Publications

isolation of west nile and sindbis viruses from mosquitoes collected in the nile valley of egypt during an outbreak of rift valley fever.	as part of an evaluation of potential vectors of arboviruses during a rift valley fever (rvf) outbreak in the nile valley of egypt in august 1993, we collected mosquitoes in villages with known rvf viral activity. mosquitoes were sorted to species, pooled, and processed for virus isolation both by intracerebral inoculation into suckling mice and by inoculation into cell culture. a total of 33 virus isolates was made from 36,024 mosquitoes. viruses were initially identified by indirect fluorescen ...	2002	11931267
virion disassembly is required for apoptosis induced by reovirus.	reovirus infection leads to apoptosis in cultured cells and in vivo. binding of viral attachment protein final sigma 1 to both sialic acid and junction adhesion molecule is required for induction of apoptosis. however, it is not known whether viral engagement of receptors is sufficient to elicit this cellular response. to determine whether steps in reovirus replication subsequent to viral attachment are required for reovirus-induced apoptosis, we used inhibitors of viral disassembly and rna synt ...	2002	11799158
molecular dissection of the semliki forest virus homotrimer reveals two functionally distinct regions of the fusion protein.	semliki forest virus (sfv) is an enveloped alphavirus that infects cells via a membrane fusion reaction triggered by the acidic ph of endosomes. in response to low ph, the e1 proteins on the virus membrane undergo a series of conformational changes, resulting in the formation of a stable e1 homotrimer. little is known about the structural basis of either the e1 conformational changes or the resulting homotrimer or about the mechanism of action of the homotrimer in fusion. here, the e1 homotrimer ...	2002	11773395
molecular chaperone hsp90 is important for vaccinia virus growth in cells.	molecular chaperones assist protein folding, and some chaperones are induced by heat, nutrient depletion, or pathogen invasion. this study investigates the role played by hsp90 in the life cycle of vaccinia virus. the titer of vaccinia intracellular mature virions (imv) was reduced by 2 orders of magnitude in rk13 cells treated with geldanamycin (ga), which blocks the atpase activity of hsp90. ga does not affect expression from the viral early promoter, but treatment with ga delays dna replicati ...	2002	11773412
selective electrical silencing of mammalian neurons in vitro by the use of invertebrate ligand-gated chloride channels.	selectively reducing the excitability of specific neurons will (1) allow for the creation of animal models of human neurological disorders and (2) provide insight into the global function of specific sets of neurons. we focus on a combined genetic and pharmacological approach to silence neurons electrically. we express invertebrate ivermectin (ivm)-sensitive chloride channels (caenorhabditis elegans glucl alpha and beta) with a sindbis virus and then activate these channels with ivm to produce i ...	2002	12196558
acid-induced movements in the glycoprotein shell of an alphavirus turn the spikes into membrane fusion mode.	in the icosahedral (t = 4) semliki forest virus, the envelope protomers, i.e. e1-e2 heterodimers, make one-to-one interactions with capsid proteins below the viral lipid bilayer, transverse the membrane and form an external glycoprotein shell with projections. the shell is organized by protomer domains interacting as hexamers and pentamers around shell openings at icosahedral 2- and 5-fold axes, respectively, and the projections by other domains associating as trimers at 3- and quasi 3-fold axes ...	2002	12198142
bioprocess applications of a sindbis virus-based temperature-inducible expression system.	the production and study of toxic proteins requires inducible expression systems with low basal level expression and high inducibility. here, we describe bioprocess applications of the pcytts temperature-regulatable sindbis virus replicon-based expression system. we used green fluorescent protein as a marker protein to optimize the selection of stable transfected clones with increased expression levels. using the optimized protocol, clones were constructed that produced the growth-inhibiting, an ...	2002	12209807
video complicates stem-cell debate.		2002	12357222
suppression of lipopolysaccharide-induced antiviral transcription factor (stat-1 and nf-kappa b) complexes by antibody-dependent enhancement of macrophage infection by ross river virus.	subneutralizing concentrations of antibody may enhance virus infection by bringing the virus-antibody complex into contact with the cell surface fc receptors; this interaction facilitates entry of virus into the cell and is referred to as antibody-dependent enhancement (ade) of infection. northern analysis of macrophage rna demonstrated that ade infection by the indigenous australian alphavirus ross river (rrv-ade) ablated or diminished message for tumor necrosis factor alpha (tnf-alpha), nitric ...	2002	12364588
