pinecone/core-2020-05-10-deduplication huggingface dataset:
Structure of the Herpes Simplex Virus Capsid: Peptide A862-H880 of the Major Capsid Protein Is Displayed on the Rim of the Capsomer Protrusions

AbstractThe herpes simplex virus-1 (HSV-1) capsid shell has 162 capsomers arranged on aT= 16 icosahedral lattice. The major capsid protein, VP5 (MW = 149,075) is the structural component of the capsomers. VP5 is an unusually large viral capsid protein and has been shown to consist of multiple domains. To study the conformation of VP5 as it is folded into capsid protomers, we identified the sequence recognized by a VP5-specific monoclonal antibody and localized the epitope on the capsid surface by cryoelectron microscopy and image reconstruction. The epitope of mAb 6F10 was mapped to residues 862–880 by immunoblotting experiments performed with (1) proteolytic fragments of VP5, (2) GST-fusion proteins containing VP5 domains, and (3) synthetic VP5 peptides. As visualized in a three-dimensional density map of 6F10-precipitated capsids, the antibody was found to bind at sites on the outer surface of the capsid just inside the openings of thetrans-capsomeric channels. We conclude that these sites are occupied by peptide 862–880 in the mature HSV-1 capsid
Vaccination of Cats for Feline Rhinotracheitis Results in a Quantitative Reduction of Virulent Feline Herpesvirus-1 Latency Load after Challenge

AbstractWe recently described the construction of a feline herpesvirus-1 (FHV-1) recombinant vaccine strain, FHVβ-galgIgEΔ, containing a deletion in both the gI and the gE genes. We also reported comparative tests of its safety and efficacy in cats. These cats were unvaccinated or subcutaneously vaccinated with FHVβ-galgIgEΔ, its isotypic parent strain (FHV-1SA), or a commercial FHV-1 vaccine strain (FHV-1CV) and subsequently challenged with a virulent field strain of FHV-1. Here we report the determination of FHV-1 field virus latency load after challenge in the same experimental animals. FHV-1 specific quantitative PCR was carried out on feline genomic DNA isolated from trigeminal ganglia, olfactory bulbs, and brain stems. We have determined that a reduction in field virus latency load in cats vaccinated subcutaneously with wild-type FHV-1 strains prior to challenge is dependent upon glycoproteins gI and gE deleted in FHVβ-galgIgEΔ
Demonstration of Equine Herpesvirus-1 Neuronal Latency in Murine Olfactory Bulbs Using a Novel Combinedin SituPCR and Protein Synthesis Method

AbstractEquine herpesvirus-1 (EHV-1) latency in murine olfactory bulbs was demonstrated by a novel combinedin situPCR andin vitroprotein synthesis method (in situPS–PCR). TheEscherichia coli lacZgene replacing a deletion in EHV-1 gene 71 (EUS4) was thus amplified and transcribed/translatedin situfollowed by enzymatic detection using X-Gal (5-bromo-4-chloro-3-indoyl-β-d-galactopyranoside). β-Galactosidase was found to be concentrated over mitral/tufted neurons indicating those to be the sites of latency. Our results suggest that, in common with other α-herpesviruses, EHV-1 can establish latency in central nervous system neurons and that the unique membrane glycoprotein encoded by EHV-1 gene 71 is nonessential for infection of neural tissues
Inhibition of Apoptosis by the African Swine Fever Virus Bcl-2 Homologue: Role of the BH1 Domain

AbstractThe function of the African swine fever virus (ASFV)bcl-2homologue, geneA179L,in the regulation of apoptosis was investigated using as a model system the human myeloid leukemia cell line K562 induced to die by apoptosis with inhibitors of macromolecular synthesis, a process that is prevented by overexpression of humanbcl-2.It is shown that transfection of K562 cells with the ASFVA179Lgene protects these cells from apoptotic cell death induced by a combination of cycloheximide and actinomycin D or by treatment with cytosine arabinoside. To test the functional role of the highly conserved BH1 domain present in the A179L protein, the Gly residue at position 85 was mutated to Ala, since it has been shown that substitution of the corresponding Gly in human Bcl-2 abrogates its death-repressor activity. It was found that the Gly-to-Ala mutation in the BH1 domain of the viral protein abolished its capacity to protect the K562 cells from apoptosis, indicating that this Gly is essential for A179L action. This finding stresses the functional similarity of the BH1 domains of the viral protein and cellular Bcl-2
The Cowpox Virus-Encoded Homolog of the Vaccinia Virus Complement Control Protein Is an Inflammation Modulatory Protein

