PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Targeted expression”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1997

Targeting gene expression to hypoxic tumor cells.

Solid tumors with areas of low oxygen tension (hypoxia) have a poor prognosis, as cells in this environment often survive radiation and chemotherapy. In this report we describe how this hypoxic environment can be used to activate heterologous gene expression driven by a hypoxia-responsive element (HRE), which interacts with the transcriptional complex hypoxia-inducible factor-1 (HIF-1). Our results demonstrate that the HIF-1/HRE system of gene regulation is active in hypoxic tumor cells and show the potential of exploiting tumor-specific conditions for the targeted expression of diagnostic or therapeutic genes in cancer therapy.

Animals↗
PubMed1997

HIV-1 induces cytotoxic T lymphocytes in the cervix of infected women.

Although T lymphocytes are present in the genital mucosa, their function in sexually transmitted diseases is unproven. To determine if cervical T cells mediate HIV-specific cytolysis, mononuclear cells in cytobrush specimens from HIV-1-infected women were stimulated in vitro with antigen. Resultant cell lines lysed autologous targets expressing HIV-1 proteins in 12/19 (63%) subjects, and these responses were detected intermittently on repeated visits. All 8 subjects with blood CD4+ counts > or =500 cells/microl had HIV-1-specific cervical CTL, whereas only 4/11 with counts <500 cells/microl had detectable responses (P = 0.008). Class II MHC-restricted CD4+ CTL clones lysed targets expressing Env gp41 or infected with HIV-1. Class I MHC-restricted CD8+ clones recognized HIV-1 Gag- or Pol-expressing targets, and the epitopes were mapped to within 9-20 amino acids. Comparisons of intra-individual cervical and blood CTL specificities indicate that epitopes recognized by CTL in the cervix were commonly recognized in the blood. These studies provide the first definitive evidence for an MHC-restricted effector function in human cervical lymphocytes.

Cell Line, Transformed↗
PubMed2005

[Expression of target gene in eukaryotic cells driven by prokaryotic T7 promoter and its RNA polymerase].

To enhance the efficiency of the expression of target gene in eukaryotic cells, one of the strongest prokaryotic expression systems, the T7 RNA polymerase and T7 promoter, was introduced into eukaryotic cells. A duel-plasmid gene expression system of T7 bacteriophage components was developed; one containing the T7 phage RNA polymerase gene under the control of eukaryotic promoter CMV (pCMV-T7pol) and the other (pT7IRES) containing the T7 promoter and T7 terminator as well as EMCV IRES. To test the feasibility of this plasmid system for eukaryotic expression, hepatitis B virus envelop HBV preS2/S was used to construct pT7IRES-HBs. The target genes were expressed efficiently by the eukaryonized prokaryotic expression system in a variety of the cells indicating C2C12, SP2/0, NIH3T3 and BALB/c 3T3, suggesting the potential applications of the expression system in gene therapy and gene immunization.

Animals↗
PubMed2004

Quantitative analysis of p53-targeted gene expression and visualization of p53 transcriptional activity following intratumoral administration of adenoviral p53 in vivo.

