bluuebunny/crossref_metadata_2025_split huggingface dataset:
Borna Disease Virus P Protein Affects Neural Transmission through Interactions with Gamma-Aminobutyric Acid Receptor-Associated Protein
Authors: Peng Guiqing , Yan Yan , Zhu Chengliang , Wang Shiqun , Yan Xiaohong , Lu Lili , Li Wei , Hu Jing , Wei Wei , Mu Yongxin , Chen Yanni , Feng Yong , Gong Rui , Wu Kailang , Zhang Fengmin , Zhang Xiaolian , Zhu Ying , Wu Jianguo 
Published: September 2008

ABSTRACT
Borna disease virus (BDV) is one of the infectious agents that causes diseases of the central nervous system in a wide range of vertebrate species and, perhaps, in humans. The phosphoprotein (P) of BDV, an essential cofactor of virus RNA-dependent RNA polymerase, is required for virus replication. In this study, we identified the gamma-aminobutyric acid receptor-associated protein (GABARAP) with functions in neurobiology as one of the viral P protein-interacting cellular factors by using an approach of phage display-based protein-protein interaction analysis. Direct binding between GABARAP and P protein was confirmed by coimmunoprecipitation, protein pull-down, and mammalian two-hybrid analyses. GABARAP originally was identified as a linker between the gamma-aminobutyric acid receptor (GABAR) and the microtubule to regulate receptor trafficking and plays important roles in the regulation of the inhibitory neural transmitter gamma-aminobutyric acid (GABA). We showed that GABARAP colocalizes with P protein in the cells infected with BDV or transfected with the P gene, which resulted in shifting the localization of GABARAP from the cytosol to the nucleus. We further demonstrated that P protein blocks the trafficking of GABAR, a principal GABA-gated ion channel that plays important roles in neural transmission, to the surface of cells infected with BDV or transfected with the P gene. We proposed that during BDV infection, P protein binds to GABARAP, shifts the distribution of GABARAP from the cytoplasm to the nucleus, and disrupts the trafficking of GABARs to the cell membranes, which may result in the inhibition of GABA-induced currents and in the enhancement of hyperactivity and anxiety.
Vesicular Stomatitis Virus Matrix Protein Impairs CD1d-Mediated Antigen Presentation through Activation of the p38 MAPK Pathway
Authors: Renukaradhya Gourapura J. , Khan Masood A. , Shaji Daniel , Brutkiewicz Randy R. 
Published: September 2008

ABSTRACTNatural killer T (NKT) cells are unique T lymphocytes that recognize CD1d-bound lipid antigens and play an important role in both innate and acquired immune responses against infectious diseases and tumors. We have already shown that a vesicular stomatitis virus (VSV) infection results in the rapid inhibition of murine CD1d-mediated antigen presentation to NKT cells. In the present study, it was found that the VSV matrix (VSV-M) protein is an important element in this decrease in antigen presentation postinfection. The VSV-M protein altered the intracellular distribution of murine CD1d molecules, resulting in qualitative (but not quantitative) changes in cell surface CD1d expression. The M protein was distributed throughout the infected cell, and it was found to activate the mitogen-activated protein kinase (MAPK) p38 very early postinfection. Infection of CD1d+cells with a temperature-sensitive VSV-M mutant at the nonpermissive temperature both substantially reversed the inhibition of antigen presentation by CD1d and delayed the activation of p38. Thus, the VSV-M protein plays an important role in permitting the virus to evade important components of the innate immune response by regulating specific MAPK pathways.
Escape from HLA-B*08-Restricted CD8 T Cells by Hepatitis C Virus Is Associated with Fitness Costs
Authors: Salloum Shadi , Oniangue-Ndza Cesar , Neumann-Haefelin Christoph , Hudson Laura , Giugliano Silvia , aus dem Siepen Marc , Nattermann Jacob , Spengler Ulrich , Lauer Georg M. , Wiese Manfred , Klenerman Paul , Bright Helen , Scherbaum Norbert , Thimme Robert , Roggendorf Michael , Viazov Sergei , Timm Joerg 
Published: September 2008