coxiella burnetii localizes in a rab7-labeled compartment with autophagic characteristics.	the obligate intracellular bacterium coxiella burnetii, the agent of q fever in humans and of coxiellosis in other animals, survives and replicates within large, acidified, phagolysosome-like vacuoles known to fuse homo- and heterotypically with other vesicles. to further characterize these vacuoles, hela cells were infected with c. burnetii phase ii; 48 h later, bacteria-containing vacuoles were labeled by lysotracker, a marker of acidic compartments, and accumulated monodansylcadaverine and di ...	2002	12228312
in vitro analysis of factors involved in the disassembly of sindbis virus cores by 60s ribosomal subunits identifies a possible role of low ph.	disassembly of alphavirus cores early in infection involves interaction of the core with 60s ribosomal subunits. this interaction might be subjected to regulatory processes. we have established an in vitro system of core disassembly in order to identify cellular proteins involved in the regulation of disassembly. no evidence for the existence of such proteins was found, but it became apparent that certain organic solvents and detergents or a high proton concentration (ph 6.0) stimulated core dis ...	2002	12237423
influenza virus can enter and infect cells in the absence of clathrin-mediated endocytosis.	influenza virus has been described to enter host cells via clathrin-mediated endocytosis. however, it has also been suggested that other endocytic routes may provide additional entry pathways. here we show that influenza virus may enter and infect hela cells that are unable to take up ligands by clathrin-mediated endocytosis. by overexpressing a dominant-negative form of the eps15 protein to inhibit clathrin-mediated endocytosis, we demonstrate that while transferrin uptake and semliki forest vi ...	2002	12239322
adaptation of alphaviruses to heparan sulfate: interaction of sindbis and semliki forest viruses with liposomes containing lipid-conjugated heparin.	passage of sindbis virus (sin) in bhk-21 cells has been shown to select for virus mutants with high affinity for the glycosaminoglycan heparan sulfate (hs). three loci in the viral spike protein e2 (e2:1, e2:70, and e2:114) have been identified that mutate during adaptation and independently confer on the virus the ability to bind to cell surface hs (w. b. klimstra, k. d. ryman, and r. e. johnston, j. virol. 72:7357-7366, 1998). in this study, we used hs-adapted sin mutants to evaluate a new mod ...	2002	12239287
systematic assembly of a full-length infectious cdna of mouse hepatitis virus strain a59.	a novel method was developed to assemble a full-length infectious cdna of the group ii coronavirus mouse hepatitis virus strain a59 (mhv-a59). seven contiguous cdna clones that spanned the 31.5-kb mhv genome were isolated. the ends of the cdnas were engineered with unique junctions and assembled with only the adjacent cdna subclones, resulting in an intact mhv-a59 cdna construct of approximately 31.5 kb in length. the interconnecting restriction site junctions that are located at the ends of eac ...	2002	12368349
alphaviral gene transfer in neurobiology.	semliki forest virus (sfv), sindbis virus (sin), and venezuelan equine encephalitis virus are simple, enveloped plus-strand rna viruses belonging to the alphavirus genus of the togaviridae family. they have been developed into expression vectors that infect a wide host cell range and cause rapid and high-level transgene expression. their easy and fast generation, classification into biosafety levels 1 and 2, and preferential transduction of neurons in cell and tissue cultures makes them an incre ...	2002	12372543
induction of cytolytic anti-gal antibodies in alpha-1,3-galactosyltransferase gene knockout mice by oral inoculation with escherichia coli o86:b7 bacteria.	naturally occurring antibodies against [gal alpha-1,3-gal] structures (anti-gal antibodies) are the primary effectors of human hyperacute rejection (har) of nonhuman tissue. unlike most mammals, humans lack a functional alpha-1,3-galactosyltransferase (galt) gene and produce abundant anti-gal antibodies, putatively in response to galt(+) enteric bacteria. galt knockout (ko) mice have been generated as a small animal model of har but inconsistently express anti-gal antibodies. we hypothesized tha ...	2002	12379700
roles of nonstructural protein nsp2 and alpha/beta interferons in determining the outcome of sindbis virus infection.	alphaviruses productively infect a variety of vertebrate and insect cell lines. in vertebrate cells, sindbis virus redirects cellular processes to meet the needs of virus propagation. at the same time, cells respond to virus replication by downregulating virus growth and preventing dissemination of the infection. the balance between these two mechanisms determines the outcome of infection at the cellular and organismal levels. in this report, we demonstrate that a viral nonstructural protein, ns ...	2002	12388685
role of the alfalfa mosaic virus methyltransferase-like domain in negative-strand rna synthesis.	rnas 1 and 2 of the tripartite genome of alfalfa mosaic virus (amv) encode the replicase proteins p1 and p2, respectively. p1 contains a methyltransferase-like domain in its n-terminal half, which has a putative role in capping the viral rnas. six residues in this domain that are highly conserved in the methyltransferase domains of alphavirus-like viruses were mutated individually in amv p1. none of the mutants was infectious to plants. mutant rna 1 was coexpressed with wild-type (wt) rnas 2 and ...	2002	12388692
