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analysis of venezuelan equine encephalitis virus capsid protein function in the inhibition of cellular transcription.the encephalitogenic new world alphaviruses, including venezuelan (veev), eastern (eeev), and western equine encephalitis viruses, constitute a continuing public health threat in the united states. they circulate in central, south, and north america and have the ability to cause fatal disease in humans and in horses and other domestic animals. we recently demonstrated that these viruses have developed the ability to interfere with cellular transcription and use it as a means of downregulating a ...200717913819
type i interferons are essential in controlling neurotropic coronavirus infection irrespective of functional cd8 t cells.neurotropic coronavirus infection induces expression of both beta interferon (ifn-beta) rna and protein in the infected rodent central nervous system (cns). however, the relative contributions of type i ifn (ifn-i) to direct, cell-type-specific virus control or cd8 t-cell-mediated effectors in the cns are unclear. ifn-i receptor-deficient (ifnar(-/-)) mice infected with a sublethal and demyelinating neurotropic virus variant and those infected with a nonpathogenic neurotropic virus variant both ...200817928334
venezuelan equine encephalitis virus replicon particles encoding respiratory syncytial virus surface glycoproteins induce protective mucosal responses in mice and cotton rats.respiratory syncytial virus (rsv) is an important viral pathogen that causes severe lower respiratory tract infection in infants, the elderly, and immunocompromised individuals. there are no licensed rsv vaccines to date. to prevent rsv infection, immune responses in both the upper and lower respiratory tracts are required. previously, immunization with venezuelan equine encephalitis virus replicon particles (vrps) demonstrated effectiveness in inducing mucosal protection against various pathoge ...200717928349
the zinc finger antiviral protein acts synergistically with an interferon-induced factor for maximal activity against alphaviruses.type i interferons (ifns) signal through specific receptors to mediate expression of genes, which together confer a cellular antiviral state. overexpression of the zinc finger antiviral protein (zap) imparts a cellular antiviral state against retroviridae, togaviridae, and filoviridae virus family members. since zap expression is induced by ifn, we utilized sindbis virus (sinv) to investigate the role of other ifn-induced factors in zap's inhibitory potential. overexpressed zap did not inhibit v ...200717928353
long-term protection in hamsters against human parainfluenza virus type 3 following mucosal or combinations of mucosal and systemic immunizations with chimeric alphavirus-based replicon particles.no licensed vaccines are available to protect against parainfluenza virus type 3 (piv3), a significant health risk for infants. in search of a safe vaccine, we used an alphavirus-based chimeric vector, consisting of sindbis virus (sin) structural proteins and venezuelan equine encephalitis virus (vee) replicon rna, expressing the piv3 hemagglutinin-neuraminidase (hn) glycoprotein (vee/sin-hn). we compared different routes of intramuscular (i.m.), intranasal (i.n.), or combined i.n. and i.m. immu ...200717944814
beta7-integrin-independent enhancement of mucosal and systemic anti-hiv antibody responses following combined mucosal and systemic gene delivery.vaccination strategies that can block or limit heterosexual human immunodeficiency virus (hiv) transmissions to local and systemic tissues are the goal of much research effort. herein, in a mouse model, we aimed to determine whether the enhancement of antibody responses through mucosal and systemic immunizations, previously observed with protein-based vaccines, applies to immunizations with dna- or rna-based vectors. intranasal (i.n.) followed by intramuscular (i.m.) immunizations (i.n./i.m.) wi ...200817944930
cytopathic mechanisms of hiv-1.the human immunodeficiency virus type 1 (hiv-1) has been intensely investigated since its discovery in 1983 as the cause of acquired immune deficiency syndrome (aids). with relatively few proteins made by the virus, it is able to accomplish many tasks, with each protein serving multiple functions. the envelope glycoprotein, composed of the two noncovalently linked subunits, su (surface glycoprotein) and tm (transmembrane glycoprotein) is largely responsible for host cell recognition and entry re ...200717945027
a dual-targeted lentiviral vector homing in on prostate bone metastases. 200717948046
the exanthem of dengue fever: clinical features of two us tourists traveling abroad.dengue fever is the most common identifiable cause of acute febrile illness among travelers returning from south america, south central asia, southeast asia, and the caribbean. although the characteristic exanthem of dengue fever occurs in up to 50% of patients, few descriptions of it are found in the dermatology literature, and discussions of how to distinguish the dengue exanthem from other infectious disease entities are rare. chikungunya fever is an emerging infectious disease now seen in re ...200817959270
reovirus apoptosis and virulence are regulated by host cell membrane penetration efficiency.apoptosis plays an important role in the pathogenesis of reovirus encephalitis and myocarditis in infected animals. differences in apoptosis efficiency displayed by reovirus strains are linked to the viral mu1-encoding m2 gene segment. studies using pharmacologic inhibitors of reovirus replication demonstrate that apoptosis induction by reovirus requires viral disassembly in cellular endosomes but not rna synthesis. since the mu1 protein functions to pierce endosomal membranes during this tempor ...200817959662
expression of the e3l gene of vaccinia virus in transgenic mice decreases host resistance to vaccinia virus and leishmania major infections.the e3l gene of vaccinia virus (vacv) encodes the e3 protein that in cultured cells inhibits the activation of interferon (ifn)-induced proteins, double-stranded rna-dependent protein kinase (pkr), 2'-5'-oligoadenylate synthetase/rnase l (2-5a system) and adenosine deaminase (adar-1), thus helping the virus to evade host responses. here, we have characterized the in vivo e3 functions in a murine inducible cell culture system (e3l-tetoff) and in transgenic mice (tge3l). inducible e3 expression in ...200817959665
intracellular restriction of a productive noncytopathic coronavirus infection.virus infection in vitro can either result in a cytopathic effect (cpe) or proceed without visible changes in infected cells (noncytopathic infection). we are interested in understanding the mechanisms controlling the impact of coronavirus infection on host cells. to this end, we compared a productive, noncytopathic infection of murine hepatitis virus (mhv) strain a59 in the fibroblastlike cell line nih 3t3 with cytopathic mhv infections. infected nih 3t3 cells could be cultured for up to 4 week ...200817959675
