bluuebunny/crossref_metadata_2025_split huggingface dataset:
An NF-κB-Dependent Survival Pathway Protects against Cell Death Induced by TVB Receptors for Avian Leukosis Viruses
Authors: Chi Yuling , Diaz-Griffero Felipe , Wang Chenguang , Young John A. T. , Brojatsch Jürgen 
Published: July 2002

ABSTRACT
TVB receptors are death receptors of the tumor necrosis factor receptor (TNFR) family and serve as cellular receptors for cytopathic subgroups B and D and noncytopathic subgroup E of the avian leukosis viruses (ALVs). Although TVB is essential for ALV-B-mediated cell death, binding of the ALV-B envelope protein to its cognate receptor TVB activates cell death only in the presence of protein biosynthesis inhibitors, which presumably block the expression of protective factors. In the case of TNFR-1, the main antiapoptotic pathway depends upon nuclear factor kappa B (NF-κB)-activated survival factors. Here we show that overexpression of TVB receptors in human 293 cells activates NF-κB via a mechanism involving the cytoplasmic death domains of these receptors. NF-κB is also activated upon binding of a soluble ALV-B or ALV-E surface envelope-immunoglobulin fusion protein to the cognate TVB receptors and by ALV-B infection of a chicken embryo fibroblast cell line (DF1). Importantly, the cycloheximide requirement for TVB-dependent cell death was overcome by the expression of a transdominant form of IκB-α, and downregulation of NF-κB by the immunomodulator pyrrolidinedithiocarbamate enhanced the cytopathogenicity of ALV-B. These results demonstrate that TVB receptors trigger NF-κB-dependent gene expression and that NF-κB-regulated survival factors can protect against virus-induced cell death.
Expansion of a CD28-Intermediate Subset among CD8 T Cells in Patients with Infectious Mononucleosis
Authors: Uda Hiroshi , Mima Toru , Yamaguchi Norihiko , Katada Yoshinori , Fukuda Masayuki , Fujii Naohiko , Nakamura Kojiro , Saiki Osamu 
Published: July 2002

ABSTRACTInfectious mononucleosis (IM) is an acute sporadic infection that usually affects young adults, and during infection a massive expansion of CD8 T cells is generally considered to occur. However, CD28 expression of the expanded cells has not been characterized. When peripheral blood mononuclear cells of acute IM (AIM) patients were analyzed by flow cytometry, a continuous spectrum of CD28 intensity ranging from negative to high, which could be separated into CD28 negative, intermediate (int), and positive, was seen for CD8 T cells. We studied 26 IM patients who were diagnosed on the basis of standard methods and found that all patients had the continuous CD28 spectrum. CD28 is a costimulatory molecule on T cells, and its expression is associated with the subdivision of CD8 cells into cytotoxic (CD28-positive) and suppressor (CD28-negative) T cells. After 24 h of ex vivo culturing, however, the continuous spectrum was found to consist of only CD28-positive and CD28-negative CD8 T cells, because the CD28-int cells had disappeared due to apoptosis. The CD28-int T cells have several cytotoxic functions, suggesting that CD28-int T cells are effectors. Examination of other costimulatory markers in AIM patients showed that CD80 and CD152 were not affected. In patients with other viral infections, such as measles or rubella, however, the continuous spectrum was not detected. These results suggest that there is an unusual CD28 expression pattern in patients with AIM, namely, the presence of a functional CD28-int subset among CD8 T cells. These findings are of special importance for clarifying the defense mechanism against Epstein-Barr virus infection, and the role of CD28 molecules in humans and should also be helpful for the diagnosis of AIM.
Novel Design Architecture for Genetic Stability of Recombinant Poliovirus: the Manipulation of G/C Contents and Their Distribution Patterns Increases the Genetic Stability of Inserts in a Poliovirus-Based RPS-Vax Vector System
Authors: Lee Sang-Gu , Kim Dae-You , Hyun Byung-Hwa , Bae Yong-Soo 
Published: July 2002

