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anti-sindbis activity of flavanones hesperetin and naringenin.the effect of hesperetin, naringenin and its glycoside form on the sindbis neurovirulent strain (nsv) replication in vitro was studied. all flavanones tested were not cytotoxic on baby hamster cells 21 clone 15 (bhk-21). antiviral effect was evaluated by a colorimetric assay using mtt (3-(4,5 dimethylthiazol-2-yl)-2,5-dipheyl-tetrazolium bromide) and by plaque reduction assay. hesperetin and naringenin had inhibitory activity on nsv infection. the 50% inhibitory doses (id(50%)) of both compounds ...200312520185
properly folded nonstructural polyprotein directs the semliki forest virus replication complex to the endosomal compartment.the late rna synthesis in alphavirus-infected cells, generating plus-strand rnas, takes place on cytoplasmic vacuoles (cpvs), which are modified endosomes and lysosomes. the cytosolic surface of cpvs consists of regular membrane invaginations or spherules, which are the sites of rna synthesis (p. kujala, a. ikäheimonen, n. ehsani, h. vihinen, p. auvinen, and l. kääriäinen j. virol. 75:3873-3884, 2001). to understand how cpvs arise, we have expressed the individual semliki forest virus (sfv) nons ...200312525603
alphavirus minus-strand synthesis and persistence in mouse embryo fibroblasts derived from mice lacking rnase l and protein kinase r.we report our studies to probe the possible role of the host response to double-stranded rna in cessation of alphavirus minus-strand synthesis. mouse embryo fibroblasts (mef) from mx1-deficient mice that also lack either the protein kinase r (pkr) or the latent rnase l or both pkr and rnase l were screened. in rnase l-deficient but not wild-type or pkr-deficient mef, there was continuous synthesis of minus-strand templates and the formation of new replication complexes producing viral plus stran ...200312525614
antibody-mediated targeting of an adenovirus vector modified to contain a synthetic immunoglobulin g-binding domain in the capsid.adenovirus vectors have been targeted to different cell types by genetic modification of the capsid or by using recombinant or chemically engineered adaptor molecules. however, both genetic capsid modifications and bridging adaptors have to be specifically tailored for each particular targeting situation. here, we present an efficient and versatile strategy allowing the direct use of monoclonal antibodies against cell surface antigens for targeting of adenovirus vectors. a synthetic 33-amino-aci ...200312525644
fine mapping of a cis-acting sequence element in yellow fever virus rna that is required for rna replication and cyclization.we present fine mapping of a cis-acting nucleotide sequence found in the 5' region of yellow fever virus genomic rna that is required for rna replication. there is evidence that this sequence interacts with a complementary sequence in the 3' region of the genome to cyclize the rna. replicons were constructed that had various deletions in the 5' region encoding the capsid protein and were tested for their ability to replicate. we found that a sequence of 18 nucleotides (residues 146 to 163 of the ...200312525663
entry of alphaviruses at the plasma membrane converts the viral surface proteins into an ion-permeable pore that can be detected by electrophysiological analyses of whole-cell membrane currents.alphaviruses are small enveloped viruses that have been used extensively as model enveloped viruses. during infection, virus particles are taken up into endosomes, where a low ph activates the viral fusion protein, e1. fusion of the viral and the endosomal membranes releases the viral core into the cytoplasm where cores are disassembled by interaction with 60s ribosomal subunits. recently, we have shown that in vitro this disassembly is strongly stimulated by low ph. we have proposed that after ...200312533714
long-term potentiation in the hippocampal ca1 area and dentate gyrus plays different roles in spatial learning.nmda receptor-dependent long-term potentiation (ltp) at hippocampal synapses has been considered a crucial component of the cellular basis for learning and memory. this form of ltp occurs in excitatory synapses in both the ca1 area and the dentate gyrus in the hippocampus. however, differential roles of ltp in these areas have not yet been identified. to address this issue, we enhanced the degree of ltp by expressing ca2+-permeable ampa receptors at either hippocampal ca1 or dentate gyrus synaps ...200312542671
modification of the 5' terminus of sindbis virus genomic rna allows nsp4 rna polymerases with nonaromatic amino acids at the n terminus to function in rna replication.we have previously shown that sindbis virus rna polymerase requires an n-terminal aromatic amino acid or histidine for wild-type or pseudo-wild-type function; mutant viruses with a nonaromatic amino acid at the n terminus of the polymerase, but which are otherwise wild type, are unable to produce progeny viruses and will not form a plaque at any temperature tested. we now show that such mutant polymerases can function to produce progeny virus sufficient to form plaques at both 30 and 40 degrees ...200312551967
kinetics of virus-specific cd8+ -t-cell expansion and trafficking following central nervous system infection.cd8+ t cells control acute infection of the central nervous system (cns) by neurotropic mouse hepatitis virus but do not suffice to achieve sterile immunity. to determine the lag between t-cell priming and optimal activity within the cns, the accumulation of virus-specific cd8+ t cells in the cns relative to that in peripheral lymphoid organs was assessed by using gamma interferon-specific elispot assays and class i tetramer staining. virus-specific cd8+ t cells were first detected in the cervic ...200312552021
