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)

Australia antigen [Au(1)], a particle associated with viral hepatitis, was isolated from the plasma of a patient with chronic anicteric hepatitis and leukemia who had received radioactive phosphorus. We have found that the immunoreactivity and appearance of Au(1) in the electron microscope were not altered by treatment with enzymes including trypsin, pronase, lipase, phospholipase C, ribonuclease, deoxyribonuclease, amylase, and neuraminidase. In contrast, other serum constituents were degraded by these enzymes. Therefore, treatment of the patient's plasma with many enzymes was exploited as an initial step for the isolation of Au(1). Subsequently, Au(1) was purified from the enzyme-treated (32)P-labeled plasma by gel filtration through Sephadex G-200 and centrifugation through sucrose and in cesium chloride gradients. There were no detectable human serum components in the purest fractions, as tested by immunoelectrophoresis and immunodiffusion. The density of the purified Au(1) was 1.21 in CsCl. The particle measured about 200 A in diameter, was predominantly spherical in shape and appeared to be composed of subunits. Nucleic acids were not detected by spectrophotometric, radiochemical, and chemical analyses. Immunoreactivity of purified Au(1) was destroyed by heating for 1 hr at 85 degrees C but was stable at 56 degrees C. Treatment with Carnoy's solution (3 parts ethanol:1 part glacial acetic acid) followed by pronase disrupted the particles as seen with the electron microscope. These findings, combined with other published information on Australia antigen and viral hepatitis, suggest that the bulk of Australia antigen in the blood of this patient is an incomplete virus or virus capsid.
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PMID:Australia antigen (a hepatitis-associated antigen): purification and physical properties. 424 40

We have shown by T(1) oligonucleotide fingerprinting that the genome of mouse hepatitis virus strain A59 and its intracellular RNA 1 have identical fingerprints and that RNA 1 and the subgenomic RNAs 3, 6, and 7 contain common sequences. To localize the homologous region between the RNAs, we compared fingerprints of the 3' terminus of the genome with those of RNA 7. The genome was partially degraded with alkali, and polyadenylate-containing fragments were purified by oligodeoxythymidylate-cellulose chromatography. The fragments were size fractionated by agarose-urea gel electrophoresis, and two pools, x and z, containing 3'-derived fragments of the genome with apparent molecular weights of 0.1 x 10(6) to 0.14 x 10(6) and 0.6 x 10(6) to 0.8 x 10(6), respectively, were further analyzed by RNase T(1) oligonucleotide fingerprinting. Comparison of the fingerprints of RNAs 6 and 7 with those of pools x and z showed that these subgenomic RNAs extend inwards from the 3' terminus of the genome. The RNA fragments present in pool z were on average slightly larger than RNA 7 as confirmed by the presence in pool z of T(1) oligonucleotide spots specific for RNA 6 but not present in RNA 7. However, two large oligonucleotide spots derived from RNA 7, which were also present in RNAs 1, 3, and 6 and in the virion RNA, were not found in the T(1) oligonucleotide map of pool z. A possible explanation is that the two spots were derived from a leader sequence. The results of UV transcription mapping experiments (L. Jacobs, W. J. M. Spaan, M. C. Horzinek, and B. A. M. van der Zeijst, J. Virol. 39:401-406, 1981) excluded the possibility that such a leader sequence arises by splicing from a larger precursor molecule, but either a virus-specific RNA primer molecule for the synthesis of mRNAs or an RNA polymerase jumping mechanism could explain the presence of a leader sequence.
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PMID:Sequence relationships between the genome and the intracellular RNA species 1, 3, 6, and 7 of mouse hepatitis virus strain A59. 628 66

There are seven virus-specific mRNA species in mouse hepatitis virus-infected cells (Lai et al., J. Virol. 39:823-834, 1981). In this study, we examined virus-specific negative-stranded RNA to determine whether there are corresponding multiple negative-stranded RNAs. Intracellular RNA from mouse hepatitis virus-infected cells was separated by agarose gel electrophoresis, transferred to nitrocellulose membranes, and hybridized to positive-stranded genomic 60S [32P]RNA. Only a single RNA species of genomic size was detected under these conditions. This RNA was negative stranded. No negative-stranded subgenomic RNA was detected. We also studied double-stranded replicative-form RNA in the infected cells. Only one replicative-form of genomic size was detected. When the double-stranded RNA isolated without RNase treatment was analyzed, again only one RNA species of genomic size was detectable. Furthermore, most of the virus-specific mRNAs could be released from this RNA species upon heating. These results suggest that all of the mouse hepatitis virus-specific RNAs are transcribed from a single species of negative-stranded RNA template of genomic size.
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PMID:Replication of mouse hepatitis virus: negative-stranded RNA and replicative form RNA are of genome length. 629 13