ABSTRACT

Poliovirus has been studied as a live recombinant vaccine vector because of its attractive characteristics. The genetic instability, however, has hampered recombinant polioviruses (PVs) from being developed as an appropriate vaccine. A variety of different foreign inserts were cloned directly into our poliovirus Sabin 1-based RPS-Vax vector system, resulting in the production of recombinant PVs. The genetic stability of each recombinant PV was examined during 12 rounds of consecutive passage. It was found that the genetic stability of the recombinants was not well correlated with their insert size. Instead, elevated stability was frequently observed in recombinants with inserts of high G/C contents. Furthermore, a comparative study using different constructs of the human immunodeficiency virus
env
gene revealed that the internal deletion of the unstable insert was seemingly caused by the presence of the adjacent A/T-rich region. The instability of these inserts was completely remedied by (i) increasing the G/C contents and (ii) replacing the local A/T-rich region with the G/C-rich codon without a change of the amino acid. This means that stability is closely associated with the G/C content and the G/C distribution pattern. To see whether these findings can be applied to the design of genetically stable recombinant PV, we have reconstructed the heteromultimeric insert based on our design architecture, including the above-mentioned G/C rules and the template/ligation-free PCR protocol. The heteromultimeric insert was very unstable, as expected, but the manipulated insert with the same amino acid sequence showed complete genetic stability, not only in vitro, but also in vivo. Even though this guideline was established with our RPS-Vax vector system, to some extent, it can also be applied to other live viral vaccine vectors.
Alteration of Sendai Virus Morphogenesis and Nucleocapsid Incorporation due to Mutation of Cysteine Residues of the Matrix Protein
Authors: Sakaguchi Takemasa , Uchiyama Tsuneo , Huang Cheng , Fukuhara Noriko , Kiyotani Katsuhiro , Nagai Yoshiyuki , Yoshida Tetsuya 
Published: July 2002

ABSTRACT

The matrix (M) protein of Sendai virus (SeV) has five cysteine residues, at positions 83, 106, 158, 251, and 295. To determine the roles of the cysteine residues in viral assembly, we generated mutant M cDNA possessing a substitution to serine at one of the cysteine residues or at all of the cysteine residues. Some mutant M proteins were unstable when expressed in cultured cells, suggesting that cysteine residues affect protein stability, probably by disrupting the proper conformation. In an attempt to generate virus from cDNA, SeV M-C
83
S, SeV M-C
106
S, and SeV M-C
295
S were successfully recovered from cDNA, while recombinant SeVs possessing other mutations were not. SeV M-C
83
S and SeV M-C
106
S had smaller virus particles than did the wild-type SeV, whereas SeV M-C
295
S had larger and heterogeneously sized particles. Furthermore, SeV M-C
106
S had a significant amount of empty particles lacking nucleocapsids. These results indicate that a single-point mutation at a cysteine residue of the M protein affects virus morphology and nucleocapsid incorporation, showing direct involvement of the M protein in SeV assembly. Cysteine-dependent conformation of the M protein was not due to disulfide bond formation, since the cysteines were shown to be free throughout the viral life cycle.
Ubiquitination of both Adeno-Associated Virus Type 2 and 5 Capsid Proteins Affects the Transduction Efficiency of Recombinant Vectors
Authors: Yan Ziying , Zak Roman , Luxton G. W. Gant , Ritchie Teresa C. , Bantel-Schaal Ursula , Engelhardt John F. 
Published: July 2002

ABSTRACT
In the presence of complementing adeno-associated virus type 2 (AAV-2) Rep proteins, AAV-2 genomes can be pseudotyped with the AAV-5 capsid to assemble infectious virions. Using this pseudotyping strategy, the involvement of the ubiquitin-proteasome system in AAV-5 and AAV-2 capsid-mediated infections was compared. A recombinant AAV-2 (rAAV-2) proviral luciferase construct was packaged into both AAV-2 and AAV-5 capsid particles, and transduction efficiencies in a number of cell lines were compared. Using luciferase expression as the end point, we demonstrated that coadministration of the viruses with proteasome inhibitors not only increased the transduction efficiency of rAAV-2, as previously reported, but also augmented rAAV-5-mediated gene transfer. Increased transgene expression was independent of viral genome stability, since there was no significant difference in the amounts of internalized viral DNA in the presence or absence of proteasome inhibitors. Western blot assays of immunoprecipitated viral capsid proteins from infected HeLa cell lysates and in vitro reconstitution experiments revealed evidence for ubiquitin conjugation of both AAV-2 and AAV-5 capsids. Interestingly, heat-denatured virus particles were preferential substrates for in vitro ubiquitination, suggesting that endosomal processing of the viral capsid proteins is a prelude to ubiquitination. Furthermore, ubiquitination may be a signal for processing of the capsid at the time of virion disassembly. These studies suggest that the previously reported influences of the ubiquitin-proteasome system on rAAV-2 transduction are also active for rAAV-5 and provide a clearer mechanistic framework for understanding the functional significance of ubiquitination.
Distinct Glycoprotein O Complexes Arise in a Post-Golgi Compartment of Cytomegalovirus-Infected Cells
Authors: Theiler Regan N. , Compton Teresa 
Published: July 2002

