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polyanion inhibitors of human immunodeficiency virus and other viruses. part 2. polymerized anionic surfactants derived from amino acids and dipeptides.a series of new polyanions was synthesized via gamma-polymerization, in aqueous micellar solution, of omega-unsaturated anionic surfactants whose polar head was derived from amino acids or dipeptides. the obtained polyanions were evaluated for their activity against human immunodeficiency virus (hiv-1, hiv-2) and various other rna and dna viruses. all the test compounds proved active against hiv-1 and hiv-2, their 50% inhibitory concentration (ic50) being in the range of 0.04-7.5 micrograms/ml, ...19968648602
inhibition of nitric oxide synthesis increases mortality in sindbis virus encephalitis.sindbis virus (sv) is an alphavirus that causes acute encephalomyelitis in mice. the outcome is determined by the strain of virus and by the age and genetic background of the host. the mortality rates after infection with nsv, a neurovirulent strain of sv, were as follows v: 81% (17 of 21) in balb/cj mice; 20% (4 of 20) in balb/cbyj mice (p < 0.001); 100% in a/j, c57bl/6j, sjl, and dba mice; and 79% (11 of 14) in immunodeficient scid/cb17 mice. treatment with nomega-nitro-l-arginine methyl ester ...19968648734
[analysis of the primary structure of segments of the karelian fever virus genome].primary structure of two parts of karelian fever virus (kfv) genome (29-57 nt and 10507-11591 nt) cloned in recombinant plasmids has been studied and compared with that of sindbis (hrsp strain) and ockelbo viruses. fifty-four nucleotide substitutes were revealed in the sequenced parts of kfv genome including partially 5' and 3'-nontranslated sites ( a total of 1613 nucleotides, or approximately 13.8% of the genome length), in comparison with the sindbis virus prototype hrsp strain, this being in ...19958659171
inactivation of the small gtp binding protein rho induces multinucleate cell formation and apoptosis in murine t lymphoma el4.the small g-protein rho regulates the actin microfilament-dependent cytoskeleton. exoenzyme c3 of clostridium botulinum adp-ribosylates rho at asn41, a modification that functionally inactivates rho. using a sindbis virus-based transient gene expression system, we studied the role of rho in murine el4 t lymphoma cells. we generated a double subgenomic infectious sindbis virus (dssin:c3) recombinant which expressed c3 in >95% of el4 cells. this intracellular c3 resulted in modification and inacti ...19968666781
detection of immunoglobulin g to a sindbis-related virus by a membrane antigen enzyme immunoassay.we determined the seroprevalence of a sindbis-related virus isolated for the first time in 1975 from ticks in south-east sicily and typed by gresikova et al. in 1978. an indirect enzyme immunoassay based on viral membrane antigen for coating microtiter strips was used for the detection of immunoglobulin g to the sindbis-related virus. the method appeared more sensitive than a similar enzyme immunoassay based on crude lysate antigen. comparison of the results obtained from sera tested both by mem ...19968673858
characterization of the rubella virus nonstructural protease domain and its cleavage site.the region of the rubella virus nonstructural open reading frame that contains the papain-like cysteine protease domain and its cleavage site was expressed with a sindbis virus vector. cys-1151 has previously been shown to be required for the activity of the protease (l. d. marr, c.-y. wang, and t. k frey, virology 198:586-592, 1994). here we show that his-1272 is also necessary for protease activity, consistent with the active site of the enzyme being composed of a catalytic dyad consisting of ...19968676497
viral safety of a new highly purified factor viii (octate).the inactivation of both transfusion-relevant and model viruses by modified pasteurisation (10 hours at 63 degrees c in solution) has been evaluated following the established guidelines of the eu cpmp ad hoc working party on biotechnology/pharmacy. this heat treatment was introduced into the manufacturing process of octavi, a very high purity factor viii concentrate stabilized only by von willebrand factor, in the presence of a proprietary mixture of low molecular weight stabilizers. both envelo ...19968699169
alphavirus hybrid virion vaccines. 19968718580
the gordon wilson lecture: unique interactions between viruses, neurons and the immune system.the increased susceptibility of young individuals to alphavirus encephalitis is likely to be linked to the ease with which immature neurons are induced to undergo apoptosis after infection. in the more mature individuals, virus infection of neurons may not lead to apoptosis and in the absence of an effective immune response persistent infection is established. the major mechanism by which alphavirus infection of neurons is controlled is by production and local secretion of antibody to the surfac ...19968725563
aromatic interactions define the binding of the alphavirus spike to its nucleocapsid.most enveloped viruses bud from infected cells by a process in which viral intracellular core components interact with cytoplasmic domains of transmembrane spike glycoproteins. we have demonstrated previously that a tyrosine motif in the cytoplasmic domain of the semliki forest virus (sfv) spike glycoprotein e2 is absolutely essential for budding. in contrast, hardly anything is known regarding which region of the capsid protein is involved in spike binding. therefore, the mechanism by which spi ...19968736551
identification of a protein binding site on the surface of the alphavirus nucleocapsid and its implication in virus assembly.many enveloped viruses exit cells by budding from the plasma membrane. the driving force for budding is the interaction of an inner protein nucleocapsid core with transmembrane glycoprotein spikes. the molecular details of this process are ill defined. alphaviruses, such as sindbis virus (sinv) and semliki forest virus (sfv), represent some of the simplest enveloped viruses and have been well characterized by structural, genetic and biochemical techniques. although a high-resolution structure of ...19968736552
arbovirus survey in china in recent ten years. 19968758350
nonhomologous rna-rna recombination events at the 3' nontranslated region of the sindbis virus genome: hot spots and utilization of nonviral sequences.the mechanism of rna-rna recombination at the 3' nontranslated region (3'ntr) of the sindbis virus (sin) genome was studied by using nonreplicative rna precursors. the 11.7-kb sin genome was transcribed in vitro as two nonoverlapping rna fragments. rna-1 contained the entire 11.4-kb protein coding sequence of sin and also carried an additional 1.8-kb nonviral sequence at its 3' end. rna-2 carried the remaining 0.26 or 0.3 kb of the sin genome containing the 3'ntr. transfection of these two fragm ...19968764023
disulfide bridge-mediated folding of sindbis virus glycoproteins.the sindbis virus envelope is composed of 80 e1-e2 (envelope glycoprotein) heterotrimers organized into an icosahedral protein lattice with t=4 symmetry. the structural integrity of the envelope protein lattice is maintained by e1-e1 interactions which are stabilized by intramolecular disulfide bonds. structural domains of the envelope proteins sustain the envelope's icosahedral lattice, while functional domains are responsible for virus attachment and membrane fusion. we have previously shown t ...19968764067