ABSTRACT

The inherent sequence diversity of the hepatitis C virus (HCV) represents a major hurdle for the adaptive immune system to control viral replication. Mutational escape within targeted CD8 epitopes during acute HCV infection has been well documented and is one possible mechanism for T-cell failure. HLA-B*08 was recently identified as one HLA class I allele associated with spontaneous clearance of HCV replication. Selection of escape mutations in the immunodominant HLA-B*08-restricted epitope HSKKKCDEL
1395-1403
was observed during acute infection. However, little is known about the impact of escape mutations in this epitope on viral replication capacity. Their previously reported reversion back toward the consensus residue in patients who do not possess the B*08 allele suggests that the consensus sequence in this epitope is advantageous for viral replication in the absence of immune pressure. The aim of this study was to determine the impact of mutational escape from this immunodominant epitope on viral replication. We analyzed it with a patient cohort with chronic HCV genotype 1b infection and in a single-source outbreak (genotype 1b). Sequence changes in this highly conserved region are rare and selected almost exclusively in the presence of the HLA-B*08 allele. When tested in the subgenomic replicon (Con1), the observed mutations reduce viral replication compared with the prototype sequence. The results provide direct evidence that escape mutations in this epitope are associated with fitness costs and that the antiviral effect of HLA-B*08-restricted T cells is sufficiently strong to force the virus to adopt a relatively unfavorable sequence.
Epstein-Barr Virus BGLF4 Kinase Induces Disassembly of the Nuclear Lamina To Facilitate Virion Production
Authors: Lee Chung-Pei , Huang Yu-Hao , Lin Su-Fang , Chang Yao , Chang Yu-Hsin , Takada Kenzo , Chen Mei-Ru 
Published: September 2008

ABSTRACT
DNA viruses adopt various strategies to modulate the cellular environment for efficient genome replication and virion production. Previously, we demonstrated that the BGLF4 kinase of Epstein-Barr virus (EBV) induces premature chromosome condensation through the activation of condensin and topoisomerase IIα (C. P. Lee, J. Y. Chen, J. T. Wang, K. Kimura, A. Takemoto, C. C. Lu, and M. R. Chen, J. Virol. 81:5166-5180, 2007). In this study, we show that BGLF4 interacts with lamin A/C and phosphorylates lamin A protein in vitro. Using a green fluorescent protein (GFP)-lamin A system, we found that Ser-22, Ser-390, and Ser-392 of lamin A are important for the BGLF4-induced disassembly of the nuclear lamina and the EBV reactivation-mediated redistribution of nuclear lamin. Virion production and protein levels of two EBV primary envelope proteins, BFRF1 and BFLF2, were reduced significantly by the expression of GFP-lamin A(5A), which has five Ser residues replaced by Ala at amino acids 22, 390, 392, 652, and 657 of lamin A. Our data indicate that BGLF4 kinase phosphorylates lamin A/C to promote the reorganization of the nuclear lamina, which then may facilitate the interaction of BFRF1 and BFLF2s and subsequent virion maturation. UL kinases of alpha- and betaherpesviruses also induce the disassembly of the nuclear lamina through similar sites on lamin A/C, suggesting a conserved mechanism for the nuclear egress of herpesviruses.
Evolution of CCR5 Use before and during Coreceptor Switching
Authors: Coetzer Mia , Nedellec Rebecca , Salkowitz Janelle , McLaughlin Sherry , Liu Yi , Heath Laura , Mullins James I. , Mosier Donald E. 
Published: September 2008

ABSTRACT

The envelope gene (
env
) of human immunodeficiency virus type 1 (HIV-1) undergoes rapid divergence from the transmitted sequence and increasing diversification during the prolonged course of chronic infection in humans. In about half of infected individuals or more,
env
evolution leads to expansion of the use of entry coreceptor from CCR5 alone to CCR5 and CXCR4. The stochastic nature of this coreceptor switch is not well explained by host selective forces that should be relatively constant between infected individuals. Moreover, differences in the incidence of coreceptor switching among different HIV-1 subtypes suggest that properties of the evolving virus population drive the switch. We evaluated the functional properties of sequential
env
clones from a patient with evidence of coreceptor switching at 5.67 years of infection. We found an abrupt decline in the ability of viruses to use CCR5 for entry at this time, manifested by a 1- to 2-log increase in susceptibility to CCR5 inhibitors and a reduced ability to infect cell lines with low CCR5 expression. There was an abnormally rapid 5.4% divergence in
env
sequences from 4.10 to 5.76 years of infection, with the V3 and V4/V5 regions showing the greatest divergence and evidence of positive selection. These observations suggest that a decline in the fitness of R5 virus populations may be one driving force that permits the emergence of R5X4 variants.
Clearance of Adenovirus by Kupffer Cells Is Mediated by Scavenger Receptors, Natural Antibodies, and Complement
Authors: Xu Zhili , Tian Jie , Smith Jeffrey S. , Byrnes Andrew P. 
Published: September 2008

