bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the Neurovirulence of a Vaccine and a Wild-Type Mumps Virus Strain in the Developing Rat Brain
Authors: Rubin Steven A. , Pletnikov Mikhail , Carbone Kathryn M. 
Published: December 2019

ABSTRACT
Prior to the adoption of widespread vaccination programs, mumps virus was the leading cause of virus-induced central nervous system (CNS) disease. Mumps virus-associated CNS complications in vaccinees continue to be reported; outside the United States, some of these complications have been attributed to vaccination with insufficiently attenuated neurovirulent vaccine strains. The development of potentially neurovirulent, live, attenuated mumps virus vaccines stems largely from the lack of an animal model that can reliably predict the neurovirulence of mumps virus vaccine candidates in humans. The lack of an effective safety test with which to measure mumps virus neurovirulence has also hindered analysis of the neuropathogenesis of mumps virus infection and the identification of molecular determinants of neurovirulence. In this report we show, for the first time, that mumps virus infection of the neonatal rat leads to developmental abnormalities in the cerebellum due to cerebellar granule cell migration defects. The incidence of the cerebellar abnormalities and other neuropathological and clinical outcomes of mumps virus infection of the neonatal rat brain demonstrated the ability of this model to distinguish neurovirulent (Kilham) from nonneurovirulent (Jeryl Lynn) mumps virus strains. Thus, this neonatal rat model may prove useful in evaluating the neurovirulence potential of new live, attenuated vaccine strains and may also be of value in elucidating the molecular basis of mumps virus neurovirulence.
Protection against Lethal Encephalomyocarditis Virus Infection in the Absence of Serum-Neutralizing Antibodies
Authors: Neal Zane C. , Splitter Gary A. 
Published: December 2019

ABSTRACTAlthough the ability of serum-neutralizing antibodies to protect against picornavirus infection is well established, the contribution of cell-mediated immunity to protection is uncertain. Using major histocompatibility complex class II-deficient (RHAβ−/−) mice, which are unable to mediate CD4+T-lymphocyte-dependent humoral responses, we demonstrated antibody-independent protection against lethal encephalomyocarditis virus (EMCV) infection in the natural host. The majority of RHAβ−/−mice inoculated with 104PFU of attenuated Mengo virus (vMC24) resolved infection and were resistant to lethal challenge with the highly virulent, serotypically identical cardiovirus, EMCV. Protection in these mice was in the absence of detectable serum-neutralizing antibodies. Depletion of CD8+T lymphocytes prior to lethal EMCV challenge ablated protection in vMC24-immunized RHAβ−/−mice. The CD8+T-lymphocyte-dependent protection observed in vivo may, in part, be the result of cytotoxic T-lymphocyte (CTL) activity, as CD8+T splenocytes exhibited in vitro cytolysis of EMCV-infected targets. The existence of virus-specific CD8+T-lymphocyte memory in these mice was demonstrated by increased expression of cell surface activation markers CD25, CD69, CD71, and CTLA-4 following antigen-specific reactivation in vitro. Although recall response in vMC24-immunized RHAβ−/−mice was intact and effectual shortly after immunization, protection abated over time, as only 3 of 10 vMC24-immunized RHAβ−/−mice survived when rechallenged 90 days later. The present study demonstrating CD8+T-lymphocyte-dependent protection in the absence of serum-neutralizing antibodies, coupled with our previous results indicating that vMC24-specific CD4+T lymphocytes confer protection against lethal EMCV in the absence of prophylactic antibodies, suggests the existence of nonhumoral protective mechanisms against picornavirus infections.
Expression of Measles Virus V Protein Is Associated with Pathogenicity and Control of Viral RNA Synthesis
Authors: Tober Christiane , Seufert Marion , Schneider Henriette , Billeter Martin A. , Johnston Ian C. D. , Niewiesk Stefan , ter Meulen Volker , Schneider-Schaulies Sibylle 
Published: December 2019