synthesis and antiviral activity evaluation of some new aminoadamantane derivatives. 2.the synthesis of some new aminoadamantane derivatives is described. the new compounds were evaluated against a wide range of viruses [influenza a h1n1, influenza a h2n2, influenza a h3n2, influenza b, parainfluenza 3, herpes simplex virus type 1 (hsv-1) and type 2 (hsv-2), thymidine kinase-deficient (tk-) hsv-1, vaccinia, vesicular stomatitis, polio 1, coxsackie b4, sindbis, semliki forest, reo 1, varicella-zoster virus (vzv), tk- vzv, human cytomegalovirus (hcmv), and human immunodeficiency vir ...19968765514
antiviral activities of nepalese medicinal plants.in a screening of plants used traditionally in nepal to treat diseases that could be caused by viruses, methanol extracts from 21 species were assayed for activity against three mammalian viruses: herpes simplex virus, sindbis virus and poliovirus. assays were performed in uv-a or visible light, as well as dark. individual species of hypericum, lygodium, and maesa exhibited impressive antiviral activities, although their selective effects on the three viruses suggested that the antiviral ingredi ...19968771457
interferon-gamma induced type i nitric oxide synthase activity inhibits viral replication in neurons.type i nos expression increases in ob neurons during vsv infection. immunocytochemical staining of nb41a3 cells indicates constitutive expression of interferon (ifn)-gamma receptor and type i nos. ifn-gamma treatment of nb41a3 cells increased no production and type i nos protein. in vitro replication of vsv, polio virus type i, and herpes simplex virus type i (hsv-1) is significantly inhibited by ifn-gamma induced type i nos and antagonized by nos inhibitors. in contrast, while ifn-gamma treatme ...19968784266
translational regulation of na,k-atpase alpha1 and beta1 polypeptide expression in epithelial cells.to investigate the regulation of the na,k-atpase, we have studied the expression of the na,k-atpase polypeptides in several mammalian cell lines using the vaccinia virus/t7 rna polymerase expression system. infection of several fibroblast-like cell lines with viral recombinants containing the na,k-atpase alpha and beta isoforms, the glucose transporters, glut 1 and glut 4, or the capsid protein of the sindbis virus all result in the production of the appropriate protein products. however, all ep ...19968798517
vector-borne viral diseases in sweden--a short review.ockelbo disease, caused by a sindbis-related virus transmitted to man by mosquitoes, was first described in the central part of sweden in the 1960s as clusters of patients with fever, arthralgia and rash. an average annual rate of 30 cases was recorded in the 1980s but no cases have been diagnosed during the last few years. nephropathia epidemica (ne) characterized by fever, abdominal pain and renal dysfunction has been known to cause considerable morbidity in sweden during the last 60 years but ...19968800805
travel-related vector-borne virus infections in germany.laboratory diagnosis of imported, vector-borne virus diseases during a 22-month-period in munich, germany, is summarized. in 13/317 germans returning from the mediterranean with suspected sandfly fever, acute sandfly fever, serotype toscana, was confirmed serologically: 84.6% of the infections were acquired in italy. of 249 german tourists with febrile disease returning from the tropics, acute infection with dengue virus was diagnosed serologically in 26 (10.4%): most infections were acquired in ...19968800806
analyses of the role of structural changes in the regulation of uncoating and assembly of alphavirus cores.in the late stages of alphavirus multiplication virus cores accumulate in the cytoplasm as stable structures, whereas they are unstable during the early stages of infection. three types of explanation can be put forward to understand this phenomenon: (1) a cellular uncoating process is active early which is inactivated later, (2) the core structure differs between stable cores which accumulate and labile cores which are dissociated, (3) both mechanisms cooperate. a model based exclusively on the ...19968806493
mutations in the endo domain of sindbis virus glycoprotein e2 block phosphorylation, reorientation of the endo domain, and nucleocapsid binding.exposure of the carboxyl terminus (endo domain) of sindbis virus membrane glycoprotein e2 to the cell cytoplasm is critical for the interaction of the nucleocapsid with viral envelope proteins in modified cell membranes. we have shown that the endo domain of pe2/e2 is initially translocated into membranes of the endoplasmic reticulum and subsequently drawn back into the cell cytoplasm during virus assembly. we suggested that phosphorylation of pe2/e2 might be responsible for the reorganization o ...19968806503
genetic relatedness of sindbis virus strains from europe, middle east, and africa.the relatedness of 40 strains of sindbis virus (sin) from europe, the middle east, and africa was investigated by limited sequencing within the gene encoding the e2 glycoprotein corresponding to amino acid residues 117 to 229 and encompassing one of the major neutralization epitopes. phylogenetic analyses using distance matrix and parsimonious methods identified two major genetic clusters of western sin strains, although the variability was less than that of the corresponding region for venezuel ...19968806528
complete nucleotide sequence and full-length cdna clone of s.a.ar86 a south african alphavirus related to sindbis.s.a.ar86 and girdwood s.a., two south african sindbis-like arboviruses, are closely related antigenically to the swedish isolate, ockelbo82 [lundström, j. o., vene, s., saluzzo, j. f., and niklasson, b. (1993) am. j. trop. med. hyg. 49(5), 531-537]. each of these viruses is associated with human disease, and girdwood s.a. was isolated from a human case. in addition, s.a.ar86 is unique among sindbis-like viruses in that adult mice remain sensitive to lethal infection with s.a.ar86. the complete g ...19968806532
replication and expression of a recombinant sindbis virus in mosquitoes.a recombinant sindbis virus, te/3'2j/anti-s, containing lacrosse virus small segment cdna in antisense orientation, was inoculated into aedes triseriatus mosquitoes. virus replication and lac-anti-s rna expression were analysed temporally and spatially. te/3'2j/anti-s virus titre peaked at 5.0 log10 tcid50 in heads 6-9 days post infection (p.i.) and decreased to 3.4 log10 tcid50 by 37 days p.i. salivary glands contained 4.4 log10 tcid50 of virus 6 days p.i.; titres were lower in other organs. la ...19958825762
virus validation studies of immunoglobulin preparations.a validation study of the viral safety of a new polyvalent intravenous immunoglobulin (octagam) according to eu-guideline iii/8115/89-en and the requirements of the federal agency for sera and vaccines in germany was undertaken in may 1994. the following processing steps were analyzed: cohn-oncley fractionation, solvent/detergent (sd) treatment, ph 4 exposure, storage of the final product at low ph and immune neutralisation.19968828948