stable expression of primary human immunodeficiency virus type 1 structural gene products by use of a noncytopathic sindbis virus vector.	efficient expression of the human immunodeficiency virus type 1 (hiv-1) structural gene products gag, pol, and env involves the regulation by viral rev and rev-responsive elements (rre). removal of multiple inhibitory sequences (ins) in the coding regions of these structural genes or modification of the codon usage patterns of hiv-1 genes to those used by highly expressed human genes has been found to significantly increase hiv-1 structural protein expression in the absence of rev and rre. in th ...	2002	12388704
generation of a replication-competent, propagation-deficient virus vector based on the transmissible gastroenteritis coronavirus genome.	replication-competent propagation-deficient virus vectors based on the transmissible gastroenteritis coronavirus (tgev) genome that are deficient in the essential e gene have been developed by complementation within e(+) packaging cell lines. cell lines expressing the tgev e protein were established using the noncytopathic sindbis virus replicon psinrep21. in addition, cell lines stably expressing the e gene under the cmv promoter have been developed. the sindbis replicon vector and the ectopic ...	2002	12388713
induction of cytotoxic t-lymphocytes specific for bovine herpesvirus-1 by dna immunization.	cytotoxic t-lymphocytes (ctls) are critical for the defense against herpesvirus infections, in which cell-to-cell spread occurs earlier than the hematogenous spread. the ability of bovine herpesvirus-1 (bhv-1) to undergo latency, to induce apoptosis of cd4(+) t-lymphocytes, and to down-regulate the expression of major histocompatibility complex (mhc) class i molecules, necessitates the development of immunization strategies that do not involve the live virus. the objective of this study was to e ...	2002	12399204
epidemiology of sindbis virus infections in finland 1981-96: possible factors explaining a peculiar disease pattern.	pogosta disease (pd), an epidemic rash-arthritis occurring in late summer is caused by sindbis virus (sinv) and is transmitted to humans by mosquitoes. altogether 2183 pd cases were serologically confirmed 1981-96 in finland, with an annual incidence of 2.7/100000 (18 in the most endemic area of northern karelia). the annual average was 136 (varying from 1 to 1282) with epidemics occurring in august-september with a 7-year interval. studies on 6320 patients with suspected rubella (1973-89) revea ...	2002	12403109
the myxoma poxvirus protein, m11l, prevents apoptosis by direct interaction with the mitochondrial permeability transition pore.	m11l, an antiapoptotic protein essential for the virulence of the myxoma poxvirus, is targeted to mitochondria and prevents the loss of mitochondrial membrane potential that accompanies cell death. in this study we show, using a cross-linking approach, that m11l physically associates with the mitochondrial peripheral benzodiazepine receptor (pbr) component of the permeability transition (pt) pore. close association of m11l and the pbr is also indicated by fluorescence resonance energy transfer ( ...	2002	12417624
dissection of c-mos degron.	c-mos, a map kinase kinase kinase, is a regulator of oocyte maturation. the concentration of c-mos is controlled in part through its conditional degradation. previous studies proposed the "second-codon rule", according to which the n-terminal proline (pro) of c-mos is a destabilizing residue that targets c-mos for degradation. we analyzed the degradation signal (degron) of c-mos in xenopus oocytes, found it to be a portable degron, and demonstrated that, contrary to the model above, the n-termin ...	2002	12426378
alphaviral vectors for gene transfer into neurons.	alphaviruses are small, enveloped positive-strand rna viruses that have been successfully transformed into expression vectors in the case of semliki forest virus (sfv), sindbis virus (sin), and venezuelan equine encephalitis virus. compared to other viral vectors, their advantages are easy and fast generation of recombinant viral particles, rapid onset, and high-level transgene expression. when applied to neuronal tissue, sfv and sin vectors possess the additional advantage of efficiently and pr ...	2002	12428755
effects of membrane potential and sphingolipid structures on fusion of semliki forest virus.	cells expressing the e1 and e2 envelope proteins of semliki forest virus (sfv) were fused to voltage-clamped planar lipid bilayer membranes at low ph. formation and evolution of fusion pores were electrically monitored by capacitance measurements, and membrane continuity was tracked by video fluorescence microscopy by including rhodamine-phosphatidylethanolamine in the bilayer. fusion occurred without leakage for a negative potential applied to the trans side of the planar membrane. when a posit ...	2002	12438595
