripts of key genes involved in bile acid synthesis were significantly induced by approximately 160-fold. Consistently, chenodeoxycholic acid production rate was increased by more than 20-fold. Comparison between mRNA and bile acid levels suggest that 12-alpha hydroxylation of 7-alpha-hydroxy-4-cholesten-3-one is the limiting step in cholic acid synthesis in HepG2 cells. These data reveal that introduction of three hepatocyte-related transcription factors enhance anabolic reactions in HepG2 cells and provide a suitable model to study bile acid biosynthesis under pathophysiological conditions. PMID:23641669

Blazquez, Marina; Carretero, Aitor; Ellis, James K; Athersuch, Toby J; Cavill, Rachel; Ebbels, Timothy M D; Keun, Hector C; Castell, José V; Lahoz, Agustín; Bort, Roque

2013-06-01

357

Lessons for Emerging European Constitutionalism from the United States Constitution: Trigger Rules  

Microsoft Academic Search

This essay offers some lessons from the history of the United States Constitution for constitutions for emerging democracies in Eastern Europe. The United States Constitution declined in efficacy over time because special interests eroded its restraints on rent-seeking. This essay seeks to consider solutions to prevent constitutional decline. It suggests that since special interests will try to dissolve constitutional restraints,

John O. McGinnis

2001-01-01

358

Constitutional political economy in the European Union  

Microsoft Academic Search

This article surveys recent research in constitutional political economy in Europe. Although not all of theworks discussed\\u000a necessarily focus only on European constitutional issues or are written by Europeans, European constitutional issues figure\\u000a importantly in each area surveyed. The article examines the literatures linking constitutional institutions to economic growth,\\u000a government size, government deficits and corruption, bicameralism, direct democracy and federalism.

Dennis C. Mueller

359

The Cosmological Background Radiation  

Microsoft Academic Search

This book provides an introduction to the physics, astrophysics and cosmology of the cosmic microwave background radiation. Adopting the Standard Big Bang model of the universe, the authors cover topics including the origin of the background, intrinsic fluctuations, and the universe and background radiation after recombination. Finally they present measurement of the radiation and its anisotropies, along with a review

Marc Lachièze-Rey; Edgard Gunzig

1999-01-01

360

Bothrops jararaca venom (BjV) induces differential leukocyte accumulation in mice genetically selected for acute inflammatory reaction: the role of host genetic background on expression of adhesion molecules and release of endogenous mediators.  

PubMed

The dynamics of the local inflammatory events induced by Bothrops jararaca venom (BjV) inoculation in footpad of mice genetically selected for maximal (AIRmax) and minimal (AIRmin) acute inflammatory reactivity (AIR) was investigated. The BjV injection induced a marked inflammatory cell infiltrate with predominance of neutrophils, with increased blood cell numbers before its accumulation, suggesting a stimulatory action of BjV on mechanisms of cell mobilization from bone marrow. The process of cell migration is regulated by different cell-adhesion molecules (CAM). Our results showed that neutrophil cells from both lines had the same pattern of response concerning CAMs expression, presenting the involvement of l-selectin, Mac-1 and PECAM-1 adhesion molecules in BjV-induced neutrophil accumulation. The effect of BjV on the release of pro-inflammatory cytokines and chemokines related with cellular migration was also studied and IL-1beta, IL-6, TNF-alpha and MIP-2 levels could be detected after venom injection. The AIRmax mice were shown to be more responsive than AIRmin with respect to leukocyte influx, expression of MIP-2 and release of IL-1beta and IL-6. These results demonstrate the importance of host genetic background in the local response and the involvement of alleles accumulated in AIRmax mice in the inflammatory events induced by BjV. PMID:18723041

Carneiro, Adriana S; Ribeiro, Orlando G; Cabrera, Wafa H K; Vorraro, Francisca; De Franco, Marcelo; Ibañez, Olga M; Starobinas, Nancy

2008-10-01

361

Antithetical Ethics: Kenneth Burke and the Constitution.  

ERIC Educational Resources Information Center

Shows how the textuality of the United States Constitution, the most venerable of classic democratic icons, might be exploited to nurture postmodern ethics. Shows how Kenneth Burke's reading of the Constitution accords with and augments the postmodern theories of J.-F. Lyotard and S. Jarratt. Discusses a postmodern Constitution and the…

Anderson, Virginia

1995-01-01

362

The Erosion of Democracy: Constitutional Complacency.  