structural analysis of sindbis virus capsid mutants involving assembly and catalysis.sindbis virus core protein (scp) has been isolated from virus and crystallized. the x-ray crystallographic structure showed that the amino-terminal 113 residues appeared to be either disordered or truncated during crystallization and that the carboxy-terminal residues 114 to 264 had a chymotrypsin-like structure. the carboxy-terminal residues 106 to 264 and 106 to 266 of scp have now been expressed in escherichia coli. most crystal forms of the truncated proteins were isomorphous with those of t ...19968831786
characterization of revertants of a sindbis virus 6k gene mutant that affects proteolytic processing and virus assembly.alphaviruses of the togaviridae encode a small hydrophobic polypeptide of 55 amino acids, noted as the 6k protein, that is synthesized as part of a polyprotein containing the sequences of the two major transmembranal viral structural glycoproteins. mutations, insertions and deletions in the 6k appear to selectively interfere with the final stages of virus assembly and budding, producing aberrant, multi-cored infectious viruses. in addition, some of these mutations were pleiotropic and much more ...19958837882
antiviral activities of medicinal plants of southern nepal.in a screening of plants used traditionally in nepal to treat diseases that could be caused by viruses, twenty-one methanol extracts from twenty species were quantitatively assayed for activity against three mammalian viruses: herpes simplex virus, sindbis virus and poliovirus. assays were performed in ultraviolet (uv)-a or visible light, as well as dark, and cytotoxicity was also noted. impressive antiviral activities were exhibited by species of bauhinia (fabaceae), carissa (apocynaceae), mill ...19968844464
neutralizing antibody to human rhinovirus 14 penetrates the receptor-binding canyon.the three-dimensional structure of intact human rhinovirus 14 (hrv-14) complexed with fab fragments (fab17-ia) from a strongly neutralizing antibody that binds bivalently to the virion has been determined to 4.0 angstrom resolution by a combination of x-ray crystallography and cryo-electron microscopy. in contradiction to the most commonly held model of antibody-mediated neutralization, fab17-ia does not induce a conformational change in the hrv-14 capsid. instead, the paratope of the antibody u ...19968848050
fatal sindbis virus infection of neonatal mice in the absence of encephalitis.a comparative pathogenesis study was performed in neonatal mice using a molecularly cloned laboratory variant of sindbis strain ar339, designated trsb, and a single-site attenuated mutant of trsb derived by site-directed mutagenesis of the e2 glycoprotein from ser to arg at residue 114 (trsbr114). trsb caused 100% mortality with an average survival time of 3.0 +/- 0.7 days, whereas mice inoculated with trsbr114 exhibited an attenuated disease course with 46% mortality and an extended average sur ...19968862401
efficiency of transduction by recombinant sindbis replicon virus varies among cell lines, including mosquito cells and rat sensory neurons.recombinant alphaviruses have been used as vehicles for delivery and expression of heterologous genes in mammalian, avian and insect cell lines. we have used a sindbis replicon virus (sinreplac) able to express the e. coli lacz gene to compare the efficiency of transduction in one insect, six mammalian cell lines and cultured rat dorsal neurons which apparently express beta-galactosidase over a 30-day time period. results show that different cell lines were transduced with varying degrees of eff ...19968879590
an eruption associated with alphavirus infection.some alphaviruses, e.g. sindbis, cause an acute febrile illness associated with papular rashes and arthralgia. the diagnosis is usually serological and, hence, the histopathology of the rashes has been poorly elucidated. we report on two patients with rapidly healing eruptions associated with sindbis virus infection. the histopathology of the rashes showed large, pronounced lymphohistiocytic infiltrates with atypical lymphoid cells around the hair follicles, changes not usually seen in rapidly-h ...19968881685
alphavirus infection in mosquitoes at the ross river reservoir, north queensland, 1990-1993.this study addresses the potential problem of alphavirus infection associated with recreational use of the ross river reservoir in north queensland, australia. from 1990 to 1993, 51,497 adult female mosquitoes were collected mainly by co2-supplemented light traps. four localities within the reservoir were considered and compared with mosquitoes collected during 1991 from 2 public localities around townsville city. ten isolates of ross river virus, one of barmah forest virus, and 2 of sindbis vir ...19968887221
green fluorescent protein expressed in living mosquitoes--without the requirement of transformation.mosquitoes transmit viruses, protozoa and nematodes that are major causes of morbidity and mortality in humans. details of arthropod anatomy and development, and the replication and development of pathogens in the arthropod vector, have relied upon examination of dissected or histologically processed material. we constructed a double-subgenomic sindbis (dssin) virus expressing green fluorescent protein to demonstrate the potential of this protein for studying pathogen development in living arthr ...19968891217
dominant inhibitory ras delays sindbis virus-induced apoptosis in neuronal cells.mature neurons are more resistant than dividing cells or differentiating neurons to sindbis virus-induced apoptotic death. therefore, we hypothesized that mitogenic signal transduction pathways may influence susceptibility to sindbis virus-induced apoptosis. since ras, a 21-kda gtp-binding protein, plays an important role in cellular proliferation and neuronal differentiation, we investigated the effect of an inducible dominant inhibitory ras on sindbis virus-induced death of a rat pheochromocyt ...19968892895
chimeric sindbis-ross river viruses to study interactions between alphavirus nonstructural and structural regions.sindbis virus and ross river virus are alphaviruses whose nonstructural proteins share 64% identity and whose structural proteins share 48% identity. starting from full-length cdna clones of both viruses, we have generated two reciprocal sindbis-ross river chimeric viruses in which the structural and nonstructural regions have been exchanged. these chimeric viruses replicate readily in several cell lines. both chimeras grow more poorly than do the parental viruses, with the chimera containing si ...19968892913
interactions between pe2, e1, and 6k required for assembly of alphaviruses studied with chimeric viruses.during the assembly of alphaviruses, a preassembled nucleocapsid buds through the cell plasma membrane to acquire an envelope containing two virally encoded glycoproteins, e2 and e1. using two chimeric viruses, we have studied interactions between e1, e2, and a viral peptide called 6k, which are required for budding. a chimeric sindbis virus (sin) in which the 6k gene had been replaced with that from ross river virus (rr) produced wild-type levels of nucleocapsids and abundant pe2/e1 heterodimer ...19968892914
