bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Herpesvirus 8 K14 Protein Mimics CD200 in Down-Regulating Macrophage Activation through CD200 Receptor
Authors: Foster-Cuevas Mildred , Wright Gavin J. , Puklavec Michael J. , Brown Marion H. , Barclay A. Neil 
Published: June 2004

ABSTRACTMany viral proteins limit host immune defenses, and their genes often originate from their hosts. CD200 (OX2) is a broadly distributed cell surface glycoprotein that interacts with a receptor on myeloid cells (CD200R) that is implicated in locally preventing macrophage activation. Distant, but recognizable, homologues of CD200 have been identified in many herpesviruses and poxviruses. Here, we show that the product of the K14 open reading frame from human herpesvirus 8 (Kaposi's sarcoma-associated herpesvirus) interacts with human CD200R and is expressed at the surfaces of infected cells solely during the lytic cycle. Despite sharing only 40% primary sequence identity, K14 and CD200 interacted with CD200R with an almost identical and low affinity (KD= 0.5 μM), in contrast to other characterized viral homologue interactions. Cells expressing CD200 or K14 on the cell surface were able to inhibit secretion by activated macrophages of proinflammatory cytokines such as tumor necrosis factor alpha, an effect that could be specifically relieved by addition of monoclonal antibodies and soluble monomeric CD200 protein. We conclude that CD200 delivers local down-modulatory signals to myeloid cells through direct cell-cell contact and that the K14 viral homologue closely mimics this.
E1B-55-Kilodalton Protein Is Not Required To Block p53-Induced Transcription during Adenovirus Infection
Authors: Hobom Urs , Dobbelstein Matthias 
Published: June 2004

ABSTRACT
The adenovirus E1B-55-kDa protein binds and inactivates the tumor suppressor protein p53. However, the role of this interaction during infection is still poorly understood and was therefore examined here. Infection with a virus carrying the E1B-55-kDa mutation R239A, preventing the interaction with p53, led to the accumulation of p53. However, p53 target genes were not activated in the infected cells, although p53 phosphorylation did occur and the p53 antagonists Mdm2 and ΔNp73 did not accumulate. Deletion of E4orf6, alone or in combination with E1B-55-kDa, did not allow the induction of p53-responsive genes either. In transient reporter assays, the viral E1A-13S protein antagonized p53 activity; mutational analysis suggested that this depends partially on p300 binding, but it depends even more strongly on the interaction of E1A with the p400/TRRAP protein complex. However, viruses expressing E1A mutants lacking these binding activities, in combination with E1B-55-kDa R239A, still abolished p53 activity. In contrast, when the mutation of E1B-55-kDa at R239A was combined with a deletion of the apoptosis inhibitor E1B-19-kDa, infected cells showed more extensive apoptosis than after infection with single mutants, suggesting that accumulated p53, albeit transcriptionally inactive, might nonetheless enhance apoptosis. Despite extensive apoptosis of the infected cells, the deletion of E1B-19-kDa, in combination with the E1B-55-kDa mutation or in the presence of the constitutively active p53 mutant p53mt24-28, reduced virus replication less than fivefold. In conclusion, adenovirus does not need direct binding of E1B-55-kDa to inactivate p53, and forced p53 activity with consecutive apoptosis does not severely impair virus replication.
Structural Basis for Competitive Inhibition of eIF4G-Mnk1 Interaction by the Adenovirus 100-Kilodalton Protein
Authors: Cuesta Rafael , Xi Qiaoran , Schneider Robert J. 
Published: June 2004

ABSTRACT
Translation of most cellular mRNAs involves cap binding by the translation initiation complex. Among this complex of proteins are cap-binding protein eIF4E and the eIF4E kinase Mnk1. Cap-dependent mRNA translation generally correlates with Mnk1 phosphorylation of eIF4E when both are bound to eIF4G. During the late phase of adenovirus (Ad) infection translation of cellular mRNA is inhibited, which correlates with displacement of Mnk1 from eIF4G by the viral 100-kDa (100K) protein and dephosphorylation of eIF4E. Here we describe the molecular mechanism for 100K protein displacement of Mnk1 from eIF4G and elucidate a structural basis for eIF4G interaction with Mnk1 and 100K proteins and Ad inhibition of cellular protein synthesis. The eIF4G-binding site is located in an N-terminal 66-amino-acid peptide of 100K which is sufficient to bind eIF4G, displace Mnk1, block eIF4E phosphorylation, and inhibit eIF4F (cap)-dependent cellular mRNA translation. Ad 100K and Mnk1 proteins possess a common eIF4G-binding motif, but 100K protein binds more strongly to eIF4G than does Mnk1. Unlike Mnk1, for which binding to eIF4G is RNA dependent, competitive binding by 100K protein is RNA independent. These data support a model whereby 100K protein blocks cellular protein synthesis by coopting eIF4G and cap-initiation complexes regardless of their association with mRNA and displacing or blocking binding by Mnk1, which occurs only on preassembled complexes, resulting in dephosphorylation of eIF4E.
Human Cytomegalovirus Carries a Cell-Derived Phospholipase A2 Required for Infectivity
Authors: Allal Cuider , Buisson-Brenac Claire , Marion Vincent , Claudel-Renard Clotilde , Faraut Thomas , Dal Monte Paola , Streblow Daniel , Record Michel , Davignon Jean-Luc 
Published: June 2004