ERIC Educational Resources Information Center

Knowledge of the United States Constitution was investigated for 111 randomly selected college students. Many students had little or no knowledge/understanding of the Constitution and the Bill of Rights. No significant differences were found between those who had read the Constitution and those who had never read it. (SLD)

Trostle, Lawrence C.

1990-01-01

363

Creep constitutive equations for damaged materials  

Microsoft Academic Search

The object of the present paper is to combine knowledge of microscopic mechanisms with experimental observations to obtain constitutive equations for damaged materials. The initial focus is on the mechanisms of failure in creeping materials. A general structure for the constitutive equations is obtained which gives a framework for the development of constitute equations for particular materials. In the present

A. C. F. Cocks; F. A. Leckie

1987-01-01

364

National Art Education Association Constitution and Bylaws.  

ERIC Educational Resources Information Center

Presents the constitution and bylaws of the National Art Education Association. Includes the preamble to the constitution;, the nine articles within the constitution covering topics, such as organization and governance, elections, and meetings; and the ten bylaws revised in 2001. (CMK)

Art Education, 2001

2001-01-01

365

Teaching about Democratic Constitutionalism. ERIC Digest.  

ERIC Educational Resources Information Center

There are more than 100 democracies in the world today. All but three of them--Great Britain, Israel, and New Zealand --have written constitutions. This digest examines the importance of constitutions and constitutionalism and the teaching of these concepts through the use of comparisons. The primary objectives of civic education for democratic…

Patrick, John J.

366

Constitutive Activation of the Thyroid-Stimulating Hormone Receptor (TSHR) by Mutating Ile691 in the Cytoplasmic Tail Segment  

PubMed Central

Background Autosomal dominant non-autoimmune hyperthyroidism (ADNAH) is a rare genetic disorder of the endocrine system. Molecular genetic studies in ADNAH have revealed heterozygous germline mutations in the TSHR. To data, mutations leading to an increase in the constitutive activation of the TSHR have been described in the transmembrane segments, exoloops and cytoplasmic loop of TSHR. These mutations result in constitutive activation of the G?s/cAMP or G?q/11/inositol phosphate (IP) pathways, which stimulate thyroid hormone production and thyroid proliferation. Methodology/Principal Findings In a previous study, we reported a new TSHR mutation located in the C-terminal domain of TSHR, which results in a substitution of the conserved Ile691 for Phe. In this study, to address the question of whether the I691F mutated receptor could be responsible for G?s/cAMP or G?q/11/IP constitutive activity, wild-type and TSHR mutants were expressed in COS-7 cells to determine cAMP constitutive activity and IP formation. Compared to the cell surface with expression of the A623V mutated receptor as positive control, the I691F mutated receptor showed a slight increase of cAMP accumulation. Furthermore, I691F resulted in constitutive activation of the G?q/11/IP signaling pathway. Conclusions/Significance Our results indicate that Ile691 not only contributes to keeping TSHR inactive in the G?s/cAMP pathways but also in the G?q/11/IP cascade.

Liu, Zheng; Fan, Feiyue; Xiao, Xiangjun; Sun, Yuanming

2011-01-01

367

Constitutionally Protected or Substantially Disruptive?  

ERIC Educational Resources Information Center

The 2008 presidential campaign has, by all accounts, been extraordinary. Record numbers of voters expressed their views in historic primaries, and citizens across the country have been invigorated by debate about what policies and which politician will be best for this country. Equally noteworthy is the fact that young people have not been absent…

Taylor, Kelley R.

2008-01-01

368

Injection of rat hepatocyte poly(A)+ RNA to Xenopus laevis oocytes leads to expression of a constitutively-active divalent cation channel distinguishable from endogenous receptor-activated channels.  