the new vaccines: building viruses that elicit antitumor immunity.whereas cancer cells are poor immunogens, some viruses are capable of eliciting powerful and lifelong immunity. recombinant viruses and plasmid dna encoding tumor-associated antigens can elicit powerful and specific immune responses that can be enhanced by the use of cytokines and costimulatory molecules. these immune responses have destroyed growing tumor cells in experimental animal models. for the first time, immunotherapeutic strategies that employ recombinant viruses are being tested in cli ...08902391
evidence of vertical transmission of ross river and sindbis viruses (togaviridae: alphavirus) by mosquitoes (diptera: culicidae) in southeastern australia.ross river and sindbis viruses were isolated from aedes camptorhynchus adults reared from immatures collected from a salt marsh in coastal victoria, indicating the existence of field vertical transmission. these first isolations of an arbovirus from adult mosquitoes reared from field-collected immatures in australia indicates one mechanism for arbovirus maintenance in temperate regions.19968906927
[sindbis viruses of various geographic origin and differentiation of them from western equine encephalomyelitis viruses using the polymerase chain reaction].comparison of sindbis virus strains isolated in different regions of the world (in africa, australia, and europe, including russia and its nearest neighbors) in the polymerase chain reaction (pcr) by the primary gene structure of proteins nsp1 and e1 and in the neutralization test showed the greatest similarity between geographically close strains isolated in northern europe (kfl, karelia, 1381 and 1388, estonia). sindbis strains ar339 and babanki isolated in africa were similar to each other an ...19968928504
sindbis virus vectors for expression in animal cells.sindbis virus and other alphavirus gene expression vectors have recently been used to express and study the functions of proteins and rna, to evaluate classical vaccine and novel antiviral approaches, and for nucleic acid immunization. the vectors will likely attract continuing, innovative applications that exploit their useful features: rapid and efficient gene expression, wide host range, and rna genomes.19968939619
packaging signals in alphaviruses.alphaviruses synthesize large amounts of both genomic and subgenomic rna in infected cells, but usually only the genomic rna is packaged. this implies the existence of an encapsidation or packaging signal which would be responsible for selectivity. previously, we had identified a region of the sindbis virus genome that interacts specifically with the viral capsid protein. this 132-nucleotide (nt) fragment lies within the coding region of the nsp1 gene (nt 945 to 1076). we proposed that the 132-m ...19978985344
efficient multiplication of a semliki forest virus chimera containing sindbis virus spikes.using the semliki forest virus (sfv) and sindbis virus (sin) cdnas we have constructed recombinants in which the spike genes were exchanged. analyses of expression showed that the sfv/sin(spike) rna directed efficient assembly of infectious virus, whereas the reciprocal sin/sfv(spike) rna was completely unable to assemble virus. this was apparently due to a defective capsid-spike interaction.19978985423
chimeric sindbis viruses dependent on the ns3 protease of hepatitis c virus.the hepatitis c virus (hcv) ns3 protease cleaves the viral polyprotein at specific sites to release the putative components of the hcv replication machinery. selective inhibition of this enzyme is predicted to block virus replication, and ns3 is thus considered an attractive candidate for development of anti-hcv therapeutics. to set up a system for analysis of ns3 protease activity in cultured cells, we constructed a family of chimeric sindbis viruses which carry sequences coding for ns3 and its ...19978995667
role of glycoprotein pe2 in formation and maturation of the sindbis virus spike.sindbis virus envelope assembly is a multistep process resulting in the maturation of a rigid, highly ordered t=4 icosahedral protein lattice containing 80 spikes composed of trimers of e1-e2 heterodimers. intramolecular disulfide bonds within e1 stabilize e1-e1 associations required for envelope formation and maintenance of the envelope's structural integrity. the structural integrity of the envelope protein lattice is resistant to reduction by dithiothreitol (dtt), indicating that e1 disulfide ...19978995682
[comparative analysis of primary structure of nucleocapsid protein from western equine encephalomyelitis virus and other alphaviruses].part of wee virus (strain 16310-5614) genome coding for the nucleocapsid (c) protein was cloned and sequenced in two independent clones. the c gene of wee virus is composed of 77 nucleotides, both for the bfs and 16310 strains, and is 48, 24, 33, 15, 3, and 3 nucleotides shorter than that of venezuelan equine encephalomyelitis (vee), semliki forest, ross river, sindbis, o'nyong-nyong, and eastern equine encephalomyelitis (eee) viruses, respectively. it contains 16 nucleotide changes in compariso ...19968999681
[comparative evaluation of test-systems for detection of venezuelan equine encephalomyelitis virus and variola virus using dot immunoenzyme assay and solid-phase lanthanide immunofluorescent assay].the sensitivity and specificity of 4 experimental test systems for dot enzyme immunoassay (dot-eia) and solid-phase lanthanide immunofluorescent analysis (sp lifa) were studied with venezuelan equine encephalomyelitis (vee) and variolovaccinia viruses. test systems for sp lifa proved to be 25 times more sensitive than those for dot-eia. the test systems were highly specific and did not react with the heterologous viruses and proteins. diagnostic agent for detecting vee virus in dot-eia was false ...19968999688
[comparative study of the mechanism of inhibition of sindbis virus reproduction by adamantane derivatives: remantadine and amide of 1-adamantane carboxylic acid].amide of 1-adamantane carboxylic acid (aaca), the same as remantadine, was shown to have no antiviral action and any influence on the efficiency of the sindbis virus adsorption. however, it significantly inhibited the virus specific synthesis of rna and protein. the main difference between aaca and remantadine was in the fact that the efficiency of the inhibition of the sindbis virus reproduction and synthesis of the virus specific rna in the presence of aaca did not markedly decrease even when ...19968999758
low ph-induced pore formation by spike proteins of enveloped viruses.exposure of aedes albopictus cells infected with semliki forest virus (sfv; togaviridae) to mildly acidic ph (5.6) results in a dramatic increase in the host cell membrane permeability due to pore formation by the virus spike proteins. identical results were obtained when the cells were infected with two other viruses, sindbis virus (sin, togaviridae) and vesicular stomatitis virus (vsv, rhabdoviridae). this permeability change could also be observed on isolated virions of sfv, sin and vsv by me ...19969000093
the polarity of the plasma membrane protein ret-pe2 in retinal pigment epithelium is developmentally regulated.the retinal pigment epithelium (rpe) differs from other epithelia in that the apical surface is not free; instead, it interacts with both photoreceptors and a specialized extracellular material, the interphotoreceptor matrix. biochemical characterization of the apical and basolateral surfaces of rpe in adult rat eye cups, using a novel in situ biotinylation assay, revealed very different protein compositions and identified a major surface antigen, ret-pe2, with a predominantly apical distributio ...19969004037