ABSTRACTHuman cytomegalovirus (HCMV) is known to carry host cell-derived proteins and mRNAs whose role in cell infection is not understood. We have identified a phospholipase A2 (PLA2) activity borne by HCMV by using an assay based on the hydrolysis of fluorescent phosphatidylcholine. This activity was found in all virus strains analyzed and in purified strains. It was calcium dependent and was sensitive to inhibitors of cytosolic PLA2 (cPLA2) but not to inhibitors of soluble PLA2 or calcium-independent PLA2. No other phospholipase activity was detected in the virus. Purified virus was found to contain human cellular cPLA2α, as detected by monoclonal antibody. No homology with PLA2 was found in the genome of HCMV, indicating that HCMV does not code for a PLA2. Decreased de novo expression of immediate-early proteins 1 and 2 (IE1 and IE2), tegument phosphoprotein pp65, and virus production was observed when HCMV was treated with inhibitors of cPLA2. Cell entry of HCMV was not altered by those inhibitors, suggesting the action of cPLA2 was postentry. Together, our results indicate a selective sorting of a cell-derived cPLA2 during HCMV maturation, which is further required for infectivity.
Crystal Structure of Species D Adenovirus Fiber Knobs and Their Sialic Acid Binding Sites
Authors: Burmeister Wim P. , Guilligay Delphine , Cusack Stephen , Wadell Göran , Arnberg Niklas 
Published: June 2004

ABSTRACT
Adenovirus serotype 37 (Ad37) belongs to species D and can cause epidemic keratoconjunctivitis, whereas the closely related Ad19p does not. Primary cell attachment by adenoviruses is mediated through receptor binding of the knob domain of the fiber protein. The knobs of Ad37 and Ad19p differ at only two positions, Lys240Glu and Asn340Asp. We report the high-resolution crystal structures of the Ad37 and Ad19p knobs, both native and in complex with sialic acid, which has been proposed as a receptor for Ad37. Overall, the Ad37 and Ad19p knobs are very similar to previously reported knob structures, especially to that of Ad5, which binds the coxsackievirus-adenovirus receptor (CAR). Ad37 and Ad19p knobs are structurally identical with the exception of the changed side chains and are structurally most similar to CAR-binding knobs (e.g., that of Ad5) rather than non-CAR-binding knobs (e.g., that of Ad3). The two mutations in Ad19p result in a partial loss of the exceptionally high positive surface charge of the Ad37 knob but do not affect sialic acid binding. This site is located on the top of the trimer and binds both α(2,3) and α(2,6)-linked sialyl-lactose, although only the sialic acid residue makes direct contact. Amino acid alignment suggests that the sialic acid binding site is conserved in several species D serotypes. Our results show that the altered viral tropism and cell binding of Ad19p relative to those of Ad37 are not explained by a different binding ability toward sialyl-lactose.
The Host Response to West Nile Virus Infection Limits Viral Spread through the Activation of the Interferon Regulatory Factor 3 Pathway
Authors: Fredericksen Brenda L. , Smith Maria , Katze Michael G. , Shi Pei-Yong , Gale Michael 
Published: June 2004