The mouse biliary glycoprotein 1 gene (bgp1) encodes several multifunctional glycoprotein isoforms. These glycoproteins represent members of the carcinoembryonic antigen (CEA) family which belongs to the immunoglobulin superfamily. The Bgp1 glycoproteins function as cell adhesion molecules and receptors for the mouse hepatitis viruses. In contrast to CEA, whose overexpression has been correlated with cancer progression, the human and mouse Bgp proteins are generally down-regulated upon tumor formation. In this study, we report on the mouse bgp1 gene organization and transcriptional activation. We have isolated phage and cosmid clones encompassing the entire bgp1 coding region. This gene consists of nine exons, some of which are subjected to alternative splicing producing a minimum of four splice variants. A comparison of the murine bgp1 proximal promoter with the human BGP and mouse cea10/bgp3 genes revealed sequence conservation of 66% and 95%, respectively. RNase protection assays and primer extension analyses indicated that the mouse bgp1 transcriptional start site is positioned 240 nucleotides upstream of the ATG translational initiation codon, which is 140 nucleotides further upstream than in any other CEA family member. The bgp1 promoter is transcriptionally active in reporter gene activation in vitro transfection studies and in vivo using a bgp1-containing cosmid clone. We identified three putative AP-2 or AP-2-like sites and an upstream stimulatory factor (USF) recognition sequence within the proximal mouse bgp1 promoter region at positions similar to those used by the human BGP promoter region. These data suggest that the regulation of the mouse and human BGP genes may follow some common spatial and temporal expression. Interestingly, the bgp1 proximal promoter and coding region are also well conserved throughout evolution.
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PMID:Characterization and transcriptional activity of the mouse biliary glycoprotein 1 gene, a carcinoembryonic antigen-related gene. 762 60

Although the hepatitis delta virus genome contains multiple open reading frames, only one of these reading frames is known to be expressed during replication of the virus. This open reading frame encodes two distinct molecular species of hepatitis delta antigen (HDAg), p24 delta and p27 delta, depending on the location of the stop codon which terminates translation. We found antibody specific for p27 delta to be capable of precipitating p24 delta in extracts of infected liver, indicating that p27 delta and p24 delta form heterologous complexes in vivo. After cross-linking with 0.05% glutaraldehyde, specific HDAg dimers were detected in antigen prepared from both the liver and serum of an HDV-infected woodchuck carrier of woodchuck hepatitis virus. Guanidine HCl-denatured HDAg extracted from liver and dialyzed against phosphate-buffered saline sedimented in rate-zonal sucrose density gradients as 15S multimeric complexes. These 15S multimers were stable in the presence of 1.2% Nonidet P-40. After RNase digestion, the 15S complex was reduced to a 12S complex without associated RNA, while boiling for 3 min in 1% sodium dodecyl sulfate-0.5% 2-mercaptoethanol further reduced the 15S complex to 3S HDAg monomers. In the absence of glutaraldehyde cross-linking, HDAg extracted from liver migrated as monomer species in reducing and nonreducing gels, suggesting that the conserved cysteine residue present in p27 delta does not play a role in the formation of either dimers or multimers. On the other hand, an amino-terminal chymotrypsin-digested HDAg fragment, with a predicted length of 81 or less amino acids, retained the ability to form dimers, consistent with the hypothesis that a coiled-coil motif present between residues 27 and 58 may play a role in HDAg protein interactions in vivo.
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PMID:Hepatitis delta virus antigen forms dimers and multimeric complexes in vivo. 767 57