ABSTRACT
Human cytomegalovirus (CMV) glycoproteins H, L, and O (gH, gL, and gO, respectively) form a heterotrimeric disulfide-bonded complex that participates in the fusion of the viral envelope with the host cell membrane. During virus maturation, this complex undergoes a series of intracellular assembly and processing events which are not entirely defined (M. T. Huber and T. Compton, J. Virol. 73:3886-3892, 1999). Here, we demonstrate that gO does not undergo the same posttranslational processing in transfected cells as it does in infected cells. We further determined that gO is modified by O-linked glycosylation and that this terminally processed form is highly enriched in virions. However, during studies of gO processing, novel gO complexes were discovered in CMV virions. The newly identified gO complexes, including gO-gL heterodimers, were not readily detected in CMV-infected cells. Further characterization of the trafficking of gO through the secretory pathway of infected cells localized gH, gL, and gO primarily to the Golgi apparatus and trans-Golgi network, supporting the conclusion that the novel virion-associated gO complexes arise in a post-Golgi compartment of infected cells.
Construction of a Human Immunodeficiency Virus Type 1 (HIV-1) Library Containing Random Combinations of Amino Acid Substitutions in the HIV-1 Protease due to Resistance by Protease Inhibitors
Authors: Yusa Keisuke , Song Wei , Bartelmann Matthias , Harada Shinji 
Published: July 2002

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) heterogeneity contributes to the emergence of drug-resistant virus, escape from host defense systems, and/or conversion of the cellular tropism. To establish an in vitro system to address a heterogeneous virus population, we constructed a library of HIV-1 molecular clones containing a set of random combinations of zero to 11 amino acid substitutions associated with resistance to protease inhibitors by the HIV-1 protease. The complexity (2.1 × 10
5
) of the HIV-1 library pNG-PRL was large enough to cover all of the possible combinations of zero to 11 amino acid substitutions (a total of 4,096 substitutions possible). The T-cell line MT-2 was infected with the HIV-1 library, and resistant viruses were selected after treatment by the protease inhibitor ritonavir (0.03 to 0.30 μM). The viruses that contained three to eight amino acid substitutions could be selected within 2 weeks. These results demonstrate that this HIV-1 library could serve as an alternative in vitro system to analyze the emergence of drug resistance and to evaluate the antiviral activity of novel compounds against multidrug-resistant viruses.
Ty5
gag
Mutations Increase Retrotransposition and Suggest a Role for Hydrogen Bonding in the Function of the Nucleocapsid Zinc Finger
Authors: Gao Xiang , Rowley Daniel J. , Gai Xiaowu , Voytas Daniel F. 
Published: July 2002

ABSTRACT

The Ty5 retrotransposon of
Saccharomyces paradoxus
transposes in
Saccharomyces cerevisiae
at frequencies 1,000-fold lower than do the native Ty1 elements. The low transposition activity of Ty5 could be due to differences in cellular environments between these yeast species or to naturally occurring mutations in Ty5. By screening of a Ty5 mutant library, two single mutants (D252N and Y68C) were each found to increase transposition approximately sixfold. When combined, transposition increased 36-fold, implying that the two mutations act independently. Neither mutation affected Ty5 protein synthesis, processing, cDNA recombination, or target site choice. However, cDNA levels in both single mutants and the double mutant were significantly higher than in the wild type. The D252N mutation resides in the zinc finger of nucleocapsid and increases the potential for hydrogen bonding with nucleic acids. We generated other mutations that increase the hydrogen bonding potential (i.e., D252R and D252K) and found that they similarly increased transposition. This suggests that hydrogen bonding within the zinc finger motif is important for cDNA production and builds upon previous studies implicating basic amino acids flanking the zinc finger as important for zinc finger function. Although NCp zinc fingers differ from the zinc finger motifs of cellular enzymes, the requirement for efficient hydrogen bonding is likely universal.
Replication Fidelity of the
supF
Gene Integrated in the Thymidine Kinase Locus of Herpes Simplex Virus Type 1
Authors: Hwang Ying T. , Liu Bu-Yuan , Hwang Charles B. C. 
Published: July 2002