ABSTRACTRecent outbreaks of West Nile Virus (WNV) have been associated with an increase in morbidity and mortality in humans, birds, and many other species. We have initiated studies to define the molecular mechanisms by which a recent pathogenic isolate of WNV evades the host cell innate antiviral response. Biochemical and microarray analyses demonstrated that WNV induced the expression of beta interferon (IFN-β) and several IFN-stimulated genes late in infection of cultured human cells. The late expression of these antiviral genes was due to the delayed activation of the transcription factor IFN regulatory factor 3 (IRF-3). Despite this host response, WNV was still able to replicate efficiently. The effect of the IRF-3 pathway on WNV replication was assessed by examining virus replication and spread in cultures of wild-type or IRF-3-null mouse embryo fibroblasts. The absence of IRF-3 was marked by a significant increase in plaque size and a sustained production of infectious particles. Although the activation of the IRF-3 pathway was not sufficient to block virus replication, our results suggest that IRF-3 target genes function to constrain WNV infection and limit cell-to-cell virus spread.
New Simian Immunodeficiency Virus Infecting De Brazza's Monkeys (
Cercopithecus neglectus
): Evidence for a
Cercopithecus
Monkey Virus Clade
Authors: Bibollet-Ruche Frederic , Bailes Elizabeth , Gao Feng , Pourrut Xavier , Barlow Katrina L. , Clewley Jonathan P. , Mwenda Jason M. , Langat Daudi K. , Chege Gerald K. , McClure Harold M. , Mpoudi-Ngole Eitel , Delaporte Eric , Peeters Martine , Shaw George M. , Sharp Paul M. , Hahn Beatrice H. 
Published: June 2004

ABSTRACT

Nearly complete sequences of simian immunodeficiency viruses (SIVs) infecting 18 different nonhuman primate species in sub-Saharan Africa have now been reported; yet, our understanding of the origins, evolutionary history, and geographic distribution of these viruses still remains fragmentary. Here, we report the molecular characterization of a lentivirus (SIVdeb) naturally infecting De Brazza's monkeys (
Cercopithecus neglectus
). Complete SIVdeb genomes (9,158 and 9,227 bp in length) were amplified from uncultured blood mononuclear cell DNA of two wild-caught De Brazza's monkeys from Cameroon. In addition, partial
pol
sequences (650 bp) were amplified from four offspring of De Brazza's monkeys originally caught in the wild in Uganda. Full-length (9,068 bp) and partial
pol
(650 bp) SIVsyk sequences were also amplified from Sykes's monkeys (
Cercopithecus albogularis
) from Kenya. Analysis of these sequences identified a new SIV clade (SIVdeb), which differed from previously characterized SIVs at 40 to 50% of sites in Pol protein sequences. The viruses most closely related to SIVdeb were SIVsyk and members of the SIVgsn/SIVmus/SIVmon group of viruses infecting greater spot-nosed monkeys (
Cercopithecus nictitans
), mustached monkeys (
Cercopithecus cephus
), and mona monkeys (
Cercopithecus mona
), respectively. In phylogenetic trees of concatenated protein sequences, SIVdeb, SIVsyk, and SIVgsn/SIVmus/SIVmon clustered together, and this relationship was highly significant in all major coding regions. Members of this virus group also shared the same number of cysteine residues in their extracellular envelope glycoprotein and a high-affinity AIP1 binding site (YPD/SL) in their p6 Gag protein, as well as a unique transactivation response element in their viral long terminal repeat; however, SIVdeb and SIVsyk, unlike SIVgsn, SIVmon, and SIVmus, did not encode a
vpu
gene. These data indicate that De Brazza's monkeys are naturally infected with SIVdeb, that this infection is prevalent in different areas of the species' habitat, and that geographically diverse SIVdeb strains cluster in a single virus group. The consistent clustering of SIVdeb with SIVsyk and the SIVmon/SIVmus/SIVgsn group also suggests that these viruses have evolved from a common ancestor that likely infected a
Cercopithecus
host in the distant past. The
vpu
gene appears to have been acquired by a subset of these
Cercopithecus
viruses after the divergence of SIVdeb and SIVsyk.
Parvovirus B19-Induced Apoptosis of Hepatocytes
Authors: Poole Brian D. , Karetnyi Yuory V. , Naides Stanley J. 
Published: June 2004

ABSTRACT
Parvovirus B19 (B19 virus) can persist in multiple tissues and has been implicated in a variety of diseases, including acute fulminant liver failure. The mechanism by which B19 virus induces liver failure remains unknown. Hepatocytes are nonpermissive for B19 virus replication. We previously reported that acute fulminant liver failure associated with B19 virus infection was characterized by hepatocellular dropout. We inoculated both primary hepatocytes and the hepatocellular carcinoma cell line Hep G2 with B19 virus and assayed for apoptosis by using annexin V staining. Reverse transcriptase PCR analysis and immunofluorescence demonstrated that B19 virus was able to infect the cells and produce its nonstructural protein but little or no structural capsid protein. Infection with B19 virus induced means of 28% of Hep G2 cells and 10% of primary hepatocytes to undergo apoptosis, which were four- and threefold increases, respectively, over background levels. Analysis of caspase involvement showed that B19 virus-inoculated cultures had a significant increase in the number of cells with active caspase 3. Inhibition studies demonstrated that caspases 3 and 9, but not caspase 8, are required for B19 virus-induced apoptosis.
Rotavirus Serotype G9 Strains Belonging to VP7 Gene Phylogenetic Sequence Lineage 1 May Be More Suitable for Serotype G9 Vaccine Candidates than Those Belonging to Lineage 2 or 3
Authors: Hoshino Yasutaka , Jones Ronald W. , Ross Jerri , Honma Shinjiro , Santos Norma , Gentsch Jon R. , Kapikian Albert Z. 
Published: June 2004