in vivo antitumor activity of sindbis viral vectors.	sindbis virus, a blood-borne virus transmitted by mosquitoes, has been used as a vector to efficiently express exogenous genes in vitro and in vivo and to induce apoptosis. because sindbis virus infects mammalian cells by interacting with the high-affinity laminin receptors, which are expressed at higher levels in several human cancers than in normal cells, we determined whether a sindbis viral vector could be used to target cancers in vivo.	2002	12464651
alphavirus vectors as tools in cancer gene therapy.	alphavirus vectors, particularly those based on the replicon of semliki forest virus, have shown great potential as gene delivery vehicles for various applications in cancer gene therapy. the rapid production of high-titer recombinant sfv particles, which show impressive transduction rates in various mammalian cell lines, primary cultures and in vivo, results in high levels of transgene expression. additionally, sfv vectors induce apoptosis in transduced host cells, which can further increase th ...	2002	12614181
abstracts of the fourth international symposium on molecular insect science. may 28-june 2, 2002. tucson, arizona, usa.		2002	15455051
semliki forest virus and sindbis virus vectors.	semliki forest virus (sfv) and sindbis virus (sin) are two, positive-strand rna viruses of the alphavirus genus. vectors for both have been developed to express high levels of foreign genes in vitro and in vivo. basic protocol 1 describes the preparation of packaged sfv and sin replicons by co-electroporation of helper and vector rna into baby hamster kidney (bhk)-21 cells. basic protocol 2 describes the activation of packaged sfv replicons with a-chymotrypsin. basic protocol 3 provides a method ...	2002	18428324
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 ...	2003	12857875
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 ...	2003	12525699
experience strengthening transmission by driving ampa receptors into synapses.	the mechanisms underlying experience-dependent plasticity in the brain may depend on the ampa subclass of glutamate receptors (ampa-rs). we examined the trafficking of ampa-rs into synapses in the developing rat barrel cortex. in vivo gene delivery was combined with in vitro recordings to show that experience drives recombinant glur1, an ampa-r subunit, into synapses formed between layer 4 and layer 2/3 neurons. moreover, expression of the glur1 cytoplasmic tail, a construct that inhibits synapt ...	2003	12624270
facilitation of dendritic mrna transport by cpeb.	in neurons, the proteins derived from mrnas localized in dendrites have been implicated in synaptic plasticity. the cytoplasmic polyadenylation element (cpe), a cis element in the 3'-utrs of specific dendritic mrnas, promotes cytoplasmic polyadenylation-induced translation in response to synaptic stimulation. here, we demonstrate that the cpe and its binding protein cpeb facilitate mrna transport to dendrites. in rat hippocampal neurons infected with recombinant viruses, the cpe is sufficient to ...	2003	12629046
the abundant nuclear enzyme parp participates in the life cycle of simian virus 40 and is stimulated by minor capsid protein vp3.	the abundant nuclear enzyme poly(adp-ribose) polymerase (parp) functions in dna damage surveillance and repair and at the decision between apoptosis and necrosis. here we show that parp binds to simian virus 40 (sv40) capsid proteins vp1 and vp3. furthermore, its enzymatic activity is stimulated by vp3 but not by vp1. experiments with purified mutant proteins demonstrated that the parp binding domain in vp3 is localized to the 35 carboxy-terminal amino acids, while a larger peptide of 49 amino a ...	2003	12634384
complexes of poliovirus serotypes with their common cellular receptor, cd155.	structures of all three poliovirus (pv) serotypes (pv1, pv2, and pv3) complexed with their cellular receptor, pv receptor (pvr or cd155), were determined by cryoelectron microscopy. both glycosylated and fully deglycosylated cd155 exhibited similar binding sites and orientations in the viral canyon for all three pv serotypes, showing that all three serotypes use a common mechanism for cell entry. difference maps between the glycosylated and deglycosylated cd155 complexes determined the sites of ...	2003	12663789
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 ...	2003	12857904
bak alters neuronal excitability and can switch from anti- to pro-death function during postnatal development.	bak is a pro-apoptotic bcl-2 family protein that localizes to mitochondria. here we evaluate the function of bak in several mouse models of neuronal injury including neuronotropic sindbis virus infection, parkinson's disease, ischemia/stroke, and seizure. bak promotes or inhibits neuronal death depending on the specific death stimulus, neuron subtype, and stage of postnatal development. bak protects neurons from excitotoxicity and virus infection in the hippocampus. as mice mature, bak is conver ...	2003	12689595
luciferase imaging of a neurotropic viral infection in intact animals.	the identification of viral determinants of virulence and host determinants of susceptibility to virus-induced disease is essential for understanding the pathogenesis of infection. obtaining this information requires infecting large numbers of animals to assay amounts of virus in a variety of organs and to observe the onset and progression of disease. as an alternative approach, we have used a murine model of viral encephalitis and an in vivo imaging system that can detect light generated by luc ...	2003	12692235