sindbis virus infection of neonatal mice results in a severe stress response.neonatal mice were infected with virus derived from a molecular clone of a laboratory strain of sindbis virus, trsb. the resulting acute fatal infection was typified by few if any of the classic hallmarks of encephalitis, very high levels of interferon-alpha/beta (ifnalphabeta), and lesions in the thymus and hematopoietic tissues usually associated with a severe stress response. infection with an attenuated mutant of trsb, which harbors a single amino acid change in the e2 surface glycoprotein ( ...19979007079
a bcl-2 homolog encoded by kaposi sarcoma-associated virus, human herpesvirus 8, inhibits apoptosis but does not heterodimerize with bax or bak.the bcl-2 protein family is characterized by the ability to modulate cell death, and members of this family share two highly conserved domains called bcl-2 homology 1 (bh1) and 2 (bh2) which have been shown to be critical for the death-repressor activity of bcl-2 and bcl-xl. through sequence analysis we identified a novel viral bcl-2 homolog, designated ksbcl-2, from human herpesvirus 8 (hhv8) or kaposi sarcoma-associated herpesvirus. the overall amino acid sequence identity between ksbcl-2 and ...19979012846
monoclonal antibodies specific for semliki forest virus replicase protein nsp2.a panel of monoclonal antibodies (mabs) was raised against semliki forest virus (sfv) nonstructural protein nsp2, which is a protease, an ntpase, a putative rna helicase, and a regulator of the synthesis of the subgenomic 26s mrna encoding the structural proteins. nsp2, used for immunization, was expressed as a histidine fusion protein in escherichia coli and purified by metal affinity chromatography. dot-blot assay, using a membrane fraction from sfv-infected cells as antigen, gave 33 positive ...19979018056
complementation of and interference with sindbis virus replication by full-length and deleted forms of the nonstructural protein, nsp1, expressed in stable transfectants of hela cells.stable transfectants of hela cells were isolated which expressed either the full-length 540-amino-acid sindbis virus (sv) nonstructural protein, nsp1 (the form encoded by the mutant, sv(lm21)), or one of four forms with a carboxyl-terminal deletion. sv(lm21), in contrast to standard sv (sv(std)), can replicate in hela cells maintained in low-methionine (lm) medium. expression of full-length nsp1(1-540), nsp1(1-492), or nsp1(1-448) resulted in complementation of sv(std) when infected hela cells w ...19979018135
identification of mutations in a sindbis virus variant able to establish persistent infection in bhk cells: the importance of a mutation in the nsp2 gene.sindbis virus is a positive strand rna virus that has provided a valuable model for studying virus structure and replication. it is also being developed as a vector for the expression of heterologous proteins. many studies with this virus are carried out in cultured bhk cells where infection is usually highly cytopathic and within 1 or 2 days after infection all of the cells are dead. weiss et al. had established a persistently infected culture of bhk cells by infecting the cells with a virus pr ...19979024811
expression of parvovirus luiii ns1 from a sindbis replicon for production of luiii-luciferase transducing virus.in order to develop an alternative packaging system for recombinant parvoviruses, the gene for the major nonstructural protein (ns1) of parvovirus luiii was inserted into a sindbis replicon vector. cells infected with recombinant sinns1 virus produced ns1 rna from the sindbis 26s promoter and expressed ns1 protein which was able to transactivate a parvovirus p38 promoter. co-transfections of sindbis-ns1 rna together with a packageable luiii transducing genome and a coat protein expression plasmi ...19969029782
regulation of brain-derived t cells during acute central nervous system inflammation.the unique immunologic environment of the central nervous system (cns) regulates most local inflammatory responses. in some circumstances, however, immune-mediated injury to the brain can occur. to understand how lymphocytes are regulated within the cns during an inflammatory response that does not produce immunopathology, we have studied t cells isolated from the brains of mice with sindbis virus (sv) encephalitis. even though they express activation markers, these t cells are arrested in the c ...19979036980
rotation function calculations with glrf program. 19979048382
genetic determinants of sindbis virus neuroinvasiveness.after peripheral inoculation of mice, sindbis virus replicates in a variety of tissues, leading to viremia. in some cases, the virus can enter the central nervous system (cns) and cause lethal encephalitis. the outcome of infection is age and virus strain dependent. recently, two pairs of sindbis virus variants differing in neurovirulence and neuroinvasiveness were derived by limited serial passaging in mouse brain. two early passage isolates (sva and svb) were neurotropic but did not cause leth ...19979060616
rna-rna recombination in sindbis virus: roles of the 3' conserved motif, poly(a) tail, and nonviral sequences of template rnas in polymerase recognition and template switching.sindbis virus (sin), a mosquito-transmitted animal rna virus, carries a 11.7-kb positive-sense rna genome which is capped and polyadenylated. we recently reported that the sin rna-dependent rna polymerase (rdrp) could initiate negative-strand rna synthesis from a 0.3-kb 3'-coterminal sin rna fragment and undergo template switching in vivo (m. hajjou, k. r. hill, s. v. subramaniam, j. y. hu, and r. raju, j. virol. 70:5153-5164, 1996). to identify and characterize the viral and nonviral sequences ...19979060622
sindbis virus replicons and sindbis virus: assembly of chimeras and of particles deficient in virus rna.alphaviruses are a well-characterized group of positive-strand rna viruses. the identification of cis-acting elements in their genomes and their replication strategy have made them useful as vectors for the expression of heterologous genes. in infected cells, the nonstructural proteins, required for replication and transcription of the viral genes, are translated from the genomic rna; the structural proteins, the capsid protein that interacts with the rna to form the nucleocapsid and the protein ...19979060637
isolation of japanese encephalitis virus from culex annulirostris in australia.mosquitoes were collected using co2 and octenol-baited light traps during an outbreak of japanese encephalitis (je) on badu island in the torres strait, australia in april 1995. a total of 13,300 mosquitoes comprising 12 species were processed for virus isolation. eight isolates of je virus were obtained from culex annulirostris, with a carriage rate of 2.97:1,000; this mosquito also yielded one sindbis virus isolate. a reverse transcriptase-polymerase chain reaction was used to sequence the je ...19979063367
