pinecone/core-2020-05-10-deduplication huggingface dataset:
Sindbis Virus Infection of Neonatal Mice Results in a Severe Stress Response

AbstractNeonatal mice were infected with virus derived from a molecular clone of a laboratory strain of Sindbis virus, TRSB. The resulting acute fatal infection was typified by few if any of the classic hallmarks of encephalitis, very high levels of interferon-alpha/beta (IFNαβ), and lesions in the thymus and hematopoietic tissues usually associated with a severe stress response. Infection with an attenuated mutant of TRSB, which harbors a single amino acid change in the E2 surface glycoprotein (TRSBr114), was characterized by encephalitis, reduced mortality, low levels of IFNαβ, and no thymic pathology (J. Trgovcich, J.F. Aronson, and R.E. Johnston, 1996,Virology224, 73–83). Here we report that infection of neonatal mice with TRSB, but not TRSBr114, resulted in induction of high levels of tumor necrosis factor-α as well as high and sustained levels of adrenalcorticotropin-releasing hormone and corticosterone. This syndrome of potentially toxic cytokine and stress hormone induction correlates with lethal Sindbis virus infection and constitutes a previously unrecognized aspect of Sindbis virus pathogenesis in mice
Characterization of a Disassembly Deficient Mutant of Cowpea Chlorotic Mottle Virus

AbstractAn understanding of virus disassembly requires a detailed understanding of the protein–protein and protein–nucleic acid interactions which stabilize the virion. We have characterized a mutant of cowpea chlorotic mottle virus [cpR26C (coat protein R26C)] that displays increased virion stability and is abnormal in virion disassembly when purified under nonreducing conditions. Reduced virions are infectious, whereas nonreduced virions are noninfectious. The cpR26C mutant virions purified under nonreducing conditions resist disassembly in 0.5MCaCl2, pH 7.5. The nonreduced cpR26C mutant virions swell in neutral pH conditions (pH 7.5) but do not disassociate when the ionic strength is increased. In contrast, wild-type virions or cpR26C mutant virions isolated under reducing conditions completely disassociate into the RNA and capsid protein components at pH 7.5 and high ionic strength (i> 1.0). Sequence analysis of the cpR26C mutant identified a single C to U nucleotide change at position 1435 of RNA 3 (position 86 of RNA 4), which results in a arginine to cysteine change at position 26 of the coat protein. The cpR26C mutant provides an ideal chemical switch for examining virion assembly and disassembly
Gazelle Herpesvirus 1: A New Neurotropic Herpesvirus Immunologically Related to Equine Herpesvirus 1

AbstractA herpesvirus was isolated from Thomson's gazelle (Gazella thomsoni) kept at a zoological garden in Japan during an outbreak of epizootic acute encephalitis. The virus, gazelle herpesvirus 1 (GHV-1), was serologically related to equine herpesvirus 1 (EHV-1). However, DNA fingerprints of GHV-1 were different from those of EHV-1 and other equine herpesviruses. Southern hybridization with probes of clonedBamHI fragments derived from ULand USsegments of EHV-1 revealed differences in the DNA restriction profiles throughout the entire genome. Nucleotide sequences were determined for a conserved region of an essential envelope glycoprotein B (gB) gene and a type-specific glycoprotein G (gG) homologue gene. The predicted amino acid sequence of GHV-1 gB showed 97, 92, 61, and 57% identity to EHV-1, EHV-4, feline herpesvirus, and pseudorabies virus, respectively, indicating that GHV-1 was closer to EHV-1 than any other herpesvirus. The GHV-1 gG gene showed 93.2, 92.3, and 53% identity to EHV-1, EHV-8, and EHV-4 gGs, respectively. GHV-1 was virulent to suckling mice of the ICR strain by intracerebral inoculation and was virulent to 4-week-old BALB/c mice by intranasal inoculation, causing neurological symptoms and death. We conclude that GHV-1 is a new type of equine herpesvirus with strong neurotropism
Proteolytic Processing ofChlorellaVirus CVK2 Capsid Proteins