AbstractVaccinia virus complement control protein (VCP) is encoded by vaccinia virus, with its homolog encoded by other pathogenic poxviruses including variola virus. Since rodents are the primary reservoir hosts of cowpox virus (CPV) and since CPV encodes a highly conserved functional homolog of VCP, termed here the inflammation modulatory protein (IMP), the effects of injection of CPV into the footpads of mice was determined in order to study the precisein vivoeffects of IMP. Macroscopic examination of the site of injection with a recombinant virus lacking IMP (CPV–IMP) showed greater tissue damage, with more hemorrhage and induration, than sites injected with the wild-type cowpox virus. In addition, the measurement of the specific swelling response carried out for several weeks revealed significantly greater swelling in mice injected with CPV–IMP. Thus, IMP modulates the complement-activated inflammatory responsein vivo.Furthermore, the diminished destruction of host tissue observed in the presence of IMP indicates symbiosis in which the virus ensures the preservation of surrounding host tissue, possibly to support the growth of its progeny
Posttranscriptional Regulation by Rev Protein of Human Immunodeficiency Virus Type 1 Results in Nonrandom Nuclear Localization ofgagmRNA

AbstractThe expression of the human immunodeficiency virus type 1 mRNAs containing the Rev-responsive element is regulated at the posttranscriptional level by the viral Rev protein. Rev increases the nucleocytoplasmic export of these mRNAs, leading to high expression. Usingin situhybridization and electron microscopy, we investigated the localization of a subgenomicgagmRNA in the absence and presence of Rev. In addition to the previously shown cytoplasmic accumulation of the Rev-dependent mRNA, we observed that in the presence of Rev the nucleargagmRNA accumulates nonrandomly and forms specific localization patterns at the nuclear membrane and in the nucleoplasm. Cellular mRNAs for β-actin and glyceraldehyde-3-phosphate dehydrogenase were not found to form such patterns. These data suggest that Rev leads thegagmRNA to specific subnuclear locations, which further supports the transport function of Rev
Binding of HIV-1 to Its Receptor Induces Tyrosine Phosphorylation of Several CD4-Associated Proteins, Including the Phosphatidylinositol 3-Kinase

AbstractCell surface CD4 molecules are known to be important in several physiological responses of T lymphocytes. The use of human immunodeficiency virus (HIV) particles or purified gp120 molecules as CD4 cross-linking agents has been shown to result in a cascade of intracellular biochemical events. In addition, we and others have provided evidence suggesting that virus-mediated CD4 multimerization can lead to modulation of HIV-1 long terminal repeat-dependent activity and virus production. We were thus interested in measuring the effect of HIV-1 particles on intracellular tyrosine-phosphorylation levels, mostly of CD4-associated proteins. Using the T cell line CEM-T4, we observed that HIV-1 induces an increase in tyrosine phosphorylation of four major proteins physically complexed to the CD4 molecule. Immunoblot analysis permitted the identification of two of these proteins, p56lckand phosphatidylinositol 3-kinase (PI 3-kinase) p85α. No concomitant variation in the level of these two CD4-associated proteins was observed after HIV-1-induced CD4 cross-linking. To our knowledge, this is the first report linking HIV-1-mediated CD4 multimerization to an increase in tyrosine phosphorylation of the PI 3-kinase complex. The four CD4-associated molecules described in this report are most likely implicated in virus-induced CD4-linked signaling events
Phosphorylated States of Vesicular Stomatitis Virus P Proteinin Vitroandin Vivo

AbstractWe have previously shown that the phosphoprotein (P) of vesicular stomatitis virus (VSV), New Jersey serotype (PNJ) is phosphorylated by casein kinase II, within the N-terminal domain I (P1 form), whereas the C-terminal domain II is phosphorylated by a protein kinase activity associated with the L protein (P2 form) (D. J. Chattopadhyay and A.K. Banerjee,Cell49, 407, 1987; A.M. Takacset al., J. Virol.66, 5842, 1992). In the present studies, we have mapped the corresponding P1 and P2 phosphorylation sites in the P protein of the well-studied Indiana serotype (PIND) and compared that with the two previously designated NS1 and NS2 forms presentin vivo.The PINDexpressed inEscherichia coliin an unphosphorylated form (P0) was used as substrate for recombinant casein kinase II (CKII). By site-directed mutagenesis, the CKII-mediated phosphorylation sites in the P protein were mapped at S60, T62, and S64 within the acidic domain Iin vitro.In contrast, using BHK cell extract as the source of CKII or expressing P protein in COS cells labeled with32Pi, the phosphorylation sites were mapped at S60 and S64 with no phosphorylation at T62 residue. We used a peptide mapping technique by which the phosphorylation sites within domain I and domain II were determined. Using this method we demonstrated that the P1 and P2 forms are similar, if not identical, to the previously designated NS1 and NS2 forms, respectively. The domain II phosphorylating kinase activity, associated with the L protein, is shown to be present also in the N-RNA complex, indicating that this activity is of cellular origin. By site-directed mutagenesis, we have shown that S226 and S227 are involved in phosphorylation within domain II. We also demonstrate that the P1 and P2 forms are interconvertible and arise by phosphorylation/dephosphorylation of the phosphate groups in domain II, confirming the precursor–product relationship between the two phosphorylated forms of P protein
Host-Derived Intracellular Immunization against Mouse Hepatitis Virus Infection