individual expression of sindbis virus glycoproteins. e1 alone promotes cell fusion.the envelope of alphavirus particles contains two major glycoproteins, e1 and e2, that participate in virus entry and assembly of new virus particles. interactions between these glycoproteins determine their correct functioning. the expression of each glycoprotein in the absence of the other counterpart was achieved by means of electroporation of modified sindbis virus (sv) genomes. in addition, in trans coexpression of both glycoproteins was also tested in bhk cells. synthesis of the e1 glycopr ...200312573591
the avian retrovirus avian sarcoma/leukosis virus subtype a reaches the lipid mixing stage of fusion at neutral ph.we previously showed that the envelope glycoprotein (enva) of avian sarcoma/leukosis virus subtype a (aslv-a) binds to liposomes at neutral ph following incubation with its receptor, tva, at >or=22 degrees c. we also provided evidence that aslv-c fuses with cells at neutral ph. these findings suggested that receptor binding at neutral ph and >or=22 degrees c is sufficient to activate env for fusion. a recent study suggested that two steps are necessary to activate avian retroviral envs: receptor ...200312584331
cellular proteins from human monocytes bind to dengue 4 virus minus-strand 3' untranslated region rna.the synthesis of plus and minus rna strands of several rna viruses requires as a first step the interaction of some viral regulatory sequences with cellular and viral proteins. the dengue 4 virus genome, a single-stranded, positive-polarity rna, is flanked by two untranslated regions (utr) located in the 5' and 3' ends. the 3'utr in the minus-strand rna [3'utr (-)] has been thought to function as a promoter for the synthesis of plus-strand rna. to study the initial interaction between this 3'utr ...200312584332
subcellular localization of herpes simplex virus type 1 ul51 protein and role of palmitoylation in golgi apparatus targeting.the herpes simplex virus type 1 (hsv-1) ul51 gene products are virion-associated phosphoproteins with apparent molecular masses of 27, 29, and 30 kda in hsv-1-infected cells. in this study, we have investigated the intracellular localization and distribution of ul51 protein both in infected cells and in transfected cells expressing only ul51. we found that this protein colocalized closely with golgi marker proteins such as the golgi-58k protein and gm130 in transfected cells expressing only ul51 ...200312584344
polystyrene derivatives substituted with arginine interact with babanki (togaviridae) and kedougou (flaviviridae) viruses.outbreaks of new or old diseases appear primarily in tropical zones such as africa, south and central america, or asia. among these diseases, those induced by arboviruses (the best known of which are being yellow fever, dengue, ebola, and sindbis) are under intensive observation by the world health organization. rapid isolation and identification of the viral species is the first step in the diagnosis, study, and control of epidemics. one major problem with the isolation of viruses is capturing ...200312601758
functional nmda receptor channels generated by nmdar2b gene transfer in rat cerebellar purkinje cells.the adult cerebellar purkinje cell is an exceptional neuron in the central nervous system in that it expresses high levels of nmdar1 (nr1) mrna without expressing any nmdar2 (nr2) mrnas. it has no functional nmda receptor (nmdar) channels, although it receives enormous numbers of excitatory inputs. despite the high level of nr1 mrna expression, the presence and localization of nr1 protein in mature purkinje cells are controversial. to examine the presence of nr1 protein and its ability to form f ...200312603279
induction of apoptosis by paramyxovirus simian virus 5 lacking a small hydrophobic gene.simian virus 5 (sv5) is a member of the paramyxovirus family, which includes emerging viruses such as hendra virus and nipah virus as well as many important human and animal pathogens that have been known for years. sv5 encodes eight known viral proteins, including a small hydrophobic integral membrane protein (sh) of 44 amino acids. sv5 without the sh gene (rsv5deltash) is viable, and growth of rsv5deltash in tissue culture cells and viral protein and mrna production in rsv5deltash-infected cel ...200312610112
interactions between the transmembrane segments of the alphavirus e1 and e2 proteins play a role in virus budding and fusion.the alphavirus envelope is built by heterodimers of the membrane proteins e1 and e2. the complex is formed as a p62e1 precursor in the endoplasmic reticulum. during transit to the plasma membrane (pm), it is cleaved into mature e1-e2 heterodimers, which are oligomerized into trimeric complexes, so-called spikes that bind both to each other and, at the pm, also to nucleocapsid (nc) structures under the membrane. these interactions drive the budding of new virus particles from the cell surface. th ...200312610119
the 5'-end sequence of the genome of aichi virus, a picornavirus, contains an element critical for viral rna encapsidation.picornavirus positive-strand rnas are selectively encapsidated despite the coexistence of viral negative-strand rnas and cellular rnas in infected cells. however, the precise mechanism of the rna encapsidation process in picornaviruses remains unclear. here we report the first identification of an rna element critical for encapsidation in picornaviruses. the 5' end of the genome of aichi virus, a member of the family picornaviridae, folds into three stem-loop structures (sl-a, sl-b, and sl-c, fr ...200312610129