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 ...	2003	12885905
human rhinovirus type 2 is internalized by clathrin-mediated endocytosis.	using several approaches, we investigated the importance of clathrin-mediated endocytosis in the uptake of human rhinovirus serotype 2 (hrv2). by means of confocal immunofluorescence microscopy, we show that k(+) depletion strongly reduces hrv2 internalization. viral uptake was also substantially reduced by extraction of cholesterol from the plasma membrane with methyl-beta-cyclodextrin, which can inhibit clathrin-mediated endocytosis. in accordance with these data, overexpression of dynamin k44 ...	2003	12692238
immunoregulation of a viral model of multiple sclerosis using the synthetic cannabinoid r+win55,212.	theiler murine encephalomyelitis virus-induced demyelinating disease (tmev-idd) is a mouse model of chronic-progressive multiple sclerosis (ms) characterized by th1-mediated cns demyelination and spastic hindlimb paralysis. existing ms therapies reduce relapse rates in 30% of relapsing-remitting ms patients, but are ineffective in chronic-progressive disease, and their effects on disability progression are unclear. experimental studies demonstrate cannabinoids are useful for symptomatic treatmen ...	2003	12697742
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 ...	2003	12915543
modified apoptotic molecule (bid) reduces hepatitis c virus infection in mice with chimeric human livers.	hepatitis c virus (hcv) encodes a polyprotein consisting of core, envelope (e1, e2, p7), and nonstructural polypeptides (ns2, ns3, ns4a, ns4b, ns5a, ns5b). the serine protease (ns3/ns4a), helicase (ns3), and polymerase (ns5b) constitute valid targets for antiviral therapy. we engineered bh3 interacting domain death agonist (bid), an apoptosis-inducing molecule, to contain a specific cleavage site recognized by the ns3/ns4a protease. cleavage of the bid precursor molecule by the viral protease ac ...	2003	12704395
genetic screen for monitoring hepatitis c virus ns3 serine protease activity.	we have developed a genetic system to monitor the activity of the hepatitis c virus (hcv) ns3 serine protease. this genetic system is based on the bacteriophage lambda regulatory circuit where the viral repressor ci is specifically cleaved to initiate the switch from lysogeny to lytic infection. an hcv protease-specific target, ns5a-5b, was inserted into the lambda phage ci repressor. the target specificity of the hcv ns5a-5b repressor was evaluated by coexpression of this repressor with a beta- ...	2003	12709356
the prevalence of antibodies against sindbis-related (pogosta) virus in different parts of finland.	to study the occurrence of sindbis-related (pogosta) disease in finland by serological means.	2003	12709538
effects of collagen matrix on sindbis virus infection of bhk cells.	the effects of extracellular matrix (ecm) components on the outcomes of alphavirus interaction with cells are not known. studies that address such interactions have to address several methodological difficulties, including: the survival of the cells within the matrix; the passage of the virus through the matrix to infect embedded cells; and the dissociation of cells and matrix into single-cell suspension, before and after virus infection, for quantitative analysis. herein, these issues were addr ...	2003	12711058
effect of p38 mitogen-activated protein kinase on the replication of encephalomyocarditis virus.	cellular phosphorylation events during viral infection are necessary for effective viral replication. encephalomyocarditis (emc) virus has been used for studies on the molecular mechanisms of viral replication, but little is known about the cellular signaling pathways involved. this investigation was initiated to determine whether mitogen-activated protein kinases (mapks), which are central components of signal transduction pathways in the regulation of cell proliferation, play a role in the rep ...	2003	12719557
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 ...	2003	12941916
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 ...	2003	12951471
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 ...	2003	12970424
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 ...	2003	12970438
transcription strategy in a closterovirus: a novel 5'-proximal controller element of citrus tristeza virus produces 5'- and 3'-terminal subgenomic rnas and differs from 3' open reading frame controller elements.	citrus tristeza virus (ctv) produces more than thirty 3'- or 5'-terminal subgenomic rnas (sgrnas) that accumulate to various extents during replication in protoplasts and plants. among the most unusual species are two abundant populations of small 5'-terminal sgrnas of approximately 800 nucleotides (nt) termed low-molecular-weight tristeza (lmt1 and lmt2) rnas. remarkably, ctv replicons with all 10 3' genes deleted produce only the larger lmt1 rnas. these 5'-terminal positive-sense sgrnas do not ...	2003	12477839