antiviral activities of photoactive perylenequinones.nine perylenequinones (pq), including some familiar naturally occurring pigments, were compared for their light-mediated antiviral efficacies. calphostin c was the most active compound against the two target viruses, herpes simplex virus type 1 and sindbis virus. hypocrellins a and b were also very active. however, three cercosporin-like pq were substantially less active in spite of their high quantum yields of singlet oxygen, whereas phleichrome, another efficient singlet oxygen producer, showe ...19979066311
traffic control of completely assembled mhc class i molecules beyond the endoplasmic reticulum.it is generally assumed that mhc class i molecules arrive at the plasma membrane following biosynthesis, assembly and architectural editing in the endoplasmic reticulum by constitutive forward movement without requirement for specific signals (bulk flow). if this is true then all overexpressed completely assembled class i molecules should arrive at the cell surface. to study the itinerary of class i traffic beyond the endoplasmic reticulum, mammalian cells that overexpress 20 to 50-fold higher a ...19979086276
immunization with nonstructural proteins promotes functional recovery of alphavirus-infected neurons.the encephalitic alphaviruses are useful models for understanding virus-neuron interactions. a neurovirulent strain of sindbis virus (nsv) causes fatal paralysis in mice by infecting motor neurons and inducing apoptosis of these nonrenewable cells. antibodies to the surface glycoproteins suppress virus replication, but other recovery-promoting components of the immune response have not been recognized. we assessed the effect on the outcome of nsv-induced encephalomyelitis of immunization of mice ...19979094611
structure of semliki forest virus core protein.alphaviruses are enveloped, insect-borne viruses, which contains a positive-sense rna genome. the protein capsid is surrounded by a lipid membrane, which is penetrated by glycoprotein spikes. the structure of the sindbis virus (sinv) (the type virus) core protein (scp) was previously determined and found to have a chymotrypsin-like structure. scp is a serine proteinase which cleaves itself from a polyprotein. semliki forest virus (sfv) is among the most distantly related alphaviruses to sinv. si ...19979094737
prevention of insect-borne disease: an approach using transgenic symbiotic bacteria.expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting insects may serve as a powerful approach to control certain arthropod-borne diseases. the endosymbiont of the chagas disease vector, rhodnius prolixus, has been transformed to express cecropin a, a peptide lethal to the parasite, trypanosoma cruzi. in insects carrying the transformed bacteria, cecropin a expression results in elimination or reduction in number of t. cruzi. a ...19979096383
astrocyte activation by sindbis virus: expression of gfap, cytokines, and adhesion molecules.sindbis virus (sv) is a member of the alphaviruses which has served as a model system for studying viral encephalitis. although astrocytes are reported to be involved in the pathogenesis of various virus-related diseases, the effects of sv on astrocyte function have not been reported. in this study we compared the effects of two strains of sv, sva, and svni, which differ in their neurovirulent properties, on astrocytes with the use of cultured mouse astrocytes and the rat c6 glial cell line. we ...19979097072
uncoupling of membrane ruffling and pinocytosis during ras signal transduction.activation of ras stimulates cell surface membrane ruffling and pinocytosis. although seen as coupled events, our study demonstrates that membrane ruffling and pinocytosis are regulated by distinct ras signal transduction pathways. ras controls membrane ruffling via the small gtpase rac. in bhk-21 cells, expression of the constitutively active rac1(g12v) mutant, via a sindbis virus vector, resulted in a dramatic stimulation of membrane ruffling without affecting the uptake of horseradish peroxid ...19979099668
the n-end rule pathway of protein degradation.the n-end rule relates the in vivo half-life of a protein to the identity of its n-terminal residue. similar but distinct versions of the n-end rule operate in all organisms examined, from mammals to fungi and bacteria. in eukaryotes, the n-end rule pathway is a part of the ubiquitin system. ubiquitin is a 76-residue protein whose covalent conjugation to other proteins plays a role in many biological processes, including cell growth and differentiation. i discuss the current understanding of the ...19979112437
efficient removal of viruses by a novel polyvinylidene fluoride membrane filter.virus removal by a novel filter (ultipor vf dv50), comprising three layers of pvdf membrane, has been evaluated by infectivity studies using a range of viruses and conditions. the filter was able to remove at least 6 log of various viruses, i.e. sindbis and semliki forest (40-70 nm), herpes simplex (120-200 nm) and vaccinia (200 x 350 nm), from cell-culture medium or phosphate buffered saline ph 6.8 containing 0.5% albumin. however, the removal of polio virus (25-30 nm) under these conditions wa ...19979128859
alphavirus budding is dependent on the interaction between the nucleocapsid and hydrophobic amino acids on the cytoplasmic domain of the e2 envelope glycoprotein.the interaction between the nucleocapsid core and the glycoprotein spikes is a critical component in the budding process of alphaviruses. a molecular model was previously proposed which suggested that this interaction was mediated by the binding of the cytoplasmic domain of glycoprotein e2 into a hydrophobic pocket found on the surface of the nucleocapsid protein [s. lee, k. e. owen, h.-k. choi, h. lee, g. lu, g. wengler, d. t. brown, m. g. rossmann, and r. j. kuhn (1996) structure 4, 531-541; u ...19979143274
rotavirus contains integrin ligand sequences and a disintegrin-like domain that are implicated in virus entry into cells.rotavirus contains two outer capsid viral proteins, the spike protein vp4 and major capsid component vp7, both of which are implicated in cell entry. we show that vp4 and vp7 contain tripeptide sequences previously shown to act as recognition sites for integrins in extracellular matrix proteins. vp4 contains the alpha2beta1 integrin ligand site dge. in vp7, the alphaxbeta2 integrin ligand site gpr and the alpha4beta1 integrin ligand site ldv are embedded in a novel disintegrin-like domain that a ...19979144247
rapid diagnosis of dengue viremia by reverse transcriptase-polymerase chain reaction using 3'-noncoding region universal primers.a reverse transcriptase-polymerase chain reaction (rt-pcr) method was developed as a rapid diagnostic test of dengue viremia. to detect dengue viruses in serum or plasma specimens, a pair of universal primers was designed for use in the rt-pcr. using these primers, the 3'-noncoding region of dengue virus types 1, 2, 3, and 4 could be amplified, but not those of other flaviviruses, such as west nile virus, japanese encephalitis virus, and yellow fever virus, or the alphavirus sindbis virus. the s ...19979158052
construction of hepatitis c-sin virus recombinants with replicative dependency on hepatitis c virus serine protease activity.an in vivo assay system was developed for the serine protease of hepatitis c virus (hcv) using the sindbis (sin) viral replication system in which hcv serine protease activity is essential for the replication of the hcv-sin chimeric virus. two chimeric viral cdna clones were constructed by inserting the ns3/4a region and ns3/4a region with the putative helicase deleted, into the n-terminal region of sin core protein. the constructs were named tpro ct and tpro t, respectively. bhk-21 cells transf ...19979186943