PubMed

The expression of hepatocyte plasma membrane receptor-activated divalent cation channels in immature (stages V and VI) Xenopus laevis oocytes and the properties which allow these channels to be distinguished from endogenous receptor-activated divalent cation channels were investigated. Divalent cation inflow to oocytes housed in a multiwell plate was measured using the fluorescent dyes Fluo-3 and Fura-2. In control oocytes, ionomycin, cholera toxin, thapsigargin, 3-fluoro-inositol 1,4,5-trisphosphate (InsP3F) and guanosine 5'-[gamma-thio]triphosphate (GTP gamma S) stimulated Ca2+ and Mn2+ inflow following addition of these ions to the oocytes. Ionomycin-, cholera-toxin-, thapsigargin- and InsP3F-stimulated Ca2+ inflow was inhibited by Gd3+ (half maximal inhibition at less thari 5 microM Gd3+ for InsP3F-stimulated Ca2+ inflow). GTP gamma S-stimulated Ca2+ inflow was insensitive to 50 microM Gd3+ and to SK&F 96365. These results indicate that at least three types of endogenous receptor-activated Ca2+ channels can be detected in Xenopus oocytes using Ca(2+)-sensitive fluorescent dyes: lanthanide-sensitive divalent cation channels activated by intracellular Ca2+ store depletion, lanthanide-sensitive divalent cation channels activated by cholera toxin, and lanthanide-insensitive divalent cation channels activated by an unknown trimeric G-protein. Oocytes microinjected with rat hepatocyte poly(A)+ RNA exhibited greater rates of Ca2+ and Mn2+ inflow in the basal (no agonist) state, greater rates of Ca2+ inflow in the presence of vasopressin or InsP3F and greater rates of Ba2+ inflow in the presence of InsP3F, when compared with "mock"-injected oocytes. In poly(A)+ RNA-injected oocytes, vasopressin- and InsP3F-stimulated Ca2+ inflow, but not basal Ca2+ inflow, was inhibited by Gd3+. It is concluded that at least one type of hepatocyte plasma membrane divalent cation channel, which admits Mn2+ as well as Ca2+ and is lanthanide-insensitive, can be expressed and detected in Xenopus oocytes. PMID:8793184

Auld, A M; Bawden, M J; Berven, L A; Harland, L; Hughes, B P; Barritt, G J

1996-05-01

369

Non-coplanar polychlorinated biphenyls (PCBs) are direct agonists for the human pregnane-X receptor and constitutive androstane receptor, and activate target gene expression in a tissue-specific manner  

SciTech Connect

The polychlorinated biphenyl group possesses high environmental persistence, leading to bioaccumulation and a number of adverse effects in mammals. Whilst coplanar PCBs elicit their toxic effects through agonism of the aryl hydrocarbon receptor; however, non-coplanar PCBs are not ligands for AhR, but may be ligands for members of the nuclear receptor family of proteins. To better understand the biological actions of non-coplanar PCBs, we have undertaken a systematic analysis of their ability to activate PXR and CAR-mediated effects. Cells were exposed to a range of non-coplanar PCBs (99, 138, 153, 180 and 194), or the coplanar PCB77: Direct activation of PXR and CAR was measured using a mammalian receptor activation assay in human liver cells, with rifampicin and CITCO used as positive controls ligands for PXR and CAR, respectively; activation of target gene expression was examined using reporter gene plasmids for CYP3A4 and MDR1 transfected into liver, intestine and lung cell lines. Several of the non-coplanar PCBs directly activated PXR and CAR, whilst the coplanar PCB77 did not. Non-coplanar PCBs were also able to activate PXR/CAR target gene expression in a substitution- and tissue-specific manner. Non-coplanar PCBs act as direct activators for the nuclear receptors PXR and CAR, and are able to elicit transcriptional activation of target genes in a substitution- and tissue-dependent manner. Chronic activation of PXR/CAR is linked to adverse effects and must be included in any risk assessment of PCBs. -- Highlights: ? Several Non-coplanar PCBs are able to directly activate both PXR and CAR in vitro. ? PCB153 is the most potent direct activator of PXR and CAR nuclear receptors. ? Non-coplanar PCB activation of CYP3A4/MDR1 reporter genes is structure-dependent. ? Non-coplanar PCB activate CYP3A4/MDR1 reporter genes in a tissue-dependent. ? PCB153 is the most potent activator of PXR/CAR target gene in all tissues.

Al-Salman, Fadheela; Plant, Nick, E-mail: N.Plant@Surrey.ac.uk

2012-08-15

370

Constitutional factors in alcoholic cirrhosis.  