AbstractMouse hepatitis virus (MHV) utilizes the murine biliary glycoprotein receptor (BgpA) for entry into susceptible cells. TheBgp1agene was transfected into a murine DBT cell clone that expressed little if any BgpA receptor and resisted wild-type MHV infection. Clones which expressed low levels of receptor were efficient hosts for MHV-A59 replication. Clones which expressed 20- to 69-fold more BgpA receptor than controls were also susceptible to MHV-A59 infection, yet few infectious progeny virions were released. Pretreatment of clones with monoclonal antibody CC1, which binds to the N-terminus of BgpA, blocked MHV-A59 replication in DBT clones that expressed wild-type levels of receptor protein. In the overexpressing cell clones, however, CC1 pretreatment reversed the BgpA overexpression blockade and increased virus titers by 3–4 logs. BgpA overexpression inhibited the formation of infectious extracellular and intracellular virions, but levels of virus transcription were equivalent to those of controls. Ultrastructural studies revealed normal cell cytopathology in both the MHV-A59-infected controls and the overexpressing cell clones. Although equivalent numbers of virions were released compared with the control, peplomer spike glycoproteins were rarely evident in virions derived from the BgpA-overexpressing cell clones. Consonant with these findings, purified virions from BgpA-overexpressing cell clones demonstrated a 70% reduction in the amount of S glycoprotein, but not of N or M proteins. These data suggest that BgpA receptor overexpression establishes an intracellular trap which blocks MHV replication during the maturation and release of infectious progeny virions
Transactivation of Dianthin Transgene Expression by African Cassava Mosaic Virus AC2

AbstractWe have recently described a novel strategy for engineering resistance to African cassava mosaic virus (ACMV) in transgenicNicotiana benthamianaplants using a virus-inducible promoter to control the expression of a plant ribosome-inactivating protein (RIP) transgene (Y. Honget al., Virology220, 119–127, 1996). Here, we have used a potato virus X (PVX) vector to express the ACMV transactivator protein, AC2,in planta.We confirm that amplification of RIP activity in transgenic plants is mediated by AC2; disruption of AC2 expression by either the introduction of an in-frame stop codon or the deletion of 5′-terminal or 3′-terminal coding sequences reduced RIP expression to the basal level associated with PVX-infected plants. AC2 expression from the PVX vector induced necrosis in nontransformed plants as well as in plants containing the RIP transgene, suggesting that the protein can functionally interact with PVX and/or host factors. The potential of this system to provide a direct and sensitive assay to investigate AC2 functionin plantais discussed
Construction and Characterization of a Recombinant Herpes Simplex Virus Type 1 Which Overexpresses the Transrepressor Protein ICP0R

AbstractICP0R is a truncated form of the herpes simplex virus type 1 (HSV-1) transactivator protein ICP0 that is synthesized at low levels during infection through an alternative splicing mechanism. In transient expression assays, ICP0R has been shown to inhibit the transactivation function of several HSV-1 regulatory proteins, suggesting that an antiviral strategy which alters normal ICP0 mRNA splicing and thereby stimulates the synthesis of ICP0R protein may have potential in suppressing HSV-1 infections. To explore the feasibility of this approach, a recombinant virus was constructed which expressed high levels of ICP0R instead of ICP0. Surprisingly, overexpression of the ICP0R protein in this virus, HSV-KST, had no detectable effect on virus replication, since the growth properties of HSV-KST were indistinguishable from those of the ICP0/ICP0R null mutant dl1403, and HSV-KST was no more efficient than dl1403 at inhibiting the replication of an ICP0-expressing wild-type virus. The absence of a demonstrable phenotype in HSV-KST was not due to the acquisition of an inactivating mutation in the gene encoding ICP0R, since copies of the gene rescued from this virus retained full transrepression capability in transient expression assays. These results indicate that the ability of ICP0R to act as a transrepressor is significantly reduced if not completely eliminated in the context of a productive HSV-1 infection and suggest that this protein may not represent an exploitable target for the development of novel antiviral therapies
Genetic Analysis of the Monopartite Tomato Yellow Leaf Curl Geminivirus: Roles of V1, V2, and C2 ORFs in Viral Pathogenesis