construction and characterization of a reovirus double temperature-sensitive mutant.the infectious reovirus rna system was used to construct a mutant with two temperature-sensitive (ts) lesions in genome segments m2 and s2, respectively. the double mutant is about 300 times more ts than either of its parents, which are about 1,500 and 170 times more ts than their wild-type parent reovirus st3 strain dearing. at 39 degrees c the double mutant is essentially unable to multiply. in spite of its striking temperature sensitivity, the double mutant elicits the formation of significan ...19979192650
detection of expressed chloramphenicol acetyltransferase in the saliva of culex pipiens mosquitoes.mosquito salivary glands play an important role in the transmission of arthropod-borne pathogens. the ability to express genes in mosquitoes would be a powerful approach to characterize salivary gland genes, and to reveal important vector determinants of pathogen transmission. here we report the use of a double subgenomic sindbis (dssin) virus, designated te/3'2j/cat, and a packaged sindbis replicon virus, designated rep5/cat/26s, to express chloramphenicol acetyltransferase (cat) protein in the ...19979219368
effect of enforced expression of human bcl-2 on japanese encephalitis virus-induced apoptosis in cultured cells.infection by japanese encephalitis virus (jev), a mosquito-borne flavivirus, causes acute encephalitis in humans and induces severe cytopathic effects in different types of cultured cells. this study attempted to determine whether apoptosis contributes to virus-induced cell death in a culture system by characterizing jev lytic infection in baby hamster kidney bhk-21 cells, murine neuroblastoma n18 cells, and human neuronal progenitor nt2 cells. according to our results, the replication of jev, a ...19979223486
a single amino acid change in the e2 glycoprotein of sindbis virus confers neurovirulence by altering an early step of virus replication.amino acid changes in the envelope glycoproteins of sindbis virus have been linked to neurovirulence; however, the molecular mechanisms by which these amino acid changes alter neurovirulence are not known. recombinant-virus studies have mapped an important determinant of neurovirulence in adult mice to a single amino acid change, glutamine to histidine, at position 55 of the e2 glycoprotein (p. c. tucker, e. g. strauss, r. j. kuhn, j. h. strauss, and d. e. griffin, j. virol. 67:4605-4610, 1993). ...19979223504
amino acid changes in the sindbis virus e2 glycoprotein that increase neurovirulence improve entry into neuroblastoma cells.sindbis virus (sv) is an alphavirus that causes encephalitis in mice and results in age-dependent mortality. the outcome is dependent on the virus strain. residues at 55 and 172 in the e2 glycoprotein determine the neurovirulence for mice of different ages and the efficiency of replication in the nervous system and neuronal cells. to determine the effects of these two residues on the initial steps in replication, we studied viruses with a histidine or glutamine at e2 position 55 and a glycine or ...19979223505
transcriptional strategy of closteroviruses: mapping the 5' termini of the citrus tristeza virus subgenomic rnas.citrus tristeza virus (ctv) induces formation of a nested set of at least nine 3' coterminal subgenomic rnas (sgrnas) in infected tissue. the organization and expression of the 19,296-nucleotide (nt) ctv genome resembles that of coronaviruses, with polyprotein processing, translational frameshifting, and multiple sgrna formation, but phylogenetically the ctv polymerase, like polymerases of other closteroviruses, belongs to the sindbis virus-like lineage of rna virus polymerases. both positive-st ...19979223524
incorporation of beta-globin untranslated regions into a sindbis virus vector for augmentation of heterologous mrna expression.polynucleotide immunization has been employed as a means of inducing immune responses through the introduction of antigen-encoding dna. while immunization against specific tumor antigens may be achieved through this strategy, various candidate tumor antigens may not be approached via dna-based vaccines as they represent transforming oncogenes. as an alternative approach, we have explored the utility of mrna vectors for polynucleotide immunization. the transient expression achieved by mrna may pr ...19979231080
short-order sindbis vector targeting. 19979255777
cell-specific targeting of sindbis virus vectors displaying igg-binding domains of protein a.sindbis virus can infect a broad range of insect and vertebrate cell types due to the widespread distribution of the cellular receptor for the virus. the development of sindbis virus vectors that target specific cell types could have important implications for the design of gene therapy strategies. to achieve this goal we have designed and constructed sindbis virus particles displaying the igg-binding domain of protein a. the protein a-envelope chimeric sindbis virus vector has minimal infectivi ...19979255791
characterization of the infection of aedes albopictus cell clones by sindbis virus.we have investigated the infection of aedes albopictus (mosquito) cell clones by sindbis virus. variation in the multiplicity of infection (moi) from ranges of 50-0.00005 pfu/cell was determined to have no effect on the progression of the infection to high acute phase titer, suggesting that intracellular factors alone are responsible for the restriction of virus production seen as the infection enters the persistent phase: while persistently infected (over 1 year post infection) cell clones are ...19979255930
superinfection exclusion of alphaviruses in three mosquito cell lines persistently infected with sindbis virus.three aedes albopictus (mosquito) cell lines persistently infected with sindbis virus excluded the replication of both homologous (various strains of sindbis) and heterologous (aura, semliki forest, and ross river) alphaviruses. in contrast, an unrelated flavivirus, yellow fever virus, replicated equally well in uninfected and persistently infected cells of each line. sindbis virus and semliki forest virus are among the most distantly related alphaviruses, and our results thus indicate that mosq ...19979261447
heterogeneous nuclear ribonucleoprotein a1 binds to the transcription-regulatory region of mouse hepatitis virus rna.a cellular protein, previously described as p35/38, binds to the complementary (-)-strand of the leader rna and intergenic (ig) sequence of mouse hepatitis virus (mhv) rna. the extent of the binding of this protein to ig sites correlates with the efficiency of the subgenomic mrna transcription from that ig site, suggesting that it is a requisite transcription factor. we have purified this protein and determined by partial peptide sequencing that it is heterogeneous nuclear ribonucleoprotein (hnr ...19979275159