ABSTRACTKupffer cells (KCs) rapidly remove intravenously injected adenovirus (Ad) vectors from the circulation. A better understanding of the mechanisms involved could suggest strategies to improve Ad gene delivery by suppressing or evading KC uptake. We recently showed that clearance of Ad type 5 vectors by KCs does not involve the interaction of Ad with the well-established Ad receptors, namely, integrins or the coxsackievirus and Ad receptor (J. S. Smith, Z. Xu, J. Tian, S. C. Stevenson, and A. P. Byrnes, Hum. Gene Ther. 19:547-554, 2008). In the current study, we systematically quantified the contributions of various receptors and plasma proteins to the clearance of Ad by KCs. We found that scavenger receptors are a predominant mechanism for the clearance of Ad by KCs. In addition, we found that Ad is opsonized by natural immunoglobulin M antibodies and complement and that these opsonins play a contributory role in the clearance of Ad by KCs. We also examined additional mechanisms that have been postulated to be involved in the clearance of Ad, including the binding of Ad to platelets and vitamin K-dependent coagulation factors, but we found that neither of these were required for the clearance of Ad by KCs.
Compatibility among Polymerase Subunit Proteins Is a Restricting Factor in Reassortment between Equine H7N7 and Human H3N2 Influenza Viruses
Authors: Li Chengjun , Hatta Masato , Watanabe Shinji , Neumann Gabriele , Kawaoka Yoshihiro 
Published: September 2008

ABSTRACT
Reassortment is an important driving force for influenza virus evolution, and a better understanding of the factors that affect this process could improve our ability to respond to future influenza pandemics and epidemics. To identify factors that restrict the generation of reassortant viruses, we cotransfected human embryonic kidney cells with plasmids for the synthesis of viral RNAs of both A/equine/Prague/1/56 (Prague; H7N7) and A/Yokohama/2017/03 (Yokohama; H3N2) viruses together with the supporting protein expression plasmids. Of the possible 256 genotypes, we identified 29 genotypes in 120 randomly plaque-picked reassortants examined. Analyses of these reassortants suggested that the formation of functional ribonucleoprotein (RNP) complexes was a restricting factor, a finding that correlated with the activities of RNP complexes composed of different combinations of the proteins from the two viruses, as measured in a minigenome assay. For at least one nonfunctional RNP complex (i.e., Prague PB2, Prague PB1, Yokohama PA, and Prague NP), the lack of activity was due to the inability of the three polymerase subunit proteins to form a heterotrimer. Adaptation of viruses possessing a gene encoding a chimera of the PA proteins of the two viruses and the remaining genes from Prague virus resulted in compensatory mutations in the PB2 and/or PA protein. These results indicate substantial incompatibility among the gene products of the two test viruses, a critical role for the RNP complex in the generation of reassortant viruses, and a functional interaction of PB2 and PA.
The Immune Evasion Paradox: Immunoevasins of Murine Cytomegalovirus Enhance Priming of CD8 T Cells by Preventing Negative Feedback Regulation
Authors: Böhm Verena , Simon Christian O. , Podlech Jürgen , Seckert Christof K. , Gendig Dorothea , Deegen Petra , Gillert-Marien Dorothea , Lemmermann Niels A. W. , Holtappels Rafaela , Reddehase Matthias J. 
Published: September 2008