To analyze the mechanism of the antitumor effect of an adenoviral vector expressing the p53 tumor suppressor (Ad-p53) in vivo, we quantitatively assessed p53-targeted gene expression and visualized transcriptional activity of p53 in tumors in nude mice treated with Ad-p53. Human lung cancer (H1299) xenografts established in nude mice were treated by intratumoral administration of Ad-p53. The levels of expression of exogenous p53 and p53-targeted genes p21, MDM2, Noxa, and p53AIP1 were quantified by real-time reverse transcription-PCR (RT-PCR) and induction of apoptosis was observed histochemically on days 1-3, 7, and 14 after treatment. Expression of mRNA of exogenous p53 and p53-targeted genes (except p53AIP1) was at its maximum 1 day after Ad-p53 treatment and then decreased rapidly; apoptosis was evident in situ 2-3 days after treatment. We developed a noninvasive and simple method for monitoring the transcriptional activity of exogenous p53 following intratumoral administration of Ad-p53 in nude mice. We established H1299 cells that express the green fluorescent protein (GFP) reporter gene under the control of p53-responsive p21 promoter (i.e., the p53R-GFP reporter system). Xenografts of these cells in nude mice were treated by intratumoral administration of Ad-p53, and the transcriptional activity of exogenous p53 could be visualized as intratumoral GFP expression in real time by 3-CCD camera. Expression of GFP was maximal 3 days after treatment and decreased remarkably by 7 days after treatment. We demonstrated that Ad-p53 treatment rapidly induced p53-targeted genes and apoptosis in tumors and succeeded in visualizing p53 transcriptional activity in vivo. We also found that Ad-p53 infection induced phosphorylation of p53 at Ser(46) in p53-sensitive H1299 cells in vitro but not in p53-resistant H226Br cells, suggesting that phosphorylation of Ser(46) is involved in p53-dependent apoptosis. Our data indicate that quantitative analysis of p53-targeted gene expression by real-time quantitative RT-PCR and visualization of p53 transcriptional activity in fresh xenografts by using the p53R-GFP reporter system may be useful in assessing the mechanisms of the antitumor effects of Ad-p53 and novel therapeutic approaches.

Adenoviridae↗
PubMed1991

Binary system for regulating transgene expression in mice: targeting int-2 gene expression with yeast GAL4/UAS control elements.

We have developed a binary transgenic system that activates an otherwise silent transgene in the progeny of a simple genetic cross. The system consists of two types of transgenic mouse strains, targets and transactivators. A target strain bears a transgene controlled by yeast regulatory sequences (UAS) that respond only to the yeast transcriptional activator GAL4. A transactivator strain expresses an active GAL4 gene that can be driven by any selected promoter. The current paradigm uses the murine growth factor int-2 cDNA as the target gene and the GAL4 gene driven by the mouse mammary tumor virus long terminal repeat as the transactivator. Both target and transactivator strains are phenotypically normal. By contrast, the bigenic offspring of these two strains express high levels of the target int-2 gene in each organ expressing the GAL4 transactivator. They also display a characteristic dominant int-2 phenotype that consists of epithelial hyperplasia in mammary and salivary glands, as well as prostatic and epididymal hypertrophy, which results in male sterility.

Animals↗
PubMed2001

Regulation of p53 target gene expression by cisplatin-induced extracellular signal-regulated kinase.

The extracellular signal-regulated kinase (ERK) pathway is among several signal transduction pathways that are activated in response to exposure to the DNA damage-inducing chemotherapeutic agent cisplatin. We have previously reported that inhibition of cisplatin-induced ERK activity enhances sensitivity to cisplatin. Furthermore, we have demonstrated that cisplatin-induced ERK activation is required for optimal p53 protein accumulation following cisplatin-induced DNA damage. In the present study, we expanded our investigations to examine the effect of cisplatin-induced ERK activation on the expression of p53-targeted genes that have been shown to be important in the cellular response to DNA damage including Bax, Bcl-2, Bcl-x1, Cyclin G, Gadd45, p21WAF1, and Mdm2. In the ovarian carcinoma cell line A2780, cisplatin was shown to induce expression of p21WAF1, Gadd45 and Mdm2, but cisplatin had no effect on expression of Bax, Bcl-2, Bcl-x1, or Cyclin G. Inhibition of cisplatin-induced ERK activity by PD98059 resulted in decreased levels of p21WAF1, Gadd45 and Mdm2. These results provide evidence that ERK activity during the cisplatin DNA damage response, regulates in part, these cell cycle control (p21WAF1, Gadd45), DNA repair (Gadd45) and p53-regulatory (Mdm2) proteins.

Antineoplastic Agents↗
PubMed2006

The effect of immunosuppressive therapy on the messenger RNA expression of target genes in the urinary sediment of patients with active lupus nephritis.

