Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Replication-competent retroviral vectors (pFOV-1 to -3 and -7) were constructed on the basis of an infectious human foamy virus molecular clone which has deletions in the U3 region of the long terminal repeat and in the 3' region of the genome, previously identified to be nonessential for virus replication in vitro. The CAT and luciferase indicator genes were expressed as C-terminal fusion proteins to 215 amino acids of the viral Bet protein in the pFOV-1 vector. Introduction of the foot-and-mouth disease 2A protease sequence between the truncated bet coding sequence and the cloning site for the insertion of foreign genes in the pFOV-7 vector resulted in self-cleaving of the recombinant fusion protein. Alternatively, an internal ribosomal binding site was introduced, allowing expression of authentic foreign protein (pFOV-2 and -3 vectors). DNA fragments derived from the mouse hepatitis virus surface gene up to the length of 1.3 kb were inserted into pFOV-1. The vector constructs gave rise to viruses which were fully infectious in diploid human fibroblasts and recombinant viruses stably expressed high levels of foreign protein indicating that the pFOV vectors may be useful tools to study the effects of proteins of interest at least in tissue culture cells.
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PMID:Replicating foamy virus-based vectors directing high level expression of foreign genes. 779 69

Activation of the N-myc2 oncogene by integration of woodchuck hepatitis virus (WHV) DNA is a central event in woodchuck liver oncogenesis. In this study, we have evaluated the influence of several cellular and viral trans-acting factors and mediators of inflammation on N-myc2 promoter activity in hepatoma cell lines. Ets oncoproteins, including Ets1, Ets2 and PEA3 efficiently activated a chimeric N-myc2 promoter/luciferase reporter gene. By electrophoretic mobility shift assays, we show that Etsl and Ets2 proteins can efficiently bind two consensus Ets sites located within a 59 bp sequence upstream of the N-myc2 transcription start site. Site-directed mutagenesis of these Ets-binding motifs abolished transactivation of the N-myc2 promoter by Ets proteins. Addition of interleukin-6 (IL-6) induced a weak but reproducible activation of the N-myc2 promoter, while IL-1 was ineffective. We further show that the N-myc2 promoter can be transactivated by the hepadna-virus X protein, and that distal promoter sequences are required for both IL-6 and X responsiveness. Similar effects of these factors were observed in the context of the N-myc2 promoter activated by WHV cis-regulatory elements. In view of the high-level expression of the N-myc2 oncogene in most woodchuck liver tumors, the Ets oncoproteins, inflammation-associated cytokine IL-6 and the viral X transactivator might play important roles in hepadnavirus-associated tumorigenesis.
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PMID:Cellular and viral trans-acting factors modulate N-myc2 promoter activity in woodchuck liver tumors. 928 65

Based on the natural ability of coronaviruses to undergo homologous RNA recombination, we are working to produce infectious bronchitis virus (IBV) recombinants using RNA generated from recombinant fowlpox viruses (FPV). The aim is to replace the spike (S) gene of an existing IBV vaccine strain with the S gene of a heterologous strain. CD-61 is an IBV defective RNA (D-RNA) derived from a naturally occurring IBV D-RNA (CD-91). CD-61 D-RNA is being investigated as an RNA vector for the expression of heterologous genes. T7-derived RNA transcripts of CD-61 can be replicated and passaged in the presence of helper virus, following electroporation into IBV-infected cells. CD-61 cDNA was modified by the addition of the hepatitis delta virus ribozyme plus T7 terminator downstream of the 3'UTR. This allowed the synthesis of discreet RNA transcripts. The complete cassette was cloned into an FPV transfer vector (pEFL10) for generating recombinant fowlpox viruses. FPV/CD-61 recombinants will be assessed for D-RNA production in IBV-infected cells. The luciferase reporter gene sequence has been inserted into the modified CD-61, under the control of the IBV transcription associated sequence (TAS) from gene 5. Luciferase has been successfully expressed from CD-61 in helper virus-infected cells.
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PMID:Utilising a defective IBV RNA for heterologous gene expression with potential prophylactic application. 978 45

Hepatitis C virus (HCV) is the major cause of non-A, non-B hepatitis worldwide. Current treatments are not curative for most infected individuals, and there is an urgent need for both novel therapeutic agents and small-animal models which can be used to evaluate candidate drugs. A small-animal model of HCV gene expression was developed with recombinant vaccinia virus vectors. VHCV-IRES (internal ribosome entry site) is a recombinant vaccinia viral vector containing the HCV 5' nontranslated region (5'-NTR) and a portion of the HCV core coding region fused to the firefly luciferase gene. Intraperitoneal injection of VHCV-IRES produced high levels of luciferase activity in the livers of BALB/c mice. Antisense oligonucleotides complementary to the HCV 5'-NTR and translation initiation codon regions were then evaluated for their effects on the expression of these target HCV sequences in BALB/c mice infected with the vaccinia virus vector. Treatment of VHCV-IRES-infected mice with 20-base phosphorothioate oligonucleotides complementary to the sequence surrounding the HCV initiation codon (nucleotides 330 to 349) specifically reduced luciferase expression in the livers in a dose-dependent manner. Inhibition of HCV reporter gene expression in this small-animal model suggests that antisense oligonucleotides may provide a novel therapy for treatment of chronic HCV infection.
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PMID:Antisense oligonucleotide inhibition of hepatitis C virus (HCV) gene expression in livers of mice infected with an HCV-vaccinia virus recombinant. 992 30