AbstractChlorellavirus CVK2 particles contain several capsid proteins that are selectively released by treatment with 4Murea. Seven of them (Vp52, Vp45, Vp41, Vp25, Vp20.5, Vp20, and Vp16.2) have been identified based on amino acid sequences at the N-terminus. Comparison of the amino acid sequences with the corresponding ORFs deduced from the nucleotide sequence of PBCV-1, the prototype member ofPhycodnaviridae,revealed that the CVK2 proteins were processed at the N-terminal region by two different proteolytic activities
Dual NF1-Requiring Effect of Human Neurotropic JC Virus Composite Pentanucleotide Repeat Elements on Early and Late Viral Gene Expression

AbstractHuman polyoma JC virus (JCV) is a largely brain cell-specific virus that is associated with AIDS. The neurotropism involves the various transcription factors interacting with their cognate sequences in the JCV early (JCVE) and late (JCVL) promoters-enhancer, but the mechanism is unclear. The JCV tandem AGGGA pentanucleotide double repeat element (Pnt2) and the abutting NF1 site form a composite Pnt2 (cPnt2). Here, we studied the roles of both sites of cPnt2 in the expression of JCVEand JCVL. JCVEactivity was progressively increased in U-87 MG human glioblastoma cells following the site-specific mutation of Pnt2 in one and both 98-bp repeats. In contrast, the activity for JCVLwas progressively reduced by mutating single and double Pnt2s. However, JCVEactivity was unaffected by mutating both Pnt2s when both NF1 sites of cPnt2 were mutated. The activity of JCVLwas also unaffected by double Pnt2 mutations after the NF1 sites were mutated. Differentiating P19 glial cells showed similar results. Next, Pnt2-interacting proteins were examined by twoin vitroassays with a Pnt2 oligonucleotide. Mobility shift assays showed one Pnt2–protein complex for U-87 MG cell extracts and two for P19 glial cell extracts. However, similar results were obtained for glial, muscle, and undifferentiated P19 cells. In UV cross-linking assays, two Pnt2-binding proteins (Pnt2BPs) were detected. The results suggested that the effects on JCVEand JCVLexpression of Pnt2BP and NF1 via cPnt2 are dual and require a glial cell-specific NF1 function
Plasmas from Lymphocyte- and Macrophage-Tropic SIVmac-Infected Macaques Have Antibodies with a Broader Spectrum of Virus Neutralization Activity in Macrophage versus Lymphocyte Cultures

AbstractWe examined plasma from macaques infected with three different phenotypes of SIVmacfor their ability to neutralize the infectivity of homologous and heterologous virus in lymphocyte (CEMx174 cells or normal rhesus macaque peripheral blood lymphocytes) or normal rhesus macaque macrophage (Mφ) cultures. Similar to previous findings, we observed that some plasmas failed to neutralize or poorly neutralized the infectivity of SIVmac239 and SIVmac251(<1:20 plasma dilution) in lymphocyte cultures. In contrast, when primary rhesus Mφ cultures were used as the indicator cells, the same plasmas neutralized both viruses at high dilutions (1:200 to 1:20,000). Neutralization of virus infectivity by the various plasmas was confirmed by SIV core antigen capture assays. We excluded the possibility that this differential neutralization in Mφ was related to the differences in the ability of the virus strain to replicate in these two cell types by demonstrating that the replication efficiency of SIVmac251 in CEMx174 cells, PBMC, and Mφ cultures was very similar. The role of Fc receptors on the Mφ surface in the clearance of the virus–antibody complexes was also excluded since similar neutralizing results were obtained using whole plasmas, purified IgG antibodies, and purified Fab fragments derived from the IgG fraction of these plasmas. The mechanism of virus neutralization in Mφ does not appear to involve blocking of virus entry into the cells since radiolabeled virus reacted with anti-SIV antibodies was taken up by rhesus Mφ as efficiently as virus reacted with normal antibody. DNA of the neutralized virus was identified in the Mφ cultures, but virus replication, as evidenced by accumulation of viral protein products, was not detectable so long as the antibodies were present in the medium. Removal of the antibodies resulted in a resumption of virus replication in the Mφ. These results indicate that virus infectivity can be efficiently neutralized by antibodies in Mφ cultures by a mechanism that is fundamentally different from that in lymphocyte cultures
Cations in Human Rhinoviruses