BACKGROUND: Previous studies have shown that messenger RNA (mRNA) expression of target genes is increased in the urinary sediment of patients with active lupus. We study the effect of immunosuppressive therapy on the urinary gene expression profile in patients with active lupus nephritis. Method. We recruited nine patients with active systemic lupus erythematosus (SLE) and renal disease, and required corticosteroid, with or without cytotoxic treatment. They were followed for 6 months, urine samples were collected at 0, 4, 12 and 24 weeks and gene expression profile was determined by polymerase chain reactions. The pattern of gene expression was compared to clinical parameters of therapeutic response. RESULTS: Amongst the target genes studied, there was a progressive decline in the urinary expression of T-bet, interleukin (IL)-10, transforming growth factor-beta (TGF-beta), monocyte chemoattractant protein-1 (MCP-1), and interferon-gamma (IFN-gamma) after immunosuppressive treatment, although the change of IFN-gamma was not statistically significant. The time course of their urinary expression was parallel to the systemic activity as reflected by the systemic lupus erythematosus disease activity index (SLEDAI). Throughout the study period, the SLEDAI score correlated significantly with the expressions of IFN-gamma (r = 0.43, P = 0.009), T-bet (r = 0.40, P = 0.016), TGF-beta (r = 0.51, P = 0.002) and MCP-1 (r = 0.38, P = 0.022). The anti-double strand(anti-ds)DNA antibody titer correlated significantly with the expressions of IFN-gamma (r = 0.45, P = 0.009), T-bet (r = 0.37, P = 0.034), IL-10 (r = 0.59, P<0.001), TGF-beta (r = 0.44, P = 0.010) and MCP-1 (r = 0.49, P = 0.004). On the other hand, the expression level of IL-2, IL-4, IL-12, IL-18 and GATA-3 remained static throughout the study period. CONCLUSIONS: The mRNA expression of T-bet, IL-10, TGF-beta, MCP-1, and probably IFN-gamma in the urinary sediment of patients with active lupus nephritis improves with successful immunosuppressive therapy, and the change in gene expression profile is in phase with the clinical disease activity. Measurement of urinary mRNA expression of target genes may be a potential non-invasive tool for the monitoring of lupus disease activity.

Adult↗
PubMed1995

Controlled, targeted, intracellular expression of ribozymes: progress and problems.

Significant progress has been made in the development of ribozymes for a wide variety of intracellular applications, including human gene therapy. Further advances are likely to come from innovative strategies to improve the delivery, expression, co-localization, targeting specificity and substrate turnover of ribozymes. In order to stimulate problem solving in these areas, this article discusses examples of recent successes in intracellular ribozyme applications, and identifies some of the obstacles that remain. In addition, some testable, but as yet untried, ideas for overcoming several of these obstacles are presented.

Animals↗
PubMed1997

Targeted gene expression without a tissue-specific promoter: creating mosaic embryos using laser-induced single-cell heat shock.

We have developed a method to target gene expression in the Drosophila embryo to a specific cell without having a promoter that directs expression in that particular cell. Using a digitally enhanced imaging system to identify single cells within the living embryo, we apply a heat shock to each cell individually by using a laser microbeam. A 1- to 2-min laser treatment is sufficient to induce a heat-shock response but is not lethal to the heat-shocked cells. Induction of heat shock was measured in a variety of cell types, including neurons and somatic muscles, by the expression of beta-galactosidase from an hsp26-lacZ reporter construct or by expression of a UAS target gene after induction of hsGAL4. We discuss the applicability of this technique to ectopic gene expression studies, lineage tracing, gene inactivation studies, and studies of cells in vitro. Laser heat shock is a versatile technique that can be adapted for use in a variety of research organisms and is useful for any studies in which it is desirable to express a given gene in only a distinct cell or clone of cells, either transiently or constitutively, at a time point of choice.

Animals↗
PubMed2006

In vivo molecular imaging of adenoviral versus lentiviral gene therapy in two bone formation models.