AbstractTomato yellow leaf curl virus (TYLCV) is a whitefly-transmitted geminivirus with a monopartite genome. We have investigated the functions of the V1, V2, and C2 ORFs by mutational analysis. We analyzed the ability of TYLCV mutants containing disrupted ORFs V1, V2, or C2 to replicate, spread, and cause symptoms inNicotiana benthamianaand tomato plants. All the mutants retained the capability of autonomous replication in protoplast-derived cells of tomato and leaf discs ofN. benthamiana,although both V1 and V2 gene products appeared to play a role in the accumulation of viral single-stranded DNA. In contrast, none of the mutants was able to systemically infect tomato plants, demonstrating that the V1, V2, and C2 gene products are all required for a successful infection process in this host. The effect of the mutation in ORF C2 appeared to be host-specific, sinceN. benthamianaplants were systemically infected, although symptom development was attenuated
Simian T-Lymphotropic Virus Type 1 (STLV-1) Infection in Wild Yellow Baboons (Papio hamadryas cynocephalus) from Mikumi National Park, Tanzania

AbstractSerum and peripheral blood leukocytes from wild yellow baboons (Papio hamadryas cynocephalus) were tested for the presence of STLV-1-specific antibodies and proviral DNA. Fourteen of 30 sera tested positive by radioimmunoprecipitation assay (RIPA) with HTLV-1. Among 36 DNA samples tested by PCR 15 were positive by double nested PCR for a fragment of the STLV-1envgene, the most sensitive assay among PCR tests employed. Of 30 animals that were tested both serologically and by PCR in only 1 case were the results discordant (PCR-positive, antibody-negative). The DNA sequences fromenv(378 bp),pol(212 bp), andLTR(705 bp) were determined for 5, 5, and 2 Mikumi STLV-1 isolates, respectively. The DNA sequences of Mikumi STLV-1 isolates were virtually identical and phylogenetic analysis revealed that they were clearly distinct from previously published baboon STLV-1 sequences, including those STLV-1 isolates presumed to be from yellow baboons. The results of this study suggest that reliable placement of individual STLV-1 within the PTLV-1 phylogeny requires genomic sequences of STLV-1 isolates from wild animals whose taxonomic identity and geographical origin are firmly established and that the LTR is the genomic region of STLV-1 which is the most informative for cladistic analysis of these viruses
Propagation of the Human Polyomavirus, JCV, in Human Neuroblastoma Cell Lines

AbstractSusceptibility to infection by the human polyomavirus, JCV, is determined by intracellular mechanisms which control transcription and replication. Originally thought to propagate well only in human cells of oligodendroglial lineage, JCV has recently been shown to infect astrocytes, astrogliomas, and a neuroblastoma cell line. The data reported here describe two cell types that have been subcultured from a human neuroblastoma cell line, SK-N-SH. The SH-SY5Y subclone displays neuronal phenotypes and is not susceptible to JCV infection, while the SH-EP subclone displays glial cell phenotypes and is susceptible to infection. Binding of nuclear proteins from the permissive SH-EP cells to the nuclear factor-1 (NF-1) site in the JCV regulatory DNA sequences results in a gel shift pattern that is different from the nonpermissive SH-SY5Y cell proteins. Northern analysis of mRNA for the four classes of NF-1 proteins showed a predominance of the NF-1/X class in SH-EP cells similar to the highly permissive human fetal glial cells. Very low levels of mRNA for NF-1/X were seen in the nonpermissive SH-SY5Y cells, similar to that seen for the nonpermissive HeLa cells. Several other cell lines tested that were permissive for JCV infection also showed synthesis of the NF-1/X class of proteins. SH-EP cells represent a cell line in a glial cell lineage which is susceptible to JCV multiplication. These cells may be a useful cell culture system for the investigation of DNA binding factors which correlates with viral susceptibility
Variable Transduction Efficiency of Murine Leukemia Retroviral Vector on Mammalian Cells: Role of Cellular Glycosylation