hepatitis c virus glycoproteins mediate ph-dependent cell entry of pseudotyped retroviral particles.hiv pseudotypes bearing native hepatitis c virus (hcv) glycoproteins (strain h and con1) are infectious for the human hepatoma cell lines huh-7 and plc/pr5. infectivity depends on coexpression of both e1 and e2 glycoproteins, is ph-dependent, and can be neutralized by mabs mapping to amino acids 412-447 within e2. cell-surface expression of one or all of the candidate receptor molecules (cd81, low-density lipoprotein receptor, scavenger receptor class b type 1, and dendritic cell-specific interc ...200312761383
flavivirus capsid is a dimeric alpha-helical protein.the capsid proteins of two flaviviruses, yellow fever virus and dengue virus, were expressed in escherichia coli and purified to near homogeneity suitable for biochemical characterization and structure determination by nuclear magnetic resonance. the oligomeric properties of the capsid protein in solution were investigated. in the absence of nucleic acid, both proteins were predominantly dimeric in solution. further analysis of both proteins with far-uv circular dichroism spectroscopy indicated ...200312768036
structures of immature flavivirus particles.structures of prm-containing dengue and yellow fever virus particles were determined to 16 and 25 a resolution, respectively, by cryoelectron microscopy and image reconstruction techniques. the closely similar structures show 60 icosahedrally organized trimeric spikes on the particle surface. each spike consists of three prm:e heterodimers, where e is an envelope glycoprotein and prm is the precursor to the membrane protein m. the pre-peptide components of the prm proteins in each spike cover th ...200312773377
transduction of dominant negative atf-1 suppresses the px gene expression in joint fibroblastic cells derived from htlv-i transgenic rats.tax (p40tax) encoded by the env-px gene of human t-cell leukemia virus type i (htlv-i) interacts with cyclic adenosine-3',5'-monophosphate response element binding protein/activation transcription factor 1 (creb/atf-1) transcription factors of host cells and activates the viral long terminal repeat (ltr) promoter. this molecular interaction induces augmentation of viral gene expression and may result in development of htlv-i-associated diseases, including adult t-cell leukemia, htlv-i associated ...200312782019
assessing the feasibility of using neural precursor cells and peripheral blood mononuclear cells for detection of bioactive sindbis virus.viruses form a significant class of bio-threat agents. currently, the only method to determine the bioactivity of viruses in vitro is to measure viral and cellular responses after co-incubation of cells with virus. our goal is to find biomarkers for classification of agents, establishment of bioactivity, and/or prediction of disease outcomes. to begin development of a cell-based biosensor for detection of bioactive sindbis virus (sv), our model analyte, we surveyed the outcomes of sv interaction ...200312782470
murine cytomegalovirus abortively infects human dendritic cells, leading to expression and presentation of virally vectored genes.dendritic cells (dc) are potent antigen-presenting cells that play a crucial role in antigen-specific immune responses. thus, the targeting of exogenous antigens to dc has become a popular approach for cancer immunotherapy and vaccine development. in this report, we studied the interplay between murine cytomegalovirus (mcmv) and human monocyte-derived dc. the results showed that an enhanced green fluorescent protein (egfp)-encoding, replication-competent mcmv vector underwent abortive infection ...200312805417
common host genes are activated in mouse brain by japanese encephalitis and rabies viruses.this study identified nine genes whose expression is upregulated in the central nervous system (cns) of mice during japanese encephalitis virus (jev) infection. these include: cathepsin s, oligoadenylate synthetase (oas), garg49/irg2, lymphocyte antigen-6a (ly-6a), macrophage activation gene-2 (mpa2), early growth response gene1 (egr1), pyrimidine 5'-nucleotidase (p5n), apolipoprotein d (apod) and stat1. activation of all nine genes during jev infection was confirmed by northern blot analysis. j ...200312810866
disc1 (disrupted-in-schizophrenia 1) is a centrosome-associated protein that interacts with map1a, mipt3, atf4/5 and nudel: regulation and loss of interaction with mutation.disrupted-in-schizophrenia 1 (disc1) is a novel gene associated with schizophrenia by multiple genetic studies. in order to determine how mutations in disc1 might cause susceptibility to schizophrenia, we undertook a comprehensive study of the cellular biology of disc1 in its full-length and disease-associated mutant forms. disc1 interacts by yeast two-hybrid, mammalian two-hybrid, and co-immunoprecipitation assays with multiple proteins of the centrosome and cytoskeletal system, including mipt3 ...200312812986
use of a sindbis virus dna-based expression vector for induction of protective immunity against pseudorabies virus in pigs.injection of plasmid dna encoding pseudorabies virus (prv) glycoproteins into pig muscle has been shown to result in protective immunity against lethal infection. nevertheless, such dna vaccines are still less efficient than some attenuated or killed live vaccines. one way to increase dna vaccine efficacy is to improve the vectorisation system at the molecular level, thereby enhancing the rate of in vivo-produced immunogen protein and consequently specific acquired immunity. the present study co ...200312814698