enhanced immunogenicity to mycobacterium tuberculosis by vaccination with an alphavirus plasmid replicon expressing antigen 85a.	the immunogenicity of a plasmid dna vaccine incorporating sindbis virus rna replicase functions (psincp) and expressing antigen 85a (ag85a) from mycobacterium tuberculosis was compared with a conventional plasmid dna vector encoding ag85a. psincp-85a was highly immunogenic in mice and gave enhanced long-term protection against m. tuberculosis compared with the conventional vector.	2003	12496215
alphavirus-based dna vaccine breaks immunological tolerance by activating innate antiviral pathways.	cancer vaccines targeting 'self' antigens that are expressed at consistently high levels by tumor cells are potentially useful in immunotherapy, but immunological tolerance may block their function. here, we describe a novel, naked dna vaccine encoding an alphavirus replicon (self-replicating mrna) and the self/tumor antigen tyrosinase-related protein-1. unlike conventional dna vaccines, this vaccine can break tolerance and provide immunity to melanoma. the vaccine mediates production of double- ...	2003	12496961
antiviral effect and virus-host interactions in response to alpha interferon, gamma interferon, poly(i)-poly(c), tumor necrosis factor alpha, and ribavirin in hepatitis c virus subgenomic replicons.	the recently developed hepatitis c virus (hcv) subgenomic replicon system was utilized to evaluate the efficacy of several known antiviral agents. cell lines that persistently maintained a genotype 1b replicon were selected. the replicon resident in each cell line had acquired adaptive mutations in the ns5a region that increased colony-forming efficiency, and some replicons had acquired ns3 mutations that alone did not enhance colony-forming efficiency but were synergistic with ns5a mutations. a ...	2003	12502825
an attenuating mutation in nsp1 of the sindbis-group virus s.a.ar86 accelerates nonstructural protein processing and up-regulates viral 26s rna synthesis.	the sindbis-group alphavirus s.a.ar86 encodes a threonine at nonstructural protein 1 (nsp1) 538 that is associated with neurovirulence in adult mice. mutation of the nsp1 538 thr to the consensus ile found in nonneurovirulent sindbis-group alphaviruses attenuates s.a.ar86 for adult mouse neurovirulence, while introduction of thr at position 538 in a nonneurovirulent sindbis virus background confers increased neurovirulence (m. t. heise et al., j. virol. 74:4207-4213, 2000). since changes in the ...	2003	12502831
alphavirus cdna-based expression vectors: effects of rna transcription and nuclear export.	the construction of layered dna-rna replicons has facilitated and expanded the use of alphavirus vectors to vaccine development, construction of packaging cell lines and long-term heterologous gene expression. in these vector systems, the alphavirus replicon is under the control of a strong rna polymerase ii promoter and replicon rna is transcribed from dna before transport to the cytoplasm. efficient rna amplification catalyzed by the viral replicase results in high levels of mrna and the recom ...	2003	12514804
sindbis virus vectors designed to express a foreign protein as a cleavable component of the viral structural polyprotein.	alphavirus-based expression vectors commonly use a duplicated 26s promoter to drive expression of a foreign gene. here we describe an expression strategy in which the foreign sequences are linked to the gene encoding the 2a protease of foot-and-mouth disease virus and then inserted in frame between the capsid and e3 genes of sindbis virus. during replication, the 2a fusion protein is synthesized as a component of the viral structural polyprotein that is then released by intramolecular cleavages ...	2003	12719552
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 ...	2003	12520185
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 ...	2003	12525603
human immunodeficiency virus type 1 envelope-mediated neuropathogenesis: targeted gene delivery by a sindbis virus expression vector.	sindbis virus (sin) expression vectors offer the opportunity for studying neuropathogenesis because of their distinct neural cell tropism. here, we demonstrate that a recombinant sin vector expressing egfp (sinrep5-egfp) infected multiple cell types including neural cells from several species relevant to lentivirus pathogenesis with high levels of transgene expression. infection of human neurons by a recombinant sin (sinrep5-jrfl) expressing the full-length envelope from a neurovirulent human im ...	2003	12726727
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 ...	2003	12525644
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 ...	2003	12533714
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 ...	2003	12542671
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 ...	2003	12761383
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 ...	2003	12551967
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 ...	2003	12773377
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 ...	2003	12782019
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 ...	2003	12552021
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 ...	2003	12805417