AbstractTo elucidate the cellular tropism of Moloney murine leukemia virus (MuLV), we have studied the transduction efficiency of a recombinant MuLV vector carrying the β-galactosidase reporter gene on a variety of rodent cells. Under optimal conditions forin vitrocell transduction, primary cultures of adult rat fibroblasts derived from various organs were very poorly transduced by the ecotropic MuLV vector (0.02–0.12%) when compared to immortalized cells such as the F2408 (42%) and 3Y1 (defined as 100%) lines. Primary cultures of fibroblasts from neonatal (3.7%) or embryonic rat tissues (4.6%) and primary cultures of rat mammary epithelial cells (3–4%) were somewhat more susceptible. Immortalization of rodent fibroblasts with Polyomavirus Large T, SV40 Large T, and E6-E7 genes of human papilloma virus resulted in a modest or minimal increase in transduction efficiency, and introduction of the transforming genes v-Src, v-Ras, and v-Raf was in most instances associated with a decrease in MuLV vector entry. Variability of transduction efficiency was not related to differences in cellular growth rate and treatment of MuLV vectorsin vitrowith deoxyribonucleoside triphosphates and treatment of cells in culture with protease inhibitors failed to modify cellular entry of the MuLV vector. On the other hand, inhibition of cellular glycosylation with swansonine, 1-deoxymannojirimycin and, primarily, tunicamycin enhanced entry of the ecotropic vector by up to 220-fold, particularly into cells which were otherwise highly resistant. These findings demonstrate major differences in transduction efficiency of the ecotropic MuLV vector on rodent cells and indicate that cellular glycosylation plays a critical role in determining MuLV cellular tropism
The bZip Dimerization Domain of the Epstein–Barr Virus BZLF1 (Z) Protein Mediates Lymphoid-Specific Negative Regulation

AbstractThe Epstein–Barr virus (EBV) immediate-early (IE) protein, BZLF1 (Z), initiates the switch from latent to lytic infection. Z transactivation of an early viral promoter, BMRF1, is relatively inefficient in lymphoid cells (compared with epithelial cells), unless the other EBV IE protein, BRLF1, is also present. Cellular proteins, including the p65 component of NF-κB, have been shown to interact directly with Zin vitrothrough the bZip dimerization domain and inhibit Z-induced transactivation. Here we precisely define a residue within the bZip dimerization domain of Z (amino acid 200) which is required for interactionin vitrowith the p65 component of NF-κB, but is not essential for Z homodimerization. In lymphoid cells, a Z mutant which has been altered at amino acid 200 (tyrosine to glutamic acid) transactivates both the early BMRF1 promoter and the immediate-early BZLF1 promoter (Zp) four- to fivefold better than wild-type Z. In contrast, mutation of amino acid 200 does not affect Z transactivator function in epithelial cells. The results suggest that Z function is specifically inhibited by a lymphoid-specific protein(s) through amino acid 200 in the bZip dimerization domain. Modulation of Z's activator function may help to regulate the stringency of viral latency in lymphocytes
Treatment of Spontaneously Arising Retinoblastoma Tumors in Transgenic Mice with an Attenuated Herpes Simplex Virus Mutant

AbstractThe use of viruses to treat tumors has received renewed interest with the availability of genetically defined attenuated mutants. Herpes simplex virus (HSV) type 1 in particular has been shown to be effective for tumors of neuronal origin. However, the model systems used for these studies rely on the use of explanted tumor cells in immunodeficient animals. We have used a recently developed transgenic mouse model, wherein mice spontaneously develop retinoblastomas, to determine if a mutant HSV has a therapeutic effect against an endogenously arising tumor in an immunocompetent host. The injection of 1 × 106PFU of the neuroattenuated HSV-1/HSV-2 recombinant RE6 into the vitreous of transgenic mice resulted in a significant inhibition of tumor growth compared to injection of medium alone (P= 0.0063). Immunohistochemical analysis of viral antigen showed that viral replication was restricted to focal areas of the tumors and the retinal pigment epithelium. Viral growth was not significantly different in the eyes of transgene-positive and transgene-negative mice, suggesting that enhanced replication in tumor cells may not explain the effects. Tumor cells in the treated eyes were significantly less differentiated than those in the untreated eyes (P= 0.04), suggesting that the virus may replicate better in certain cell types in the tumors. Although the injection of RE6 resulted in a difference in tumor size, the treatment did not result in the elimination of tumors in any of the mice. Improvements in the efficacy of tumor control are needed if this therapy is to be of use