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)

Sera from patients with halothane hepatitis contain immunoglobulin G (IgG) antibodies to trifluoroacetylated liver microsomal proteins of 100, 76, 59, 57 and 54 kDa, which are produced as a consequence of metabolism of halothane to trifluoroacetyl halide by cytochrome(s) P450. In the present study, the membrane topographies of the various antigens in rat liver microsomal fractions were investigated. Liver microsomal fractions from rats treated with halothane in vivo, and rat liver microsomal fractions which had been incubated with halothane in vitro, were used as the source of trifluoroacetyl antigens. The antigens were detected by immunoblotting. Whereas the 100, 76, 59 and 57 kDa antigens were solubilized from the microsomal membrane by either 0.1 M sodium carbonate or 0.1% (w/v) sodium deoxycholate, the 54 kDa antigen was not solubilized by 0.1% (w/v) sodium deoxycholate. In intact microsomal fractions, the 100, 76, 59 and 57 kDa antigens were not degraded appreciably by trypsin unless detergent was added to permeabilize the microsomal membrane. These results indicate that the 54 kDa antigen is an integral membrane protein, whereas the 100, 76, 59 and 57 kDa antigens are peripheral membrane proteins situated within the lumen of microsomal vesicles, and hence presumably located within the lumen of the endoplasmic reticulum in vivo.
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PMID:The topography of trifluoroacetylated protein antigens in liver microsomal fractions from halothane treated rats. 151 Jul 11

Interaction between woodchuck hepatitis virus surface antigen and proteins of hepatocyte plasma membranes were examined in the course of woodchuck hepatitis virus infection. Membranes purified from animals with histologically confirmed acute hepatitis, active or persistent chronic hepatitis and the virus-related hepatocellular carcinoma were evaluated for the virus surface antigen contents, treated with agents eluting plasma membrane-bound antigen to test the extent of the antigen-membrane associations and incubated with purified, particulate woodchuck hepatitis virus surface antigen to determine membrane potential for the antigen adsorption. Hepatocyte plasma membranes originating from woodchucks chronically infected with the virus showed the highest quantities of the incorporated virus surface antigen among membranes studied, the behavior of bound antigen as an integral and a peripheral membrane protein and the resistance to bind an exogenous antigen. Similar properties were expressed by plasma membranes prepared from hepatocytes of nontumor parenchyma displaying chronic active hepatitis of a woodchuck hepatitis virus carrier with hepatoma. Furthermore, plasma membranes originating from animals with active or persistent chronic hepatitis demonstrated identical properties, implicating that histologic activity of the chronic liver inflammatory process is not dependent on the quantity of the virus surface antigen insertion into the membrane. In contrast, hepatocyte plasma membranes from animals with acute hepatitis showed significantly lower antigen quantities, presence of the antigen specificity exclusively behaving as an integral membrane protein and noticeable ability to bind an exogenous surface antigen of the virus. Comparable, but not identical, features were observed for hepatocyte membranes purified from nodules of hepatocellular carcinoma, suggesting that neoplastic transformation of infected hepatocytes is associated with loss of the membrane-bound antigen and with simultaneous, partial recovery of the membrane potential for the antigen binding. Comparative analysis of the properties on the woodchuck hepatitis virus surface antigen incorporation into hepatocyte plasma membranes in studied cases indicated that sustained infection with woodchuck hepatitis virus leads to an increase in the quantity of the membrane-incorporated antigen and to the appearance of the virus surface antigen specificity behaving as a peripheral membrane protein. In conclusion, this study demonstrated that the extent and the character of the antigen interaction with hepatocyte plasma membranes undergoes significant variations in the natural course of hepadna viral infect
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PMID:Characterization of the incorporation of woodchuck hepatitis virus surface antigen into hepatocyte plasma membrane in woodchuck hepatitis and in the virus-induced hepatocellular carcinoma. 253 20