AbstractAll known crystal structures of rhinoviruses have some uninterpreted electron density on their fivefold axes at a distance of about 152 ± 3 Å from the viral center. This density had been assumed to be a Ca2+ion, based on its shape, height, and the presence of Ca2+ions in the crystallization solutions. Difference electron density maps between EGTA-soaked crystals of human rhinovirus 14 (HRV14), as well as HRV16, and their corresponding native structures show that this density is an EGTA-chelatable ion. Analysis of the coordination geometry indicates that the ions in HRV3, HRV14, and HRV1A could be Ca2+and the ion in HRV16 might be Zn2+. These cations may play a role in regulation of rhinovirus stability, although the loss of the ion itself does not seem sufficient to lead to viral disassembly
Latent Murine Cytomegalovirus Infection in Macrophages

AbstractIn this study we show that macrophages (Mφ) are latently infected with murine cytomegalovirus (MCMV). After clearance of acute MCMV infection, the predominant form of chronic infection in Balb mice is latency rather than persistence. Peritoneal exudate cells (PECs) from latently infected Balb mice (3–9 months postinfection) contained MCMV genome and reactivatable virus. Adherent cells from both resident and thioglycollate-elicited PECs carried more MCMV DNA (measured by PCR) than nonadherent cells, and were selectively enriched for Mφ. FACS sorted F4/80+Mφ contained MCMV DNA, while other FACS sorted cell populations from PECs were never positive for MCMV DNA. MCMV reactivated from FACS sorted F4/80+Mφ in 32% of cocultures with murine embryonic fibroblasts (MEFs). Since Mφ carry MCMV genome and reactivatable virus, but not lytic virus, they are latently infected with MCMV. We determined the frequency of Mφ carrying MCMV genome in PECs (about 1/50,000) using a limiting dilution PCR assay. Using this frequency and estimates of the total amount of MCMV genome in populations, we estimate that latently infected Mφ carry 1–10 copies of MCMV genome. To evaluate the origin of latently infected Mφ, we compared the frequency of cells carrying MCMV genome in the resident and elicited PECs. The frequency of Mφ carrying MCMV DNA was the same in resident and thioglycollate-elicited PECs, despite the fact that there was a ninefold increase in the number of Mφ recovered after thioglycollate elicitation. This argued for recruitment of bone marrow-derived Mφ (BMMφ) carrying MCMV genome into the peritoneum during inflammatory responses. Consistent with this hypothesis, MCMV genome, but not persistent virus, was detected in bone marrow cells from latently infected mice
Association of a Baculovirus-Encoded Protein with the Capsid Basal Region

AbstractAn open reading frame homologous to AcMNPV ORF9 (ORF1629) was characterized in theOrgyia pseudotsugatamultinucleocapsid nuclear polyhedrosis virus (OpMNPV). Sequence analysis indicated that the OpMNPV homolog (called ORF2) encoded a protein predicted to contain 545 amino acids with a molecular weight of 61 kDa. The first 80 amino acids did not have a counterpart in the AcMNPV homolog. The remainder of the ORF was poorly conserved with 29% amino acid identity overall with the AcMNPV ORF. However, the amino terminal 150 amino acids of AcMNPV ORF9 demonstrated about 45% amino acid sequence identity with OpMNPV ORF2 and conserved runs of proline residues were present in internal regions of both molecules. Transcriptional mapping indicated the ORF2 transcripts were initiated at a late promoter sequence, ATAAG, beginning about 24 hr p.i. These transcripts terminated near the 3′ end of the ORF2 reading frame. Antibodies were produced against a fusion protein derived from the bacterial gene encoding the maltose binding protein and most of the ORF2 sequence. These antibodies reacted with a protein of 69 kDa on Western blots and the protein was found to be associated with virions isolated from both polyhedra and budded virus. The OpMNPV ORF2 antiserum also reacted with the AcMNPV ORF9 gene product. Immunoelectron microscopic analyses indicated that ORF2 was associated with the ends of the capsids which contain the basal structure. This end appears to be oriented away from both the virogenic stroma and membranes involved in intranuclear envelopment. In addition, as virions bud from the nucleus into the cytoplasm, this end also appears to be oriented away from the nuclear membrane
Isolation of the Interferon-Inducible RNA-Dependent Protein KinasePkrPromoter and Identification of a Novel DNA Element within the 5′-Flanking Region of Human and MousePkrGenes