possible involvement of rap1 and ras in glutamatergic synaptic transmission.rap1a, first identified as a suppressor of transformed phenotype induced by an activated ras oncogene, is abundantly expressed in the brain. its neurophysiological function, however, is poorly understood. when an activated rap1a mutant (rap1-12v) or a dominant negative h-ras mutant (ras-17n) was expressed in ca1 neurons in cultured hippocampal slices using the sindbis virus-mediated gene transfer technique, nmda receptor current in response to schaffer collateral stimulation was suppressed. expr ...200312824760
nonstructural protein precursor ns4a/b from hepatitis c virus alters function and ultrastructure of host secretory apparatus.the nonstructural proteins of hepatitis c virus (hcv) have been shown previously to localize to the endoplasmic reticulum (er) when expressed singly or in the context of other hcv proteins. to determine whether the expression of hcv nonstructural proteins alters er function, we tested the effect of expression of ns2/3/4a, ns4a, ns4b, ns4a/b, ns4b/5a, ns5a, and ns5b from genotype 1b hcv on anterograde traffic from the er to the golgi apparatus. only the nominal precursor protein ns4a/b affected t ...200312829824
fitness of a turnip crinkle virus satellite rna correlates with a sequence-nonspecific hairpin and flanking sequences that enhance replication and repress the accumulation of virions.satc, a satellite rna associated with turnip crinkle virus (tcv), enhances the ability of the virus to colonize plants by interfering with stable virion accumulation (f. zhang and a. e. simon, unpublished data). previous results suggested that the motif1-hairpin (m1h), a replication enhancer on minus strands, forms a plus-strand hairpin flanked by ca-rich sequence that may be involved in enhancing systemic infection (g. zhang and a. e. simon, j. mol. biol. 326:35-48, 2003). in this study, sequen ...200312829828
extensive immune-mediated hippocampal damage in mice surviving infection with neuroadapted sindbis virus.viral infections of the central nervous system and immune responses to these infections cause a variety of neurological diseases. infection of weanling mice with sindbis virus causes acute nonfatal encephalomyelitis followed by clearance of infectious virus, but persistence of viral rna. infection with a neuroadapted strain of sindbis virus (nsv) causes fatal encephalomyelitis, but passive transfer of immune serum after infection protects from fatal disease and infectious virus is cleared. to de ...200312832200
human embryonic germ cell derivatives facilitate motor recovery of rats with diffuse motor neuron injury.we have investigated the potential of human pluripotent cells to restore function in rats paralyzed with a virus-induced motor neuronopathy. cells derived from embryonic germ cells, termed embryoid body-derived (ebd) cells, introduced into the csf were distributed extensively over the rostrocaudal length of the spinal cord and migrated into the spinal cord parenchyma in paralyzed, but not uninjured, animals. some of the transplanted human cells expressed the neuroglial progenitor marker nestin, ...200312832537
a modified sindbis vector for prolonged gene expression in neurons.sindbis viruses have been widely used in neurobiology to express a variety of genes in cultured neurons, in cultured slices, and in vivo. they provide fast onset and high levels of expression of foreign genes, but the expression is limited to a short time window due to a shut-off of host protein synthesis. we have used a mutation in an essential gene (nsp2) of the life cycle of sindbis, which allows the functional analysis of changes in protein expression for >/=6 days after infection. this sind ...200312853440
a heterologous coiled coil can substitute for helix i of the sindbis virus capsid protein.alphavirus core assembly proceeds along an assembly pathway involving a dimeric assembly intermediate. several regions of the alphavirus capsid protein have been implicated in promoting and stabilizing this dimerization, including a putative heptad repeat sequence named helix i. this sequence, which spans residues 38 to 55 of the sindbis virus capsid protein, was implicated in stabilizing dimeric contacts initiated through the c-terminal two-thirds of the capsid protein and nucleic acid. the stu ...200312857904
complete genomic sequence of the australian south-west genotype of sindbis virus: comparisons with other sindbis strains and identification of a unique deletion in the 3'-untranslated region.our previous studies have shown that two distinct genotypes of sindbis (sin) virus occur in australia. one of these, the oriental/australian type, circulates throughout most of the australian continent, whereas the recently identified south-west (sw) genetic type appears to be restricted to a distinct geographic region located in the temperate south-west of australia. we have now determined the complete nucleotide and translated amino acid sequences of a sw isolate of sin virus (sw6562) and perf ...200312876458
adaptation of puumala hantavirus to cell culture is associated with point mutations in the coding region of the l segment and in the noncoding regions of the s segment.we previously developed a model for studies on hantavirus host adaptation and initiated genetic analysis of puumala virus variants passaged in colonized bank voles and in cultured vero e6 cells. with the data presented in this paper, the sequence comparison of the wild-type and vero e6-adapted variants of puumala virus, strain kazan, has been completed. the only amino acid substitution that distinguished the two virus variants was found in the l protein, ser versus phe at position 2053. another ...200312885898