We have previously shown that gp65 (E3) is a virion structural protein which varies widely in quantity among different strains of mouse hepatitis virus (MHV). In this study, the biosynthetic pathway and possible biological activities of this protein were examined. The glycosylation of gp65 in virus-infected cells was inhibited by tunicamycin but not by monensin, suggesting that it contains an N-glycosidic linkage. Glycosylation is cotranslational and appears to be complete before the glycoprotein reaches the Golgi complex. Pulse-chase experiments showed that this protein decreased in size after 30 min of chase, suggesting that the carbohydrate chains of gp65 undergo trimming during its transport across the Golgi. This interpretation is supported by the endoglycosidase treatment of gp65, which showed that the peptide backbone of gp65 did not decrease in size after pulse-chase periods. This maturation pathway is distinct from that of the E1 or E2 glycoproteins. Partial endoglycosidase treatment indicated that gp65 contains 9 to 10 carbohydrate side chains; thus, almost all of the potential glycosylation sites of gp65 were glycosylated. In vitro translation studies coupled with protease digestion suggest that gp65 is an integral membrane protein. The presence of gp65 in the virion is correlated with the presence of an acetylesterase activity. No hemagglutinin activity was detected.
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PMID:Biosynthesis, structure, and biological activities of envelope protein gp65 of murine coronavirus. 255 47

The extent of association between woodchuck hepatitis virus surface antigen and host hepatocyte plasma membrane in chronic hepatitis was studied. Purified membranes containing the antigen were treated with various agents which perturb plasma membrane constituents to elute woodchuck hepatitis virus surface antigen. The products from disrupted membranes were analyzed by sedimentation in sucrose gradients and tested to identify the antigen reactivity. The results indicated that membrane-bound woodchuck hepatitis virus surface antigen was partially released by 4 M potassium chloride, potassium thiocyanate and guanidine, 6 M urea or 0.1 N sodium hydroxide (pH 13.5), but not in the presence of low concentrations of these reagents or by 10% 2-mercaptoethanol and 1% sodium dodecyl sulfate. No more than 15% of the total membrane-associated woodchuck hepatitis virus surface antigen was eluted by 0.1 N NaOH, which was found to be the most effective eluent among tested agents at the antigen removal. The remaining woodchuck hepatitis virus surface antigen was resistant to further extraction with sodium hydroxide, as expected for an integral membrane protein. Treatment of the infected membranes with 1% Triton X-100 or 50 mM deoxycholic acid, that solubilize the membrane lipid bilayer releasing most of the integral membrane proteins, resulted in the sedimentation of almost all detectable woodchuck hepatitis virus surface antigen reactivity with the detergent-insoluble membrane residues, suggesting a firm interaction of the antigen with the plasma membrane matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction of woodchuck hepatitis virus surface antigen with hepatocyte plasma membrane in woodchuck chronic hepatitis. 328 58

Fas (APO-1, CD95) is a type I integral membrane protein initially identified by mAbs that induce apoptotic cell death upon binding to certain tumor cells and its belongs to the TNFR family. Fas is expressed on activated lymphocytes and in various tissues including the liver, lung, intestine, and skin. Molecular cloning of Fas ligand (FasL) revealed that it is a type II integral membrane protein homologous to TNF. FasL is predominantly expressed on activated T and NK cells, and mediates Fas divided by target cell lysis by these effector cells. The Fas/FasL system has been also implicated in the pathogenesis of autoimmune diseases, fulminant hepatitis, GVHD, and AIDS. It has been recently reported that human FasL was released as a 26 kD soluble form from COS cells transfected with human FasL cDNA and activated human T cells. In this communication, metalloproteinase-mediated release of FasL and it's clinical relevance are discussed.
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PMID:[Metalloproteinase-mediated release of human fas ligand]. 874 61

Previous studies have demonstrated that sera from patients with autoimmune hepatitis type 1 contain antibodies which react with proteins other than the endoplasmic reticulum integral membrane protein of apparent Mr 50,000, now known to be a cytochrome P450 of the IID subfamily. Sera from 141 patients found by immunofluorescence to be positive for anti-liver-kidney microsome antibodies type 1, and sera from 50 blood donors used as controls, were analyzed by immunoblotting experiments on rat liver microsomes, microsomal subfractions, and also microsomes subjected to various treatments, as described in the text. These fractions were characterized morphologically by electronic microscopy and biochemically by different enzymatic activities. Five bands were found to be stained more often by the patients' sera than by the controls' and with a statistically significant difference in frequency. These antigenic proteins were located at apparent Mr 62,000, 58,000, 50,000, 40,000, and 35,000. The 50,000 protein was of course more often stained than the others. Antibodies against these antigens belonged essentially to the IgG1 subclass. For some of them, subcellular localization and membrane topography are discussed. Interestingly, the 58,000 protein is not an integral membrane protein.
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PMID:Detection on immunoblot of new proteins from the microsomal fraction recognized by anti-liver-kidney microsome antibodies type 1. 881 Oct 45