AbstractThe RNA-dependent protein kinase (PKR) is inducible by interferon (IFN) and is implicated in the antiviral and antiproliferative actions of IFN. We have now isolated human genomic clones that contain the promoter region required for transcription of thePkrgene. Transient transfection analyses, using chloramphenicol acetyltransferase (CAT) as the reporter in constructs possessing various 5′-flanking fragments of thePkrgene, led to the identification of a functional TATA-less promoter that directed IFN-inducible transcription of CAT. Sequence determination and deletion analysis of the promoter region revealed an element (5′GGAAAACGAAACT3′) involved in IFN inducibility that corresponds to the consensus sequence of the IFN-stimulated response element (ISRE). Comparison of the promoter sequence of the humanPkrgene to that of the mouse homolog identified a novel element (5′GGGAAGGCGGAGTCC3′) immediately upstream of the ISRE element which so far is unique to the human and mousePkrgene promoters. We have designated this new motif as KCS, for kinase conserved sequence. Deletion and substitution mutants of thePkrpromoter region showed that the ISRE element was required for transcriptional induction by type I IFN, whereas the KCS motif increased promoter activity mediated by the ISRE. Additional potential regulatory cis-elements were identified in the humanPkrpromoter that are commonly associated with growth control regulation and differentiation. Other than the ISRE and novel KCS elements, the overall organization of potential binding sites for transcription factors was not well conserved between the IFN-inducible promoters of the human and mousePkrgenes. The strict conservation of sequence, distance, and position of KCS, relative to ISRE, together with mutagenesis results, suggest an important functional role for the newly recognized KCS motif
Evaluation of a Live-Attenuated Foot-and-Mouth Disease Virus as a Vaccine Candidate

AbstractA variant of foot-and-mouth disease virus (FMDV) lacking the leader (L) coding region (A12-LLV2) was previously constructed and shown to be less virulent in cattle than its wild-type parent (A12-IC). In this study, cattle were tested for their clinical and immunological responses to subcutaneous inoculation with A12-LLV2 or A12-IC or to intramuscular vaccination with chemically inactivated A12-IC. Five weeks postinoculation animals were challenged by intradermal inoculation in the tongue with a virulent cattle-passaged virus. A12-LLV2-inoculated animals showed no clinical signs of disease and developed a neutralizing antibody response by 4 days postinoculation, whereas a companion control bovine did not seroconvert. After challenge, two of three inoculated animals did not develop lesions, but showed mild signs of infection. The third inoculated animal developed some lesions, but these were less severe than in the uninoculated control animal, which showed classical FMD. All animals inoculated with A12-IC developed a fever, two showed typical FMD lesions, and the companion control seroconverted, indicating that it had acquired infection by contact. The A12-IC-inoculated animals and the control were protected from challenge. Animals vaccinated with inactivated virus showed no clinical signs of disease and developed a neutralizing antibody response, and the control did not seroconvert. Upon challenge none of the vaccinated animals developed lesions, one developed a fever, and the control developed FMD. These experiments demonstrate the potential of a rationally designed live-attenuated FMDV vaccine
ORF 3 of Lactate Dehydrogenase-Elevating Virus Encodes a Soluble, Nonstructural, Highly Glycosylated, and Antigenic Protein

AbstractOpen reading frame (ORF) 3 of the genome of lactate dehydrogenase-elevating virus (LDV), strain P, was cloned into the plasmid pcDNAI/Amp andin vitrotranscribed and translated. Translation of ORF 3 yielded a soluble protein of the expected size (about 21 kDa). When synthesized in the presence of endoplasmic reticulum (ER) membranes the resulting glycoprotein of about 36 kDa became associated with the membranes. However, disruption of the ER vesicles by incubation in carbonate buffer, pH 11.5, resulted in the release of the protein from the membranes. Hydrophobic moment analysis of the ORF 3 protein indicated the absence of any potential transmembrane segments, except for a N-terminal signal peptide, but no cleavage of the signal peptide was observed during membrane-associatedin vitrosynthesis. The ORF 3 protein elicited a strong antibody response in infected mice. The antibodies from infected mice as well as a monoclonal antibody specifically precipitated thein vitro-synthesized ORF 3 protein, but no protein from LDV virions. The overall results suggest that the ORF 3 protein is a nonstructural, highly glycosylated, and antigenic glycoprotein that is probably soluble and secreted or at most only weakly associated with membranes via the signal peptide
Anin VitroSystem for the Investigation of Heterologous RNA Recombination