ABSTRACT

Recombinant viruses were constructed to have an
Escherichia coli
replicon containing a mutagenesis marker, the
supF
gene, integrated within the thymidine kinase locus (
tk
) of herpes simplex virus type 1. These viruses expressed either wild-type or mutant DNA polymerase (Pol) and were tested in a mutagenesis assay for the fidelity of their replication of the
supF
gene. A mutation frequency of approximately 10
−4
was observed for wild-type strain KOS-derived recombinants in their replication of the
supF
gene. However, recombinants derived from the PAA
r
5 Pol mutant, which has been demonstrated to have an antimutator phenotype in replicating the
tk
gene, had three- to fourfold increases in
supF
mutation frequency (
P
< 0.01), a result similar to that exhibited when the
supF
gene was induced to replicate as episomal DNA (Y. T. Hwang, B.-Y. Liu, C.-Y. Hong, E. J. Shillitoe, and C. B. C. Hwang, J. Virol. 73:5326-5332, 1999). Thus, the PAA
r
5 Pol mutant had an antimutator function in replicating the
tk
gene and was less accurate in replicating the
supF
gene than was the wild-type strain. The spectra of mutations and distributions of substituted bases within the
supF
genes that replicated as genomic DNA were different from those in the genes that replicated as episomal DNA. Therefore, the differences in sequence contents between the two target genes influenced the accuracy of the Pol during viral replication. Furthermore, the replication mode of the target gene also affected the mutational spectrum.
Oligomerization and Cooperative RNA Synthesis Activity of Hepatitis C Virus RNA-Dependent RNA Polymerase
Authors: Wang Q. May , Hockman Michelle A. , Staschke Kirk , Johnson Robert B. , Case Katharine A. , Lu Jirong , Parsons Steve , Zhang Faming , Rathnachalam Radhakrishnan , Kirkegaard Karla , Colacino Joseph M. 
Published: July 2002

ABSTRACT

The NS5B RNA-dependent RNA polymerase encoded by hepatitis C virus (HCV) plays a key role in viral replication. Reported here is evidence that HCV NS5B polymerase acts as a functional oligomer. Oligomerization of HCV NS5B protein was demonstrated by gel filtration, chemical cross-linking, temperature sensitivity, and yeast cell two-hybrid analysis. Mutagenesis studies showed that the C-terminal hydrophobic region of the protein was not essential for its oligomerization. Importantly, HCV NS5B polymerase exhibited cooperative RNA synthesis activity with a dissociation constant,

K
d

, of ≈22 nM, suggesting a role for the polymerase-polymerase interaction in the regulation of HCV replicase activity. Further functional evidence includes the inhibition of the wild-type NS5B polymerase activity by a catalytically inactive form of NS5B. Finally, the X-ray crystal structure of HCV NS5B polymerase was solved at 2.9 Å. Two extensive interfaces have been identified from the packing of the NS5B molecules in the crystal lattice, suggesting a higher-order structure that is consistent with the biochemical data.
Selective STAT Protein Degradation Induced by Paramyxoviruses Requires both STAT1 and STAT2 but Is Independent of Alpha/Beta Interferon Signal Transduction
Authors: Parisien Jean-Patrick , Lau Joe F. , Rodriguez Jason J. , Ulane Christina M. , Horvath Curt M. 
Published: July 2002

ABSTRACT

The alpha/beta interferon (IFN-α/β)-induced STAT signal transduction pathway leading to activation of the ISGF3 transcription complex and subsequent antiviral responses is the target of viral pathogenesis strategies. Members of the
Rubulavirus
genus of the Paramyxovirus family of RNA viruses have acquired the ability to specifically target either STAT1 or STAT2 for proteolytic degradation as a countermeasure for evading IFN responses. While type II human parainfluenza virus induces STAT2 degradation, simian virus 5 induces STAT1 degradation. The components of the IFN signaling system that are required for STAT protein degradation by these paramyxoviruses have been investigated in a series of human somatic cell lines deficient in IFN signaling proteins. Results indicate that neither the IFN-α/β receptor, the tyrosine kinases Jak1 or Tyk2, nor the ISGF3 DNA-binding subunit, IFN regulatory factor 9 (IRF9), is required for STAT protein degradation induced by either virus. Nonetheless, both STAT1 and STAT2 are strictly required in the host cell to establish a degradation-permissive environment enabling both viruses to target their respective STAT protein. Complementation studies reveal that STAT protein-activating tyrosine phosphorylation and functional src homology 2 (SH2) domains are dispensable for creating a permissive STAT degradation environment in degradation-incompetent cells, but the N terminus of the missing STAT protein is essential. Protein-protein interaction analysis indicates that V and STAT proteins interact physically in vitro and in vivo. These results constitute genetic and biochemical evidence supporting a virus-induced, IFN-independent STAT protein degradation complex that contains at least STAT1 and STAT2.
Pervaporation of Ethanol and Water Through Polymeric Membranes with Incorporated N-(Halogenophenyl)maleimide Units
Authors: Lokaj Jan , Bílá Jitka 
Published: July 2002

