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sindbis virus nsp1 functions in negative-strand rna synthesis.a mutation at nucleotide 1101 of sindbis virus ts11 nsp1 caused temperature-sensitive negative-strand synthesis and suppressed the 24r phenotype, which is caused by a mutation in nsp4. nonstructural proteins synthesized and accumulated by ts11 at 40 degrees c did not cause the reactivation of negative-strand synthesis upon return to 30 degrees c and did not prevent the formation of new replication complexes at 30 degrees c.19911824787
mutations that confer resistance to mycophenolic acid and ribavirin on sindbis virus map to the nonstructural protein nsp1.svmpa, a mutant of sindbis virus derived by serial passage on aedes albopictus mosquito cells maintained after infection in the presence of mycophenolic acid (mpa), is resistant not only to mpa but also to ribavirin. both of these compounds inhibit the synthesis of gmp and thereby reduce the level of gtp. we had suggested earlier that svmpa had become resistant to mpa because it coded for an altered rna guanylyltransferase enzyme with an increased affinity for gtp, enabling it to replicate in ce ...19911826574
expression of sindbis virus nsp1 and methyltransferase activity in escherichia coli.we have constructed two plasmids, psr5-42 and psr5-toto, which under lac control expressed the svlm21 and the svtoto forms, respectively, of the sindbis virus nonstructural protein, nsp1. the induced protein, which was the major protein made following induction with iptg, had an apparent molecular weight of 60,000 and an amino terminal sequence in agreement with that expected for nsp1. following induction with iptg, cells carrying psr5-42 (which contains the svlm21 gene sequence) generated much ...19911831311
x-ray solution scattering of sindbis virus. changes in conformation induced at low ph.alphaviruses, like many enveloped animal viruses, enter the cell by fusing with the cell membrane. this fusion occurs only in coated vesicles at a low ph. by using x-ray solution scattering of highly purified virus particles we have gained direct evidence that a drop in ph does not alter the structure of the virus core but does cause a significant change in the structure of the virus envelope. thus these experiments give direct evidence to support the hypothesis that a reduction in ph causes a c ...19911920415
in vitro protein synthesis. 19911706461
the cytoplasmic domain of alphavirus e2 glycoprotein contains a short linear recognition signal required for viral budding.intracellular alphavirus nucleocapsids express a binding site for the cytoplasmic domain of the viral e2 spike glycoprotein. this binding site is recognized by the anti-idiotype monoclonal antibody, f13. the monoclonal anti-anti-idiotype antibody, raised against f13 and designated 3g10, recognizes the carboxy-terminal eight residues of the e2 cytoplasmic domain in semliki forest virus (sfv), identifying this as the signal for nucleocapsid interaction. f13 binding to cells infected with sfv or a ...19911714373
solubilization and immunoprecipitation of alphavirus replication complexes.alphavirus replication complexes that are located in the mitochondrial fraction of infected cells which pellets at 15,000 x g (p15 fraction) were used for the in vitro synthesis of viral 49s genome rna, subgenomic 26s mrna, and replicative intermediates (ris). comparison of the polymerase activity in p15 fractions from sindbis virus (sin)- and semliki forest virus (sfv)-infected cells indicated that both had similar kinetics of viral rna synthesis in vitro but the sfv fraction was twice as activ ...19911847467
comparative behavior of lysosomes and the pre-lysosome compartment (plc) in in vivo cell fusion experiments.interspecies cell fusion was used to compare protein intermixing within the mannose 6-phosphate receptor (mpr)-enriched pre-lysosome compartment (plc) and within the mpr-negative lysosomal compartment. both compartments were positive for lysosomal glycoprotein (lgp) membrane markers but were morphologically distinct. in most experiments, rat-mouse cell syncytia were formed by u.v.-inactivated sindbis virus-mediated fusion. by immunogold electron microscopy of syncytia, extensive intermixing of s ...19911658017
a mutant cho-k1 strain with resistance to pseudomonas exotoxin a and alphaviruses fails to cleave sindbis virus glycoprotein pe2.rpe.40, a mutant cho-k1 strain selected for resistance to pseudomonas exotoxin a, is defective in the production of infectious alphaviruses, although viruses are taken in and processed normally (j. m. moehring and t. j. moehring, infect. immun. 41:998-1009, 1983). to determine the cause of this defect, the synthesis of sindbis virus proteins was examined. rpe.40 cells produced and glycosylated structural glycoprotein precursors pe2 and immature e1 normally. mature e1 was formed, but pe2 was not ...19911850015