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 ...	2003	12584344
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 ...	2003	12603279
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 ...	2003	12610119
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 ...	2003	12610129
attenuated salmonella enterica serovar typhi and shigella flexneri 2a strains mucosally deliver dna vaccines encoding measles virus hemagglutinin, inducing specific immune responses and protection in cotton rats.	measles remains a leading cause of child mortality in developing countries. residual maternal measles antibodies and immunologic immaturity dampen immunogenicity of the current vaccine in young infants. because cotton rat respiratory tract is susceptible to measles virus (mv) replication after intranasal (i.n.) challenge, this model can be used to assess the efficacy of mv vaccines. pursuing a new measles vaccine strategy that might be effective in young infants, we used attenuated salmonella en ...	2003	12692223
morphological variants of sindbis virus produced by a mutation in the capsid protein.	sindbis virus is a complex aggregate of rna, protein and lipid. the virus is organized as two nested t = 4 icosahedral protein shells between which is sandwiched a lipid bilayer. the virus rna resides within the inner protein shell. the inner protein shell is attached to the outer protein shell through contacts to proteins in the outer shell, which penetrate the lipid bilayer. the data presented in the following manuscript show that mutations in the capsid protein can result in the assembly of t ...	2003	12667814
engineering the transmissible gastroenteritis virus genome as an expression vector inducing lactogenic immunity.	the genome of the coronavirus transmissible gastroenteritis virus (tgev) has been engineered as an expression vector with an infectious cdna. the vector led to the efficient (>40 micro g/10(6) cells) and stable (>20 passages) expression of a heterologous gene (green fluorescent protein [gfp]), driven by the transcription-regulating sequences (trs) of open reading frame (orf) 3a inserted in the site previously occupied by the nonessential orfs 3a and 3b. expression levels driven by this trs were ...	2003	12634392
diverse dengue type 2 virus populations contain recombinant and both parental viruses in a single mosquito host.	envelope (e) protein genes sampled from populations of dengue 2 (den-2) virus in individual aedes aegypti mosquitoes and in serum from dengue patients were copied to cdna, cloned, and sequenced. the nucleotide sequences of the e genes in more than 70% of the clones differed from the consensus sequence for the corresponding virus population at up to 11 sites, and 24 of the 94 clones contained at least one stop codon. virus populations recovered up to 2 years apart yielded clones with similar poly ...	2003	12634407
development of an orally infectious sindbis virus transducing system that efficiently disseminates and expresses green fluorescent protein in aedes aegypti.	we have constructed an orally infectious sindbis virus, me2/5'2j/gfp, that expresses green fluorescent protein (gfp) in the midgut of aedes aegypti and in other tissues as the virus disseminates. this virus has two unique features that are improvements over the sin-based expression systems currently used in mosquitoes. first, a subgenomic rna promoter and gfp coding sequence is located 5'- to the second subgenomic promoter and structural genes of the virus. second, the e2 glycoprotein gene of te ...	2003	12653932
foamy virus envelope glycoprotein-mediated entry involves a ph-dependent fusion process.	in general, enveloped viruses use two different entry strategies and are classified accordingly into ph-dependent and ph-independent viruses. different members of the retrovirus family use one or the other strategy. little is known about the uptake of foamy viruses (fv), a special group of retroviruses, into the target cells. in this study, we examined the ph dependence of fv entry by analyzing fv envelope glycoprotein (env)-mediated infection of target cells with murine leukemia virus or fv vec ...	2003	12663779
kinetics of cd4+ and cd8+ memory t-cell responses during hepatitis c virus rechallenge of previously recovered chimpanzees.	the immunological correlates of hepatitis c virus (hcv)-specific immunity are not well understood. antibodies to hcv structural proteins do not appear to play a key role in clearance of the virus and do not persist after recovery. here, we studied the kinetics of the cellular immune responses of three hcv-recovered chimpanzees during rechallenge with increasing doses of homologous hcv. although hcv envelope antibodies remained undetectable throughout the rechallenge, all animals mounted rapid hc ...	2003	12663785
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 ...	2003	12424249
american genotype structures decrease dengue virus output from human monocytes and dendritic cells.	the dengue virus type 2 structures probably involved in human virulence were previously defined by sequencing the complete genome of both american and southeast (se) asian genotype templates in patient serum (k. c. leitmeyer et al., j. virol. 73:4738-4747, 1999). we have now evaluated the effects of introducing a mutation in the envelope glycoprotein (e) gene and/or replacement of 5'- and 3'-nontranslated regions on dengue virus replication in human primary cell cultures. a series of chimeric in ...	2003	12634353