ABSTRACT

Nonstructural proteins encoded by measles virus (MV) include the V protein which is translated from an edited P mRNA. V protein is not associated with intracellular or released viral particles and has recently been found to be dispensable for MV propagation in cell culture (H. Schneider, K. Kaelin, and M. A. Billeter, Virology 227:314–322, 1997). Using recombinant MVs (strain Edmonston [ED]) genetically engineered to overexpress V protein (ED-V+) or to be deficient for V protein (ED-V−), we found that in the absence of V both MV-specific proteins and RNAs accumulated to levels higher than those in the parental MV molecular clone (ED-tag), whereas MV-specific gene expression was strongly attenuated in human U-87 glioblastomas cells after infection with ED-V+. The titers of virus released from these cells 48 h after infection with either V mutant virus were lower than those from cells infected with ED-tag. Similarly, significantly reduced titers of infectious virus were reisolated from lung tissue of cotton rats (
Sigmodon hispidus
) after intranasal infection with both editing mutants compared to titers isolated from ED-tag-infected animals. In cell culture, expression of V protein led to a redistribution of MV N protein in doubly transfected Cos-7 cells, indicating that these proteins form heterologous complexes. This interaction was further confirmed by using a two-hybrid approach with both proteins expressed as Gal4 or VP16 fusion products. Moreover, V protein efficiently competed complexes formed between MV N and P proteins. These findings indicate that V protein acts to balance accumulation of viral gene products in cell culture, and this may be dependent on its interaction with MV N protein. Furthermore, expression of V protein may contribute to viral pathogenicity in vivo.
Measles Virus Fusion Protein Is Palmitoylated on Transmembrane-Intracytoplasmic Cysteine Residues Which Participate in Cell Fusion
Authors: Caballero Monserrat , Carabaña Juan , Ortego Javier , Fernández-Muñoz Rafael , Celma María L. 
Published: December 2019

ABSTRACT

[
3
H]palmitic acid was metabolically incorporated into the viral fusion protein (F) of Edmonston or freshly isolated measles virus (MV) during infection of human lymphoid or Vero cells. The uncleaved precursor F
0
and the F
1
subunit from infected cells and extracellular virus were both labeled, indicating that palmitoylation can take place prior to F
0
cleavage and that palmitoylated F protein was incorporated into virus particles. [
3
H]palmitic acid was released from F protein upon hydroxylamine or dithiothreitol treatment, indicating a thioester linkage. In cells transfected with the cloned MV F gene, in which the cysteines located in the intracytoplasmic and transmembrane domains (Cys 506, 518, 519, 520, and 524) were replaced by serine, a major reduction of [
3
H]palmitic acid incorporation was observed for F mutated at Cys 506 and, to a lesser extent, at Cys 518 and Cys 524. We also observed incorporation of [
3
H]palmitic acid in the F
1
subunit of canine distemper virus F protein. Cell fusion induced by cotransfection of cells with MV F and H (hemagglutinin) genes was significantly reduced after replacement of Cys 506 or Cys 519 with serine in the MV F gene. Transfection with the F gene with a mutation for Cys 518 abolished cell fusion, although less mutant protein was detected on the cell surface. These results suggest that the F protein transmembrane domain cysteines 506 and 518 participate in structures involved in cell fusion, possibly mediated by palmitoylation.
Structure and Distribution of Endogenous Nonecotropic Murine Leukemia Viruses in Wild Mice
Authors: Tomonaga Keizo , Coffin John M. 
Published: December 2019

ABSTRACT

Virtually all of our present understanding of endogenous murine leukemia viruses (MLVs) is based on studies with inbred mice. To develop a better understanding of the interaction between endogenous retroviruses and their hosts, we have carried out a systematic investigation of endogenous nonecotropic MLVs in wild mice. Species studied included four major subspecies of
Mus musculus
(
M. m. castaneus
,
M. m. musculus
,
M. m. molossinus
, and
M. m. domesticus
) as well as four common inbred laboratory strains (AKR/J, HRS/J, C3H/HeJ, and C57BL/6J). We determined the detailed distribution of nonecotropic proviruses in the mice by using both
env
- and long terminal repeat (LTR)-derived oligonucleotide probes specific for the three different groups of endogenous MLVs. The analysis indicated that proviruses that react with all of the specific probes are present in most wild mouse DNAs tested, in numbers varying from 1 or 2 to more than 50. Although in common inbred laboratory strains the linkage of group-specific sequences in
env
and the LTR of the proviruses is strict, proviruses which combine
env
and the LTR sequences from different groups were commonly observed in the wild-mouse subspecies. The “recombinant” nonecotropic proviruses in the mouse genomes were amplified by PCR, and their genetic and recombinant natures were determined. These proviruses showed extended genetic variation and provide a valuable probe for study of the evolutionary relationship between MLVs and the murine hosts.
Mx1-Based Resistance to Thogoto Virus in A2G Mice Is Bypassed in Tick-Mediated Virus Delivery
Authors: Dessens Johannes T. , Nuttall Patricia A. 
Published: December 2019