AbstractBacteriophage Φ6 has a genome of three segments of double-stranded RNA enclosed in a polyhedral procapsid. Purified procapsids are capable of the specific packaging of viral plus strands and the synthesis of their complementary minus strands. The genomic segments of Φ6 are capable of heterologous recombination. We have prepared anin vitrosystem containing purified procapsids that is capable of packaging plus strands of the genomic segments and synthesizing minus strands on these templates. The system generates heterologous recombination products when stimulated by having one of the plus strands incapable of serving as a template for minus strand synthesis. Recombinants were produced upon transfection of spheroplasts with thein vitropackaged and replicated RNA. Sites of recombination were not found to be localized in particular regions of either the donor or the recipient strands
Complementation of Defective Picornavirus Internal Ribosome Entry Site (IRES) Elements by the Coexpression of Fragments of the IRES

AbstractMutant forms of the encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) have been produced and shown to be severely defective in directing internal initiation of protein synthesis within cells using the vaccinia/T7 RNA polymerase system. Mutants in different regions of the IRES were complementedin transby coexpression of the intact EMCV IRES but not by coexpression of the related IRES elements from Theiler's murine encephalomyelitis virus (another cardiovirus) or from foot-and-mouth disease virus. Distinct, truncated regions of the EMCV IRES, insufficient to direct internal initiation, were also shown to complement defective EMCV IRES elements. It was necessary for the complementing molecule, whether truncated or full length, to be expressed in the positive sense orientation. RT-PCR analysis provided no support for the idea that any recombination event was responsible for the complementation. The data suggest that multiple activities are performed by distinct functional entities within the IRES in the process of internal initiation of protein synthesis. At least some of these different functions may be achieved by different molecules actingin trans
Acquired Fusion Activity of a Murine Coronavirus MHV-2 Variant with Mutations in the Proteolytic Cleavage Site and the Signal Sequence of the S Protein

AbstractThe spike (S) protein of a nonfusogenic murine coronavirus, MHV-2, was compared to the S protein of a variant with fusion activity, MHV-2f. Two amino acids differed between the S proteins of these viruses; one was located in the signal sequence and the other was in the putative cleavage site. The amino acid at position 12 in the signal sequence was S in MHV-2 and C in MHV-2f. The amino acid sequence of the cleavage site of MHV-2 was HRARS, while that of MHV-2f was HRARR, showing one amino acid replacement at position 757. In DBT cells infected with MHV-2, the S protein was not cleaved, while the S protein of MHV-2f was cleaved. The S protein of MHV-2f expressed in a transient vaccinia virus expression system was cleaved and was fusogenic in contrast to the nonfusogenic activity of uncleaved MHV-2 S protein. Because the signal sequence is assumed to be removed from the mature S protein soon after synthesis, and because the S protein of MHV-2 was expressed on the cell surface in the same way as the S protein of MHV-2f, the difference in the signal sequence seemed to have had little effect on the transportation and the fusion activity of the S protein. These results showed that MHV-2 does not fuse cells due to the lack of cleavage of its S protein. This conclusion differs from studies on the activity of syncytium formation by the S proteins of fusogenic MHV-JHM and -A59 strains. Possible reasons for these differences in fusion activity are discussed
Light-Dependent Systemic Infection of Solanaceous Species by Cauliflower Mosaic Virus Can Be Conditioned by a Viral Gene Encoding an Aphid Transmission Factor

AbstractGene II of cauliflower mosaic virus (CaMV), which encodes an 18-kDa protein originally identified as an aphid transmission factor (ATF), influences host specificity in a light-dependent manner. A point mutation within the ATF gene that occurs in several CaMV strains was responsible for conditioning light-dependent systemic infections. A point mutant of CaMV strain W260 that carried the single mutation within the ATF gene was able to systemically infectNicotiana bigeloviiat low light intensity (100–180 μmol m−2sec−1), but not at a higher light intensity level (350–450 μmol m−2sec−1), while the wild-type W260 virus could systemically infectN. bigeloviiunder both light conditions. The same point mutation also affected the stability of the amorphous CaMV inclusions and previous studies have shown that it abolishes transmission of CaMV by aphids. The point mutation within the ATF gene that mediated light-dependent infections was complemented by transgenicN. bigeloviiplants that express the CaMV gene VI product, a viral protein that has been identified as a translational transactivator. The complementation studies indicated that the ATF gene may influence systemic infections through an interaction with the CaMV gene VI product. The ATF gene of CaMV may contribute to viral infections by regulating expression of downstream genes or by influencing cell-to-cell or long distance movement within the plant