PubMed

The different sensitivity of the male and the female liver is well established, but there is an obvious difference in male livers as well. One possible explanation for these differences might be the existence of genetic peculiarities among patients with alcoholic cirrhosis. In the early twentieth, Chvostek in Vienna was the first to draw attention to a constitutional element which he believed to be fundamental: Absent body hair, absent or extremely spare hair on the limbs, and pubic hair of the female type, i.e. with horizontal upper border (1) (Fig. 1). Chvostek laid special stress on the fact that these anomalies were of genetic origin and were not a secondary phenomenon do to alcoholism or cirrhosis. The feminine pattern of hair distribution, the so-called "Chvostek's habitus", is a frequently seen condition but the statistical proof of its association with alcoholic cirrhosis in man is still missing. The purpose of our study was to investigate if the feminine pattern of hair distribution in male patients with alcoholic cirrhosis is a genetic characteristic, this anomaly is more frequently encountered in the alcoholic type than in the post-hepatitis type of cirrhosis, the reported discrepancies of HLA frequencies are due to genetic differences. PMID:6537037

Thaler, H; Thaler, H; Mayr, W R

1984-10-01

371

Constitutive model for porous materials  

SciTech Connect

A simple pressure versus porosity compaction model is developed to calculate the response of granular porous bed materials to shock impact. The model provides a scheme for calculating compaction behavior when relatively limited material data are available. While the model was developed to study porous explosives and propellants, it has been applied to a much wider range of materials. The early development of porous material models, such as that of Hermann, required empirical dynamic compaction data. Erkman and Edwards successfully applied the early theory to unreacted porous high explosives using a Gruneisen equation of state without yield behavior and without trapped gas in the pores. Butcher included viscoelastic rate dependance in pore collapse. The theoretical treatment of Carroll and Holt is centered on the collapse of a circular pore and includes radial inertia terms and a complex set of stress, strain and strain rate constitutive parameters. Unfortunately data required for these parameters are generally not available. The model described here is also centered on the collapse of a circular pore, but utilizes a simpler elastic-plastic static equilibrium pore collapse mechanism without strain rate dependence, or radial inertia terms. It does include trapped gas inside the pore, a solid material flow stress that creates both a yield point and a variation in solid material pressure with radius. The solid is described by a Mie-Gruneisen type EOS. Comparisons show that this model will accurately estimate major mechanical features which have been observed in compaction experiments.

Weston, A.M.; Lee, E.L.

1982-01-01

372

Constitutional Amendment A: Prohibit Property Taxes for School Funding. Issue Memorandum 98-13.  

ERIC Educational Resources Information Center

This issue memorandum describes Constitutional Amendment A, an initiative in South Dakota that, if approved, would prohibit taxation of real property for school purposes. The report provides background information on Constitutional Amendment A, which reads as follows: "The legislature shall make such provision by general taxation as with the…

Becker, David

373

The Cosmic Background Explorer.  

ERIC Educational Resources Information Center

Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

Gulkis, Samuel; And Others

1990-01-01

374

The Theory of Constitutional Synthesis. A Constitutional Theory for a Democratic European Union  

Microsoft Academic Search

This paper puts forward the main elements of the theory of constitutional synthesis as a constitutional theory of European integration. Constitutional synthesis is both a political philosophy of European integration (which dilucidates what kind of polity the Union is an what is its basis of legitimacy) and a theoreticalframework capable of guiding constitutional adjudication in hard cases (such as the

John Erik Fossum; Agustín José Menéndez

2010-01-01

375

Caerulein-induced acute pancreatitis in mice that constitutively overexpress Reg/PAP genes  

PubMed Central

Background The cystic fibrosis (CF) mouse pancreas has constitutively elevated expression of the Reg/PAP cell stress genes (60-fold greater Reg3?, and 10-fold greater PAP/Reg3? and Reg3?). These genes are suggested to be involved in protection or recovery from pancreatic injury. Methods To test this idea the supramaximal caerulein model was used to induce acute pancreatitis in wild type and CF mice. Serum amylase, pancreatic water content (as a measure of edema), pancreatic myeloperoxidase activity, and Reg/PAP expression were quantified. Results In both wild type and CF mice caerulein induced similar elevations in serum amylase (maximal at 12 h), pancreatic edema (maximal at 7 h), and pancreatic myeloperoxidase activity (MPO, a marker of neutrophil infiltration; maximal at 7 h). By immunohistochemistry, Reg3? was strongly expressed in the untreated CF pancreas but not in wild type. During pancreatitis, Reg3? was intensely expressed in foci of inflamed tissue in both wild type and CF. Conclusion These data demonstrate that the severity of caerulein-induced pancreatitis is not ameliorated in the CF mouse even though the Reg/PAP stress genes are already highly upregulated. While Reg/PAP may be protective they may also have a negative effect during pancreatitis due to their anti-apoptotic activity, which has been shown to increase the severity of pancreatitis.