Regional gene therapy techniques are promising methods to enhance bone formation in large bone defects that would be difficult to treat with allograft or autograft bone stock. In this study, we compared in vivo temporal expression patterns of adenoviral- and lentiviral-mediated gene therapy in two bone formation models. Primary rat bone marrow cells (RBMC) were transduced with lentiviral or adenoviral vectors containing luciferase (Luc) or BMP-2 cDNA, or cotransduced with vectors containing Luc and bone morphogenetic protein 2 (BMP-2). In vitro protein production was determined with luciferase assay or ELISA (for BMP-2 production) weekly for 12 weeks. Two bone formation models were used -- a hind limb muscle pouch or radial defect -- in SCID mice. A cooled charged-coupled device (CCD) camera was used to image in vivo luciferase expression weekly for 12 weeks. In vitro, adenoviral expression of BMP-2 and luciferase was detected by ELISA or luciferase assay, respectively, for 4 weeks. Lentiviral expression of BMP-2 and luciferase was sustained in culture for 3 months. Using the CCD camera, we found that adenoviral vectors expressed luciferase expression for up to 21 days, but lentiviral vectors expressed target gene expression for 3 months in vivo in both bone formation models. There was no detectable difference in the amount of bone formed between the adenoviral and lentiviral groups. Lentiviral-mediated delivery of BMP-2 can induce long term in vitro and in vivo gene expression, which may be beneficial when developing tissue engineering strategies to heal large bone defects or defects with a compromised biologic environment.

Adenoviridae↗
PubMed2006

Characterizations of Hirudo medicinalis DNA promoters for targeted gene expression.

The expression of exogenous genes in neurons and other cells has become a powerful means for studying the function of encoded proteins. We report here on the isolation and functional analysis of three Hirudo medicinalis actin gene promoters and the 5' UTR of a leech elongation factor-1alpha (HmEF-1alpha) gene. In situ hybridization labeling revealed that the EF-1alpha gene and one of the actins had pan-neuronal expression, whereas, the other two actin genes were expressed by the embryo's body wall musculature. Comparative analysis shows that they all display many features typical of actin and EF-1alpha promoters from other species, including canonical TATA box sequences and predicted general transcription factor binding sites (such as CCATT, CarB boxes and CG-rich regions). The ability of these 5' UTR sequences to drive expression of the enhanced green fluorescent protein (EGFP), leech cytoplasmic actin and leech synaptobrevin was examined. Direct intracellular nuclear, but not cytoplasmic, microinjection of each of the promoter sequences was found to produce reliably cellular expression of the reporter construct in both neuronal and muscle cells. These results introduce reliable and effective methods to selectively express genes in individual cells of the leech in vivo during embryonic development.

5' Untranslated Regions↗
PubMed2005

Homeotic proboscipedia function modulates hedgehog-mediated organizer activity to pattern adult Drosophila mouthparts.

Drosophila proboscipedia (pb; HoxA2/B2 homolog) mutants develop distal legs in place of their adult labial mouthparts. Here we examine how pb homeotic function distinguishes the developmental programs of labium and leg. We find that the labial-to-leg transformation in pb mutants occurs progressively over a 2-day period in mid-development, as viewed with identity markers such as dachshund (dac). This transformation requires hedgehog activity, and involves a morphogenetic reorganization of the labial imaginal disc. Our results implicate pb function in modulating global axial organization. Pb protein acts in at least two ways. First, Pb cell autonomously regulates the expression of target genes such as dac. Second, Pb acts in opposition to the organizing action of hedgehog. This latter action is cell-autonomous, but has a nonautonomous effect on labial structure, via the negative regulation of wingless/dWnt and decapentaplegic/TGF-beta. This opposition of Pb to hedgehog target expression appears to occur at the level of the conserved transcription factor cubitus interruptus/Gli that mediates hedgehog signaling activity. These results extend selector function to primary steps of tissue patterning, and lead us to suggest the notion of a homeotic organizer.

Animals↗
PubMed2005

Transgenic expression of pancreatic secretory trypsin inhibitor-I ameliorates secretagogue-induced pancreatitis in mice.