deletions in the putative cell receptor-binding domain of sindbis virus strain mre16 e2 glycoprotein reduce midgut infectivity in aedes aegypti.the sindbis virus (alphavirus; togaviridae) strain mre16 efficiently infects aedes aegypti mosquitoes that ingest a blood meal containing 8 to 9 log(10) pfu of virus/ml. however, a small-plaque variant of this virus, mre16sp, poorly infects mosquitoes after oral infection with an equivalent titer. to determine the genetic differences between mre16 and mre16sp viruses, we have sequenced the mre16sp structural genes and found a 90-nucleotide deletion in the e2 glycoprotein that spans the 3' end of ...200312885905
reovirus-induced alteration in expression of apoptosis and dna repair genes with potential roles in viral pathogenesis.reoviruses are a leading model for understanding cellular mechanisms of virus-induced apoptosis. reoviruses induce apoptosis in multiple cell lines in vitro, and apoptosis plays a key role in virus-induced tissue injury of the heart and brain in vivo. the activation of transcription factors nf-kappab and c-jun are key events in reovirus-induced apoptosis, indicating that new gene expression is critical to this process. we used high-density oligonucleotide microarrays to analyze cellular transcri ...200312885910
characterization of the intracellular transport of glur1 and glur2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunits in hippocampal neurons.little is known about the dynamics of the dendritic transport of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (ampars) to synapses. here, using virally expressed green fluorescent protein (gfp)-glur1 and gfp-glur2 and confocal photobleach techniques we show near real-time movement of these subunits in living cultured hippocampal neurons. gfp-glur1 fluorescence was widely distributed throughout the extranuclear compartment with no evidence for discrete intracellular stores. ...200312909632
recombinant sindbis/venezuelan equine encephalitis virus is highly attenuated and immunogenic.venezuelan equine encephalitis virus (veev) is an important, naturally emerging zoonotic virus. veev was a significant human and equine pathogen for much of the past century, and recent outbreaks in venezuela and colombia (1995), with about 100,000 human cases, indicate that this virus still poses a serious public health threat. the live attenuated tc-83 vaccine strain of veev was developed in the 1960s using a traditional approach of serial passaging in tissue culture of the virulent trinidad d ...200312915543
complementation of a deletion in the rubella virus p150 nonstructural protein by the viral capsid protein.rubella virus (rub) replicons with an in-frame deletion of 507 nucleotides between two noti sites in the p150 nonstructural protein (deltanoti) do not replicate (as detected by expression of a reporter gene encoded by the replicon) but can be amplified by wild-type helper virus (tzeng et al., virology 289:63-73, 2001). surprisingly, virus with deltanoti was viable, and it was hypothesized that this was due to complementation of the noti deletion by one of the virion structural protein genes. int ...200312915564
low ph, caprylate incubation as a second viral inactivation step in the manufacture of albumin. parametric and validation studies.caprylate has long been used as a stabiliser for albumin solutions, as well as a precipitation agent for immunoglobulins, ceruloplasmin and more recently in removing contaminants during albumin purification. its virucidal properties have been explored and it has been proposed that the non-ionised form of the caprylate acid disrupts the integrity of the lipid bilayer and membrane associated proteins of enveloped viruses. the studies reported here further explore the use of this fatty acid to inac ...200312935811
antiviral effects of geranylgeranylacetone: enhancement of mxa expression and phosphorylation of pkr during influenza virus infection.a cyclic polyisoprenoid compound, geranylgeranylacetone (gga), has been used as antiulcer drug. gga is also a potent inducer of heat shock proteins (hsps). hsps are considered to induce an antiviral effect; however, the detailed mechanism is unknown. to determine whether gga might show antiviral activity and what the mechanism is, the effect of gga against influenza virus (strain pr8) infection in vivo and in vitro was investigated. the results demonstrated that gga treatment strongly suppressed ...200312936994
packaging of brome mosaic virus rna3 is mediated through a bipartite signal.the three genomic and a single subgenomic rna of brome mosaic virus (bmv), an rna virus infecting plants, are packaged by a single-coat protein (cp) into three morphologically indistinguishable icosahedral virions with t = 3 quasi-symmetry. genomic rnas 1 and 2 are packaged individually into separate particles whereas genomic rna3 and subgenomic rna4 (coat protein mrna) are copackaged into a single particle. we report here that packaging of dicistronic rna3 requires a bipartite signal. a highly ...200312941883
cis-acting elements required for efficient packaging of brome mosaic virus rna3 in barley protoplasts.brome mosaic virus (bmv) is a positive-sense rna plant virus, the tripartite genomic rnas of which are separately packaged into virions. rna3 is copackaged with subgenomic rna4. in barley protoplasts coinoculated with rna1 and rna2, an rna3 mutant with a 69-nucleotide (nt) deletion in the 3'-proximal region of the 3a open reading frame (orf) was very poorly packaged compared with other rna3 mutants and wild-type rna3, despite their comparable accumulation in the absence of coat protein. computer ...200312941908