structure of l-a virus: a specialized compartment for the transcription and replication of double-stranded rna.the genomes of double-stranded (ds)rna viruses are never exposed to the cytoplasm but are confined to and replicated from a specialized protein-bound compartment-the viral capsid. we have used cryoelectron microscopy and three-dimensional image reconstruction to study this compartment in the case of l-a, a yeast virus whose capsid consists of 60 asymmetric dimers of gag protein (76 kd). at 16-a resolution, we distinguish multiple domains in the elongated gag subunits, whose nonequivalent packing ...19979281577
characterization of truncated forms of hepatitis c virus glycoproteins.hepatitis c virus (hcv) glycoproteins (e1 and e2) both contain a carboxy-terminal hydrophobic region, which presumably serves as a membrane anchor. when they are expressed in animal cell cultures, these glycoproteins, in both mature complexes and misfolded aggregates, are retained in the endoplasmic reticulum. the effect of carboxy-terminal deletions on hcv glycoprotein secretion and folding was examined in this study. sindbis and/or vaccinia virus recombinants expressing truncated forms of thes ...19979292018
[comparative analysis of expression of genes for 2',5'-oligoadenylate synthetase and mrna for dsrna-protein kinase in human fibroblasts infected with the sindbis alphavirus and induced by alpha-interferon].expression of 2,5-oas and ds-protein kinase (ds-pk) in human fibroblast culture following treatment with alpha-if in a dose of 1000 u or challenge with karelian fever virus (kfv) (5 pfu/cell, 4 h.p.i.) was compared. a highly sensitive and rapid method, coupled rt-pcr, was used to detect mrna transcription levels. alpha-if had an expressed stimulating effect on 2,5-oas mrna level, whereas the virus markedly inhibited the synthesis of ds-pk mrna.19979297349
the formation of intramolecular disulfide bridges is required for induction of the sindbis virus mutant ts23 phenotype.the sindbis virus envelope protein spike is a hetero-oligomeric complex composed of a trimer of glycoprotein e1-e2 heterodimers. spike assembly is a multistep process which occurs in the endoplasmic reticulum (er) and is required for the export of e1 from the er. pe2 (precursor to e2), however, can transit through the secretory pathway and be expressed at the cell surface in the absence of e1. although oligomer formation does not appear to be required for the export of pe2, there is evidence tha ...19979311853
sequence-specific recognition of a subgenomic rna promoter by a viral rna polymerase.rna templates of 33 nucleotides containing the brome mosaic virus (bmv) core subgenomic promoter were used to determine the promoter elements recognized by the bmv rna-dependent rna polymerase (rdrp) to initiate rna synthesis. nucleotides at positions -17, -14, -13, and -11 relative to the subgenomic initiation site must be maintained for interaction with the rdrp. changes to every other nucleotide at these four positions allow predictions for the base-specific functional groups required for rdr ...19979326593
[effect of the amide of 1-adamantanecarboxylic acid (aaca) and its combination with ribavirin on the course of experimental infection, caused by the sindbis virus in tissue culture and in mouse brain. possible isolation of the virus mutant resistant to ribavirin and to a combination of the inhibitors].it was shown advisable to use ribavirin (a weak inhibitor of sindbis virus reproduction) in combination with acaa. the effect observed was of marked synergistic nature. subcultures of the susceptible strain in the presence of ribavirin/ acaa did not lead to the development of resistance to acaa, ribavirin or their combination. the acaa resistant strain preserved its susceptibility to ribavirin after serial subcultures in the presence of both the inhibitors. however, no synergistic effect of the ...19979334146
expression of beta-galactosidase in mouse brain: utilization of a novel nonreplicative sindbis virus vector as a neuronal gene delivery system.sindbis virus expression has been used for in vitro investigations of antigen processing, presentation and epitope mapping. the recent development of a replication-deficient recombinant sindbis virus expression vector has made in vivo expression possible with minimal pathogenic risk. advantages of sindbis virus over other available viral systems include a comparatively smaller genome size making it possible to clone larger inserts, the ability to infect a wide range of host cell types with reduc ...19979338010
comparison of various expression plasmids for the induction of immune response by dna immunization.intramuscular injection of plasmid dna is an efficient method to introduce a foreign gene into a live animal. we investigated several factors affecting the gene transfer efficiency and the following immune response by intramuscular injection of plasmid dna. when the strength of several highly efficient viral promoters was compared in muscle by using the chloramphenicol acetyltransferase (cat) gene as an indicator, cytomegalovirus (cmv) immediate early promoter was found to be stronger than any o ...19979339893
regulators of apoptosis on the road to persistent alphavirus infection.alphavirus infection can trigger the host cell to activate its genetically programmed cell death pathway, leading to the morphological features of apoptosis. the ability to activate this death pathway is dependent on both viral and cellular determinants. the more virulent strains of alphavirus induce apoptosis with increased efficiency both in animal models and in some cultured cells. although the immune system clearly plays a central role in clearing virus, the importance of other cellular fact ...19979343360
cyclin dependent kinase inhibitors and dominant negative cyclin dependent kinase 4 and 6 promote survival of ngf-deprived sympathetic neurons.neuronal apoptosis plays a critical role in both normal development and disease. however, the precise molecular events controlling neuronal apoptosis are not well understood. previously, we hypothesized that cell cycle regulatory molecules function in controlling the apoptotic pathways of trophic factor-deprived neurons. to test this hypothesis, we used the rna alphavirus sindbis to express three known cyclin dependent kinase inhibitors (ckis), p16(ink4), p21(waf/cip), and p27(kip1), and dominan ...19979364045
a novel viral rna species in sindbis virus-infected cells.sindbis virus (sin), the type alphavirus, has been studied extensively to identify the viral cis-acting sequences and proteins involved in rna transcription and replication. however, very little is known about how these processes are coordinated. for example, synthesis of the genomic rna and the subgenomic mrna depends on the minus strand. do these activities occur independently on different templates, or can replication and transcription take place simultaneously on the same template? we descri ...19979371567
trans-complementation of yellow fever virus ns1 reveals a role in early rna replication.mutational analysis of the nonstructural protein 1 (ns1) of yellow fever virus (yf) has implicated it in viral rna replication. to further explore this observation, we sought a method for uncoupling ns1 function from ns1 expression and processing as part of the large yf polyprotein. here we describe a strategy for providing ns1 in trans, utilizing a noncytopathic sindbis virus vector. replication of a defective yf genome containing a large in-frame deletion of ns1 was dependent on functional exp ...19979371625
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