Norkina, Oxana; Graf, Rolf; Appenzeller, Philippe; De Lisle, Robert C

2006-01-01

376

Constitutively released adenosine diphosphate regulates proplatelet formation by human megakaryocytes  

PubMed Central

Background The interaction of adenosine diphosphate with its P2Y1 and P2Y12 receptors on platelets is important for platelet function. However, nothing is known about adenosine diphosphate and its function in human megakaryocytes. Design and Methods We studied the role of adenosine diphosphate and P2Y receptors on proplatelet formation by human megakaryocytes in culture. Results Megakaryocytes expressed all the known eight subtypes of P2Y receptors, and constitutively released adenosine diphosphate. Proplatelet formation was inhibited by the adenosine diphosphate scavengers apyrase and CP/CPK by 60-70% and by the P2Y12 inhibitors cangrelor and 2-MeSAMP by 50-60%, but was not inhibited by the P2Y1 inhibitor MRS 2179. However, the active metabolites of the anti-P2Y12 drugs, clopidogrel and prasugrel, did not inhibit proplatelet formation. Since cangrelor and 2-MeSAMP also interact with P2Y13, we hypothesized that P2Y13, rather than P2Y12 is involved in adenosine diphosphate-regulated proplatelet formation. The specific P2Y13 inhibitor MRS 2211 inhibited proplatelet formation in a concentration-dependent manner. Megakaryocytes from a patient with severe congenital P2Y12 deficiency showed normal proplatelet formation, which was inhibited by apyrase, cangrelor or MRS 2211 by 50-60%. The platelet count of patients with congenital delta-storage pool deficiency, who lack secretable adenosine diphosphate, was significantly lower than that of patients with other platelet function disorders, confirming the important role of secretable adenosine diphosphate in platelet formation. Conclusions This is the first demonstration that adenosine diphosphate released by megakaryocytes regulates their function by interacting with P2Y13. The clinical relevance of this not previously described physiological role of adenosine diphosphate and P2Y13 requires further exploration.

Balduini, Alessandra; Di Buduo, Christian Andrea; Malara, Alessandro; Lecchi, Anna; Rebuzzini, Paola; Currao, Manuela; Pallotta, Isabella; Jakubowski, Joseph A.; Cattaneo, Marco

2012-01-01

377

Constitutively active UVR8 photoreceptor variant in Arabidopsis  

PubMed Central

Arabidopsis thaliana UV RESISTANCE LOCUS 8 (UVR8) is a UV-B photoreceptor that initiates photomorphogenic responses underlying acclimation and UV-B tolerance in plants. UVR8 is a homodimer in its ground state, and UV-B exposure results in its instantaneous monomerization followed by interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1), a major factor in UV-B signaling. UV-B photoreception by UVR8 is based on intrinsic tryptophan aromatic amino acid residues, with tryptophan-285 as the main chromophore. We generated transgenic plants expressing UVR8 with a single amino acid change of tryptophan-285 to alanine. UVR8W285A appears monomeric and shows UV-B–independent interaction with COP1. Phenotypically, the plants expressing UVR8W285A exhibit constitutive photomorphogenesis associated with constitutive activation of target genes, elevated levels of anthocyanins, and enhanced, acclimation-independent UV-B tolerance. Moreover, we have identified COP1, REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 and 2 (RUP1 and RUP2), and the SUPPRESSOR OF PHYA-105 (SPA) family as proteins copurifying with UVR8W285A. Whereas COP1, RUP1, and RUP2 are known to directly interact with UVR8, we show that SPA1 interacts with UVR8 indirectly through COP1. We conclude that UVR8W285A is a constitutively active UVR8 photoreceptor variant in Arabidopsis, as is consistent with the crucial importance of monomer formation and COP1 binding for UVR8 activity.