BACKGROUND & AIMS: Endogenous trypsin inhibitors are believed to inhibit protease activity if trypsin becomes inadvertently activated within the acinar cell. However, this action remains unproven, and the role of endogenous pancreatic trypsin inhibitors in acute pancreatitis is unknown. In this study, we tested whether increased levels of pancreatic secretory trypsin inhibitor-I (PSTI-I) in mice could prevent secretagogue-induced pancreatitis. METHODS: Rat PSTI-I expression was targeted to pancreatic acinar cells in transgenic mice by creating a minigene driven by the rat elastase I enhancer/promoter. Secretagogue-induced pancreatitis was achieved by 12 hourly intraperitoneal injections of caerulein. The severity of pancreatitis was assessed by measurements of serum amylase, histologic grading, and pancreas wet weight-to-body weight ratio. Trypsinogen activation and trypsin activity were measured in pancreatic extracts. RESULTS: Targeted expression of PSTI-I to the pancreas increased endogenous trypsin inhibitor capacity by 190% (P <.01) in transgenic vs. nontransgenic mice. Caerulein administration to nontransgenic mice produced histologic evidence of acute pancreatitis, and significantly elevated serum amylase and pancreas weight ratio. In caerulein-treated transgenic mice, the histologic severity of pancreatitis was significantly reduced. There was no difference in trypsinogen activation peptide levels between caerulein-treated transgenic and nontransgenic mice. However, trypsin activity was significantly lower in transgenic mice receiving caerulein compared with nontransgenic mice. CONCLUSIONS: These data demonstrate that the severity of secretagogue-induced pancreatitis is significantly ameliorated in mice with higher pancreatic levels of trypsin inhibitor. We propose that PSTI-I prevents pancreatitis by inhibiting the activity of trypsin, rather than by reducing trypsinogen activation.

Animals↗
PubMed1997

Role of gamma delta TCR+ lymphocytes in the augmented resistance of trehalose 6,6'-dimycolate-treated mice to influenza virus infection.

Trehalose 6,6'-dimycolate (TDM), an immunomodulator, potentiates non-specific resistance in mice to influenza virus infection. When mice were injected intravenously with TDM, the striking proliferation of a minority of T-lymphocytes bearing gamma/delta T-cell receptors (gamma delta T-cells) that accumulated in granulomatous lungs was thought to be associated with the maintenance of acquired resistance to lethal influenza virus infection. To clarify the cellular basis of the defence against influenza virus, mice were depleted of gamma delta T-cells, alpha/beta (alpha beta) T-cells, or natural killer (NK) cells by in vivo administration of corresponding antibodies prior to influenza virus infection. The depletion of gamma delta T-cells significantly abrogated the augmented resistance of TDM-treated mice to infection, as did depletion of either alpha beta T-cells or NK cells. To gain insight into the functional ability of gamma delta T-cells, we evaluated the cytotoxic activity of this T-cell subset against a panel of target cell lines that were stably transfected with the influenza virus haemagglutinin (HA) gene from A/PR/8/34(H1N1) and A/Aichi/2/68(H3N2) strains. The gamma delta T-cells from TDM-treated mice showed profound cytotoxicity against the target cells expressing HA of either the H1 or H3 subtype, in a non-major histocompatibility complex-restricted manner. Taken together, these results indicate that gamma delta T-cells play a non-specific role, in conjunction with alpha beta T-cells and NK cells, in protecting mice against influenza virus infection, and that the recognition and destruction of HA-expressing target cells by the activated gamma delta T-cells is one of the steps involved in this anti-influenza virus immunosurveillance.

Adjuvants, Immunologic↗
PubMed1996

Fructan Accumulation and Sucrose Metabolism in Transgenic Maize Endosperm Expressing a Bacillus amyloliquefaciens SacB Gene.