ABSTRACT

The interferon-induced mouse Mx1 protein has intrinsic antiviral activity against orthomyxoviruses, including Thogoto virus. Thus,
Mx1
+
A2G mice are apparently resistant to infection following needle- or tick-borne virus challenge. However, tick-borne challenge and, to a lesser degree, injection of virus mixed with tick salivary gland extract resulted in virus transmission to uninfected ticks feeding on the A2G mice. The data indicate that immunomodulatory components in tick saliva can overcome a natural antiviral mechanism.
The Major Open Reading Frame of the β2.7 Transcript of Human Cytomegalovirus: In Vitro Expression of a Protein Posttranscriptionally Regulated by the 5′ Region
Authors: Bergamini Giovanna , Reschke Marko , Battista Maria Concetta , Boccuni Maria Cristina , Campanini Fabio , Ripalti Alessandro , Landini Maria Paola 
Published: December 2019

ABSTRACT
β2.7 is the major early transcript produced during human cytomegalovirus infection. This abundantly expressed RNA is polysome associated, but no protein product has ever been detected. In this study, a stable peptide of 24 kDa was produced in vitro from the major open reading frame (ORF), TRL4. Following transient transfection, the intracellular localization was nucleolar and the expression was posttranscriptionally inhibited by the 5′ sequence of the transcript, which harbors two short upstream ORFs.
Optimal Induction of Hepatitis C Virus Envelope-Specific Immunity by Bicistronic Plasmid DNA Inoculation with the Granulocyte-Macrophage Colony-Stimulating Factor Gene
Authors: Lee Seung Woo , Cho Jae Ho , Sung Young Chul 
Published: December 2019

ABSTRACTIn this study, we have constructed various DNA vaccine vectors that carried hepatitis C virus (HCV) envelope genes without and with the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene in several different ways. In Buffalo rats that received plasmids carrying the HCV envelope genes, which encode envelope proteins E1 and E2, both antibody and lymphoproliferative responses against these proteins were induced. These responses were greatly enhanced by the codelivery of the GM-CSF gene. In particular, inoculation with a bicistronic plasmid that independently expressed the GM-CSF gene and the envelope genes in the same construct generated the highest antibody titers and significantly increased lymphoproliferative responses against these proteins. Moreover, strong antibody responses to homologous and heterologous hypervariable region 1 peptides were elicited in the immunized rats.
High-Mobility Group 1/2 Proteins Are Essential for Initiating Rolling-Circle-Type DNA Replication at a Parvovirus Hairpin Origin
Authors: Cotmore Susan F. , Tattersall Peter 
Published: December 2019

ABSTRACTRolling-circle replication is initiated by a replicon-encoded endonuclease which introduces a single-strand nick into specific origin sequences, becoming covalently attached to the 5′ end of the DNA at the nick and providing a 3′ hydroxyl to prime unidirectional, leading-strand synthesis. Parvoviruses, such as minute virus of mice (MVM), have adapted this mechanism to amplify their linear single-stranded genomes by using hairpin telomeres which sequentially unfold and refold to shuttle the replication fork back and forth along the genome, creating a continuous, multimeric DNA strand. The viral initiator protein, NS1, then excises individual genomes from this continuum by nicking and reinitiating synthesis at specific origins present within the hairpin sequences. Using in vitro assays to study ATP-dependent initiation within the right-hand (5′) MVM hairpin, we have characterized a HeLa cell factor which is absolutely required to allow NS1 to nick this origin. Unlike parvovirus initiation factor (PIF), the cellular complex which activates NS1 endonuclease activity at the left-hand (3′) viral origin, the host factor which activates the right-hand hairpin elutes from phosphocellulose in high salt, has a molecular mass of around 25 kDa, and appears to bind preferentially to structured DNA, suggesting that it might be a member of the high-mobility group 1/2 (HMG1/2) protein family. This prediction was confirmed by showing that purified calf thymus HMG1 and recombinant human HMG1 or murine HMG2 could each substitute for the HeLa factor, activating the NS1 endonuclease in an origin-specific nicking reaction.
Ribosomal S27a Coding Sequences Upstream of Ubiquitin Coding Sequences in the Genome of a Pestivirus
Authors: Becher Paul , Orlich Michaela , Thiel Heinz-Jürgen 
Published: December 2019