Heijde, Marc; Binkert, Melanie; Yin, Ruohe; Ares-Orpel, Florence; Rizzini, Luca; Van De Slijke, Eveline; Persiau, Geert; Nolf, Jonah; Gevaert, Kris; De Jaeger, Geert; Ulm, Roman

2013-01-01

378

Correlators in nontrivial backgrounds  

SciTech Connect

Operators in N=4 super Yang-Mills theory with an R-charge of O(N{sup 2}) are dual to backgrounds which are asymtotically AdS{sub 5}xS{sup 5}. In this article we develop efficient techniques that allow the computation of correlation functions in these backgrounds. We find that (i) contractions between fields in the string words and fields in the operator creating the background are the field theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free field theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations.

Mello Koch, Robert de [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa); Stellenbosch Institute for Advanced Studies, Stellenbosch (South Africa); Ives, Norman; Stephanou, Michael [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa)

2009-01-15

379

Radio brightness distribution within cosmic background fluctuations  

SciTech Connect

The angular fluctuations deltaT in the microwave background temperature constitute a random process. Calculations are performed for the number of ''pips'' above a base level T/sub s/ that might be produced by primordial scalar density perturbations or gravitational waves. The flux density expected for typical pips is determined, as well as the mean solid angle subtended by a pip that would exceed a level three times the dispersion in deltaT.

Sazhin, M.V.

1985-07-01

380

HOXB7 constitutively activates basic fibroblast growth factor in melanomas.  

PubMed Central

Homeobox (HOX) genes control axial specification during mammalian development and also regulate skin morphogenesis. Although selected HOX genes are variably expressed in leukemias and kidney and colon cancer cell lines, their relationship with the neoplastic phenotype remains unclear. In both normal development and neoplastic transformation, HOX target genes are largely unknown. We investigated the expression and function of HOXB cluster genes in human melanoma. The HOXB7 gene was constitutively expressed in all 25 melanoma cell lines and analyzed under both normal and serum-starved conditions, as well as in in vivo primary and metastatic melanoma cells; conversely, HOXB7 was expressed in proliferating but not quiescent normal melanocytes. Treatment of melanoma cell lines with antisense oligomers targeting HOXB7 mRNA markedly inhibited cell proliferation and specifically abolished expression of basic fibroblast growth factor (bFGF) mRNA. Band shift and cotransfection experiments showed that HOXB7 directly transactivates the hFGF gene through one out of five putative homeodomain binding sites present in its promoter. These novel findings indicate a key role for constitutive HOXB7 expression in melanoma cell proliferation via bFGF. The results also raise the possibility that growth factor genes are critical HOX target genes in other developmental and/or neoplastic cell systems.

Care, A; Silvani, A; Meccia, E; Mattia, G; Stoppacciaro, A; Parmiani, G; Peschle, C; Colombo, M P

1996-01-01

381

FindLaw Constitutional Law Center  

NSDL National Science Digital Library

This offering from FindLaw (last discussed in the January 15, 1999 Scout Report) focuses on the US Constitution. The site is composed of two primary sections. The first offers an annotated Constitution, commentary on selected topics with links to key sections of the Constitution or The Federalist Papers, a history of the Constitution, and brief biographies of notable "Founding Fathers" and delegates to the Constitutional Convention. The second section highlights the Third Branch of government, with a history of the Supreme Court, landmark decisions regarding civil rights with the full opinions, a summary and analysis of the criminal law and procedure decisions of the October 1998 Supreme Court Term, and several links for current Supreme Court news and information. Both sections also feature a search engine. Additional resources at the site include a Town Hall section that explores Hot Topics (currently flag burning) and message boards on a wide variety of Constitutional issues.

1994-01-01

382

Background stratospheric aerosol layer  

SciTech Connect

Balloonborne aerosol particle counter measurements are used in studying the stratospheric sulfate layer at Laramie, Wyoming, during 1978 and 1979, a 2-year volcanically quiescent period in which the layer appears to have been in a near equilibrium background state. Subtracting the background aerosol concentration from data obtained during an earlier volcanically active period indicates that the actual decay rate of volcanic aerosol is over 30% faster than one would obtain without this correction. At background, the aerosol size distribution is found to remain remarkably constant between the tropopause and an altitude of approx.25 km, with a sudden transition to a distribution dominated by smaller particles above this altitude. The observations, in some respects, compare favorably with equilibrium one-dimensional stratospheric aerosol models and thus to some extent support the concept of relatively inert tropospheric sulfurous gases, such as carbonyl sulfide and carbon disulfide, as the main background stratospheric aerosol sulfur source. Models which incorporate sulfur chemistry are apparently not able to predict the observed variation of particle size with altitude. The 2-year background period is not long enough in itself to establish long-term trends. The eruption of Mt. St. Helens in May 1980 has considerably disrupted the background stratospheric aerosol which will probably not recover for several years. A comparison of the 1978--79 observations with Junge's original measurements made some 20 years earlier, also during a period void of volcanic perturbations, does not preclude a long-term increase in the background stratospheric aerosol level.