The initial step in mouse hepatitis virus (MHV) RNA replication is the synthesis of negative-strand RNA from a positive-strand genomic RNA template. Our approach to begin studying MHV RNA replication is to identify the cis-acting signals for RNA synthesis and the proteins which recognize these signals at the 3' end of genomic RNA of MHV. To determine whether host cellular and/or viral proteins interact with the 3' end of the coronavirus genome, an RNase T1 protection/gel mobility shift electrophoresis assay was used to examine cytoplasmic extracts from mock- and MHV-JHM-infected 17Cl-1 murine cells for the ability to form complexes with defined regions of the genomic RNA. We demonstrated the specific binding of host cell proteins to multiple sites within the 3' end of MHV-JHM genomic RNA. By using a set of RNA probes with deletions at either the 5' or 3' end or both ends, two distinct binding sites were located. The first protein-binding element was mapped in the 3'-most 42 nucleotides of the genomic RNA [3' (+42) RNA], and the second element was mapped within an 86-nucleotide sequence encompassing nucleotides 171 to 85 from the 3' end of the genome (171-85 RNA). A single potential stem-loop structure is predicted for the 3' (+)42 RNA, and two stem-loop structures are predicted for the 171-85 RNA. Proteins interacting with these two elements were identified by UV-induced covalent cross-linking to labeled RNAs followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The RNA-protein complex formed with the 3'-most 42 nucleotides contains approximately five host polypeptides, a highly labeled protein of 120 kDa and four minor species with sizes of 103, 81, 70, and 55 kDa. The second protein-binding element, contained within a probe representing nucleotides 487 to 85 from the 3' end of the genome, also appears to bind five host polypeptides, 142, 120, 100, 55, and 33 kDa in size, with the 120-kDa protein being the most abundant. The RNA-protein complexes observed with MHV-infected cells in both RNase protection/gel mobility shift and UV cross-linking assays were identical to those observed with uninfected cells. The possible involvement of the interaction of host proteins with the viral genome during MHV replication is discussed.
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PMID:Specific binding of host cellular proteins to multiple sites within the 3' end of mouse hepatitis virus genomic RNA. 788 46

Minus-strand RNA is the first RNA species made by plus-strand RNA viruses, such as mouse hepatitis virus (MHV), and serves as a template for subsequent RNA replication and transcription. The regulation of minus-strand RNA synthesis has been difficult to study because of the paucity of minus-strand RNA. We have optimized a ribonuclease (RNase) protection assay which enabled the detection of minus-strand RNA synthesis from nonreplicating RNAs, thus clearly separating minus-strand from plus-strand RNA synthesis. We used an MHV defective interfering (DI) RNA containing a chloramphenicol acetyltransferase gene as a reporter to determine the cis-acting signal for MHV minus-strand RNA synthesis. It was found that minus-strand RNAs existed in double-stranded RNA form in the cell. By using various deletion clones, we demonstrated that the cis-acting signal for minus-strand RNA synthesis resides in the 55 nucleotides from the 3' end plus poly(A) tail of the MHV genome. This is much shorter than the 436 nucleotides previously reported for the 3'-end replication signal. No specific upstream MHV sequence was required for the initiation of minus-strand RNA synthesis. This finding suggests that the requirement for minus-strand RNA synthesis is much less stringent than that for genomic and subgenomic plus-strand RNA synthesis and that some of the minus-strand RNAs made may not be functional since they may lack the recognition signals for RNA replication or transcription. We further showed that the DI clones which actively transcribed a subgenomic mRNA from an internal intergenic sequence synthesized much less minus-strand RNA than those clones which did not transcribe subgenomic mRNAs, indicating that minus-strand RNA synthesis was inhibited by transcription from an internal promoter of the same DI RNA. This result also suggests that the regulation of the quantities of subgenomic mRNAs is not at the point of minus-strand RNA synthesis but rather at plus-strand RNA synthesis. Furthermore, the finding that the leader sequence was not required for minus-strand RNA synthesis suggests that the leader RNA regulates mRNA transcription during plus-strand RNA synthesis.
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PMID:Identification of the cis-acting signal for minus-strand RNA synthesis of a murine coronavirus: implications for the role of minus-strand RNA in RNA replication and transcription. 796 4

To investigate the mechanism by which viruses are cleared from neurons in the central nervous system, we have utilized a mouse model involving infection with a neurotropic variant of mouse hepatitis virus (OBLV60). After intranasal inoculation, OBLV60 grew preferentially in the olfactory bulbs of BALB/c mice. Using in situ hybridization, we found that viral RNA localized primarily in the outer layers of the olfactory bulb, including neurons of the mitral cell layer. Virus was cleared rapidly from the olfactory bulb between 5 and 11 days. Athymic nude mice failed to eliminate the virus, demonstrating a requirement for T lymphocytes. Immunosuppression of normal mice with cyclophosphamide also prevented clearance. Both CD4+ and CD8+ T-cell subsets were important, as depletion of either of these subsets delayed viral clearance. Gliosis and infiltrates of CD4+ and CD8+ cells were detected by immunohistochemical analysis at 6 days. The role of cytokines in clearance was investigated by using an RNase protection assay for interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, tumor necrosis factor alpha (TNF-alpha), TNF-beta, and gamma interferon (IFN-gamma). In immunocompetent mice there was upregulation of RNA for IL-1 alpha, IL-1 beta, IL-6, TNF-alpha, and IFN-gamma at the time of clearance. Nude mice had comparable increases in these cytokine messages, with the exception of IFN-gamma. Induction of major histocompatibility complex class I (MHC-I) molecules on cells in infected brains was demonstrated by immunohistochemical analyses in normal and nude mice, suggesting that IFN-gamma may not be necessary for induction of MHC-I on neural cells in vivo.
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PMID:Cytokine induction during T-cell-mediated clearance of mouse hepatitis virus from neurons in vivo. 805 31