The unique region of mRNA 5 of murine hepatitis virus contains two open reading frames, ORF 5a and ORF 5b. The downstream ORF 5b encodes the envelope (E) protein, an integral membrane protein of the virus. We have shown previously that the expression of ORF 5b is mediated by the internal entry of ribosomes. In the experiments reported here, we have used the in vitro translation of synthetic mRNAs to identify the region of mRNA 5 that mediates internal ribosome entry. Our results show that the 5' border of the MHV mRNA 5 IRES element is located between nucleotides 227 and 244 in ORF 5a, while the 3' border is located between nucleotides 140 and 172 in ORF 5b. The MHV mRNA 5 IRES element, therefore, contains not more than 280 nucleotides and encompasses the ORF 5b initiation codon. As evidenced by electrophoretic mobility shift assays, the IRES element of mRNA 5 interacts specifically with protein factors present in an L-cell lysate.
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PMID:Characterization of an internal ribosome entry site within mRNA 5 of murine hepatitis virus. 1041 75

Coronavirus E protein is a small viral envelope protein that plays an essential role in coronavirus assembly; coexpression of coronavirus M and E proteins results in the production of virus-like particles. The present study demonstrated that mouse hepatitis virus (MHV) E protein was released as an integral membrane protein in lipid vesicles from E-protein-expressing mammalian cells, in the absence of other MHV proteins. Furthermore, our data indicated that the E-protein-containing vesicles, which had a slightly lighter buoyant density than that of MHV, were released from MHV-infected cells. These data implied that E protein alone can drive the production and release of coronavirus envelope in the absence of M protein.
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PMID:Release of coronavirus E protein in membrane vesicles from virus-infected cells and E protein-expressing cells. 1054

We report the isolation and characterization of GP73, a novel 73kDa human Golgi protein. The GP73 cDNA was cloned by differential screening of a cDNA library derived from the liver of a patient with adult giant-cell hepatitis (GCH), a rare form of hepatitis with presumed viral etiology. In vitro transcription-translation studies indicate that GP73 is an integral membrane protein, and immunolocalization experiments using epitope-tagged GP73 demonstrate that the protein is localized to the Golgi apparatus. Northern blot analysis of RNA from multiple human tissues reveals a single GP73 mRNA transcript with a size of approximately 3.0kb. Immunohistochemical studies using rabbit polyclonal antisera directed against recombinant GP73 demonstrate that the protein is preferentially expressed by epithelial cells in many human tissues. In normal livers, GP73 is consistently present in biliary epithelial cells, whereas hepatocytes show little or no signal. In contrast, livers of patients with GCH display strong GP73 immunoreactivity in multinucleated hepatocytes. GP73 mRNA and protein are expressed in highly differentiated HepG2 hepatoma cells after infection with adenovirus in vitro. We conclude that GP73 represents a novel, epithelial cell-specific integral membrane Golgi protein that can be upregulated in response to viral infection.
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PMID:GP73, a novel Golgi-localized protein upregulated by viral infection. 1083 38

The coronavirus membrane (M) protein is the most abundant virion protein and the key component in viral assembly and morphogenesis. The M protein of mouse hepatitis virus (MHV) is an integral membrane protein with a short ectodomain, three transmembrane segments, and a large carboxy-terminal endodomain facing the interior of the viral envelope. The carboxy terminus of MHV M has previously been shown to be extremely sensitive to mutation, both in a virus-like particle expression system and in the intact virion. We have constructed a mutant, M(Delta)2, containing a two-amino-acid truncation of the M protein that was previously thought to be lethal. This mutant was isolated by means of targeted RNA recombination with a powerful host range-based selection allowed by the interspecies chimeric virus fMHV (MHV containing the ectodomain of the feline infectious peritonitis virus S protein). Analysis of multiple second-site revertants of the M(Delta)2 mutant has revealed changes in regions of both the M protein and the nucleocapsid (N) protein that can compensate for the loss of the last two residues of the M protein. Our data thus provide the first genetic evidence for a structural interaction between the carboxy termini of the M and N proteins of MHV. In addition, this work demonstrates the efficacy of targeted recombination with fMHV for the systematic genetic analysis of coronavirus structural protein interactions.
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PMID:Genetic evidence for a structural interaction between the carboxy termini of the membrane and nucleocapsid proteins of mouse hepatitis virus. 1196 15


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