The expression of genes delivered by retroviral vectors is often inefficient, a potential obstacle for their widespread use in human gene therapy. Here, we explored the possibility that the posttranscriptional regulatory element of woodchuck hepatitis virus (WPRE) might help resolve this problem. Insertion of the WPRE in the 3' untranslated region of coding sequences carried by either oncoretroviral or lentiviral vectors substantially increased their levels of expression in a transgene-, promoter- and vector-independent manner. The WPRE thus increased either luciferase or green fluorescent protein production five- to eightfold, and effects of a comparable magnitude were observed with either the immediate-early cytomegalovirus or the herpesvirus thymidine kinase promoter and with both human immunodeficiency virus- and murine leukemia virus-based vectors. The WPRE exerted this influence only when placed in the sense orientation, consistent with its predicted posttranscriptional mechanism of action. These results demonstrate that the WPRE significantly improves the performance of retroviral vectors and emphasize that posttranscriptional regulation of gene expression should be taken into account in the design of gene delivery systems.
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PMID:Woodchuck hepatitis virus posttranscriptional regulatory element enhances expression of transgenes delivered by retroviral vectors. 1007 36

Using a set of parental and recombinant murine hepatitis virus strains, we demonstrate that the nucleocapsid protein induces transcription of the novel fgl2 prothrombinase gene and elevated procoagulant activity in those strains that produce fulminant hepatitis. Chinese hamster ovary cells cotransfected with a construct expressing nucleocapsid protein from susceptible strains and with a luciferase reporter construct containing the fgl2 promoter showed a 6-fold increase in luciferase activity compared with nontransfected cells or cells cotransfected with a construct expressing nucleocapsid protein from resistant strains. Two deletions found at coding sites 111-123 and 1143-1145 of structural domains I and III, respectively, of the nucleocapsid gene may account for the differences between pathogenic and nonpathogenic strains. Preliminary mapping of the fgl2 promoter has defined a region from -372 to -306 upstream from the ATG translation initiation site to be responsive to nucleocapsid protein. Hence, mapping of genetic determinants in parental and recombinant strains demonstrates that the nucleocapsid protein of strains that induce fulminant hepatitis is responsible for transcription of the fgl2 prothrombinase gene. These studies provide new insights into the role of the nucleocapsid gene in the pathogenesis of viral hepatitis.
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PMID:The nucleocapsid protein of murine hepatitis virus type 3 induces transcription of the novel fgl2 prothrombinase gene. 1018 67

NFkappaB is an essential survival factor in several physiological conditions such as embryonal liver development and liver regeneration. However, NFkappaB is also a main mediator of the cellular response to a variety of extracellular stress stimuli, and it has been shown that some viral-induced host cell apoptosis appears to be dependent on NFkappaB activation. The activation of NFkappaB upon viral infection may be a rapid way of initiating an innate immune response against the viral particles. We have assessed the role of NFkB during the early phase of adenoviral hepatitis in a nude mouse model using an adenoviral vector expressing a mutant form of IkappaBalpha. Administration of a LacZ-expressing adenoviral vector induces NFkB DNA and correlates with the up-regulation of Fas (CD95) mRNA, but not FasL (CD95L) mRNA, during the early phase of adenoviral hepatitis. The rapid increase in NFkappaB DNA binding after adenoviral infection of the liver could be very effectively inhibited by IkappaBalpha. Compared with the LacZ control virus, the IkappaBalpha-expressing adenoviral vector inhibits the increase of Fas (CD95) mRNA expression, in particular in the very early phase of the hepatitis. Reporter gene experiments in hepatoma cell lines with a Fas promoter-luciferase construct indicated that the repression of Fas (CD95) mRNA by IkappaBalpha was transcriptionally mediated. The functional relevance of the NFkappaB-dependent increase in Fas (CD95) transcription was assessed by caspase 3 assays and terminal dUTP nick-end labeling tests. Compared with the control, IkappaBalpha adenoviral infection resulted in reduced caspase 3 activity during the early phase of viral hepatitis and in a prevention of liver cell apoptosis 24 h after adenoviral administration. Therefore our study demonstrates a new pro-apoptotic function of NFkappaB in Fas (CD95)-mediated apoptosis of hepatocytes. Interestingly, NFkappaB mediates liver cell apoptosis upon viral infection even in a phase where tumor necrosis factor-alpha is already induced, as shown by the time curves of tumor necrosis factor-alpha serum levels. Therefore, the pro- or anti-apoptotic role of NFkappaB appears to be more determined by the nature of the death stimulus than by the origin of the tissue.
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PMID:NFkappaB mediates apoptosis through transcriptional activation of Fas (CD95) in adenoviral hepatitis. 1069 45