ABSTRACTCytomegaloviruses express glycoproteins that interfere with antigen presentation to CD8 T cells. Although the molecular modes of action of these “immunoevasins” differ between cytomegalovirus species, the convergent biological outcome is an inhibition of the recognition of infected cells. In murine cytomegalovirus, m152/gp40 retains peptide-loaded major histocompatibility complex class I molecules in acis-Golgi compartment, m06/gp48 mediates their vesicular sorting for lysosomal degradation, and m04/gp34, although not an immunoevasin in its own right, appears to assist in the concerted action of all three molecules. Using the Ld-restricted IE1 epitope YPHFMPTNL in the BALB/c mouse model as a paradigm, we provide here an explanation for the paradox that immunoevasins enhance CD8 T-cell priming although they inhibit peptide presentation in infected cells. Adaptive immune responses are initiated in the regional lymph node (RLN) draining the site of pathogen exposure. In particular for antigens that are not virion components, the magnitude of viral gene expression providing the antigens is likely a critical parameter in priming efficacy. We have therefore focused on the events in the RLN and have related priming to intranodal viral gene expression. We show that immunoevasins enhance priming by downmodulating an early CD8 T-cell-mediated “negative feedback” control of the infection in the cortical region of the RLN, thus supporting the model that immunoevasins improve antigen supply for indirect priming by uninfected antigen-presenting cells. As an important consequence, these findings predict that deletion of immunoevasin genes in a replicative vaccine virus is not a favorable option but may, rather, be counterproductive.
Human Cytomegalovirus Glycoproteins gB and gH/gL Mediate Epithelial Cell-Cell Fusion When Expressed either in
cis
or in
trans
Authors: Vanarsdall Adam L. , Ryckman Brent J. , Chase Marie C. , Johnson David C. 
Published: September 2008

ABSTRACT

Herpesviruses use a cascade of interactions with different cell surface molecules to gain entry into cells. In many cases, this involves binding to abundant glycosaminoglycans or integrins followed by interactions with more limited cell surface proteins, leading to fusion with cellular membranes. Human cytomegalovirus (HCMV) has the ability to infect a wide variety of human cell types in vivo. However, very little is known about which HCMV glycoproteins mediate entry into various cell types, including relevant epithelial and endothelial cells. For other herpesviruses, studies of cell-cell fusion induced by viral proteins have provided substantial information about late stages of entry. In this report, we describe the fusion of epithelial, endothelial, microglial, and fibroblast cells in which HCMV gB and gH/gL were expressed from nonreplicating adenovirus vectors. Fusion frequently involved the majority of cells, and gB and gH/gL were both necessary and sufficient for fusion, whereas no fusion occurred when either glycoprotein was omitted. Coexpression of UL128, UL130, and UL131 did not enhance fusion. We concluded that the HCMV core fusion machinery consists of gB and gH/gL. Coimmunoprecipitation indicated that HCMV gB and gH/gL can interact. Importantly, expression of gB and gH/gL in
trans
(gB-expressing cells mixed with other gH/gL-expressing cells) resulted in substantial fusion. We believe that this is the first description of a multicomponent viral fusion machine that can be split between cells. If gB and gH/gL must interact for fusion, then these molecules must reach across the space between apposing cells. Expression of gB and gH/gL in
trans
with different cell types revealed surface molecules that are required for fusion on HCMV-permissive cells but not on nonpermissive cells.
Mutational Analysis of
cis
-Acting RNA Signals in Segment 7 of Influenza A Virus
Authors: Hutchinson Edward C. , Curran Martin D. , Read Eliot K. , Gog Julia R. , Digard Paul 
Published: September 2008

ABSTRACT

The genomic viral RNA (vRNA) segments of influenza A virus contain specific packaging signals at their termini that overlap the coding regions. To further characterize
cis
-acting signals in segment 7, we introduced synonymous mutations into the terminal coding regions. Mutation of codons that are normally highly conserved reduced virus growth in embryonated eggs and MDCK cells between 10- and 1,000-fold compared to that of the wild-type virus, whereas similar alterations to nonconserved codons had little effect. In all cases, the growth-impaired viruses showed defects in virion assembly and genome packaging. In eggs, nearly normal numbers of virus particles that in aggregate contained apparently equimolar quantities of the eight segments were formed, but with about fourfold less overall vRNA content than wild-type virions, suggesting that, on average, fewer than eight segments per particle were packaged. Concomitantly, the particle/PFU and segment/PFU ratios of the mutant viruses showed relative increases of up to 300-fold, with the behavior of the most defective viruses approaching that predicted for random segment packaging. Fluorescent staining of infected cells for the nucleoprotein and specific vRNAs confirmed that most mutant virus particles did not contain a full genome complement. The specific infectivity of the mutant viruses produced by MDCK cells was also reduced, but in this system, the mutations also dramatically reduced virion production. Overall, we conclude that segment 7 plays a key role in the influenza A virus genome packaging process, since mutation of as few as 4 nucleotides can dramatically inhibit infectious virus production through disruption of vRNA packaging.
Profiling the Specificity of Neutralizing Antibodies in a Large Panel of Plasmas from Patients Chronically Infected with Human Immunodeficiency Virus Type 1 Subtypes B and C
Authors: Binley James M. , Lybarger Elizabeth A. , Crooks Emma T. , Seaman Michael S. , Gray Elin , Davis Katie L. , Decker Julie M. , Wycuff Diane , Harris Linda , Hawkins Natalie , Wood Blake , Nathe Cory , Richman Douglas , Tomaras Georgia D. , Bibollet-Ruche Frederic , Robinson James E. , Morris Lynn , Shaw George M. , Montefiori David C. , Mascola John R. 
Published: September 2008