ABSTRACT
Molecular characterization of cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain CP Rit, a temperature-sensitive strain widely used for vaccination, revealed that the viral genomic RNA is about 15.2 kb long, which is about 2.9 kb longer than the one of noncytopathogenic (noncp) BVDV strains. Molecular cloning and nucleotide sequencing of parts of the genome resulted in the identification of a duplication of the genomic region encoding nonstructural proteins NS3, NS4A, and part of NS4B. In addition, a nonviral sequence was found directly upstream of the second copy of the NS3 gene. The 3′ part of this inserted sequence encodes an N-terminally truncated ubiquitin monomer. This is remarkable since all described cp BVDV strains with ubiquitin coding sequences contain at least one complete ubiquitin monomer. The 5′ region of the nonviral sequence did not show any homology to cellular sequences identified thus far in cp BVDV strains. Databank searches revealed that this second cellular insertion encodes part of ribosomal protein S27a. Further analyses included molecular cloning and nucleotide sequencing of the cellular recombination partner. Sequence comparisons strongly suggest that the S27a and the ubiquitin coding sequences found in the genome of CP Rit were both derived from a bovine mRNA encoding a hybrid protein with the structure NH2-ubiquitin-S27a-COOH. Polyprotein processing in the genomic region encoding the N-terminal part of NS4B, the two cellular insertions, and NS3 was studied by a transient-expression assay. The respective analyses showed that the S27a-derived polypeptide, together with the truncated ubiquitin, served as processing signal to yield NS3, whereas the truncated ubiquitin alone was not capable of mediating the cleavage. Since the expression of NS3 is strictly correlated with the cp phenotype of BVDV, the altered genome organization leading to expression of NS3 most probably represents the genetic basis of cytopathogenicity of CP Rit.
Effects of Mutations in the Rubella Virus E1 Glycoprotein on E1-E2 Interaction and Membrane Fusion Activity
Authors: Yang Decheng , Hwang Dorothy , Qiu Zhiyong , Gillam Shirley 
Published: December 2019

ABSTRACTRubella virus (RV) virions contain two glycosylated membrane proteins, E1 and E2, that exist as a heterodimer and form the viral spike complexes on the virion surface. Formation of an E1-E2 heterodimer is required for transport of E1 out of the endoplasmic reticulum lumen to the Golgi apparatus and plasma membrane. To investigate the nature of the E1-E2 interaction, we have introduced mutations in the internal hydrophobic region (residues 81 to 109) of E1. Substitution of serine at Cys82 (mutant C82S) or deletion of this hydrophobic domain (mutant dt) of E1 resulted in a disruption of the E1 conformation that ultimately affected E1-E2 heterodimer formation and cell surface expression of both E1 and E2. Substitution of either aspartic acid at Gly93 (G93D) or glycine at Pro104 (P104G) was found to impair neither E1-E2 heterodimer formation nor the transport of E1 and E2 to the cell surface. Fusion of RV-infected cells is induced by a brief treatment at a pH below 6.0. To test whether this internal hydrophobic domain is involved in the membrane fusion activity of RV, transformed BHK cell lines expressing either wild-type or mutant spike proteins were exposed to an acidic pH and polykaryon formation was measured. No fusion activity was observed in the C82S, dt, and G93D mutants; however, the wild type and the P104G mutant exhibited fusogenic activities, with greater than 60% and 20 to 40% of the cells being fused, respectively, at pH 4.8. These results suggest that it is likely that the region of E1 between amino acids 81 and 109 is involved in the membrane fusion activity of RV and that it may be important for the interaction of that protein with E2 to form the E1-E2 heterodimer.
Heterogeneous Nuclear Ribonucleoprotein L Interacts with the 3′ Border of the Internal Ribosomal Entry Site of Hepatitis C Virus
Authors: Hahm Bumsuk , Kim Yoon Ki , Kim Jong Heon , Kim Tae Yoon , Jang Sung Key 
Published: December 2019