t cells cause acute immunopathology and are required for long-term survival in mouse adenovirus type 1-induced encephalomyelitis.infection of adult c57bl/6 (b6) mice with mouse adenovirus type 1 (mav-1) results in dose-dependent encephalomyelitis. utilizing immunodeficient mice, we analyzed the roles of t cells, t-cell subsets, and t-cell-related functions in mav-1-induced encephalomyelitis. t cells, major histocompatibility complex (mhc) class i, and perforin contributed to acute disease signs at 8 days postinfection (p.i.). acute mav-1-induced encephalomyelitis was absent in mice lacking t cells and in mice lacking perf ...200312941916
synthesis, antiviral and cytotoxic activity of 6-bromo-2,3-disubstituted-4(3h)-quinazolinones.in the present study, a series of 6-bromo-2,3-disubstitued-4(3h)-quinazolinones was synthesized by condensation of 6-bromo-2-substituted-benzoxazin-4-one with trimethoprim, pyrimethamine and lamotrigine. the chemical structures of the synthesized compounds were confirmed by means of ir, (1)h-nmr and mass spectral and elemental analysis. the antiviral activity and cytotoxicity of the compounds were tested in e(6)sm (herpes simplex-1 kos, herpes simplex-1 tk-kos acv, herpes simplex-2 g, vaccinia v ...200312951471
an alphavirus replicon particle chimera derived from venezuelan equine encephalitis and sindbis viruses is a potent gene-based vaccine delivery vector.alphavirus replicon particle-based vaccine vectors derived from sindbis virus (sin), semliki forest virus, and venezuelan equine encephalitis virus (vee) have been shown to induce robust antigen-specific cellular, humoral, and mucosal immune responses in many animal models of infectious disease and cancer. however, since little is known about the relative potencies among these different vectors, we compared the immunogenicity of replicon particle vectors derived from two very different parental ...200312970424
glycoprotein of nonpathogenic rabies viruses is a key determinant of human cell apoptosis.we showed that, unlike pathogenic rabies virus (rv) strain cvs, attenuated rv strain era triggers the caspase-dependent apoptosis of human cells. furthermore, we observed that the induction of apoptosis is correlated with a particular virus antigen distribution: the overexpression of the viral g protein on the cell surface, with continuous localization on the cytoplasmic membrane, and large cytoplasmic inclusions of the n protein. to determine whether one of these two major rv proteins (g and n ...200312970438
interfacial domains in sindbis virus 6k protein. detection and functional characterization.alphavirus 6k is a short, constitutive membrane protein involved in virus glycoprotein processing, membrane permeabilization, and the budding of virus particles. the amino-terminal region that immediately precedes the transmembrane anchor contains a conserved sequence motif consisting of two interfacial domains separated by asn and gln residues. the presence of this motif confers on the 6k pretransmembrane region the tendency to partition into the membrane interface. to study the functional impo ...200312424249
zic2 patterns binocular vision by specifying the uncrossed retinal projection.during cns development, combinatorial expression of transcription factors controls neuronal subtype identity and subsequent axonal trajectory. regulatory genes designating the routing of retinal ganglion cell (rgc) axons at the optic chiasm to the appropriate hemisphere, a pattern critical for proper binocular vision, have not been identified. here, we show that the zinc finger transcription factor zic2, a vertebrate homolog of the drosophila gene odd-paired, is expressed in rgcs with an uncross ...200313678579
serological evidence of west nile virus, usutu virus and sindbis virus infection of birds in the uk.the introduction and rapid dispersal of the african flavivirus west nile virus (wnv) throughout north america, and the high fatality rate due to encephalitis in birds, horses, other wildlife species and humans, has attracted major attention worldwide. usutu virus, another flavivirus, came to prominence in 2001, when it was identified as the agent responsible for a drop in the bird population in austria; previously this encephalitic virus was found only in birds and mosquitoes in africa. sindbis ...200313679615
use of sindbis virus-mediated rna interference to demonstrate a conserved role of broad-complex in insect metamorphosis.the transcription factor broad-complex (br-c) is required for differentiation of adult structures as well as for the programmed death of obsolete larval organs during metamorphosis of the fruit fly drosophila melanogaster. whether br-c has a similar role in other holometabolous insects could not be proven without a loss-of-function genetic test, performed in a non-drosophilid species. here we use a recombinant sindbis virus as a tool to silence br-c expression in the silkmoth bombyx mori. the vi ...200314668449
flavivirus isolations from mosquitoes collected from western cape york peninsula, australia, 1999-2000.after the 1st appearance of japanese encephalitis virus (je) on mainland australia in 1998, a study was undertaken to investigate whether je had become established in enzootic transmission cycles on western cape york peninsula. adult mosquitoes were collected during the late wet season from kowanyama and pormpuraaw in april 1999, and pormpuraaw and barr's yard in april 2000. despite processing 269,270 mosquitoes for virus isolation, no isolates of je were obtained. however, other flaviviruses co ...200314710742