Murine coronaviruses such as mouse hepatitis virus (MHV) infect mouse cells via cellular receptors that are isoforms of biliary glycoprotein (Bgp) of the carcinoembryonic antigen gene family (G. S. Dveksler, C. W. Dieffenbach, C. B. Cardellichio, K. McCuaig, M. N. Pensiero, G.-S. Jiang, N. Beauchemin, and K. V. Holmes, J. Virol. 67:1-8, 1993). The Bgp isoforms are generated through alternative splicing of the mouse Bgp1 gene that has two allelic forms called MHVR (or mmCGM1), expressed in MHV-susceptible mouse strains, and mmCGM2, expressed in SJL/J mice, which are resistant to MHV. We here report the cloning and characterization of a new Bgp-related gene designated Bgp2. The Bgp2 cDNA allowed the prediction of a 271-amino-acid glycoprotein with two immunoglobulin domains, a transmembrane, and a putative cytoplasmic tail. There is considerable divergence in the amino acid sequences of the N-terminal domains of the proteins coded by the Bgp1 gene from that of the Bgp2-encoded protein. RNase protection assays and RNA PCR showed that Bgp2 was expressed in BALB/c kidney, colon, and brain tissue, in SJL/J colon and liver tissue, in BALB/c and CD1 spleen tissue, in C3H macrophages, and in mouse rectal carcinoma CMT-93 cells. When Bgp2-transfected hamster cells were challenged with MHV-A59, MHV-JHM, or MHV-3, the Bgp2-encoded protein served as a functional MHV receptor, although with a lower efficiency than that of the MHVR glycoprotein. The Bgp2-mediated virus infection could not be inhibited by monoclonal antibody CC1 that is specific for the N-terminal domain of MHVR. Although CMT-93 cells express both MHVR and Bgp2, infection with the three strains of MHV was blocked by pretreatment with monoclonal antibody CC1, suggesting that MHVR was the only functional receptor in these cells. Thus, a novel murine Bgp gene has been identified that can be coexpressed in inbred mice with the Bgp1 glycoproteins and that can serve as a receptor for MHV strains when expressed in transfected hamster cells.
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PMID:Bgp2, a new member of the carcinoembryonic antigen-related gene family, encodes an alternative receptor for mouse hepatitis viruses. 820 27

A conserved 11-nucleotide sequence, UGAAUGAAGUU, at the 3' end of the genomic RNA of coronavirus mouse hepatitis virus was required for host protein binding and viral RNA synthesis. An RNA probe containing this 11-nucleotide sequence bound four cellular proteins with a highly labeled protein of 120 kDa and three minor species with sizes of 103, 81, and 55 kDa. Mutation of the 11-nucleotide motif abolished cellular protein binding. The RNA-protein complexes observed with cytoplasmic extracts from MHV-JHM-infected cells in both RNase protection/gel mobility shift and UV cross-linking assays were indistinguishable from those observed with extracts from uninfected cells. Both negative-strand synthesis and positive-strand replication of viral defective interfering RNAs in the presence of helper virus were affected by mutations that disrupt RNA-protein complex formation, even though the 11 mutated nucleotides were converted to the wild-type sequence, presumably by recombination with helper virus. Kinetic analysis indicated that recombination between DI RNA and helper virus occurred relatively early in the MHV replicative cycle at 5.5 to 7.5 hr postinfection, a time when viral RNA synthesis and replication of positive-strand DI RNA were at barely detectable levels. A DI RNA with a mutation upstream of the protein binding element replicated as efficiently as wild type without undergoing recombination. Thus, the 11-nucleotide conserved host protein binding motif appears to play an important role in viral RNA replication.
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PMID:A conserved motif at the 3' end of mouse hepatitis virus genomic RNA required for host protein binding and viral RNA replication. 852 8


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