viroporins from rna viruses induce caspase-dependent apoptosis.the virus-encoded viroporins are known to modify membrane permeability and play an essential role in virus budding. here, a comparative analysis of the membrane permeabilization capacity of a number of viroporins was performed in baby hamster kidney cells. synthesis of 6k protein from sindbis virus, e from mouse hepatitis virus, m2 from influenza a virus, and 2b and 3a from poliovirus enhanced membrane permeability to different extents. we show that two proteins from hepatitis c virus, p7 and ns ...200817961183
control of gag-pol gene expression in the candida albicans retrotransposon tca2.in the c. albicans retrotransposon tca2, the gag and pol orfs are separated by a uga stop codon, 3' of which is a potential rna pseudoknot. it is unclear how the tca2 gag uga codon is bypassed to allow pol expression. however, in other retroelements, translational readthrough of the gag stop codon can be directed by its flanking sequence, including a 3' pseudoknot.200717961216
genistein treatment of cells inhibits arenavirus infection.arenaviridae is a family of enveloped viruses some of which are capable of causing hemorrhagic fever syndromes in humans. in this report, we demonstrate that treatment of host cells with the tyrosine kinase inhibitor genistein inhibits infection of cells with the new world arenavirus pichindé (picv). the greatest degree of inhibition was observed in pre-treated target cells, but modest inhibition of infection was also seen when drug was added to cultures up to 48h after infection. we show that p ...200817961732
recombination-ready sindbis replicon expression vectors for transgene expression.sindbis viruses have been widely used as tools to study gene function in cells. despite the utility of these systems, the construction and production of alphavirus replicons is time consuming and inefficient due to potential additional restriction sites within the insert region and lack of directionality for insert ligation. in this report, we present a system useful for producing recombinant sindbis replicons that uses lambda phage recombination technology to rapidly and specifically construct ...200717963504
antiviral properties of cobalt(iii)-complexes.we have investigated the potential antiviral activity of three cobalt(iii) compounds. two compounds, co(iii)-cyclen-methylbenzoic acid and its methyl ester derivative, are based on the macrocyclic chelator, cyclen, and were synthesized in our laboratory. both compounds have been shown to bind tightly to nucleic acids and to hydrolyze phosphodiester bonds. however, neither compound exhibited any significant antiviral activity in an in vitro model of sindbis virus replication. in contrast, a third ...200817967542
heterologous prime-boost strategy to immunize very young infants against measles: pre-clinical studies in rhesus macaques.infants in developing countries are at high risk of developing severe clinical measles if they become infected during the "window of vulnerability" (age 4-9 months), when declining maternal antibodies do not protect against wild virus, yet impede successful immunization by attenuated measles vaccine. we developed two sindbis replicon-based dna vaccines expressing measles virus hemagglutinin and fusion protein with the goal of priming young infants to respond safely and effectively to subsequent ...200717971812
recent advances in strategies for immunotherapy of human papillomavirus-induced lesions.human papillomavirus (hpv)-induced lesions are distinct in that they have targetable foreign antigens, the expression of which is necessary to maintain the cancerous phenotype. hence, they pose as a very attractive target for "proof of concept" studies in the development of therapeutic vaccines. this review will focus on the most recent clinical trials for the immunotherapy of mucosal and cutaneous hpv-induced lesions as well as emerging therapeutic strategies that have been tested in preclinica ...200817973257
the 3' untranslated region of sindbis virus represses deadenylation of viral transcripts in mosquito and mammalian cells.the positive-sense transcripts of sindbis virus (sinv) resemble cellular mrnas in that they possess a 5' cap and a 3' poly(a) tail. it is likely, therefore, that sinv rnas must successfully overcome the cytoplasmic mrna decay machinery of the cell in order to establish an efficient, productive infection. in this study, we have taken advantage of a temperature-sensitive polymerase to shut off viral transcription, and we demonstrate that sinv rnas are subject to decay during a viral infection in b ...200817977976
human immunodeficiency virus type 1 vaccine development: recent advances in the cytotoxic t-lymphocyte platform "spotty business". 200817989174
possible stimulation of anti-tumor immunity using repeated cold stress: a hypothesis.the phenomenon of hormesis, whereby small amounts of seemingly harmful or stressful agents can be beneficial for the health and lifespan of laboratory animals has been reported in literature. in particular, there is accumulating evidence that daily brief cold stress can increase both numbers and activity of peripheral cytotoxic t lymphocytes and natural killer cells, the major effectors of adaptive and innate tumor immunity, respectively. this type of regimen (for 8 days) has been shown to impro ...200717999770
gamma-herpesvirus kinase actively initiates a dna damage response by inducing phosphorylation of h2ax to foster viral replication.dna virus infection can elicit the dna damage response in host cells, including atm kinase activation and h2ax phosphorylation. this is considered to be the host cell response to replicating viral dna. in contrast, we show that during infection of macrophages murine gamma-herpesvirus 68 (gammahv68) actively induces h2ax phosphorylation by expressing a viral kinase (orf36). gammahv68-encoded orf36 kinase and its ebv homolog, bglf4, induce h2ax phosphorylation independently of other viral genes. t ...200718005708
altered levels of stat1 and stat3 influence the neuronal response to interferon gamma.as immune responses in the cns are highly regulated, cell-specific differences in ifngamma signaling may be integral in dictating the outcome of host cell responses. in comparing the response of ifngamma-treated primary neurons to control mef, we observed that neurons demonstrated lower basal expression of both stat1 and stat3, the primary signal transducers responsible for ifngamma signaling. following ifngamma treatment of these cell populations, we noted muted and delayed stat1 phosphorylatio ...200718006082
maturation-dependent responses of human neuronal cells to western equine encephalitis virus infection and type i interferons.innate cell-autonomous antiviral responses are essential first lines of defense against central nervous system infections but may also contribute to neuropathogenesis. we investigated the relationships between innate immunity and neuronal differentiation using an in vitro culture system with human cell lines to analyze cellular responses to the neurotropic alphavirus western equine encephalitis virus. human neuronal cells displayed a maturation-dependent reduction in virus-induced cytopathology ...200818022665
venezuelan equine encephalitis virus in the mosquito vector aedes taeniorhynchus: infection initiated by a small number of susceptible epithelial cells and a population bottleneck.we evaluated infection of aedes taeniorhynchus mosquitoes, vectors of venezuelan equine encephalitis virus (veev), using radiolabeled virus and replicon particles expressing green (gfp) or cherry fluorescent protein (cfp). more epidemic veev bound to and infected mosquito midguts compared to an enzootic strain, and a small number of midgut cells was preferentially infected. chimeric replicons infected midgut cells at rates comparable to those of the structural gene donor. the numbers of midgut c ...200818023837