screening of medicinal plants from yunnan province in southwest china for antiviral activity.in an ethnopharmacological screening of medicinal plants used in yunnan province of china, ethanol extracts from 31 plant species were assayed for inhibition of murine cytomegalovirus and sindbis virus infections. parallel assays were carried out with and without exposure to uva radiation to test for photo-mediation of activity. antiviral activity was observed with 16 of the plant extracts. eight plant extracts have been selected for further studies, with the objective of characterizing the anti ...19911661356
infection initiated by the rna pregenome of a dna virus.we describe experiments demonstrating that after transfection into permissive cells, the rna pregenome of an avian hepadnavirus, the duck hepatitis b virus, is infectious. using a sindbis virus expression vector, we showed that cytoplasmic synthesis of the pregenome resulted in hepadnaviral dna synthesis. moreover, complete infectious virus was produced from cells transfected with hepadnaviral pregenomic rna. we conclude that the pregenome of hepadnaviruses can express all the proteins required ...19911895392
isolation of brain parenchymal lymphocytes for flow cytometric analysis. application to acute viral encephalitis.a strategy for the isolation of mononuclear cells from the brain parenchyma of mice with ongoing central nervous system (cns) inflammation has been developed in order to permit flow cytometric (fcm) analysis of these cell populations. sindbis virus (sv) encephalitis in mice is characterized morphologically by an infiltration of mononuclear cells into both brain parenchyma and cerebrospinal fluid (csf). perfused brain tissue from infected animals is collected, homogenized, and subjected to a mild ...19911675228
identification of a putative alphavirus receptor on mouse neural cells.alphaviruses replicate in a wide variety of cells in vitro. the prototype alphavirus, sindbis virus, causes an age-dependent encephalitis in mice and serves as an important model system for the study of alphavirus neurovirulence. to begin to understand the role of cellular virus receptors in the pathogenesis of sindbis virus infection, we developed an anti-idiotypic antibody made in rabbits against a neutralizing monoclonal antibody specific for the e2 surface glycoprotein. the anti-idiotypic an ...19911658382
antiviral activity of the photoactive plant pigment hypericin.the polycyclic compound hypericin, a known photodynamic agent, was investigated for antiviral activity in the presence and absence of light. the three viruses tested: murine cytomegalovirus; sindbis virus; and human immunodeficiency virus type 1, were all susceptible to hypericin; but these antiviral activities were considerably enhanced, in a dose-dependent manner, by exposure to light.19911658826
structure of the ockelbo virus genome and its relationship to other sindbis viruses.ockelbo virus was first isolated in 1982 in sweden. it is the causal agent of disease in humans characterized by arthritis, rash, and fever and is antigenically very closely related to sindbis virus. we have determined the nucleotide and translated amino acid sequences of the prototype ockelbo virus isolate (82-5) to determine the relatedness of ockelbo virus to sindbis virus at the genomic level and clarify the taxonomic position of ockelbo virus within the alphavirus genus. the numbers of nucl ...19911673813
site-directed mutations in sindbis virus e2 glycoprotein's cytoplasmic domain and the 6k protein lead to similar defects in virus assembly and budding.site-directed mutagenesis was used to obtain four mutants with amino acid replacements in the cytoplasmic domain of the e2 glycoprotein and three with replacements in the 6k protein of sindbis virus. all but one of these mutants yielded progeny virus after transfection of chicken embryo fibroblasts with rna prepared by in vitro transcription of the virus cdna; however, even this nonproducer mutant made virus structural proteins in the transfected cells. the other six mutants divided into two gro ...19911647069
mutational analysis of a virulence locus in the e2 glycoprotein gene of sindbis virus.the substitution of arginine for serine at position 114 of glycoprotein e2 in several biological and recombinant sindbis virus mutants was shown previously to attenuate the virus for neonatal mice and also to accelerate virus penetration into bhk cells. to further examine the genetically linked effects on both virus penetration into cultured cells and pathogenesis in vivo, mutants containing each of 16 different amino acid coding changes at this position were generated by site-directed mutagenes ...19911656101
infectious rna transcripts from ross river virus cdna clones and the construction and characterization of defined chimeras with sindbis virus.we have constructed a full-length cdna clone of the virulent t48 strain of ross river virus, a member of the alphavirus genus. infectious rna can be transcribed from this clone using sp6 or t7 rna polymerase. the rescued virus has properties indistinguishable from those of the t48 strain of ross river virus. we have used this clone, together with a full-length cdna clone of sindbis virus, to construct chimeric plasmids in which the 5' and the 3' nontranslated regions of the sindbis and ross rive ...19911673812