Over 40,000 species of plants accumulate fructan, [beta]-2-1- and [beta]-2-6-linked polymers of fructose as a storage reserve. Due to their high fructose content, several commercial applications for fructans have been proposed. However, plants that accumulate these polymers are not agronomically suited for large-scale cultivation or processing. This study describes the transformation of a Bacillus amyloliquefaciens SacB gene into maize (Zea mays L.) callus by particle bombardment. Tissue-specific expression and targeting of the SacB protein to endosperm vacuoles resulted in stable accumulation of high-molecular-weight fructan in mature seeds. Accumulation of fructan in the vacuole had no detectable effect on kernel development or germination. Fructan levels were found to be approximately 9-fold higher in sh2 mutants compared to wild-type maize kernels. In contrast to vacuole-targeted expression, starch synthesis and endosperm development in mature seeds containing a cytosolically expressed SacB gene were severely affected. The data demonstrate that hexose resulting from cytosolic SacB activity was not utilized for starch synthesis. Transgenic seeds containing a chimeric SacB gene provide further evidence that the dominant pathway for starch synthesis in maize endosperm is through uridine diphosphoglucose catalyzed by the enzyme sucrose synthase.

Journal Article↗
PubMed2003

Role of 14-3-3-mediated p38 mitogen-activated protein kinase inhibition in cardiac myocyte survival.

14-3-3 family members are dimeric phosphoserine-binding proteins that regulate signal transduction, apoptotic, and checkpoint control pathways. Targeted expression of dominant-negative 14-3-3eta (DN-14-3-3) to murine postnatal cardiac tissue potentiates Ask1, c-jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) activation. DN-14-3-3 mice are unable to compensate for pressure overload, which results in increased mortality, dilated cardiomyopathy, and cardiac myocyte apoptosis. To evaluate the relative role of p38 MAPK activity in the DN-14-3-3 phenotype, we inhibited cardiac p38 MAPK activity by pharmacological and genetic methods. Intraperitoneal injection of SB202190, an inhibitor of p38alpha and p38beta MAPK activity, markedly increased the ability of DN-14-3-3 mice to compensate for pressure overload, with decreased mortality. DN-14-3-3 mice were bred with transgenic mice in which dominant-negative p38alpha (DN-p38alpha) or dominant-negative p38beta (DN-p38beta) MAPK expression was targeted to the heart. Compound transgenic DN-14-3-3/DN-p38beta mice, and to a lesser extent compound transgenic DN-14-3-3/DN-p38alpha mice, exhibited reduced mortality and cardiac myocyte apoptosis in response to pressure overload, demonstrating that DN-14-3-3 promotes cardiac apoptosis due to stimulation of p38 MAPK activity.

14-3-3 Proteins↗
PubMed2002

T cell antigen receptor engagement and specificity in the recognition of stress-inducible MHC class I-related chains by human epithelial gamma delta T cells.

Human gamma delta T cells with the TCR variable region V(delta)1 occur mainly in epithelia and respond to stress-induced expression of the MHC class I-related chains A and B, which have no function in Ag presentation. MIC function as ligands for NKG2D-DAP10, an activating receptor complex that triggers NK cells, costimulates CD8 alpha beta and V(gamma)9V(delta)2 gamma delta T cells, and is required for stimulation of V(delta)1 gamma delta T cells. It is unresolved, however, whether triggering of V(delta)1 gamma delta TCRs is also mediated by MIC or by unidentified cell surface components. Soluble MICA tetramers were used as a binding reagent to demonstrate specific interactions with various V(delta)1 gamma delta TCRs expressed on transfectants of a T cell line selected for lack of NKG2D. Tetramer binding was restricted to TCRs derived from responder T cell clones classified as reactive against a broad range of MIC-expressing target cells and was abrogated when TCRs were composed of mismatched gamma- and delta-chains. These results and the inability of V(delta)1 gamma delta T cells to respond to target cells expressing the ULBP/N2DL ligands of NKG2D, which are highly divergent from MIC, indicate that MIC delivers both the TCR-dependent signal 1 and the NKG2D-dependent costimulatory signal 2. This dual function may serve to prevent erroneous gamma delta T cell activation by cross-reactive cell surface determinants.

Epithelial Cells↗