a glur1-cgkii interaction regulates ampa receptor trafficking.trafficking of ampa receptors (ampars) is regulated by specific interactions of the subunit intracellular c-terminal domains (ctds) with other proteins, but the mechanisms involved in this process are still unclear. we have found that the glur1 ctd binds to cgmp-dependent protein kinase ii (cgkii) adjacent to the kinase catalytic site. binding of glur1 is increased when cgkii is activated by cgmp. cgkii and glur1 form a complex in the brain, and cgkii in this complex phosphorylates glur1 at s845 ...200718031684
replication-coupled packaging mechanism in positive-strand rna viruses: synchronized coexpression of functional multigenome rna components of an animal and a plant virus in nicotiana benthamiana cells by agroinfiltration.flock house virus (fhv), a bipartite rna virus of insects and a member of the nodaviridae family, shares viral replication features with the tripartite brome mosaic virus (bmv), an rna virus that infects plants and is a member of the bromoviridae family. in bmv and fhv, genome packaging is coupled to replication, a widely conserved mechanism among positive-strand rna viruses of diverse origin. to unravel the events that modulate the mechanism of replication-coupled packaging, in this study, we h ...200818032497
amino acid substitutions in the s2 subunit of mouse hepatitis virus variant v51 encode determinants of host range expansion.we previously described mouse hepatitis virus (mhv) variant v51 derived from a persistent infection of murine dbt cells with an expanded host range (r. s. baric, e. sullivan, l. hensley, b. yount, and w. chen, j. virol. 73:638-649, 1999). sequencing of the v51 spike gene, the mediator of virus entry, revealed 13 amino acid substitutions relative to the originating mhv a59 strain. seven substitutions were located in the amino-terminal s1 cleavage subunit, and six were located in the carboxy-termi ...200818032498
rotavirus infection induces the phosphorylation of eif2alpha but prevents the formation of stress granules.early during the infection process, rotavirus causes the shutoff of cell protein synthesis, with the nonstructural viral protein nsp3 playing a vital role in the phenomenon. in this work, we have found that the translation initiation factor 2alpha (eif2alpha) in infected cells becomes phosphorylated early after virus infection and remains in this state throughout the virus replication cycle, leading to a further inhibition of cell protein synthesis. under these restrictive conditions, however, t ...200818032499
bovine viral diarrhea virus core is an intrinsically disordered protein that binds rna.pestiviruses, including bovine viral diarrhea virus (bvdv), are important animal pathogens and close relatives of hepatitis c virus. pestivirus particles are composed of an rna genome, a host-derived lipid envelope, and four virion-encoded structural proteins, core (c), e(rns), e1, and e2. core is a small, highly basic polypeptide that is processed by three enzymatic cleavages before its incorporation into virions. little is known about its biological properties or its role in virion assembly an ...200818032507
hippocampal poly(adp-ribose) polymerase 1 and caspase 3 activation in neonatal bornavirus infection.infection of neonatal rats with borna disease virus results in a characteristic behavioral syndrome and apoptosis of subsets of neurons in the hippocampus, cerebellum, and cortex (neonatal borna disease [nbd]). in the nbd rat hippocampus, dentate gyrus granule cells progressively degenerate. apoptotic loss of granule cells in nbd is associated with accumulation of zinc in degenerating neurons and reduced zinc in granule cell mossy fibers. excess zinc can trigger poly(adp-ribose) polymerase 1 (pa ...200818057239
the heat shock protein 70 cochaperone ydj1 is required for efficient membrane-specific flock house virus rna replication complex assembly and function in saccharomyces cerevisiae.the assembly of rna replication complexes on intracellular membranes is an essential step in the life cycle of positive-sense rna viruses. we have previously shown that hsp90 chaperone complex activity is essential for efficient flock house virus (fhv) rna replication in drosophila melanogaster s2 cells. to further explore the role of cellular chaperones in viral rna replication, we used both pharmacologic and genetic approaches to examine the role of the hsp90 and hsp70 chaperone systems in fhv ...200818057252
negative feedback regulation of rig-i-mediated antiviral signaling by interferon-induced isg15 conjugation.rig-i senses intracellular virus-specific nucleic acid structures and initiates an antiviral response that induces interferon (ifn) production, which, in turn, activates the transcription of rig-i to increase rig-i protein levels. upon intracellular poly(i:c) stimulation, however, the levels of rig-i protein did not correlate with the expression patterns of rig-i transcripts. when the isg15 conjugation system was overexpressed, isg15 was conjugated to rig-i and cellular levels of the unconjugate ...200818057259
man-threatening viruses isolated from ticks in saudi arabia.to determine tick viruses transmissible to man in saudi arabia.200718060218
replicating and non-replicating viral vectors for vaccine development.viral vectors provide a convenient means to deliver vaccine antigens to select target cells or tissues. a broad spectrum of replicating and non-replicating vectors is available. an appropriate choice for select applications will depend on the biology of the infectious agent targeted, as well as factors such as whether the vaccine is intended to prevent infection or boost immunity in already infected individuals, prior exposure of the target population to the vector, safety, and the number and si ...200718063357
crystal structure of the human laminin receptor precursor.the human laminin receptor (lamr) interacts with many ligands, including laminin, prions, sindbis virus, and the polyphenol (-)-epigallocatechin-3-gallate (egcg), and has been implicated in a number of diseases. lamr is overexpressed on tumor cells, and targeting lamr elicits anti-cancer effects. here, we report the crystal structure of human lamr, which provides insights into its function and should facilitate the design of novel therapeutics targeting lamr.200818063583
manipulation of rab gtpase function by intracellular bacterial pathogens.intracellular bacterial pathogens have evolved highly specialized mechanisms to enter and survive within their eukaryotic hosts. in order to do this, bacterial pathogens need to avoid host cell degradation and obtain nutrients and biosynthetic precursors, as well as evade detection by the host immune system. to create an intracellular niche that is favorable for replication, some intracellular pathogens inhibit the maturation of the phagosome or exit the endocytic pathway by modifying the identi ...200718063721
a single mutation in chikungunya virus affects vector specificity and epidemic potential.chikungunya virus (chikv) is an emerging arbovirus associated with several recent large-scale epidemics. the 2005-2006 epidemic on reunion island that resulted in approximately 266,000 human cases was associated with a strain of chikv with a mutation in the envelope protein gene (e1-a226v). to test the hypothesis that this mutation in the epidemic chikv (strain lr2006 opy1) might influence fitness for different vector species, viral infectivity, dissemination, and transmission of chikv were comp ...200718069894
efficient targeted transduction of primary human endothelial cells with dual-targeted lentiviral vectors.angiogenesis is a rate-limiting factor for numerous human diseases. angiogenic vessels and also the endothelium of certain organs such as the lung display molecular addresses that can be exploited for the selective delivery of gene therapeutics. lentiviral vectors (lvs) are powerful tools for stable gene delivery but their integration and expression in undesired cell types poses a serious safety concern. we have developed a dual-targeted lv that can specifically target primary endothelial cells ...200818074400
larval competition alters susceptibility of adult aedes mosquitoes to dengue infection.dengue, the most important human arboviral disease, is transmitted primarily by aedes aegypti and, to a lesser extent, by aedes albopictus. the current distributions of these invasive species overlap and are affected by interspecific larval competition in their container habitats. here we report that competition also enhances dengue infection and dissemination rates in one of these two vector species. we determined the effects of competition on adult a. aegypti and a. albopictus, comparing their ...200818077250
glur1 links structural and functional plasticity at excitatory synapses.long-term potentiation (ltp), a cellular model of learning and memory, produces both an enhancement of synaptic function and an increase in the size of the associated dendritic spine. synaptic insertion of ampa receptors is known to play an important role in mediating the increase in synaptic strength during ltp, whereas the role of ampa receptor trafficking in structural changes remains unexplored. here, we examine how the cell maintains the correlation between spine size and synapse strength d ...200718077682
hepatitis c virus genotype 1a growth and induction of autophagy.we have previously reported that immortalized human hepatocytes (ihh) support the generation of infectious hepatitis c virus (hcv) genotype 1a (clone h77). in the present study, we have investigated the growth of hcv genotype 1a (clone h77) through serial passages and accompanying changes in ihh in response to infection. eleven serial passages of hcv genotype 1a (clone h77) in ihh were completed. virus replication was ascertained from the presence of hcv-specific sequences, the detection of core ...200818077704
identification of three interferon-inducible cellular enzymes that inhibit the replication of hepatitis c virus.hepatitis c virus (hcv) infection is a common cause of chronic hepatitis and is currently treated with alpha interferon (ifn-alpha)-based therapies. however, the underlying mechanism of ifn-alpha therapy remains to be elucidated. to identify the cellular proteins that mediate the antiviral effects of ifn-alpha, we created a hek293-based cell culture system to inducibly express individual interferon-stimulated genes (isgs) and determined their antiviral effects against hcv. by screening 29 isgs t ...200818077728
ovarian tumor domain-containing viral proteases evade ubiquitin- and isg15-dependent innate immune responses.ubiquitin (ub) and interferon-stimulated gene product 15 (isg15) reversibly conjugate to proteins and mediate important innate antiviral responses. the ovarian tumor (otu) domain represents a superfamily of predicted proteases found in eukaryotic, bacterial, and viral proteins, some of which have ub-deconjugating activity. we show that the otu domain-containing proteases from nairoviruses and arteriviruses, two unrelated groups of rna viruses, hydrolyze ub and isg15 from cellular target proteins ...200718078692
bh3 domains define selective inhibitory interactions with bhrf-1 and kshv bcl-2.the epstein-barr and kaposi's sarcoma gamma-herpesviruses (kshvs) are associated with certain cancers, and encode b-cell leukemia/lymphoma 2 (bcl-2) homologs, bhrf-1 and kshv bcl-2, respectively. little is known, however, about the molecular interactions allowing viral bcl-2 homologs to mediate their anti-apoptotic function. cellular anti-apoptotic proteins, such as bcl-2 and mcl-1, prevent death via selective interactions with pro-death bh3-only proteins. to investigate whether bhrf-1 and kshv ...200818084238
immunological thresholds in neurological gene therapy: highly efficient elimination of transduced cells might be related to the specific formation of immunological synapses between t cells and virus-infected brain cells.first-generation adenovirus can be engineered with powerful promoters to drive expression of therapeutic transgenes. numerous clinical trials for glioblastoma multiforme using first generation adenoviral vectors have either been performed or are ongoing, including an ongoing, phase iii, multicenter trial in europe and israel (ark therapeutics, inc.). although in the absence of anti-adenovirus immune responses expression in the brain lasts 6-18 months, systemic infection with adenovirus induces i ...200618084640
visualization of double-stranded rna in cells supporting hepatitis c virus rna replication.the mechanisms involved in hepatitis c virus (hcv) rna replication are unknown, and this aspect of the virus life cycle is not understood. it is thought that virus-encoded nonstructural proteins and rna genomes interact on rearranged endoplasmic reticulum (er) membranes to form replication complexes, which are believed to be sites of rna synthesis. we report that, through the use of an antibody specific for double-stranded rna (dsrna), dsrna is readily detectable in huh-7 cells that contain repl ...200818094154
jaagsiekte sheep retrovirus utilizes a ph-dependent endocytosis pathway for entry.using moloney murine leukemia virus pseudovirions bearing the envelope protein of jaagsiekte sheep retrovirus (jsrv), we report here that entry was weakly inhibited by lysosomotropic agents but was profoundly blocked by bafilomycin a1 (bafa1). kinetics studies revealed that jsrv entry is a slow process and was substantially blocked by a dominant-negative mutant of dynamin. interestingly, a low-ph pulse overcame the bafa1 block to jsrv infection, although this occurred only if virus-bound cells w ...200818094164
dominant-negative fadd rescues the in vivo fitness of a cytomegalovirus lacking an antiapoptotic viral gene.genes that inhibit apoptosis have been described for many dna viruses. herpesviruses often contain even more than one gene to control cell death. apoptosis inhibition by viral genes is postulated to contribute to viral fitness, although a formal proof is pending. to address this question, we studied the mouse cytomegalovirus (mcmv) protein m36, which binds to caspase-8 and blocks death receptor-induced apoptosis. the growth of mcmv recombinants lacking m36 (deltam36) was attenuated in vitro and ...200818094168
west nile virus - where did it come from and where might it go? 200018159286
genetic determinants of sindbis virus mosquito infection are associated with a highly conserved alphavirus and flavivirus envelope sequence.wild-type sindbis virus (sinv) strain mre16 efficiently infects aedes aegypti midgut epithelial cells (mec), but laboratory-derived neurovirulent sinv strain te/5'2j infects mec poorly. sinv determinants for mec infection have been localized to the e2 glycoprotein. the e2 amino acid sequences of mre16 and te/5'2j differ at 60 residue sites. to identify the genetic determinants of mec infection of mre16, the te/5'2j virus genome was altered to contain either domain chimeras or more focused nucleo ...200818160430
cis- and trans-acting functions of brome mosaic virus protein 1a in genomic rna1 replication.rna viruses employ a combination of mechanisms to regulate their gene expression and replication. brome mosaic virus (bmv) is a tripartite positive-strand rna virus used to study the requirements for virus infection. bmv genomic rna1 encodes protein 1a, which contains a methyltransferase (mt) domain and a helicase domain that are required for replication. 1a forms a complex with the 2a rna-dependent rna polymerase for the replication and transcription of all bmv rnas. rna1 expressed with 2a from ...200818160434
alpha/beta interferon inhibits cap-dependent translation of viral but not cellular mrna by a pkr-independent mechanism.the alpha/beta interferon (ifn-alpha/beta) response is critical for host protection against disseminated replication of many viruses, primarily due to the transcriptional upregulation of genes encoding antiviral proteins. previously, we determined that infection of mice with sindbis virus (sb) could be converted from asymptomatic to rapidly fatal by elimination of this response (k. d. ryman et al., j. virol. 74:3366-3378, 2000). probing of the specific antiviral proteins important for ifn-mediat ...200818160435
synthetic heterovalent inhibitors targeting recognition e3 components of the n-end rule pathway.multivalent binding allows high selectivity and affinity in a ligand-protein interaction. the n-end rule pathway is a ubiquitin (ub)-dependent proteolytic system in which specific e3s, called n-recognins, mediate ubiquitylation through the recognition of types 1 and 2, destabilizing n-terminal residues of substrates. we recently identified a set of e3 ub ligases (named ubr1-ubr7) containing the 70-residue ubr box, and we demonstrated that ubr1, ubr2, ubr4, and ubr5 can bind to destabilizing n-te ...200818162545
envelope protein palmitoylations are crucial for murine coronavirus assembly.the coronavirus assembly process encloses a ribonucleoprotein genome into vesicles containing the lipid-embedded proteins s (spike), e (envelope), and m (membrane). this process depends on interactions with membranes that may involve palmitoylation, a common posttranslational lipidation of cysteine residues. to determine whether specific palmitoylations influence coronavirus assembly, we introduced plasmid dnas encoding mouse hepatitis coronavirus (mhv) s, e, m, and n (nucleocapsid) into 293t ce ...200818184706
experimental infection of aedes sollicitans and aedes taeniorhynchus with two chimeric sindbis/eastern equine encephalitis virus vaccine candidates.two chimeric vaccine candidates for eastern equine encephalitis virus (eeev) were developed by inserting the structural protein genes of either a north american (na) or south american (sa) eeev into a sindbis virus (sinv) backbone. to assess the effect of chimerization on mosquito infectivity, experimental infections of two potential north american bridge vectors of eeev, aedes sollicitans and ae. taeniorhynchus, were attempted. both species were susceptible to oral infection with all viruses af ...200818187790
autophagy in the pathogenesis of disease.autophagy is a lysosomal degradation pathway that is essential for survival, differentiation, development, and homeostasis. autophagy principally serves an adaptive role to protect organisms against diverse pathologies, including infections, cancer, neurodegeneration, aging, and heart disease. however, in certain experimental disease settings, the self-cannibalistic or, paradoxically, even the prosurvival functions of autophagy may be deleterious. this review summarizes recent advances in unders ...200818191218
intra-axonal translation and retrograde trafficking of creb promotes neuronal survival.during development of the nervous system, axons and growth cones contain mrnas such as beta-actin, cofilin and rhoa, which are locally translated in response to guidance cues. intra-axonal translation of these mrnas results in local morphological responses; however, other functions of intra-axonal mrna translation remain unknown. here, we show that axons of developing mammalian neurons contain mrna encoding the camp-responsive element (cre)-binding protein (creb). creb is translated within axons ...200818193038
the inflammatory cytokine, interleukin-1 beta, mediates loss of astroglial glutamate transport and drives excitotoxic motor neuron injury in the spinal cord during acute viral encephalomyelitis.astrocytes remove glutamate from the synaptic cleft via specific transporters, and impaired glutamate reuptake may promote excitotoxic neuronal injury. in a model of viral encephalomyelitis caused by neuroadapted sindbis virus (nsv), mice develop acute paralysis and spinal motor neuron degeneration inhibited by the ampa receptor antagonist, nbqx. to investigate disrupted glutamate homeostasis in the spinal cord, expression of the main astroglial glutamate transporter, glt-1, was examined. glt-1 ...200818194440
yellow fever virus ns3 plays an essential role in virus assembly independent of its known enzymatic functions.in flaviviruses it has been proposed that there is a coupling between genome replication and virion assembly and that nonstructural proteins are involved in this process. it was previously reported that mutations in yellow fever virus (yfv) nonstructural protein ns2a blocked production of infectious virus and that this block could be released by a suppressor mutation in ns3. here, based on studies using a yfv replicon-based trans-packaging system as well as full-length yfv cdna, we report that m ...200818199634
virus detection and monitoring of viral load in crimean-congo hemorrhagic fever virus patients.we developed a real-time reverse transcription--pcr that detected 1,164 copies/ml of crimean-congo hemorrhagic fever virus per milliliter of serum at 95% probability (probit analysis) and was 100% concordant with nested pcr on 63 samples from 31 patients with confirmed infection. infected patients who died appeared to have higher viral loads; low viral loads correlated with igg detection.200718214191
a two-phase innate host response to alphavirus infection identified by mrnp-tagging in vivo.a concept fundamental to viral pathogenesis is that infection induces specific changes within the host cell, within specific tissues, or within the entire animal. these changes are reflected in a cascade of altered transcription patterns evident during infection. however, elucidation of this cascade in vivo has been limited by a general inability to distinguish changes occurring in the minority of infected cells from those in surrounding uninfected cells. to circumvent this inherent limitation o ...200718215114
potential of alphavirus vectors in the treatment of advanced solid tumors.alphaviruses are positive-strand rna viruses that are being developed as a high level transient expression vectors. although most work so far has centered on their use as vaccine vectors, they do have potential as tumor therapy agents. the region of the genome coding for non-structural proteins induces rapid apoptosis in most infected cells, leaving the multiple cloning site (mcs) of the vector free for other purposes. two types of vector have been developed: recombinant suicide particles capabl ...200718221060
structural and biochemical bases for the inhibition of autophagy and apoptosis by viral bcl-2 of murine gamma-herpesvirus 68.all gammaherpesviruses express homologues of antiapoptotic b-cell lymphoma-2 (bcl-2) to counter the clearance of infected cells by host antiviral defense machineries. to gain insights into the action mechanisms of these viral bcl-2 proteins, we carried out structural and biochemical analyses on the interactions of m11, a viral bcl-2 of murine gamma-herpesvirus 68, with a fragment of proautophagic beclin1 and bcl-2 homology 3 (bh3) domain-containing peptides derived from an array of proapoptotic ...200818248095
annotation and expression profiling of apoptosis-related genes in the yellow fever mosquito, aedes aegypti.apoptosis has been extensively studied in drosophila by both biochemical and genetic approaches, but there is a lack of knowledge about the mechanisms of apoptosis regulation in other insects. in mosquitoes, apoptosis occurs during plasmodium and arbovirus infection in the midgut, suggesting that apoptosis plays a role in mosquito innate immunity. we searched the aedes aegypti genome for apoptosis-related genes using drosophila and anopheles gambiae protein sequences as queries. in this study we ...200818252247
venezuelan equine encephalitis virus capsid protein inhibits nuclear import in mammalian but not in mosquito cells.venezuelan equine encephalitis virus (veev) represents a continuous public health threat in the united states. it has the ability to cause fatal disease in humans and in horses and other domestic animals. we recently demonstrated that replicating veev interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. veev capsid protein was found to play a critical role in this process, and its approximately 35-amino-acid-long peptide, fus ...200818256144
sindbis virus infection in resident birds, migratory birds, and humans, finland.sindbis virus (sinv), a mosquito-borne virus that causes rash and arthritis, has been causing outbreaks in humans every seventh year in northern europe. to gain a better understanding of sinv epidemiology in finland, we searched for sinv antibodies in 621 resident grouse, whose population declines have coincided with human sinv outbreaks, and in 836 migratory birds. we used hemagglutination-inhibition and neutralization tests for the bird samples and enzyme immunoassays and hemagglutination-inhi ...200818258075
killing of macrophages by anthrax lethal toxin: involvement of the n-end rule pathway.macrophages from certain inbred mouse strains are rapidly killed (< 90 min) by anthrax lethal toxin (lt). lt cleaves cytoplasmic mek proteins at 20 min and induces caspase-1 activation in sensitive macrophages at 50-60 min, but the mechanism of lt-induced death is unknown. proteasome inhibitors block lt-mediated caspase-1 activation and can protect against cell death, indicating that the degradation of at least one cellular protein is required for lt-mediated cell death. proteins can be degraded ...200818266992
the 67 kda laminin receptor: structure, function and role in disease.the 67lr (67 kda laminin receptor) is a cell-surface receptor with high affinity for its primary ligand. its role as a laminin receptor makes it an important molecule both in cell adhesion to the basement membrane and in signalling transduction following this binding event. the protein also plays critical roles in the metastasis of tumour cells. isolation of the protein from either normal or cancerous cells results in a product with an approx. molecular mass of 67 kda. this protein is believed t ...200818269348
mutations in the nuclear localization signal of nsp2 influencing rna synthesis, protein expression and cytotoxicity of semliki forest virus.the cytotoxicity of semliki forest virus (sfv) infection is caused partly by the non-structural protein nsp2, an essential component of the sfv replicase complex. due to the presence of a nuclear localization signal (nls), nsp2 also localizes in the nucleus of infected cells. the present study analysed recombinant sfv replicons and genomes with various deletions or substitutions in the nls, or with a proline-to-glycine mutation at position 718 of nsp2 (p718g). deletion of one or two arginine res ...200818272758
translational control of the innate immune response through irf-7.transcriptional activation of cytokines, such as type-i interferons (interferon (ifn)-alpha and ifn-beta), constitutes the first line of antiviral defence. here we show that translational control is critical for induction of type-i ifn production. in mouse embryonic fibroblasts lacking the translational repressors 4e-bp1 and 4e-bp2, the threshold for eliciting type-i ifn production is lowered. consequently, replication of encephalomyocarditis virus, vesicular stomatitis virus, influenza virus an ...200818272964
increased virus replication in mammalian cells by blocking intracellular innate defense responses.the mammalian innate immune system senses viral infection by recognizing viral signatures and activates potent antiviral responses. besides the interferon (ifn) response, there is accumulating evidence that rna silencing or rna interference (rnai) serves as an antiviral mechanism in mammalian cells. mammalian viruses encode ifn antagonists to counteract the ifn response in infected cells. a number of ifn antagonists are also capable of blocking rnai in infected cells and therefore serve as rna-s ...200818273055
a mouse model for chikungunya: young age and inefficient type-i interferon signaling are risk factors for severe disease.chikungunya virus (chikv) is a re-emerging arbovirus responsible for a massive outbreak currently afflicting the indian ocean region and india. infection from chikv typically induces a mild disease in humans, characterized by fever, myalgia, arthralgia, and rash. cases of severe chikv infection involving the central nervous system (cns) have recently been described in neonates as well as in adults with underlying conditions. the pathophysiology of chikv infection and the basis for disease severi ...200818282093
isg15 inhibits nedd4 ubiquitin e3 activity and enhances the innate antiviral response.interferons regulate diverse immune functions through the transcriptional activation of hundreds of genes involved in anti-viral responses. the interferon-inducible ubiquitin-like protein isg15 is expressed in cells in response to a variety of stress conditions like viral or bacterial infection and is present in its free form or is conjugated to cellular proteins. in addition, protein ubiquitination plays a regulatory role in the immune system. many viruses modulate the ubiquitin (ub) pathway to ...200818287095
dose-dependent protection against or exacerbation of disease by a polylactide glycolide microparticle-adsorbed, alphavirus-based measles virus dna vaccine in rhesus macaques.measles remains an important cause of vaccine-preventable child mortality. development of a low-cost, heat-stable vaccine for infants under the age of 6 months could improve measles control by facilitating delivery at the time of other vaccines and by closing a window of susceptibility prior to immunization at 9 months of age. dna vaccines hold promise for development, but achieving protective levels of antibody has been difficult and there is an incomplete understanding of protective immunity. ...200818287579
a luciferase-based screening method for inhibitors of alphavirus replication applied to nucleoside analogues.several members of the widespread alphavirus group are pathogenic, but no therapy is available to treat these rna virus infections. we report here a quantitative assay to screen for inhibitors of semliki forest virus (sfv) replication, and demonstrate the effects of 29 nucleosides on sfv and sindbis virus replication. the anti-sfv assay developed is based on a sfv strain containing renilla luciferase inserted after the nsp3 coding region, yielding a marker virus in which the luciferase is cleave ...200818294708
protection from fatal viral encephalomyelitis: ampa receptor antagonists have a direct effect on the inflammatory response to infection.neuronal cell death during fatal acute viral encephalomyelitis can result from damage caused by virus replication, glutamate excitotoxicity, and the immune response. a neurovirulent strain of the alphavirus sindbis virus (nsv) causes fatal encephalomyelitis associated with motor neuron death in adult c57bl/6 mice that can be prevented by treatment with the prototypic noncompetitive alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (ampa) glutamate receptor antagonist gyki 52466 [nargi-ai ...200818296635
engineered lentivector targeting of dendritic cells for in vivo immunization.we report a method of inducing antigen production in dendritic cells by in vivo targeting with lentiviral vectors that specifically bind to the dendritic cell-surface protein dc-sign. to target dendritic cells, we enveloped the lentivector with a viral glycoprotein from sindbis virus engineered to be dc-sign-specific. in vitro, this lentivector specifically transduced dendritic cells and induced dendritic cell maturation. a high frequency (up to 12%) of ovalbumin (ova)-specific cd8(+) t cells an ...200818297056
inhibition of arp2/3-mediated actin polymerization by pick1 regulates neuronal morphology and ampa receptor endocytosis.the dynamic regulation of actin polymerization plays crucial roles in cell morphology and endocytosis. the mechanistic details of these processes and the proteins involved are not fully understood, especially in neurons. pick1 is a pdz-bar-domain protein involved in regulated ampa receptor (ampar) endocytosis in neurons. here, we demonstrate that pick1 binds filamentous (f)-actin and the actin-nucleating arp2/3 complex, and potently inhibits arp2/3-mediated actin polymerization. rna interference ...200818297063
proteasome inhibitor-induced apoptosis is mediated by positive feedback amplification of pkcdelta proteolytic activation and mitochondrial translocation.emerging evidence implicates impaired protein degradation by the ubiquitin proteasome system (ups) in parkinson's disease; however cellular mechanisms underlying dopaminergic degeneration during proteasomal dysfunction are yet to be characterized. in the present study, we identified that the novel pkc isoform pkcdelta plays a central role in mediating apoptotic cell death following ups dysfunction in dopaminergic neuronal cells. inhibition of proteasome function by mg-132 in dopaminergic neurona ...200818298651
rubella virus capsid protein interacts with poly(a)-binding protein and inhibits translation.during virus assembly, the capsid proteins of rna viruses bind to genomic rna to form nucleocapsids. however, it is now evident that capsid proteins have additional functions that are unrelated to nucleocapsid formation. specifically, their interactions with cellular proteins may influence signaling pathways or other events that affect virus replication. here we report that the rubella virus (rv) capsid protein binds to poly(a)-binding protein (pabp), a host cell protein that enhances translatio ...200818305028
role of sindbis virus capsid protein region ii in nucleocapsid core assembly and encapsidation of genomic rna.sindbis virus is an enveloped positive-sense rna virus in the alphavirus genus. the nucleocapsid core contains the genomic rna surrounded by 240 copies of a single capsid protein. the capsid protein is multifunctional, and its roles include acting as a protease, controlling the specificity of rna that is encapsidated into nucleocapsid cores, and interacting with viral glycoproteins to promote the budding of mature virus and the release of the genomic rna into the newly infected cell. the region ...200818305029
coronavirus infection modulates the unfolded protein response and mediates sustained translational repression.during coronavirus replication, viral proteins induce the formation of endoplasmic reticulum (er)-derived double-membrane vesicles for rna synthesis, and viral structural proteins assemble virions at the er-golgi intermediate compartment. we hypothesized that the association and intense utilization of the er during viral replication would induce the cellular unfolded protein response (upr), a signal transduction cascade that acts to modulate translation, membrane biosynthesis, and the levels of ...200818305036
formation of the arterivirus replication/transcription complex: a key role for nonstructural protein 3 in the remodeling of intracellular membranes.the replication/transcription complex of the arterivirus equine arteritis virus (eav) is associated with paired membranes and/or double-membrane vesicles (dmvs) that are thought to originate from the endoplasmic reticulum. previously, coexpression of two putative transmembrane nonstructural proteins (nsp2 and nsp3) was found to suffice to induce these remarkable membrane structures, which are typical of arterivirus infection. here, site-directed mutagenesis was used to investigate the role of ns ...200818305048
severe acute respiratory syndrome coronavirus nsp1 suppresses host gene expression, including that of type i interferon, in infected cells.the severe acute respiratory syndrome coronavirus (sars-cov) nsp1 protein has unique biological functions that have not been described in the viral proteins of any rna viruses; expressed sars-cov nsp1 protein has been found to suppress host gene expression by promoting host mrna degradation and inhibiting translation. we generated an nsp1 mutant (nsp1-mt) that neither promoted host mrna degradation nor suppressed host protein synthesis in expressing cells. both a sars-cov mutant virus, encoding ...200818305050
isg15 inhibits ebola vp40 vlp budding in an l-domain-dependent manner by blocking nedd4 ligase activity.ebola virus budding is mediated by the vp40 matrix protein. vp40 can bud from mammalian cells independent of other viral proteins, and efficient release of vp40 virus-like particles (vlps) requires interactions with host proteins such as tsg101 and nedd4, an e3 ubiquitin ligase. ubiquitin itself is thought to be exploited by ebola virus to facilitate efficient virus egress. disruption of vp40 function and thus virus budding remains an attractive target for the development of novel antiviral ther ...200818305167
orthomyxo-, paramyxo- and flavivirus infections in wild waterfowl in finland.screening wild birds for viral pathogens has become increasingly important. we tested a screening approach based on blood and cloacal and tracheal swabs collected by hunters to study the prevalence of influenza a, paramyxo-, flavi-, and alphaviruses in finnish wild waterfowl, which has been previously unknown. we studied 310 blood samples and 115 mixed tracheal and cloacal swabs collected from hunted waterfowl in 2006. samples were screened by rt-pcr and serologically by hemagglutination inhibit ...200818307758
nlrx1: friend or foe? 200818311173
c3h/hen mouse model for the evaluation of antiviral agents for the treatment of venezuelan equine encephalitis virus infection.the tc-83 vaccine strain of venezuelan equine encephalitis virus (veev) causes encephalitis and death in c3h/hen mice infected by intranasal (i.n.) instillation. since tc-83 is exempt as a select agent, this mouse model was used in the evaluation of antiviral therapies. virus titers in the brains of infected mice peaked on 4 dpi and persisted at high levels until death at 9.4+/-0.5 dpi. mouse brains appeared histologically normal on 2 dpi, but developed meningoencephalitis, neuropil vacuolation, ...200818313150
the interferon-induced protein bst-2 restricts hiv-1 release and is downregulated from the cell surface by the viral vpu protein.the hiv-1 accessory protein vpu counteracts a host factor that restricts virion release from infected cells. here we show that the interferon-induced cellular protein bst-2/hm1.24/cd317 is such a factor. bst-2 is downregulated from the cell surface by vpu, and bst-2 is specifically expressed in cells that support the vpu phenotype. exogenous expression of bst-2 inhibits hiv-1 virion release, while suppression of bst-2 relieves the requirement for vpu. downregulation of bst-2 requires both the tr ...200818342597
the enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response.arthropod-borne (arbo-) viruses have emerged as a major human health concern. viruses transmitted by mosquitoes are the cause of the most serious and widespread arbovirus diseases worldwide and are ubiquitous in both feral and urban settings. arboviruses, including dengue and west nile virus, are injected into vertebrates within mosquito saliva during mosquito feeding. mosquito saliva contains anti-haemostatic, anti-inflammatory and immunomodulatory molecules that facilitate the acquisition of a ...200818342898
experimental reovirus-induced acute flaccid paralysis and spinal motor neuron cell death.acute flaccid paralysis (afp) describes the loss of motor function in 1 or more limbs commonly associated with viral infection and destruction of motor neurons in the anterior horns of the spinal cord. therapy is limited, and the development of effective treatments is hampered by a lack of experimental models. reovirus infection of neonatal mice provides a model for the study of cns viral infection pathogenesis. injection of the reovirus serot type 3 strains abney (t3a) or dearing (t3d) into the ...200818344914
therapeutic human papillomavirus vaccines: current clinical trials and future directions.cervical cancer is the second largest cause of cancer deaths in women worldwide. it is now evident that persistent infection with high-risk human papillomavirus (hpv) is necessary for the development and maintenance of cervical cancer. thus, effective vaccination against hpv represents an opportunity to restrain cervical cancer and other important cancers. the fda recently approved the hpv vaccine gardasil for the preventive control of hpv, using hpv virus-like particles (vlp) to generate neutra ...200818352847
structural and nonstructural protein genome regions of eastern equine encephalitis virus are determinants of interferon sensitivity and murine virulence.eastern equine encephalitis virus (eeev) causes sporadic epidemics of human and equine disease in north america, but south american strains have seldom been associated with human neurologic disease or mortality, despite serological evidence of infection. in mice, most north american and south american strains of eeev produce neurologic disease that resembles that associated with human and equine infections. we identified a south american strain that is unable to replicate efficiently in the brai ...200818353963
infectivity studies of influenza virus hemagglutinin receptor binding site mutants in mice.the replicative properties of influenza virus hemagglutinin (ha) mutants with altered receptor binding characteristics were analyzed following intranasal inoculation of mice. among the mutants examined was a virus containing a y98f substitution at a conserved position in the receptor binding site that leads to a 20-fold reduction in binding. this mutant can replicate as well as wild-type (wt) virus in mdck cells and in embryonated chicken eggs but is highly attenuated in mice, exhibiting titers ...200818353965
tumor-specific th17-polarized cells eradicate large established melanoma.cd4+ t cells can differentiate into multiple effector subsets, but the potential roles of these subsets in anti-tumor immunity have not been fully explored. seeking to study the impact of cd4+ t cell polarization on tumor rejection in a model mimicking human disease, we generated a new mhc class ii-restricted, t-cell receptor (tcr) transgenic mouse model in which cd4+ t cells recognize a novel epitope in tyrosinase-related protein 1 (trp-1), an antigen expressed by normal melanocytes and b16 mur ...200818354038
human immunodeficiency virus type-1 infection inhibits autophagy.human immunodeficiency virus type-1 (hiv-1) induces a series of alterations in the host cell that modify the intracellular environment in favor of viral replication, survival and spread. this research examined the impact of hiv-1 infection on autophagy in hiv-1 infected cells.200818356598
bcl-2-family proteins and hematologic malignancies: history and future prospects.bcl-2 was the first antideath gene discovered, a milestone that effectively launched a new era in cell death research. since its discovery more than 2 decades ago, multiple members of the human bcl-2 family of apoptosis-regulating proteins have been identified, including 6 antiapoptotic proteins, 3 structurally similar proapoptotic proteins, and several structurally diverse proapoptotic interacting proteins that operate as upstream agonists or antagonists. bcl-2-family proteins regulate all majo ...200818362212
antigen-specific immunotherapy of cervical and ovarian cancer.we contrast the efforts to treat ovarian cancer and cervical cancer through vaccination because of their different pathobiology. a plethora of approaches have been developed for therapeutic vaccination against cancer, many of which target defined tumor-associated antigens (taas). persistent infection with oncogenic human papillomavirus (hpv) types causes cervical cancer. furthermore, cervical cancer patients frequently mount both humoral and t-cell immune responses to the hpv e6 and e7 oncoprote ...200818363994
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