Hofmann, D.J.; Rosen, J.M.

1981-01-01

383

Zero background yeast reporter plasmids.  

PubMed

UAS-less reporter plasmids are widespread and powerful tools for the identification and analysis of binding sites for transcriptional activators. The common reporter plasmids for the yeast Saccharomyces cerevisiae are multicopy (2mu) vectors with the CYC1 core promoter upstream of the lacZ gene. Insertion of putative or known activator binding sites upstream of the core promoter puts lacZ (beta-galactosidase) expression under the control of the corresponding activator. Although these constructs have proved to work well for most purposes, they have certain limitations: (1) they give significant and carbon-source-dependent lacZ background expression; (2) unlike most other yeast promoters, the CYC1 upstream region has a partially open chromatin structure with an accessible TATA box; (3) they use only a single, moderately sensitive reporter; and (4) the use of multicopy vectors can result in activator titration. Here, we introduce novel reporter plasmids based on the yeast MEL1 (alpha-galactosidase) gene that can overcome all of these limitations. It is also shown that background expression is due to fortuitous activator binding sites within the plasmid backbones that are insufficiently shielded from the core promoters in the common CYC1 reporter plasmids. PMID:10773444

Melcher, K; Sharma, B; Ding, W V; Nolden, M

2000-04-18

384

Testing of constitutive models in LAME.  

SciTech Connect

Constitutive models for computational solid mechanics codes are in LAME--the Library of Advanced Materials for Engineering. These models describe complex material behavior and are used in our finite deformation solid mechanics codes. To ensure the correct implementation of these models, regression tests have been created for constitutive models in LAME. A selection of these tests is documented here. Constitutive models are an important part of any solid mechanics code. If an analysis code is meant to provide accurate results, the constitutive models that describe the material behavior need to be implemented correctly. Ensuring the correct implementation of constitutive models is the goal of a testing procedure that is used with the Library of Advanced Materials for Engineering (LAME) (see [1] and [2]). A test suite for constitutive models can serve three purposes. First, the test problems provide the constitutive model developer a means to test the model implementation. This is an activity that is always done by any responsible constitutive model developer. Retaining the test problem in a repository where the problem can be run periodically is an excellent means of ensuring that the model continues to behave correctly. A second purpose of a test suite for constitutive models is that it gives application code developers confidence that the constitutive models work correctly. This is extremely important since any analyst that uses an application code for an engineering analysis will associate a constitutive model in LAME with the application code, not LAME. Therefore, ensuring the correct implementation of constitutive models is essential for application code teams. A third purpose of a constitutive model test suite is that it provides analysts with example problems that they can look at to understand the behavior of a specific model. Since the choice of a constitutive model, and the properties that are used in that model, have an enormous effect on the results of an analysis, providing problems that highlight the behavior of various constitutive models to the engineer can be of great benefit. LAME is currently implemented in the Sierra based solid mechanics codes Adagio [3] and Presto [4]. The constitutive models in LAME are available in both codes. Due to the nature of a transient dynamics code--e.g. Presto--it is difficult to test a constitutive model due to inertia effects that show up in the solution. Therefore the testing of constitutive models is primarily done in Adagio. All of the test problems detailed in this report are run in Adagio. It is the goal of the constitutive model test suite to provide a useful service for the constitutive model developer, application code developer and engineer that uses the application code. Due to the conflicting needs and tight time constraints on solid mechanics code development, no requirements exist for implementing test problems for constitutive models. Model developers are strongly encouraged to provide test problems and document those problems, but given the choice of having a model without a test problem or no model at all, certain requirements must be kept loose. A flexible code development environment, especially with regards to research and development in constitutive modeling, is essential to the success of such an environment. This report provides documentation of a number of tests for the constitutive models in LAME. Each section documents a separate test with a brief description of the model, the test problem and the results. This report is meant to be updated periodically as more test problems are created and put into the test suite.