hepatitis c virus glycoproteins interact with dc-sign and dc-signr.	dc-sign and dc-signr are two closely related membrane-associated c-type lectins that bind human immunodeficiency virus (hiv) envelope glycoprotein with high affinity. binding of hiv to cells expressing dc-sign or dc-signr can enhance the efficiency of infection of cells coexpressing the specific hiv receptors. dc-sign is expressed on some dendritic cells, while dc-signr is localized to certain endothelial cell populations, including hepatic sinusoidal endothelial cells. we found that soluble ver ...	2003	12634366
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 ...	2003	12610112
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 ...	2003	12601758
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 ...	2003	12573591
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 ...	2003	12584331
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 ...	2003	12584332
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 ...	2003	12525663
poliovirus-induced apoptosis is reduced in cells expressing a mutant cd155 selected during persistent poliovirus infection in neuroblastoma cells.	poliovirus (pv) can establish persistent infections in human neuroblastoma imr-32 cells. we previously showed that during persistent infection, specific mutations were selected in the first extracellular domain of the pv receptor (cd155) of these cells (n. pavio, t. couderc, s. girard, j. y. sgro, b. blondel, and f. colbère-garapin, virology 274:331-342, 2000). these mutations included the ala 67 --> thr substitution, corresponding to a previously described allelic form of the pv receptor. the m ...	2003	12477887
small interfering rna-mediated inhibition of hepatitis c virus replication in the human hepatoma cell line huh-7.		2003	12477890
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 ...	2003	12525614
glycosaminoglycan binding properties of natural venezuelan equine encephalitis virus isolates.	equine-virulent, epidemic/epizootic strains of venezuelan equine encephalitis (vee) virus (veev) arise via mutation of progenitor enzootic strains that replicate poorly in equines. sequencing studies have implicated positively charged amino acids on the surface of the e2 envelope glycoprotein in the acquisition of equine virulence and viremia potential, suggesting that changes in binding to cell surface glycosaminoglycans (gags) may mediate vee emergence. therefore, we evaluated the binding of n ...	2003	12502837
hepatitis c virus f protein is a short-lived protein associated with the endoplasmic reticulum.	hepatitis c virus (hcv) f protein is a newly discovered hcv gene product that is expressed by translational ribosomal frameshift. little is known about the biological properties of this protein. by performing pulse-chase labeling experiments, we demonstrate here that the f protein is a labile protein with a half-life of <10 min in huh7 hepatoma cells and in vitro. the half-life of the f protein could be substantially increased by proteasome inhibitors, suggesting that the rapid degradation of th ...	2003	12502871
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 ...	2003	14671320
antizyme frameshifting as a functional probe of eukaryotic translational termination.	translation termination in eukaryotes is mediated by the release factors erf1 and erf3, but mechanisms of the interplay between these factors are not fully understood, due partly to the difficulty of measuring termination on eukaryotic mrnas. here, we describe an in vitro system for the assay of termination using competition with programmed frameshifting at the recoding signal of mammalian antizyme. the efficiency of antizyme frameshifting in rabbit reticulocyte lysates was reduced by addition o ...	2003	14530443
changes in mumps virus gene sequence associated with variability in neurovirulent phenotype.	mumps virus is highly neurotropic and, prior to widespread vaccination programs, was the major cause of viral meningitis in the united states. nonetheless, the genetic basis of mumps virus neurotropism and neurovirulence was until recently not understood, largely due to the lack of an animal model. here, nonneurovirulent (jeryl lynn vaccine) and highly neurovirulent (88-1961 wild type) mumps virus strains were passaged in human neural cells or in chicken fibroblast cells with the goal of neuroad ...	2003	14557647
mitogenic effect of orphan receptor tr3 and its regulation by mekk1 in lung cancer cells.	tr3, also known as ngfi-b or nur77, is an immediate-early response gene and an orphan member of the steroid/thyroid/retinoid receptor superfamily. we previously reported that tr3 expression was induced by apoptotic stimuli and was required for their apoptotic effect in lung cancer cells. here, we present evidence that tr3 was also induced by epidermal growth factor (egf) and serum and was required for their mitogenic effect in lung cancer cells. ectopic expression of tr3 in both h460 and calu-6 ...	2003	14612408