Deletion mutants of hepatitis B virus (HBV) are often found in chronically HBV-infected patients. It has not been possible to study the significance of such deletion mutants on liver diseases in a suitable animal model. In this study, we characterized naturally occurring deletion mutants of woodchuck hepatitis virus (WHV) in 11 chronically WHV-infected woodchucks. Deletions within the WHV preS region (nt 2992-338) had a length of 72 or 84 bp and were located in the amino terminal part of preS1. Internal deletions within the core gene (CID) had variable lengths (103 to 312 bp) and were identified within the center of this gene (nt 2021-2587). Four of seven CIDs were in-frame deletions, whereas the remaining three CIDs were out-of-frame deletions and led to the interruption of the reading frame. Sequence analysis of cloned PCR products of CIDs showed that heterogeneous WHV deletion mutants coexisted in single woodchucks. In addition, WHV genomes with double deletions in the preS1 and the core region could be found. We were unable to detect the expression of truncated core proteins in transfection experiments. The CID mutations led to a marked increase of the expression of the luciferase gene which was fused to the start codon of WHV polymerase, probably due to the shortening of the untranslated region or the removal of AUGs preceding the polymerase start codon. The characterization of naturally occurring WHV deletion mutants will allow us to study their biological and pathogenic properties in the woodchuck model in the future.
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PMID:Naturally occurring woodchuck hepatitis virus (WHV) deletion mutants in chronically WHV-infected woodchucks. 1108 Apr 71

Coronavirus defective RNAs (D-RNAs) have been used as RNA vectors for the expression of heterologous genes and as vehicles for reverse genetics by modifying coronavirus genomes by targetted recombination. D-RNAs based on the avian coronavirus infectious bronchitis virus (IBV) D-RNA CD-61 have been rescued (replicated and packaged into virions) in a helper virus-dependent manner following electroporation of in vitro-generated T7 transcripts into IBV-infected cells. In order to increase the efficiency of rescue of IBV D-RNAs, cDNAs based on CD-61, under the control of a T7 promoter, were integrated into the fowlpox virus (FPV) genome. The 3'-UTR of the D-RNAs was flanked by a hepatitis delta antigenomic ribozyme and T7 terminator sequence to generate suitable 3' ends for rescue by helper IBV. Cells were co-infected simultaneously with IBV, the recombinant FPV (rFPV) containing the D-RNA sequence and a second rFPV expressing T7 RNA polymerase for the initial expression of the D-RNA transcript, subsequently rescued by helper IBV. Rescue of rFPV-derived CD-61 occurred earlier and with higher efficiency than demonstrated previously for electroporation of in vitro T7-generated RNA transcripts in avian cells. Rescue of CD-61 was also demonstrated for the first time in mammalian cells. The rescue of rFPV-derived CD-61 by M41 helper IBV resulted in leader switching, in which the Beaudette-type leader sequence on CD-61 was replaced with the M41 leader sequence, confirming that helper IBV virus replicated the rFPV-derived D-RNA. An rFPV-derived D-RNA containing the luciferase gene under the control of an IBV transcription-associated sequence was also rescued and expressed luciferase on serial passage.
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PMID:Utilizing fowlpox virus recombinants to generate defective RNAs of the coronavirus infectious bronchitis virus. 1108 16

Baculovirus gp64 envelope glycoprotein is a major component of the envelope of the budded virus and is involved in virus entry into the host cells by endocytosis. To investigate the cell-surface molecules important for infection of baculovirus into mammalian cells, we constructed a recombinant baculovirus, Ac64-CAluc, which has gp64 and luciferase genes under the polyhedrin and the CAG promoter, respectively. For controls, we constructed recombinant viruses possessing vesicular stomatitis virus (VSV) G protein, mouse hepatitis virus (MHV) S protein, or green fluorescent protein (GFP) gene under the polyhedrin promoter and the luciferase gene under the CAG promoter (AcVSVG-CAluc, AcMHVS-CAluc, and AcGFP-CAluc). Treatment of HepG2 cells with phospholipase C markedly reduced the reporter gene expression by Ac64-CAluc or AcVSVG-CAluc in a dose-dependent manner, whereas AcMHVS-CAluc was shown to be resistant to the treatment. Inhibition with purified lipids and susceptibility to the mutant CHO hamster cell lines deficient in phospholipids synthesis suggest that the interaction of gp64 and phospholipids on the cell surface might play an important role in baculovirus infection into mammalian cells.
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PMID:Characterization of cell-surface determinants important for baculovirus infection. 1114 15


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