systematic, genome-wide identification of host genes affecting replication of a positive-strand rna virus.positive-strand rna viruses are the largest virus class and include many pathogens such as hepatitis c virus and the severe acute respiratory syndrome coronavirus (sars). brome mosaic virus (bmv) is a representative positive-strand rna virus whose rna replication, gene expression, and encapsidation have been reproduced in the yeast saccharomyces cerevisiae. by using traditional yeast genetics, host genes have been identified that function in controlling bmv translation, selecting bmv rnas as rep ...200314671320
unique inflammatory rna profiles of microglia in creutzfeldt-jakob disease.previous studies in creutzfeldt-jakob disease (cjd) have shown that myeloid cells in the periphery as well as derivative microglial cells in the brain are infectious. microglia can show an activated phenotype before prion protein (prp) pathology is detectable in brain, and isolated infectious microglia contain very little prp. to find whether a set of inflammatory genes are significantly induced or suppressed with infection, we analyzed rna from isolated microglia with relevant cdna arrays, and ...200312525699
p250gap, a novel brain-enriched gtpase-activating protein for rho family gtpases, is involved in the n-methyl-d-aspartate receptor signaling.n-methyl-d-aspartate (nmda) receptors regulate structural plasticity by modulating actin organization within dendritic spines. herein, we report identification and characterization of p250gap, a novel gtpase-activating protein for rho family proteins that interacts with the glurepsilon2 (nr2b) subunit of nmda receptors in vivo. the p250gap mrna was enriched in brain, with high expression in cortex, corpus striatum, hippocampus, and thalamus. within neurons, p250gap was highly concentrated in the ...200312857875
sindbis virus nucleocapsid assembly: rna folding promotes capsid protein dimerization.in sindbis virus, initiation of nucleocapsid core assembly begins with recognition of the encapsidation signal of the viral rna genome by capsid protein. this nucleation event drives the recruitment of additional capsid proteins to fully encapsidate the genome, generating an icosahedral nucleocapsid core. the encapsidation signal of the sindbis virus genomic rna has previously been localized to a 132-nucleotide region of the genome within the coding region of the nsp1 protein, and the rna-bindin ...200414681591
synthesis and antiviral evaluation of benzimidazoles, quinoxalines and indoles from dehydroabietic acid.several heterocycles, such as benzimidazoles, quinoxalines and indoles incorporated into a hydrophenanthrene and naphthalene skeleton, were synthesised from two useful ortho-bromonitro precursors derived from dehydroabietic acid: methyl 12-bromo-13-nitro-deisopropyldehydroabietate and methyl 12-bromo-13,14-dinitro-deisopropyldehydroabietate. the new heterocycles were evaluated for their activity in vitro against several rna and dna viruses.200414697775
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
sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine.sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications.200414720306
borna disease virus multiplication in mouse organotypic slice cultures is site-specifically inhibited by gamma interferon but not by interleukin-12.borna disease virus (bdv) induces a nonpurulent cd4- and cd8-t-cell-dependent meningoencephalitis in susceptible animals. upon intracerebral infection, bdv replicates in the mouse central nervous system (cns), but only a few mouse strains develop neurological disorder. the antiviral t cells appear to suppress bdv replication by a noncytolytic mechanism. since bdv does not replicate in standard mouse cell cultures, the putative role of gamma interferon (ifn-gamma) in virus control could not be te ...200414722276
critical residues for gtp methylation and formation of the covalent m7gmp-enzyme intermediate in the capping enzyme domain of bamboo mosaic virus.open reading frame 1 of bamboo mosaic virus (bamv), a potexvirus in the alphavirus-like superfamily, encodes a 155-kda replicase responsible for the formation of the 5' cap structure and replication of the viral rna genome. the n-terminal domain of the viral replicase functions as an mrna capping enzyme, which exhibits both gtp methyltransferase and s-adenosylmethionine (adomet)-dependent guanylyltransferase activities. we mutated each of the four conserved amino acids among the capping enzymes ...200414722282
human immunodeficiency virus type 1-derived lentivirus vectors pseudotyped with envelope glycoproteins derived from ross river virus and semliki forest virus.ross river virus (rrv) and semliki forest virus (sfv) are two alphaviruses that have a high degree of amino acid homology, as well as a very broad host range. we show here that envelope glycoproteins derived from both viruses can pseudotype human immunodeficiency virus type 1 (hiv-1)-derived lentivirus vectors. both rrv and sfv glycoproteins considerably expand the host range of the lentivirus vector, and vectors can be efficiently concentrated by ultracentrifugation. a systematic analysis compa ...200414722297
development of a new sindbis virus transducing system and its characterization in three culicine mosquitoes and two lepidopteran species.alphavirus transducing systems (atss) are alphavirus-based tools for expressing genes in insects. here we describe an ats (5'dsmre16ic) based entirely on sindbis mre16 virus. gfp expression was used to characterize alimentary tract infections and dissemination in three culicine and two lepidopteran species. following per os infection, 5'dsmre16ic-egfp efficiently infected aedes aegypti and culex tritaeniorhynchus, but not culex pipiens pipiens. ae. aegypti clearly showed accumulation of green fl ...200414728670