ABSTRACT
A safe and effective group A rotavirus vaccine that could prevent severe diarrhea or ameliorate its symptoms in infants and young children is urgently needed in both developing and developed countries. Rotavirus VP7 serotypes G1, G2, G3, and G4 have been well established to be of epidemiologic importance worldwide. Recently, serotype G9 has emerged as the fifth globally common type of rotavirus of clinical importance. Sequence analysis of the VP7 gene of various G9 isolates has demonstrated the existence of at least three phylogenetic lineages. The goal of our study was to determine the relationship of the phylogenetic lineages to the neutralization specificity of various G9 strains. We generated eight single VP7 gene substitution reassortants, each of which bore a single VP7 gene encoding G9 specificity of one of the eight G9 strains (two lineage 1, one lineage 2 and five lineage 3 strains) and the remaining 10 genes of bovine rotavirus strain UK, and two hyperimmune guinea pig antisera to each reassortant, and we then analyzed VP7 neutralization characteristics of the eight G9 strains as well as an additional G9 strain belonging to lineage 1; the nine strains were isolated in five countries. Antisera to lineage 1 viruses neutralized lineage 2 and 3 strains to at least within eightfold of the homotypic lineage viruses. Antisera to lineage 2 virus neutralized lineage 3 viruses to at least twofold of the homotypic lineage 2 virus; however, neutralization of lineage 1 viruses was fourfold (F45 and AU32) to 16- to 64-fold (WI61) less efficient. Antisera to lineage 3 viruses neutralized the lineage 2 strain 16- to 64-fold less efficiently, the lineage 1 strains F45 and AU32 8- to 128-fold less efficiently, and WI61 (prototype G9 strain) 128- to 1,024-fold less efficiently than the homotypic lineage 3 viruses. These findings may have important implications for the development of G9 rotavirus vaccine candidates, as the strain with the broadest reactivity (i.e., a prime strain) would certainly be the ideal strain for inclusion in a vaccine.
SUMOylation of the Human Cytomegalovirus 72-Kilodalton IE1 Protein Facilitates Expression of the 86-Kilodalton IE2 Protein and Promotes Viral Replication
Authors: Nevels Michael , Brune Wolfram , Shenk Thomas 
Published: June 2004

ABSTRACTThe 72-kDa immediate-early 1 protein (IE1-72kDa) of human cytomegalovirus has been previously shown to be posttranslationally modified by covalent conjugation to the ubiquitin-related protein SUMO-1. Using an infectious bacterial artificial chromosome clone of human cytomegalovirus, we constructed a mutant virus (BADpmIE1-K450R) that is deficient for SUMOylation of IE1-72kDa due to a single amino acid exchange in the SUMO-1 attachment site. Compared to wild-type virus, this mutant grew more slowly and generated a reduced yield in infected human fibroblasts, indicating that SUMO modification is required for the full activity of IE1-72kDa. The lack of SUMOylation did not affect the intranuclear localization of IE1-72kDa, including its ability to target to and disrupt PML bodies and to bind to mitotic chromatin. Likewise, SUMOylation-deficient IE1-72kDa activated several viral promoters as efficiently as the wild-type protein. However, the failure to modify IE1-72kDa resulted in substantially reduced levels of the IE2 transcript and its 86-kDa protein (IE2-86kDa). These observations suggest that SUMO modification of IE1-72kDa contributes to efficient HCMV replication by promoting the accumulation of IE2-86kDa.
Biased Hypermutagenesis Associated with Mutations in an Untranslated Hairpin of an RNA Virus
Authors: McCormack John C. , Simon Anne E. 
Published: June 2004

ABSTRACT

The mutation frequency of
Turnip crinkle virus
can increase 12-fold without inducing error catastrophe. Lesions in a hairpin repressor frequently reverted and led to second-site alterations biased for specific mutations. These results suggest that the hairpin may also function as an RNA chaperone to properly fold the RNA-dependent RNA polymerase.
Bromodeoxyuridine-Labeled Viral Particles as a Tool for Visualization of the Immediate-Early Events of Human Cytomegalovirus Infection
Authors: Rosenke Kyle , Fortunato Elizabeth A. 
Published: June 2004