ABSTRACT
Translation initiation of hepatitis C virus (HCV) RNA occurs by internal entry of a ribosome into the 5′ nontranslated region in a cap-independent manner. The HCV RNA sequence from about nucleotide 40 up to the N terminus of the coding sequence of the core protein is required for efficient internal initiation of translation, though the precise border of the HCV internal ribosomal entry site (IRES) has yet to be determined. Several cellular proteins have been proposed to direct HCV IRES-dependent translation by binding to the HCV IRES. Here we report on a novel cellular protein that specifically interacts with the 3′ border of the HCV IRES in the core-coding sequence. This protein with an apparent molecular mass of 68 kDa turned out to be heterogeneous nuclear ribonucleoprotein L (hnRNP L). The binding of hnRNP L to the HCV IRES correlates with the translational efficiencies of corresponding mRNAs. This finding suggests that hnRNP L may play an important role in the translation of HCV mRNA through the IRES element.
Isolation and Characterization of a Neuropathogenic Simian Immunodeficiency Virus Derived from a Sooty Mangabey
Authors: Novembre Francis J. , De Rosayro Juliette , O’Neil Shawn P. , Anderson Daniel C. , Klumpp Sherry A. , McClure Harold M. 
Published: December 2019

ABSTRACTTransfusion of blood from a simian immunodeficiency virus (SIV)- and simian T-cell lymphotropic virus-infected sooty mangabey (designated FGb) to rhesus and pig-tailed macaques resulted in the development of neurologic disease in addition to AIDS. To investigate the role of SIV in neurologic disease, virus was isolated from a lymph node of a pig-tailed macaque (designated PGm) and the cerebrospinal fluid of a rhesus macaque (designated ROn2) and passaged to additional macaques. SIV-related neuropathogenic effects were observed in 100% of the pig-tailed macaques inoculated with either virus. Lesions in these animals included extensive formation of SIV RNA-positive giant cells in the brain parenchyma and meninges. Based upon morphology, the majority of infected cells in both lymphoid and brain tissue appeared to be of macrophage lineage. The virus isolates replicated very well in pig-tailed and rhesus macaque peripheral blood mononuclear cells (PBMC) with rapid kinetics. Differential replicative abilities were observed in both PBMC and macrophage populations, with viruses growing to higher titers in pig-tailed macaque cells than in rhesus macaque cells. An infectious molecular clone of virus derived from the isolate from macaque PGm (PGm5.3) was generated and was shown to have in vitro replication characteristics similar to those of the uncloned virus stock. While molecular analyses of this virus revealed its similarity to SIV isolates from sooty mangabeys, significant amino acid differences in Env and Nef were observed. This virus should provide an excellent system for investigating the mechanism of lentivirus-induced neurologic disease.
Factors Influencing Adeno-Associated Virus-Mediated Gene Transfer to Human Cystic Fibrosis Airway Epithelial Cells: Comparison with Adenovirus Vectors
Authors: Teramoto S. , Bartlett J. S. , McCarty D. , Xiao X. , Samulski R. J. , Boucher R. C. 
Published: December 2019

ABSTRACTAdeno-associated virus (AAV) vectors appear promising for use in gene therapy in cystic fibrosis (CF) patients, yet many features of AAV-mediated gene transfer to airway epithelial cells are not well understood. We compared the transduction efficiencies of AAV vectors and adenovirus (Ad) vectors in immortalized cell lines from CF patients and in nasal epithelial primary cultures from normal humans and CF patients. Similar dose-dependent relationships between the vector multiplicities of infection and the efficiencies oflacZgene transfer were observed. However, levels of transduction for both Ad and recombinant AAV (rAAV) were significantly lower in the airway epithelial cell than in the control cell lines HeLa and HEK 293. Transduction efficiencies differed among cultured epithelial cell types, with poorly differentiated cells transducing more efficiently than well-differentiated cells. A time-dependent increase in gene expression was observed after infection for both vectors. For Ad, but not for AAV, this increase was dependent on prolonged incubation of cells with the vector. Furthermore, for rAAV (but not for rAd), the delay in maximal transduction could be abrogated by wild-type Ad helper infection. Thus, although helper virus is not required for maximal transduction, it increases the kinetics by which this is achieved. Expression of Ad E4 open reading frame 6 or addition of either hydroxyurea or camptothecin resulted in increased AAV transduction, as previously demonstrated for nonairway cells (albeit to lower final levels), suggesting that second-strand synthesis may not be the sole cause of inefficient transduction. Finally, the efficiency of AAV-mediated ex vivo gene transfer to lung cells was similar to that previously described for Ad vectors in that transduction was limited to regions of epithelial injury and preferentially targeted basal-like cells. These studies address the primary factors influencing rAAV infection of human airway cells and should impact successful gene delivery in CF patients.