generation and characterization of closely related epizootic and enzootic infectious cdna clones for studying interferon sensitivity and emergence mechanisms of venezuelan equine encephalitis virus.venezuelan equine encephalitis virus (veev) is a reemerging pathogen and a continuing threat to humans and equines in the americas. identification of the genetic determinants that enable epizootic veev strains to arise and exploit equines as amplification hosts to cause widespread human disease is pivotal to understanding vee emergence. the sensitivity to murine alpha/beta interferon-mediated antiviral activity was previously correlated to the epizootic phenotype of several veev strains. infecti ...200414671082
selection of functional 5' cis-acting elements promoting efficient sindbis virus genome replication.the 5' portion of the sindbis virus (sin) genome rna is multifunctional. besides initiating translation of the nonstructural polyprotein, rna elements in the 5' 200 bases of the sin genome rna, or its complement at the 3' end of the negative-strand intermediate, play key roles in the synthesis of both negative- and positive-strand rnas. we used here a combination of genetic and biochemical approaches to further dissect the functions of this sequence. replacement of the sin 5' end in defective-in ...200414671088
a jc virus-induced signal is required for infection of glial cells by a clathrin- and eps15-dependent pathway.infectious entry of jc virus (jcv) into human glial cells occurs by receptor-mediated clathrin-dependent endocytosis. in this report we demonstrate that the tyrosine kinase inhibitor genistein blocks virus entry and inhibits infection. transient expression of dominant-negative eps15 mutants, including a phosphorylation-defective mutant, inhibited both virus entry and infection. we also show that the jcv-induced signal activates the mitogen-activated protein kinases erk1 and erk2. these data demo ...200414671106
the orf2 protein of hepatitis e virus binds the 5' region of viral rna.hepatitis e virus (hev) is a major human pathogen in much of the developing world. it is a plus-strand rna virus with a 7.2-kb polyadenylated genome consisting of three open reading frames, orf1, orf2, and orf3. of these, orf2 encodes the major capsid protein of the virus and orf3 encodes a small protein of unknown function. using the yeast three-hybrid system and traditional biochemical techniques, we have studied the rna binding activities of orf2 and orf3, two proteins encoded in the 3' struc ...200414671114
tetracycline-inducible packaging cell line for production of flavivirus replicon particles.we have previously developed replicon vectors derived from the australian flavivirus kunjin that have a unique noncytopathic nature and have been shown to direct prolonged high-level expression of encoded heterologous genes in vitro and in vivo and to induce strong and long-lasting immune responses to encoded immunogens in mice. to facilitate further applications of these vectors in the form of virus-like particles (vlps), we have now generated a stable bhk packaging cell line, tetkuncprme, carr ...200414671135
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 stimuli.in 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 cells.in 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
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
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
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
sindbis vector sinrep(nsp2s726): a tool for rapid heterologous expression with attenuated cytotoxicity in neurons.sindbis virus-based vectors have been successfully used for transient heterologous protein expression in neurons. their main limitation arises from infection-associated cytotoxicity, attributed largely to a progressive shut down of host cell protein synthesis. here we evaluated a modified sindbis vector, based on a viral strain containing a point mutation in the second nonstructural protein, nsp2 p726s, described to delay inhibition of protein synthesis in bhk cells [virology 228 (1997) 74], for ...200414757348
alterations of pr-m cleavage and virus export in pr-m junction chimeric dengue viruses.during the export of flavivirus particles through the secretory pathway, a viral envelope glycoprotein, prm, is cleaved by the proprotein convertase furin; this cleavage is required for the subsequent rearrangement of receptor-binding e glycoprotein and for virus infectivity. similar to many furin substrates, prm in vector-borne flaviviruses contains basic residues at positions p1, p2, and p4 proximal to the cleavage site; in addition, a number of charged residues are found at position p3 and be ...200414963133
analysis of the 3' cis-acting elements of rubella virus by using replicons expressing a puromycin resistance gene.a rubella virus (rub) replicon, rubrep/pac, was constructed and used to map the 3' cis-acting elements (3' cse) of the rub genome required for rub replication. the rubrep/pac replicon had the structural protein open reading frame partially replaced by a puromycin acetyltransferase (pac) gene. cells transfected with rubrep/pac transcripts expressed the pac gene from the subgenomic rna, were rendered resistant to puromycin, and thus survived selection with this drug. the relative survival followin ...200414963158
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