ABSTRACT
We describe here a simple method for labeling the genome of human cytomegalovirus, a large double-stranded DNA virus, with bromodeoxyuridine (BrdU). The labeled DNA was incorporated into viral particles, which were then collected in cell supernatant. To demonstrate the versatility and effectiveness of this method, labeled virions were used to study the immediate-early events of virus-host cell interaction via indirect immunofluorescence microscopy. It is our hope that this new methodology will prove useful in the study of binding, entry and viral genome deposition in diverse virus systems.
Human Coronavirus 229E Nonstructural Protein 13: Characterization of Duplex-Unwinding, Nucleoside Triphosphatase, and RNA 5′-Triphosphatase Activities
Authors: Ivanov Konstantin A. , Ziebuhr John 
Published: June 2004

ABSTRACT
The human coronavirus 229E (HCoV-229E) replicase gene-encoded nonstructural protein 13 (nsp13) contains an N-terminal zinc-binding domain and a C-terminal superfamily 1 helicase domain. A histidine-tagged form of nsp13, which was expressed in insect cells and purified, is reported to unwind efficiently both partial-duplex RNA and DNA of up to several hundred base pairs. Characterization of the nsp13-associated nucleoside triphosphatase (NTPase) activities revealed that all natural ribonucleotides and nucleotides are substrates of nsp13, with ATP, dATP, and GTP being hydrolyzed most efficiently. Using the NTPase active site, HCoV-229E nsp13 also mediates RNA 5′-triphosphatase activity, which may be involved in the capping of viral RNAs.
A Human Cellular Protein Activity (OF-1), Which Binds Herpes Simplex Virus Type 1 Origin, Contains the Ku70/Ku80 Heterodimer
Authors: Murata Lauren B. , Dodson Mark S. , Hall Jennifer D. 
Published: June 2004

ABSTRACT
In an effort to identify host proteins involved in herpes simplex virus type 1 replication, monkey and human cellular protein activities (called OF-1) that bind the viral replication origin, oriS, have been described. We show by mass spectrometry that the DNA-binding component of human OF-1 contains Ku70 and Ku80 proteins.
Lentiviral Transduction of Dendritic Cells Confers Protective Antiviral Immunity In Vivo
Authors: Zarei Shohreh , Abraham Shahnaz , Arrighi Jean-Francois , Haller Olivier , Calzascia Thomas , Walker Paul R. , Kündig Thomas M. , Hauser Conrad , Piguet Vincent 
Published: June 2004

ABSTRACTControl of a viral infection in vivo requires a rapid and efficient cytotoxic-T-lymphocyte response. We demonstrate that lentivirus-mediated introduction of antigen in dendritic cells confers a protective antiviral immunity in vivo in a lymphocytic choriomeningitis virus model. Therefore, lentiviral vectors may be excellent vaccine candidates for viral infections.
The 3′
cis
-Acting Genomic Replication Element of the Severe Acute Respiratory Syndrome Coronavirus Can Function in the Murine Coronavirus Genome
Authors: Goebel Scott J. , Taylor Jill , Masters Paul S. 
Published: June 2004

ABSTRACT
The 3′ untranslated region (3′ UTR) of the genome of the severe acute respiratory syndrome coronavirus can functionally replace its counterpart in the prototype group 2 coronavirus mouse hepatitis virus (MHV). By contrast, the 3′ UTRs of representative group 1 or group 3 coronaviruses cannot operate as substitutes for the MHV 3′ UTR.
An optimised protocol for the extraction of non-viral mRNA from human plasma frozen for three years
Authors: Wong S C C , Lo E S F , Cheung M T 
Published: June 2004

Aims:To detect non-viral mRNA in human plasma that has been frozen for three years using a new protocol.Methods:Plasma from 15 patients with colorectal cancer and 10 normal subjects was separated and frozen with Trizol at −80°C for three years. As a control measure, plasma from 10 of the 15 patients was separated using the same protocol but no Trizol during storage. After three years, all samples were extracted using Trizol and RNeasy before the reverse transcriptase polymerase chain reaction was performed to detect non-viral β catenin mRNA. In addition, extraction of three plasma samples by Trizol or RNeasy independently was carried out for comparison.Results:β Catenin mRNA was detected in all 15 patient plasma samples and only one of the 10 normal subjects. In contrast, no β catenin mRNA was found in the control and patient samples that were independently extracted by Trizol and RNeasy kit.Conclusions:This new protocol is a reliable method for extracting non-viral mRNA from the plasma of patients with cancer after longterm storage for three years. Extractions using Trizol and RNeasy kits independently could not isolate mRNA with sufficient quantity and quality for detection.