ABSTRACT
Identifying the viral epitopes targeted by broad neutralizing antibodies (NAbs) that sometimes develop in human immunodeficiency virus type 1 (HIV-1)-infected subjects should assist in the design of vaccines to elicit similar responses. Here, we investigated the activities of a panel of 24 broadly neutralizing plasmas from subtype B- and C-infected donors using a series of complementary mapping methods, focusing mostly on JR-FL as a prototype subtype B primary isolate. Adsorption with gp120 immobilized on beads revealed that an often large but variable fraction of plasma neutralization was directed to gp120 and that in some cases, neutralization was largely mediated by CD4 binding site (CD4bs) Abs. The results of a native polyacrylamide gel electrophoresis assay using JR-FL trimers further suggested that half of the subtype B and a smaller fraction of subtype C plasmas contained a significant proportion of NAbs directed to the CD4bs. Anti-gp41 neutralizing activity was detected in several plasmas of both subtypes, but in all but one case, constituted only a minor fraction of the overall neutralization activity. Assessment of the activities of the subtype B plasmas against chimeric HIV-2 viruses bearing various fragments of the membrane proximal external region (MPER) of HIV-1 gp41 revealed mixed patterns, implying that MPER neutralization was not dominated by any single specificity akin to known MPER-specific monoclonal Abs. V3 and 2G12-like NAbs appeared to make little or no contribution to JR-FL neutralization titers. Overall, we observed significant titers of anti-CD4bs NAbs in several plasmas, but approximately two-thirds of the neutralizing activity remained undefined, suggesting the existence of NAbs with specificities unlike any characterized to date.
Signed, sealed and delivered: “big tobacco” in Hollywood, 1927–1951
Authors: Lum K L , Polansky J R , Jackler R K , Glantz S A 
Published: September 2008

Objective:Smoking in movies is associated with adolescent and young adult smoking initiation. Public health efforts to eliminate smoking from films accessible to youth have been countered by defenders of the status quo, who associate tobacco imagery in “classic” movies with artistry and nostalgia. The present work explores the mutually beneficial commercial collaborations between the tobacco companies and major motion picture studios from the late 1920s through the 1940s.Methods:Cigarette endorsement contracts with Hollywood stars and movie studios were obtained from internal tobacco industry documents at the University of California, San Francisco (UCSF) Legacy Tobacco Documents Library and the Jackler advertising collection at Stanford.Results:Cigarette advertising campaigns that included Hollywood endorsements appeared from 1927 to 1951, with major activity in 1931–2 and 1937–8 for American Tobacco Company’s Lucky Strike, and in the late 1940s for Liggett & Myers’ Chesterfield. Endorsement contracts and communication between American Tobacco and movie stars and studios explicitly reveal the cross-promotional value of the campaigns. American Tobacco paid movie stars who endorsed Lucky Strike cigarettes US$218 750 in 1937–8 (equivalent to US$3.2 million in 2008) for their testimonials.Conclusions:Hollywood endorsements in cigarette advertising afforded motion picture studios nationwide publicity supported by the tobacco industry’s multimillion US dollar advertising budgets. Cross-promotion was the incentive that led to a synergistic relationship between the US tobacco and motion picture industries, whose artefacts, including “classic” films with smoking and glamorous publicity images with cigarettes, continue to perpetuate public tolerance of onscreen smoking. Market-based disincentives within the film industry may be a solution to decouple the historical association between Hollywood films and cigarettes.