Styrene N-(chloro- or bromophenyl)maleimide and methyl methacrylate N-(chloro- or bromophenyl)maleimide copolymers were synthesized. Membranes casted from the copolymer solutions were used for the pervaporation of ethanol water mixtures at 35 °C. The membranes were characterized by the separation factor related to the preferentially transported water and by the permeate flux. The pervaporation characteristics were dependent on the hydrophilicity or polarity of the polymer chains, on the kind and position of the halogen and on the composition of the mixture to be separated. Membranes made from the copolymers of styrene with N-(2-chlorophenyl)maleimide or N-(2-bromophenyl)maleimide show the highest separation factors in the separation of concentrated ethanol solutions. The permeate flux through membranes made from the copolymers of methyl methacrylate with N-(halogenophenyl)maleimide was by one order of magnitude higher than through membranes made from similar styrene copolymers.
The "Cyclohexane-Like" Structure of (MeOBF2)3 and Other Species Arising from Mixing (MeO)3B and BF3. An ab initio/IGLO/NMR Investigation
Authors: Rasul Golam , Williams Robert E. 
Published: July 2002

An ab initio/IGLO/NMR investigation shows that (MeOBF2)3, 3, is the thermodynamically most stable product when (MeO)3B and BF3 are mixed in a 1 : 2 ratio. Compound 3 has a symmetrical, "cyclohexane-like", structure with C3v symmetry. The ab initio calculated structures of less stable intermediates, i.e. the monomeric MeOBF2, 1, the dimeric (MeOBF2)2, 2, the "diadduct" MeOB(O(BF3)Me)O(BF3)Me, 4, and the "monoadduct" (MeO)2BO(BF3)Me, 5, are also discussed.
Persistent wheezing in infants with an atopic tendency responds to inhaled fluticasone
Authors: Chavasse R J , Bastian-Lee Y , Richter H , Hilliard T , Seddon P 
Published: July 2002

BACKGROUNDThe role of inhaled corticosteroids for the treatment of wheeze in infancy remains unclear.AIMTo investigate the effect of inhaled fluticasone on symptoms in a group of wheezy infants who had a high risk of progressing to childhood asthma.METHODSA total of 52 infants, under 1 year of age, with a history of wheeze or cough and a history (personal or first degree relative) of atopy were prescribed either 150 μg fluticasone twice daily (group F) or placebo (group P), via metered dose inhaler, for 12 weeks following a two week run in period. Symptoms were scored in a parent held diary and the mean daily symptom score (MDS) and symptom free days (SFD) calculated for each two week period.RESULTSThirty seven infants completed the study. Both MDS and SFD improved significantly between the run in and final two week period in group F, but not group P, with a mean difference in change (95% CI) between groups of 1.12 (0.05 to 2.18) for MDS and median difference of 3.0 (0.002 to 8.0) for SFD.CONCLUSIONImprovement of clinical symptoms in response to fluticasone can be shown in this high risk group of infants. In the absence of effective alternatives inhaled corticosteroids should be considered in this patient group.
Ocular sports injuries: the current picture
Authors: Barr A , Baines P S , Desai P , MacEwen C J 
Published: July 2002

Objectives—To determine the recent incidence of eye injury due to sport in Scotland, identify any trend, and establish which sports are responsible for most injury? The type of injury and final visual outcome is also evaluated.Methods—A prospective observational study of ocular injuries sustained during sport was performed over a one year period. Only patients requiring hospital admission were included. Data were collected on a standardised proforma and entered into a central database. Patients were followed up for at least three months.Results—Of 416 patients admitted because of ocular injury, 52 (12.5%) resulted from playing a sport. Although all racquet sports together accounted for 47.5% of these injuries, football was the single most common sport associated with ocular trauma, being responsible for 32.5% of cases. The most common clinical finding was macroscopic hyphaema occurring in 87.5% of patients. Overall the final visual acuity was 6/6 in 92.5% of patients.Conclusions—The incidence of eye injury due to sport at 12.5% is lower than previously reported, suggesting a change in the pattern of ocular trauma. Football is the single most common cause of ocular injury from sport in Scotland, but the wearing of protective headgear would be difficult to instigate. The incidence of hyphaema in sport related ocular trauma (87.5%) is almost double that of all ocular injury (47.8%), so the potential for serious visual loss as the result of a sports injury should not be underrated. Ophthalmologists have a role in protecting this young population at risk by actively encouraging the design and use of protective eyewear.