Hammerand, Daniel Carl; Scherzinger, William Mark

2007-09-01

385

Adaptive background model  

NASA Astrophysics Data System (ADS)

An adaptive background model aiming at outdoor vehicle detection is presented in this paper. This model is an improved model of PICA (pixel intensity classification algorithm), it classifies pixels into K-distributions by color similarity, and then a hypothesis that the background pixel color appears in image sequence with a high frequency is used to evaluate all the distributions to determine which presents the current background color. As experiments show, the model presented in this paper is a robust, adaptive and flexible model, which can deal with situations like camera motions, lighting changes and so on.

Lu, Xiaochun; Xiao, Yijun; Chai, Zhi; Wang, Bangping

2007-11-01

386

The cosmic neutrino background  

NASA Technical Reports Server (NTRS)

The cosmic neutrino background is expected to consist of relic neutrinos from the big bang, of neutrinos produced during nuclear burning in stars, of neutrinos released by gravitational stellar collapse, and of neutrinos produced by cosmic ray interactions with matter and radiation in the interstellar and intergalactic medium. Formation of baryonic dark matter in the early universe, matter-antimatter annihilation in a baryonic symmetric universe, and dark matter annihilation could have also contributed significantly to the cosmic neutrino background. The purpose of this paper is to review the properties of these cosmic neutrino backgrounds, the indirect evidence for their existence, and the prospects for their detection.

Dar, Arnon

1991-01-01

387

Building Background Knowledge  

NSDL National Science Digital Library

Too often, students enter our classrooms with insufficient knowledge of physical science. As a result, they have a difficult time understanding content in texts, lectures, and laboratory activities. This lack of background knowledge can have an impact on

Ross, Donna; Fisher, Douglas; Grant, Maria

2010-01-01

388

Background and Statistics  

MedlinePLUS

Background & Statistics FAQ About Homeless Veterans Homeless Veterans Facts Demographics of Homeless Veterans Incarcerated Veterans Research Briefs Sources FAQ ... VETERANS In May 2007, the Bureau of Justice Statistics released a special report on incarcerated veterans. The ...

389

Background Oriented Schlieren Demonstrations.  

National Technical Information Service (NTIS)

In this project report we present the application of a novel schlieren technique for two different tests. The optical method is referred to as 'Background Oriented Schlieren' (BOS) in the following. Additionally the differences between BOS and an extensio...

H. Richard M. Raffel

2000-01-01

390

Sakhalin tender background detailed  

SciTech Connect

This paper reports that on Jan. 27, 1992, the committee constituted by order of the Russian government of Dec. 23, 1991, and headed by V.I. Danilov-Danilyan, the Russian Federation's Minister for Ecology and Natural Resources, assessed the results of a tender announced in May 1991. The tender was for foreign companies to submit feasibility studies for exploration and development of oil and gas on the continental shelf off Sakhalin Island. The announced winner was the MMM group consisting of McDermott International Inc., Marathon Oil Co., and Mitsui and Co. Ltd. In its decision the governmental tender committee (GTC) begged to differ from V. Fedorov, governor of the Territory of Sakhalin, in whose opinion the U.S.-Japanese combine of Exxon Corp.-Sakhalin Oil Development Co. (Sodeco) should have been pronounced winner at the bidding's end. GTC's decision also ran counter to the verdict by a panel of experts constituted by decision of the Examining Council under the Chairman of the Russian Government on Dec. 3, 1991, and headed by F. Salmanov, first deputy Minister of Geology of the U.S.S.R.

Konoplyanik, A. (Russian Federation Ministry for Fuels and Energy (SU))

1992-03-23

391

Background stratospheric aerosol reference model  

NASA Technical Reports Server (NTRS)

In this analysis, a reference background stratospheric aerosol optical model is developed based on the nearly global SAGE 1 satellite observations in the non-volcanic period from March 1979 to February 1980. Zonally averaged profiles of the 1.0 micron aerosol extinction for the tropics and the mid- and high-altitudes for both hemispheres are obtained and presented in graphical and tabulated form for the different seasons. In addition, analytic expressions for these seasonal global zonal means, as well as the yearly global mean, are determined according to a third order polynomial fit to the vertical profile data set. This proposed background stratospheric aerosol model can be useful in modeling studies of stratospheric aerosols and for simulations of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing.