subcellular localization and calcium and ph requirements for proteolytic processing of the hendra virus fusion protein.proteolytic cleavage of the hendra virus fusion (f) protein results in the formation of disulfide-linked f1 and f2 subunits, with cleavage occurring after residue k109 in the sequence gdvk/l. this unusual cleavage site and efficient propagation of hendra virus in a furin-deficient cell line indicate that the hendra f protein is not cleaved by furin, the protease responsible for proteolytic activation of many viral fusion proteins. to identify the subcellular site of hendra f processing, vero cel ...200415308711
phototoxicity against tumor cells and sindbis virus by an octahedral rhodium bisbipyridyl complex and evidence for the genome as a target in viral octahedral rhodium complex (cis-dichloro(dipyrido[3,2a-2',3'c]phenazine)(1,10-phenanthroline)rhodium(iii) chloride; dppzphen) has been prepared that can penetrate tumor cell membranes and the sindbis viral capsid. the compound is phototoxic to these entities when irradiated with uva light. model studies with calf thymus and supercoiled plasmid dna indicate that the complex can both bind with, and nick, nucleic acid. analysis of sindbis virus, following irradiation with the metal complex, conf ...200415310216
effects of ras and rap1 on electrical excitability of differentiated ng108-15 cells.effects of two small g-proteins, rap1 and ras, on the sodium channel activity in ng108-15 cells were studied using sindbis virus-mediated gene transfer. when an activated rap1a mutant (rap1-12v, the activated mutant of rap1 carrying glycine to valine substitution at codon 12) or a dominant-negative h-ras mutant (ras-17n, carrying serine to asparagine substitution at codon 17) was expressed in differentiated ng108-15 cells, the proportion of cells generating action potential decreased and the amp ...200415312909
viral-induced spinal motor neuron death is non-cell-autonomous and involves glutamate excitotoxicity.neuroadapted sindbis virus (nsv) is a neurotropic virus capable of inducing the death of spinal motor neurons in mice and rats. in this study we investigated the mechanisms that underlie nsv-induced motor neuron death. we found that many degenerating spinal motor neurons were not infected directly with nsv, suggesting that bystander cell death occurs. an excitotoxic mechanism was confirmed when blockade of calcium-permeable ampa receptors attenuated motor neuron death both in vitro and in vivo. ...200415329404
intranasal immunization with inactivated influenza virus enhances immune responses to coadministered simian-human immunodeficiency virus-like particle antigens.intranasal immunization with inactivated influenza virus vaccine can provide protective immunity, whereas many other antigens are less effective when used for mucosal immunization. to determine whether influenza virus could enhance immune responses to an antigen coadministered to a mucosal surface, we studied the intranasal immunization of mice with a mixture of simian-human immunodeficiency virus (shiv) virus-like particles (vlps) and inactivated influenza virus. compared to mice immunized with ...200415331695
a mutant of sindbis virus which is able to replicate in cells with reduced ctp makes a replicase/transcriptase with a decreased km for ctp.we reported earlier the isolation and characterization of a sindbis virus mutant, sv(pzf), that can grow in mosquito cells treated with pyrazofurin (pzf), a compound that interferes with pyrimidine biosynthesis (y. h. lin, p. yadav, r. ravatn, and v. stollar, virology 272:61-71, 2000; y. h. lin, h. a. simmonds, and v. stollar, virology 292:78-86, 2002). three amino acid changes in nsp4, the viral rna polymerase, were required to produce this phenotype. we now describe a mutant of sindbis virus, ...200415331697
discrimination among rhinovirus serotypes for a variant icam-1 receptor molecule.intercellular adhesion molecule 1 (icam-1) is the cellular receptor for the major group of human rhinovirus serotypes, including human rhinovirus 14 (hrv14) and hrv16. a naturally occurring variant of icam-1, icam-1kilifi, has altered binding characteristics with respect to different hrv serotypes. hrv14 binds to icam-1 only transiently at physiological temperatures but forms a stable complex with icam-1kilifi. conversely, hrv16 forms a stable complex with icam-1 but does not bind to icam-1kilif ...200415331736
the immunoglobulin family member dendrite arborization and synapse maturation 1 (dasm1) controls excitatory synapse the developing mammalian brain, a large fraction of excitatory synapses initially contain only n-methyl-d-aspartate receptor and thus are "silent" at the resting membrane potential. as development progresses, synapses acquire alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (ampa-rs). although this maturation of excitatory synapses has been well characterized, the molecular basis for this developmental change is not known. here, we report that dendrite arborization and synap ...200415340156
biological diversity versus risk for mosquito nuisance and disease transmission in constructed wetlands in southern southern sweden, many wetlands have been constructed, and maintaining or increasing biological diversity is often included in the aims. some wetlands are constructed near human settlements, thus raising the problem of wetlands being associated with mosquitoes (diptera: culicidae). increased biodiversity (including mosquito diversity) is considered desirable, whereas mosquito nuisance from a human point of view is not. adult mosquito abundance, diversity and species assemblages of constructed ...200415347393
sindbis viral-mediated expression of egfp-dopamine d1 receptors in situ with real-time two-photon microscopic detection.dopamine d1 receptors (d1drs) mediate a major component of dopaminergic neurotransmission, and alterations in their synaptic and subcellular distribution may underlie a variety of neurological diseases. in order to monitor d1dr localization in real time, we subcloned a sindbis virus containing an enhanced-gfp coding region inserted at the c-terminal region of a dopamine d1 receptor (egfp-d1dr). two-photon excitation of expressed egfp-d1drs was monitored in a variety of viable neural preparations ...200415351518
zap is a crm1-dependent nucleocytoplasmic shuttling protein.the zinc finger antiviral protein (zap) is a recently isolated host antiviral factor. it specifically inhibits the replication of moloney murine leukemia virus (mmlv) and sindbis virus (sin) by preventing the accumulation of viral rna in the cytoplasm. in this report, we demonstrate that zap is predominantly localized in the cytoplasm at steady state but shuttles between the nucleus and the cytoplasm in a crm1-dependent manner. two nuclear localization sequences (nls) and one nuclear export sequ ...200415358138
human immunodeficiency virus type 1 gag-specific mucosal immunity after oral immunization with papillomavirus pseudoviruses encoding gag.mucosal surfaces are the primary portals for human immunodeficiency virus (hiv) transmission. because systemic immunization, in general, does not induce effective mucosal immune responses, a mucosal hiv vaccine is urgently needed. for this study, we developed papillomavirus pseudoviruses that express hiv-1 gag. the pseudoviruses are synthetic, nonreplicating viruses, yet they can produce antigens for a long time in the immune system. here we show that oral immunization of mice by the use of papi ...200415367590
structural properties of a multifunctional t-shaped rna domain that mediate efficient tomato bushy stunt virus rna positive-strand rna viruses, 5' untranslated regions (5' utrs) mediate many essential viral processes, including genome replication. previously, we proposed that the 5'-terminal portion of the genomic leader sequence of tomato bushy stunt virus (tbsv) forms an rna structure containing a 3-helix junction, termed the t-shaped domain (tsd). in the present study, we have carried out structure-function analysis of the proposed tsd and have confirmed an important role for this domain in mediating e ...200415367615
temporal modulation of an autoprotease is crucial for replication and pathogenicity of an rna virus.pestiviruses belong to the family flaviviridae, and their genome is a single-stranded rna of positive polarity encoding one large polyprotein which is further processed into mature proteins. noncytopathogenic (noncp) strains of the pestivirus bovine viral diarrhea virus (bvdv) can establish persistent infection. in persistently infected animals, noncp bvdvs occasionally acquire mutations in viral nonstructural protein 2 (ns2) that give rise to cytopathogenic (cp) bvdv variants, and, eventually, ...200415367643
gene therapy for malignant glioma using sindbis vectors expressing a fusogenic membrane glycoprotein.malignant glioma has a dismal prognosis. it was previously shown that glioma cells are efficiently killed when they express a gene coding for a hyperfusogenic mutant of the gibbon ape leukemia virus envelope glycoprotein (galv.fus). however, production of viral vectors expressing galv.fus has proven problematic because the transgene is toxic to vector-producing cells of human origin. we reasoned that sindbis-virus-based vectors might be ideal for galv.fus gene transfer because high-titer stocks ...200415368589
using sindbis viral vectors for specific detection and suppression of advanced ovarian cancer in animal models.we studied the therapeutic value of sindbis vectors for advanced metastatic ovarian cancer by using two highly reproducible and clinically accurate mouse models: a scid xenograft model, established by i.p. inoculation of human es-2 ovarian cancer cells, and a syngenic c57bl/6 model, established by i.p. inoculation of mouse mosec ovarian cancer cells. we demonstrate through imaging, histologic, and molecular data that sindbis vectors systemically and specifically infect/detect and kill metastasiz ...200415374985
antigenic and genetic typing of whataroa viruses in australia.we recently characterized three novel alphaviruses isolated from mosquitoes captured in new south wales, australia. initial cross-neutralization studies revealed antigenic similarity to the sindbis virus (sinv)-like whataroa virus (whav), heretofore found only in new zealand. nucleotide sequence analysis showed that the whav-like viruses shared >99% nucleotide sequence similarity with each other, and 96-97% similarity with prototype whav. enzyme-linked immunosorbent assay reactions of a panel of ...200415381803
mannose-specific plant lectins from the amaryllidaceae family qualify as efficient microbicides for prevention of human immunodeficiency virus infection.the plant lectins derived from galanthus nivalis (snowdrop) (gna) and hippeastrum hybrid (amaryllis) (hha) selectively inhibited a wide variety of human immunodeficiency virus type 1 (hiv-1) and hiv-2 strains and clinical (cxcr4- and ccr5-using) isolates in different cell types. they also efficiently inhibited infection of t lymphocytes by a variety of mutant virus strains. gna and hha markedly prevented syncytium formation between persistently infected hut-78/hiv cells and uninfected t lymphocy ...200415388446
sindbis virus--an effective targeted cancer therapeutic.viral therapies for cancer therapy have many potential positive attributes. these include the ability to specifically infect targeted cells, specifically express toxic or immune-enhancing genes, and the ability to specifically replicate within a tumor cell. despite these biological advantages, efficacy to date has been limited. a recent report demonstrates that the sindbis virus has remarkable properties in three challenging areas of gene therapy - specificity, efficacy and delivery, suggesting ...200415450742
targeted in vivo expression of proteins in the calyx of held.the calyx of held serves as a model for synaptic transmission in the mammalian central nervous system. while offering unique access to the biophysics of presynaptic function, studies addressing the molecular mechanisms of neurotransmitter exocytosis in this model have been mainly limited to pharmacological interventions. to overcome this experimental limitation we used stereotaxic delivery of viral gene shuttles to rapidly and selectively manipulate protein composition in the calyx terminal in v ...200415452710
characterization of an endogenous gene expressed in aedes aegypti using an orally infectious recombinant sindbis virus.sindbis virus expression vectors have been used successfully to express and silence genes of interest in vivo in several mosquito species, including aedes aegypti, ae. albopictus, ae. triseriatus,culex pipiens, armigeres subalbatus and anopheles gambiae. here we describe the expression of an endogenous gene, defensin, in ae. aegypti using the orally infectious sindbis virus, mre/3'2j expression vector. we optimized conditions to infect mosquito larvae per os using c6/36ae. albopictus cells infec ...200115455070
alphavirus expression systems: applications to mosquito vector this review, steve higgs, ann powers and ken olson describe how alphavirus expression systems, based on infectious cdna clones of sindbis virus, constitute a novel rna virus delivery system suitable for the efficient expression of heterologous gene products or rna sequences in mosquito cells or adult mosquitoes. the technique permits ready assessment of molecular genetic-based methods of intracellular interference to infection and provides a powerful new tool for molecular biological studies ...199315463689
trans-packaged west nile virus-like particles: infectious properties in vitro and in infected mosquito vectors.a trans-packaging system for west nile virus (wnv) subgenomic replicon rnas (reprnas), deleted for the structural coding region, was developed. wnv reprnas were efficiently encapsidated by the wnv c/prm/e structural proteins expressed in trans from replication-competent, noncytopathic sindbis virus-derived rnas. infectious virus-like particles (vlps) were produced in titers of up to 10(9) infectious units/ml. wnv vlps established a single round of infection in a variety of different cell lines w ...200415479801
evolutionary transition toward defective rnas that are infectious by complementation.passage of foot-and-mouth disease virus (fmdv) in cell culture resulted in the generation of defective rnas that were infectious by complementation. deletions (of nucleotides 417, 999, and 1017) mapped in the l proteinase and capsid protein-coding regions. cell killing followed two-hit kinetics, defective genomes were encapsidated into separate viral particles, and individual viral plaques contained defective genomes with no detectable standard fmdv rna. infection in the absence of standard fmdv ...200415479809
cd209l (l-sign) is a receptor for severe acute respiratory syndrome coronavirus.angiotensin-converting enzyme 2 (ace2) is a receptor for sars-cov, the novel coronavirus that causes severe acute respiratory syndrome [li, w. moore, m. j., vasilieva, n., sui, j., wong, s. k., berne, m. a., somasundaran, m., sullivan, j. l., luzuriaga, k., greenough, t. c., et al. (2003) nature 426, 450-454]. we have identified a different human cellular glycoprotein that can serve as an alternative receptor for sars-cov. a human lung cdna library in vesicular stomatitis virus g pseudotyped ret ...200415496474
rna encoding the mpt83 antigen induces protective immune responses against mycobacterium tuberculosis infection.we have previously demonstrated that vaccination of mice with plasmid dna vectors expressing immunodominant mycobacterial genes induced cellular immune responses and significant protection against challenge with mycobacterium tuberculosis. we demonstrate here, using in vitro-synthesized rna, that vaccination with dna or rna constructs expressing the m. tuberculosis mpt83 antigen are capable of inducing specific humoral and t-cell immune responses and confer modest but significant protection agai ...200415501761
expression of antiapoptotic genes bcl-xl and ced-9 in tomato enhances tolerance to viral-induced necrosis and abiotic stress.d satellite rna (satrna) is a strain of cucumber mosaic virus (cmv) satrna that induces an epidemic lethal disease in tomato. no natural resistance or tolerance has ever been found. previously, we demonstrated the involvement of programmed cell death in disease development. here, transgenic tomato plants expressing animal antiapoptotic genes bcl-xl and ced-9 were generated through agrobacterium-mediated transformation. high expression of bcl-xl or ced-9 affected plant growth and seed development ...200415505199
analysis of adaptive mutations in kunjin virus replicon rna reveals a novel role for the flavivirus nonstructural protein ns2a in inhibition of beta interferon promoter-driven transcription.the establishment of persistent noncytopathic replication by replicon rnas of a number of positive-strand rna viruses usually leads to generation of adaptive mutations in nonstructural genes. some of these adaptive mutations (e.g., in hepatitis c virus) increase the ability of rna replication to resist the antiviral action of alpha/beta interferon (ifn-alpha/beta); others (e.g., in sindbis virus) may also lead to more efficient ifn production. using puromycin-selectable kunjin virus (kun) replic ...200415507609
serotype-specific entry of dengue virus into liver cells: identification of the 37-kilodalton/67-kilodalton high-affinity laminin receptor as a dengue virus serotype 1 receptor.dengue virus, the causative agent of dengue fever, dengue shock syndrome, and dengue hemorrhagic fever, infects susceptible cells by initially binding to a receptor(s) located on the host cell surface. evidence to date suggests that receptor usage may be cell and serotype specific, and this study sought to identify dengue virus serotype 1 binding proteins on the surface of liver cells, a known target organ. by using a virus overlay protein binding assay (vopba), in both nondenaturing and denatur ...200415507651
the nucleoprotein is required for efficient coronavirus genome replication.the construction of a set of transmissible gastroenteritis coronavirus (tgev)-derived replicons as bacterial artificial chromosomes is reported. these replicons were generated by sequential deletion of nonessential genes for virus replication, using a modified tgev full-length cdna clone containing unique restriction sites between each pair of consecutive genes. efficient activity of tgev replicons was associated with the presence of the nucleoprotein provided either in cis or in trans. tgev rep ...200415507657
ebna2 is required for protection of latently epstein-barr virus-infected b cells against specific apoptotic addition to functioning as a transcriptional transactivator, epstein-barr virus ebna2 interacts with nur77 to protect against nur77-mediated apoptosis. estrogen-regulated ebna2 in ereb2-5 cells was replaced by either ebna2 or ebna2 with a deletion of conserved region 4 (ebna2deltacr4). both ebna2-converted and ebna2deltacr4-converted ereb2-5 cells grew in the absence of estrogen and expressed lmp1. treatment with tumor necrosis factor alpha did not induce apoptosis of ebna2- or ebna2deltacr4- ...200415507659
cross talk between metabotropic and ionotropic glutamate receptor-mediated signaling in parallel fiber-induced inositol 1,4,5-trisphosphate production in cerebellar purkinje many excitatory glutamatergic synapses, both ionotropic glutamate receptors (iglurs) and metabotropic glutamate receptors (mglurs) are closely distributed on the postsynaptic membrane. however, the functional significance of the close distribution of the two types of glutamate receptors has not been fully clarified. in this study, we examined the functional interaction between iglur and mglur at parallel fiber (pf)--> purkinje cell synapses in the generation of inositol 1,4,5-trisphosphate (i ...200415509738
retinoid x receptor regulates nur77/tr3-dependent apoptosis [corrected] by modulating its nuclear export and mitochondrial targeting.retinoid x receptor (rxr) plays a central role in the regulation of intracellular receptor signaling pathways by acting as a ubiquitous heterodimerization partner of many nuclear receptors, including the orphan receptor nur77 (also known as tr3 [corrected] or ngfi-b), which translocates from the nucleus to mitochondria, where it interacts with bcl-2 to induce apoptosis. here, we report that rxralpha is required for nuclear export and mitochondrial targeting of nur77 through their unique heterodi ...200415509776
[antibodies against mosquito-born viruses in human population of an area of central bohemia affected by the flood of 2002].in the central-bohemian area affected by the flood of 2002, 497 residents were screened for antibodies against the mosquito-borne viruses tahyna (tahv), west nile (wnv), sindbis (sinv) and batai (batv; syn. calovo) using the haemagglutination-inhibition (hit) and plaque-reduction neutralization (prnt) tests. blood samples were collected in september 2002 when the mosquito populations showed the maximum density following the flood. antibodies against tahv (16.5% persons in prnt, 14.9% in hit), si ...200415524269
preferential targeting of vesicular stomatitis virus to breast cancer cells.vesicular stomatitis virus (vsv) is a candidate for development for cancer therapy. we created a recombinant replicating vsv (rrvsv) with an altered surface protein that targeted preferentially to breast cancer cells. the rrvsv genome contained a single glycoprotein (gp) gene derived from sindbis virus. this gene expressed a chimeric sindbis e2 binding gp and the native sindbis e1 fusion gp. the chimeric e2 binding gp, called sindbis-sca-erbb2, was modified to reduce its native binding function ...200415527831
role of isg15 protease ubp43 (usp18) in innate immunity to viral infection.innate immune responses provide the host with an early protection barrier against infectious agents, including viruses, and help shape the nature and quality of the subsequent adaptive immune responses of the host. expression of isg15 (ucrp), a ubiquitin-like protein, and protein isgylation are highly increased upon viral infection. we have identified ubp43 (usp18) as an isg15 deconjugating protease. protein isgylation is enhanced in cells deficient in ubp43 (ref. 6). here we have examined the r ...200415531891
alphaviral cytotoxicity and its implication in vector development.a great variety of viruses have been engineered to serve as expression vectors. among them, the alphaviruses semliki forest virus and sindbis virus represent promising tools for heterologous gene expression in a wide variety of host cells. several applications have already been described in neurobiological studies, in gene therapy, for vaccine development and in cancer therapy. both viruses trigger stress pathways in the cells they infect, sometimes culminating in the death of the host. this inh ...200515542620
the zinc finger antiviral protein directly binds to specific viral mrnas through the ccch zinc finger motifs.the zinc finger antiviral protein (zap) is a recently isolated host antiviral factor. it specifically inhibits the replication of moloney murine leukemia virus (mlv) and sindbis virus (sin) by preventing the accumulation of viral rna in the cytoplasm. for this report, we mapped the viral sequences that are sensitive to zap inhibition. the viral sequences were cloned into a luciferase reporter and analyzed for the ability to mediate zap-dependent destabilization of the reporter. the sensitive seq ...200415542630
coexpression of hepatitis c virus e1 and e2 chimeric envelope glycoproteins displays separable ligand sensitivity and increases pseudotype infectious titer.we have previously reported that a pseudotype virus generated by reconstitution of hepatitis c virus (hcv) chimeric envelope glycoprotein e1-g or e2-g on the surface of a temperature-sensitive mutant of vesicular stomatitis virus (vsvts045) interacts independently with mammalian cells to initiate infection. here, we examined whether coexpression of both of the envelope glycoproteins on pseudotype particles would augment virus infectivity and/or alter the functional properties of the individual s ...200415542636
proteomics computational analyses suggest that the carboxyl terminal glycoproteins of bunyaviruses are class ii viral fusion protein (beta-penetrenes).the bunyaviridae family of enveloped rna viruses includes five genuses, orthobunyaviruses, hantaviruses, phleboviruses, nairoviruses and tospoviruses. it has not been determined which bunyavirus protein mediates virion:cell membrane fusion. class ii viral fusion proteins (beta-penetrenes), encoded by members of the alphaviridae and flaviviridae, are comprised of three antiparallel beta sheet domains with an internal fusion peptide located at the end of domain ii. proteomics computational analyse ...200415544707
sindbis viruses and other alphaviruses as cause of human arthritic disease.amongst the arthritis-causing arboviruses, i.e. those spread by insects, the alphavirus group is of special interest. these viruses occasionally cause vast outbreaks, such as o'nyong-nyong in africa in 1959. in fennoscandia, sindbis-related ockelbo, pogosta, or karelian fever viruses have been found to cause significant morbidity. the major symptoms in addition to joint inflammation are fever, fatigue, headache and rash. the joint symptoms may persist for weeks, even months. the diagnosis is bas ...200415554947
two amino acid mutations in the capsid protein of type 2 porcine circovirus (pcv2) enhanced pcv2 replication in vitro and attenuated the virus in vivo.porcine circovirus type 2 (pcv2) is the primary causative agent of postweaning multisystemic wasting syndrome (pmws) in pigs. to identify potential genetic determinants for virulence and replication, we serially passaged a pcv2 isolate 120 times in pk-15 cells. the viruses harvested at virus passages 1 (vp1) and 120 (vp120) were biologically, genetically, and experimentally characterized. the pcv2 vp120 virus replicated in pk-15 cells to a titer similar to that of the pk-15 cell line-derived non ...200415564454
a conserved histidine in the ij loop of the semliki forest virus e1 protein plays an important role in membrane fusion.the enveloped alphavirus semliki forest virus (sfv) infects cells via a low ph-triggered membrane fusion reaction mediated by the e1 protein. e1 is a class ii fusion protein that contains the hydrophobic fusion peptide loop and converts to a stable homotrimer during the fusion reaction. intriguingly, the fusion loop is closely associated with a loop connecting the i and j beta-strands. this ij loop plays a role in the cholesterol dependence of membrane fusion and is specifically susceptible to p ...200415564465
protein kinase c-alpha activity is required for respiratory syncytial virus fusion to human bronchial epithelial cells.respiratory syncytial virus (rsv) infection activates protein kinase c (pkc), but the precise pkc isoform(s) involved and its role(s) remain to be elucidated. on the basis of the activation kinetics of different signaling pathways and the effect of various pkc inhibitors, it was reasoned that pkc activation is important in the early stages of rsv infection, especially rsv fusion and/or replication. herein, the role of pkc-alpha during the early stages of rsv infection in normal human bronchial e ...200415564481
regulation of hcn channel surface expression by a novel c-terminal protein-protein interaction.hyperpolarization-activated cation currents (i(h)) are carried by channels encoded by a family of four genes (hcn1-4) that are differentially expressed within the brain in specific cellular and subcellular compartments. hcn1 shows a high level of expression in apical dendrites of cortical pyramidal neurons and in presynaptic terminals of cerebellar basket cells, structures with a high density of i(h). expression of i(h) is also regulated by neuronal activity. to isolate proteins that may control ...200415564593
alphaviruses and their derived vectors as anti-tumor agents.the alphaviruses semliki forest virus (sfv) and sindbis virus have recently been developed as prototype anti-cancer agents. these are rna-containing enveloped viruses that code for only 9 proteins of unique sequence. the standard recombinant sfv vector system consists of suicide particles containing recombinant rna. in addition, alphavirus vectors capable of limited multiplication in the host are also being developed. several strategies are being adopted to construct prototype sfv vectors for ca ...200415578917
rna interference acts as a natural antiviral response to o'nyong-nyong virus (alphavirus; togaviridae) infection of anopheles gambiae.rna interference (rnai) is triggered in eukaryotic organisms by double-stranded rna (dsrna), and it destroys any mrna that has sequence identity with the dsrna trigger. the rnai pathway in anopheles gambiae can be silenced by transfecting cells with dsrna derived from exon sequence of the a. gambiae argonaute2 (agago2) gene. we hypothesized that rnai may also act as an antagonist to alphavirus replication in a. gambiae because rna viruses form dsrna during replication. silencing agago2 expressio ...200415583140
ethnomedicinal uses of momordicacharantia (cucurbitaceae) in togo and relation to its phytochemistry and biological activity.investigation of the traditional uses of momordica charantia (cucurbitaceae) in togo (west africa) showed that it is one of the most important local medicinal plants both for ritual and ethnomedical practices. there was a high degree of consensus (>50%) for use in the treatment of gastrointestinal and viral disease among 47 groups of village informants in the general population, while 19 traditional healers reported a larger and broader set of uses. the use by informants in gaur and kwa language ...200515588650
expression of cellular oncogene bcl-xl prevents coronavirus-induced cell death and converts acute infection to persistent infection in progenitor rat oligodendrocytes.murine coronavirus mouse hepatitis virus (mhv) causes persistent infection of the central nervous system (cns) in rodents, which has been associated with demyelination. however, the precise mechanism of mhv persistence in the cns remains elusive. here we show that the progenitor oligodendrocytes (central glial 4 [cg-4] cells) derived from newborn rat brain were permissive to mhv infection, which resulted in cell death, although viral replication was restricted. interestingly, treatment with feta ...200515596800
prevention of virus persistence and protection against immunopathology after borna disease virus infection of the brain by a novel orf virus recombinant.the parapoxvirus orf virus represents a promising candidate for novel vector vaccines due to its immune modulating properties even in nonpermissive hosts such as mouse or rat. the highly attenuated orf virus strain d1701 was used to generate a recombinant virus (d1701-vrvp40) expressing nucleoprotein p40 of borna disease virus, which represents a major antigen for the induction of a borna disease virus-specific humoral and cellular immune response. infection with borna disease virus leads to dis ...200515596826
sindbis virus with a tricomponent genome.we established a system for propagation of sindbis virus (sin)-based replicons in tissue culture in the form of a tricomponent genome virus. three rna fragments containing complementing genetic information required for virus replication are packaged into separate viral particles, and each cell produces at least 1,000 packaged replicons and the number of packaged helpers sufficient to perform the next passage. this system can be used to generate large stocks of packaged replicons. the formation o ...200515596860
rapid functional cloning of cell adhesion molecules. 200415597539
the use of a double subgenomic sindbis virus expression system to study mosquito gene function: effects of antisense nucleotide number and duration of viral infection on gene silencing efficiency.recently we established a simple, effective antisense strategy using a double subgenomic sindbis (dssin) virus expression system to study gene function in mosquitoes. in this study, we further elucidate the effects of antisense nucleotide number and duration of viral infection on mosquito gene silencing efficiency by the dssin virus expression system. over 15 days post virus infection, the degree of parasite melanization was progressively reduced by more than 95%, 75% and 55% in the mosquito arm ...200415606808
efficient functional pseudotyping of oncoretroviral and lentiviral vectors by venezuelan equine encephalitis virus envelope proteins.murine oncoretroviruses and lentiviruses pseudotyped with envelope proteins of alphaviruses have shown great potential in providing broad-host-range, stable vectors for gene therapy. unlike vesicular stomatitis virus g protein-pseudotyped vectors, they are not neutralized by complement and do not appear to cause significant tissue damage. here we report the production of murine oncoretroviral and lentiviral vectors pseudotyped with the envelope proteins of venezuelan equine encephalitis virus (v ...200515613303
efficient rescue of hepatitis c virus rna replication by trans-complementation with nonstructural protein 5a.studies of hepatitis c virus (hcv) rna replication have become possible with the development of subgenomic replicons. this system allows the functional analysis of the essential components of the viral replication complex, which so far are poorly defined. in the present study we wanted to investigate whether lethal mutations in hcv nonstructural genes can be rescued by trans-complementation. therefore, a series of replicon rnas carrying mutations in ns3, ns4b, ns5a, and ns5b that abolish replica ...200515613318
glycine-amide is an active metabolite of the antiretroviral tripeptide glycyl-prolyl-glycine-amide.the chemically modified tripeptide glycyl-prolyl-glycine-amide (gpg-nh(2)) inhibits replication of human immunodeficiency virus (hiv) type 1 (hiv-1) in vitro, probably by interfering with capsid formation. the aim of the present study was to determine whether the metabolites glycyl-proline (gp-oh), glycine (g-oh), prolyl-glycine-amide (pg-nh(2)), proline (p-oh), and glycine-amide (g-nh(2)) from proteolytic cleavage may inhibit the replication of hiv-1 in vitro. pg-nh(2) has previously been shown ...200515616273
bioinformatic mapping of alkb homology domains in viruses.alkb-like proteins are members of the 2-oxoglutarate- and fe(ii)-dependent oxygenase superfamily. in escherichia coli the protein protects rna and dna against damage from methylating agents. 1-methyladenine and 3-methylcytosine are repaired by oxidative demethylation and direct reversal of the methylated base back to its unmethylated form. genes for alkb homologues are widespread in nature, and eukaryotes often have several genes coding for alkb-like proteins. similar domains have also been obse ...200515627404
construction and applications of yellow fever virus replicons.subgenomic replicons of yellow fever virus (yfv) were constructed to allow expression of heterologous reporter genes in a replication-dependent manner. expression of the antibiotic resistance gene neomycin phosphotransferase ii (neo) from one of these yfv replicons allowed selection of a stable population of cells (bhk-rep cells) in which the yfv replicon persistently replicated. bhk-rep cells were successfully used to trans-complement replication-defective yfv replicons harboring large internal ...200515629769
il-15-independent antiviral function of primary and memory cd8+ t cells.memory cd8+ t cells are comprised of cd122hi il-15-dependent and cd122lo il-15-independent subsets. induction and retention of il-15-independent memory cd8+ t cells was assessed in il-15-/- and wild-type (wt) mice immunized with recombinant vaccinia virus (rvv) or sindbis virus (rsin) vectors expressing the identical foreign epitope. both vectors induced epitope-specific cd8+ t cell expansion and function, independent of il-15. similar kinetics of rvv clearance confirmed effective cd8+ t cell fu ...200515629776
early events in the pathogenesis of eastern equine encephalitis virus in elucidate the pathogenesis of eastern equine encephalitis (eee) virus infections, we used histopathology, immunohistochemistry, and in situ hybridization to track the spread and early cellular targets of viral infection in mice. young mice were inoculated with virulent eee virus in their right rear footpad and were followed in a time-course study for 4 days. virulent eee virus produced a biphasic illness characterized by an early self-limiting replication phase in peripheral tissues followed ...200515632009
alphavirus replicon particles containing the gene for her2/neu inhibit breast cancer growth and tumorigenesis.overexpression of the her2/neu gene in breast cancer is associated with an increased incidence of metastatic disease and with a poor prognosis. although passive immunotherapy with the humanized monoclonal antibody trastuzumab (herceptin) has shown some effect, a vaccine capable of inducing t-cell and humoral immunity could be more effective.200415642163
protective effects of task-3 (kcnk9) and related 2p k channels during cellular stress.tandem pore domain (or 2p) k channels form a recently isolated family of channels that are responsible for background k currents in excitable tissues. previous studies have indicated that 2p k channel activity produces membrane hyperpolarization, which may offer protection from cellular insults. to study the effect of these channels in neuroprotection, we overexpressed ph-sensitive 2p k channels by transfecting the partially transformed c8 cell line with these channels. tandem pore weak inward r ...200515649441
west nile virus inhibits the signal transduction pathway of alpha interferon.west nile virus (wnv) is a human pathogen that can cause neurological disorders, including meningoencephalitis. experiments with mice and mammalian cell cultures revealed that wnv exhibited resistance to the innate immune program induced by alpha interferon (ifn-alpha). we have investigated the nature of this inhibition and have found that wnv replication inhibited the activation of many known ifn-inducible genes, because it prevented the phosphorylation and activation of the janus kinases jak1 ...200515650160
mutual interference between genomic rna replication and subgenomic mrna transcription in brome mosaic virus.replication by many positive-strand rna viruses includes genomic rna amplification and subgenomic mrna (sgrna) transcription. for brome mosaic virus (bmv), both processes occur in virus-induced, membrane-associated compartments, require bmv replication factors 1a and 2a, and use negative-strand rna3 as a template for genomic rna3 and sgrna syntheses. to begin elucidating their relations, we examined the interaction of rna3 replication and sgrna transcription in saccharomyces cerevisiae expressin ...200515650170
sindbis virus translation is inhibited by a pkr/rnase l-independent effector induced by alpha/beta interferon priming of dendritic cells.the tropism of sindbis virus (sb) for cells of the dendritic cell (dc) lineage and the virulence of sb in vivo are largely determined by the efficacy of alpha/beta interferon (ifn-alpha/beta)-mediated antiviral responses. these responses are essentially intact in the absence of pkr and/or rnase l (k. d. ryman, l. j. white, r. e. johnston, and w. b. klimstra, viral immunol. 15:53-76, 2002). in the present studies, we investigated the nature of antiviral effects and identity of antiviral effectors ...200515650175
involvement of clathrin-mediated endocytosis in human immunodeficiency virus type 1 entry.productive entry of human immunodeficiency virus (hiv) is believed to occur by direct fusion at the plasma membrane. endocytic uptake of hiv particles has been observed in several studies but is considered to be nonproductive, leading to virus degradation in the lysosome. we show here that endocytosis contributes significantly to productive hiv entry in hela cells by using trans dominant-negative mutants of dynamin and eps15. inducible expression of a dominant-negative mutant of dynamin in a cd4 ...200515650184
human immunodeficiency virus type 1 vectors with alphavirus envelope glycoproteins produced from stable packaging cells.alphavirus glycoproteins have broad host ranges. human immunodeficiency virus type 1 (hiv-1) vectors pseudotyped with their glycoproteins could extend the range of tissues that can be transduced in both humans and animal models. here, we established stable producer cell lines for hiv vectors pseudotyped with alphavirus ross river virus (rrv) and semliki forest virus (sfv) glycoproteins e2e1. rrv e2e1-stable clones could routinely produce high-titer pseudotyped vectors for at least 5 months. sfv ...200515650201
yellow fever 17d as a vaccine vector for microbial ctl epitopes: protection in a rodent malaria model.the yellow fever vaccine 17d (17d) is safe, and after a single immunizing dose, elicits long-lasting, perhaps lifelong protective immunity. one of the major challenges facing delivery of human vaccines in underdeveloped countries is the need for multiple injections to achieve full efficacy. to examine 17d as a vector for microbial t cell epitopes, we inserted the h-2k(d)-restricted ctl epitope of the circumsporozoite protein (cs) of plasmodium yoelii between 17d nonstructural proteins ns2b and n ...200515657290
requirement of the vesicular system for membrane permeabilization by sindbis virus.the vast majority of animal viruses enhance membrane permeability at two moments of infection. herein, we describe that the entry of sindbis virus (sv) in bhk cells promotes the co-entry of the macromolecule alpha-sarcin into the cytoplasm, thereby blocking translation. at a later stage, this protein toxin cannot enter the cell, while low molecular weight compounds, such as hygromycin b, readily pass through the plasma membrane of sindbis virus-infected bhk cells. to unveil the participation of ...200515661162
invariant valpha14 chain nkt cells promote plasmodium berghei circumsporozoite protein-specific gamma interferon- and tumor necrosis factor alpha-producing cd8+ t cells in the liver after poxvirus vaccination of mice.understanding the protective mechanism in the liver induced by recombinant vaccines against the pre-erythrocytic stages of malaria is important for vaccine development. most studies in mice have focused on splenic and peripheral blood t cells and identified gamma interferon (ifn-gamma)-producing cd8+ t cells as correlates of protection, which can be induced by prime-boost vaccination with recombinant poxviruses. invariant natural killer t (valpha14inkt) cells can also protect against liver stage ...200515664925
aedes aegypti salivary gland extracts modulate anti-viral and th1/th2 cytokine responses to sindbis virus infection.vector-borne viruses are naturally transmitted when a vector salivates during feeding on a vertebrate host. most laboratory studies of infection disregard the role that the vector plays in the pathogenesis of the virus. in this study, intradermal inoculations of aedes aegypti salivary gland extract (sge) and sindbis virus (sinv) were used to investigate the effect of mosquito feeding on the vertebrate immune response to infection with an arthropod-borne virus. murine cytokine expression in the s ...200415671753
heparin binding sites on ross river virus revealed by electron cryo-microscopy.cell surface glycosaminoglycans play important roles in cell adhesion and viral entry. laboratory strains of two alphaviruses, sindbis and semliki forest virus, have been shown to utilize heparan sulfate as an attachment receptor, whereas ross river virus (rrv) does not significantly interact with it. however, a single amino acid substitution at residue 218 in the rrv e2 glycoprotein adapts the virus to heparan sulfate binding and expands the host range of the virus into chicken embryo fibroblas ...200515680416
in vivo processing and isolation of furin protease-sensitive alphavirus glycoproteins: a new technique for producing mutations in virus assembly.sindbis virus particles are composed of three structural proteins (capsid/e2/e1). in the mature virion the e1 glycoprotein is organized in a highly constrained, energy-rich conformation. it is hypothesized that this energy is utilized to drive events that deliver the viral genome to the cytoplasm of a host cell. the extraction of the e1 glycoprotein from virus membranes with detergent results in disulfide-bridge rearrangement and the collapse of the protein to a number of low-energy, non-native ...200515680428
characterization of helper virus-independent cytopathogenic classical swine fever virus generated by an in vivo rna recombination system.molecular analyses revealed that most cytopathogenic (cp) pestivirus strains evolve from noncytopathogenic (noncp) viruses by nonhomologous rna recombination. in contrast to bovine viral diarrhea virus (bvdv), cp classical swine fever virus (csfv) field isolates were rarely detected and always represented helper virus-dependent subgenomes. to investigate rna recombination in more detail, we recently established an in vivo system allowing the efficient generation of recombinant cp bvdv strains in ...200515681445
proteasome inhibition protects ht22 neuronal cells from oxidative glutamate toxicity.oxidative stress caused by glutathione depletion after prolonged exposure to extracellular glutamate leads to a form of neuronal cell death that exhibits morphologically mixed features of both apoptosis and necrosis. however, specific downstream executioners involved in this form of cell death have yet to be identified. we report here that glutamate exposure does not activate caspase-3 in the ht22 neuronal cell line. furthermore, no cytoprotection was achieved with either the pan-caspase inhibit ...200515686484
subcellular localisation of recombinant alpha- and gamma-synuclein.alpha-synuclein, a protein implicated in neurodegenerative diseases and of elusive physiological function owes its name to an observed presence in presynaptic and nuclear compartments. however, its nuclear localisation has remained controversial. we expressed synuclein-egfp fusion proteins in organotypic rat hippocampal slice cultures and murine hippocampal primary neurons using a sindbis virus expression system. recombinant full-length alpha-synuclein accumulated in presynaptic locations, mimic ...200515691713
novel replicon-based reporter gene assay for detection of rubella virus in clinical specimens.proof of concept for a novel diagnostic assay for rubella virus (rub) based on rub replicons expressing reporter genes was demonstrated. rub replicons have the structural protein coding region replaced with a reporter gene such as green fluorescent protein or chloramphenicol acetyltransferase. previously, it was shown that a replicon construct with a specific in-frame deletion in the nonstructural protein coding region (noti, approximately nucleotides 1500 to 2100 of the genome) failed to replic ...200515695695
mosquitoborne viruses, czech republic, 2002.specimens from residents (n = 497) of an area affected by the 2002 flood were examined serologically for mosquitoborne viruses. antibodies were detected against tahyna (16%), sindbis (1%), and batai (0.2%) viruses, but not west nile virus. an examination of paired serum samples showed 1 tahyna bunyavirus (california group) infection.200515705333
lentiviral vector retargeting to p-glycoprotein on metastatic melanoma through intravenous injection.targeted gene transduction to specific tissues and organs through intravenous injection would be the ultimate preferred method of gene delivery. here, we report successful targeting in a living animal through intravenous injection of a lentiviral vector pseudotyped with a modified chimeric sindbis virus envelope (termed m168). m168 pseudotypes have high titer and high targeting specificity and, unlike other retroviral pseudotypes, have low nonspecific infectivity in liver and spleen. a mouse can ...200515711560
phospholipase d1-promoted release of tissue plasminogen activator facilitates neurite outgrowth.temporal lobe epilepsy (tle) is the most common form of epilepsy, affecting approximately 1-2% of the population. seizure events resulting from tle are characterized by aberrant hippocampal mossy fiber sprouting and plastic responses that affect brain function. seizure susceptibility is modulated by the enzyme tissue plasminogen activator (tpa), the normal physiological role of which includes promotion of synaptic reorganization in the mossy fiber pathway by initiating a proteolytic cascade that ...200515716416
antiviral activity of human lactoferrin: inhibition of alphavirus interaction with heparan sulfate.human lactoferrin is a component of the non-specific immune system with distinct antiviral properties. we used alphaviruses, adapted to interaction with heparan sulfate (hs), as a tool to investigate the mechanism of lactoferrin's antiviral activity. lactoferrin inhibited infection of bhk-21 cells by hs-adapted, but not by non-adapted, sindbis virus (sin) or semliki forest virus (sfv). lactoferrin also inhibited binding of radiolabeled hs-adapted viruses to bhk-21 cells or liposomes containing l ...200515721362
association of sindbis virus capsid protein with phospholipid membranes and the e2 glycoprotein: implications for alphavirus assembly.a late stage in assembly of alphaviruses within infected cells is thought to be directed by interactions between the nucleocapsid and the cytoplasmic domain of the e2 protein, a component of the viral e1/e2 glycoprotein complex that is embedded in the plasma membrane. recognition between the nucleocapsid protein and the e2 protein was explored in solution using nmr spectroscopy, as well as in binding assays using a model phospholipid membrane system that incorporated a variety of sindbis virus e ...200515723524
early expression of ampa receptors and lack of nmda receptors in developing rat climbing fibre synapses.whether nascent glutamatergic synapses acquire their ampa receptors constitutively or via a regulated pathway triggered by pre-existing nmda receptor activation is still an open issue. here, we provide evidence that some glutamatergic synapses develop without expressing nmda receptors. using immunocytochemistry, we showed that synapses between developing rat climbing fibres and purkinje cells expressed glur2-containing ampa receptors as soon as they were formed (i.e. on embryonic day 19) but nev ...200515731186
dual mechanisms of pestiviral superinfection exclusion at entry and rna replication.for many viruses, primary infection has been shown to prevent superinfection by a homologous second virus. in this study, we investigated superinfection exclusion of bovine viral diarrhea virus (bvdv), a positive-sense rna pestivirus. cells acutely infected with bvdv were protected from superinfection by homologous bvdv but not with heterologous vesicular stomatitis virus. superinfection exclusion was established within 30 to 60 min but was lost upon passaging of persistently infected cells. sup ...200515731218
characterization of an in vitro model of alphavirus infection of immature and mature neurons.terminally differentiated, mature neurons are essential cells that are not easily regenerated. neurotropic viruses, such as sindbis virus (sv), cause encephalomyelitis through their ability to replicate in neurons. sv causes the death of immature neurons, while mature neurons can often survive infection. the lack of a reproducible and convenient neuronal cell culture system has hindered a detailed study of the differences in levels of virus replication between immature and mature neurons and the ...200515731238
3'-terminal sequence in poliovirus negative-strand templates is the primary cis-acting element required for vpgpupu-primed positive-strand initiation.the 5' cloverleaf in poliovirus rna has a direct role in regulating the stability, translation, and replication of viral rna. in this study, we investigated the role of stem a in the 5' cloverleaf in regulating the stability and replication of poliovirus rna in hela s10 translation-replication reactions. our results showed that disrupting the duplex structure of stem a destabilized viral rna and inhibited efficient negative-strand synthesis. surprisingly, the duplex structure of stem a was not r ...200515731251
inhibition of viral replication by ribozyme: mutational analysis of the site and mechanism of antiviral activity.a controlled mutational study was used to determine the site and mechanism of the antiviral action of ribozymes that inhibit sindbis virus replication. a hairpin ribozyme targeting g575 of the sindbis virus genomic rna was designed and cloned into a minimized alphavirus amplicon vector. cells that were stably transfected with this construct expressed low levels of a constitutive transcript containing the ribozyme plus recognition sequences for sindbis rna replicase. upon infection, the ribozyme ...200515731266
cell type-specific targeting with sindbis pseudotyped lentiviral vectors displaying anti-ccr5 single-chain antibodies.lentiviral vectors are among the most efficient tools for gene delivery into mammalian cells. a major goal of lentiviral gene delivery systems is to develop vectors that can efficiently target specific cell types. in the present work, we attempt to generate viral particles for targeting gene delivery. we have used ccr5-positive cells as the target for our strategy. therefore, we developed a novel sindbis pseudotyped lentiviral vector where the sindbis receptor binding envelope protein was modifi ...200515761262
acid-resistant bovine pestivirus requires activation for ph-triggered fusion during entry.the route of internalization of the pestivirus bovine viral diarrhea virus (bvdv) was studied by using different chemical and biophysical inhibitors of endocytosis. expression of the dominant-negative mutant dyn(k44a) of the gtpase dynamin in mdbk cells, as well as the treatment of the cells with chlorpromazine and beta-methyl-cyclodextrin inhibited bvdv entry. bvdv infection was also abolished by potassium (k+) depletion, hyperosmolarity, and different inhibitors of endosomal acidification. we ...200515767420
identification of adult mouse neurovirulence determinants of the sindbis virus strain ar86.sindbis virus infection of mice has provided valuable insight into viral and host factors that contribute to virus-induced neurologic disease. in an effort to further define the viral genetic elements that contribute to adult mouse neurovirulence, the neurovirulent sindbis virus strain ar86 was compared to the closely related (22 single amino acid coding changes and the presence or absence of an 18-amino-acid sequence in nsp3 [positions 386 to 403]) but avirulent girdwood strain. initial studies ...200515767423
two dimensional vopba reveals laminin receptor (lamr1) interaction with dengue virus serotypes 1, 2 and 3.the search for the dengue virus receptor has generated many candidates often identified only by molecular mass. the wide host range of the viruses in vitro combined with multiple approaches to identifying the receptor(s) has led to the notion that many receptors or attachment proteins may be involved and that the different dengue virus serotypes may utilize different receptors on the same cells as well as on different cell types.200515790424
recoding elements located adjacent to a subset of eukaryal selenocysteine-specifying uga codons.incorporation of the 21st amino acid, selenocysteine, into proteins is specified in all three domains of life by dynamic translational redefinition of uga codons. in eukarya and archaea, selenocysteine insertion requires a cis-acting selenocysteine insertion sequence (secis) usually located in the 3'utr of selenoprotein mrnas. here we present comparative sequence analysis and experimental data supporting the presence of a second stop codon redefinition element located adjacent to a selenocystein ...200515791204
neuronal cell death in alphavirus encephalomyelitis.alphaviruses are mosquito-borne, enveloped, plus-strand rna viruses that cause a spectrum of diseases in humans that include fever, rash, arthritis, meningitis, and encephalomyelitis. sindbis virus (sinv) is the prototype alphavirus, causes encephalomyelitis in mice, and provides a model system for studying the pathogenesis of alphavirus-induced neurological disease. major target cells for sinv infection in the central nervous system (cns) are neurons, and both host and viral factors determine t ...200515791951
development of cell-based assays for in vitro characterization of hepatitis c virus ns3/4a protease inhibitors.a recombinant vaccinia virus, expressing the ns3-to-ns5 region of the n clone of hepatitis c virus (hcv), was generated and utilized both in a gel-based assay and in an enzyme-linked immunosorbent assay (elisa) to evaluate the pyrrolidine-5,5-trans-lactams, a series of inhibitors of the hcv ns3/4a protease. the absolute levels of processed, mature hcv nonstructural proteins in this system were found to decrease in the presence of the trans-lactams. monitoring of this reduction enabled end points ...200515793116
inhibition of flavivirus infections by antisense oligomers specifically suppressing viral translation and rna replication.rna elements within flavivirus genomes are potential targets for antiviral therapy. a panel of phosphorodiamidate morpholino oligomers (pmos), whose sequences are complementary to rna elements located in the 5'- and 3'-termini of the west nile (wn) virus genome, were designed to anneal to important cis-acting elements and potentially to inhibit wn infection. a novel arg-rich peptide was conjugated to each pmo for efficient cellular delivery. these pmos exhibited various degrees of antiviral acti ...200515795246
requirements at the 3' end of the sindbis virus genome for efficient synthesis of minus-strand rna.the 3'-untranslated region of the sindbis virus genome is 0.3 kb in length with a 19-nucleotide conserved sequence element (3' cse) immediately preceding the 3'-poly(a) tail. the 3' cse and poly(a) tail have been assumed to constitute the core promoter for minus-strand rna synthesis during genome replication; however, their involvement in this process has not been formally demonstrated. utilizing both in vitro and in vivo analyses, we have examined the role of these elements in the initiation of ...200515795249
virus-specific and bystander cd8 t cells recruited during virus-induced encephalomyelitis.neurotropic coronavirus-induced encephalitis was used to evaluate recruitment, functional activation, and retention of peripheral bystander memory cd8+ t cells. mice were first infected with recombinant vaccinia virus expressing a non-cross-reactive human immunodeficiency virus (hiv) epitope, designated p18. following establishment of an endogenous p18-specific memory cd8+ t-cell population, mice were challenged with coronavirus to directly compare recruitment, longevity, and activation characte ...200515795256
identification of structural domains involved in astrovirus capsid biology.coat proteins of non-enveloped, icosahedral viruses must perform a variety of functions during their life cycle such as assembly of the coat protein subunits into a closed shell, specific encapsidation of the viral nucleic acid, maturation of the capsid, interaction with host receptors, and disassembly to deliver the genetic information into the newly infected cell. a thorough understanding of the multiple capsid properties at the molecular level is required in order to identify potential target ...200515802951
mechanisms of reovirus-induced cell death and tissue injury: role of apoptosis and virus-induced perturbation of host-cell signaling and transcription factor activation.reoviruses have provided insight into the roles played by specific viral genes and the proteins they encode in virus-induced cell death and tissue injury. apoptosis is a major mechanism of cell death induced by reoviruses. reovirus-induced apoptosis involves both death-receptor and mitochondrial cell death pathways. reovirus infection is associated with selective activation of mitogen activated protein kinase (mapk) cascades including jnk/sapk. infection also perturbs transcription factor signal ...200515802955
class ii fusion protein of alphaviruses drives membrane fusion through the same pathway as class i proteins.viral fusion proteins of classes i and ii differ radically in their initial structures but refold toward similar conformations upon activation. do fusion pathways mediated by alphavirus e1 and influenza virus hemagglutinin (ha) that exemplify classes ii and i differ to reflect the difference in their initial conformations, or concur to reflect the similarity in the final conformations? here, we dissected the pathway of low ph-triggered e1-mediated cell-cell fusion by reducing the numbers of acti ...200515809312
Displaying items 2401 - 2500 of 5405