ecological distribution of chikungunya haemagglutination inhibition antibodies in human and domestic animals in nigeria.a serological survey to detect presence of antibodies to chikungunya virus in 477 human sera randomly sampled from four ecological zones of nigeria was carried out employing a haemagglutination inhibition (hi) test. similarly 220 animal sera collected mostly from the northern parts of nigeria were screened for hi antibody to chikungunya virus. of the 477 human sera tested a total of 68 or 14.3% were found to possess chikungunya hi antibodies made up of 10% in swampy forest, 20% in the rain fores ...19911667829
protection by dehydroepiandrosterone in mice infected with viral encephalitis.dehydroepiandrosterone (dhea) has a significant protective effect in mice infected with west nile virus (wnv), sindbis virus neurovirulent (svni) and semliki forest virus (sfv). mice injected subcutaneously (sc) with a single injection of dhea (1 g/kg) on the same day or one day pre or post infection with wnv resulted in 40-50% mortality as compared to 100% in control injected mice (p less than 0.05). the drug was effective following a single sc injection or serial intraperitoneal (ip) injection ...19911659799
effects of protein kinase c inhibitors on viral entry and infectivity.the protein kinase c inhibitor h-7 (2-20 microm) inhibited dose-dependently the infectivity of the vesicular stomatitis virus on cultured human fibroblasts. electron microscopy showed that h-7 inhibited the viral entry. h-7 also inhibited the infectivity of four other enveloped viruses, herpes simplex i, turkey herpes, vaccinia and sindbis. similar results were obtained using staurosporine (2.5 nm), tamoxifen (40 microm), phloretin (140 microm), or w-7 (40 microm). however, the infectivity of no ...19911659999
antiviral activities of hypericin.hypericin, a photodynamic plant quinone, readily inactivated murine cytomegalovirus (mcmv), sindbis virus, and human immunodeficiency virus type 1 (hiv-1), especially on exposure to fluorescent light. sindbis virus was significantly more sensitive than mcmv. the inactivated mcmv, when used to infect cells, was incapable of synthesizing early or late viral antigens. in addition to this direct virucidal effect, when hypericin was added to cells infected with viable mcmv, inhibition was also observ ...19911650164
selection of brain choline acetyltransferase synthetic peptides.choline acetyltransferase (chat) of pig brain is a 640 amino acid enzyme. the sequence has recently been published (berrard et al., 1988). we identified potentially antigenic epitopes on porcine chat by primary and secondary structure analysis. we used 12 structural parameters derived from the amino acid sequence, especially surface antigenicity, internal repetitions and protease cleavage site clusters and superposed gliding averages for the complete chat protein. four peptides from 13 to 21 ami ...19901707146
a conformational change in sindbis virus glycoproteins e1 and e2 is detected at the plasma membrane as a consequence of early virus-cell interaction.a conformational change in the structure of sindbis (sb) virus was detected after virion attachment to baby hamster kidney cells but before internalization. the alteration was manifested as increased virion binding of certain glycoprotein e1 and e2 monoclonal antibodies (mabs) that recognized transitional epitopes. these epitopes were inaccessible to mab on native virions but became accessible to their cognate mabs in the early stages of infection. transit of virions through a low-ph compartment ...19901695253
pathogenesis of encephalitis induced in newborn mice by virulent and avirulent strains of sindbis virus.strains of sindbis virus differ in their virulence for mice of different ages; this variation is related in large part to variations in the amino acid compositions of e1 and e2, the surface glycoproteins. the comparative pathogenesis of sindbis virus strains which are virulent or avirulent for newborn mice has not been previously examined. we have studied the diseases caused by a virulent wild-type strain, ar339, and two less virulent laboratory strains, toto1101 and hrsp (hr small plaque). afte ...19901691310
growth restriction of negative-strand-rna viruses in a rat 3y1 cell line.a rat fibroblast cell line, 3y1 is nonpermissive for infection by several negative-strand-rna viruses including influenza virus a, sendai virus, newcastle disease virus and vesicular stomatitis virus (vsv), but not refractory to that of a positive-strand-rna virus, sindbis virus. to elucidate the mechanism of the restricted viral growth, we compared the replication pattern of vsv in 3y1 cells and in baby hamster kidney cells, which are fully permissive for those viruses. the results indicated th ...19901691814
studies on the role of linear epitopes in neutralization of alphaviruses.by using three synthetic peptides (16-19 amino acids in length) representing different regions of glycoproteins e1 (peptide 3) and e2 (peptides 1 and 2) of sindbis and semliki forest virus and isolated glycoprotein fractions of both viruses in reduced and non-reduced form, the role of linear epitopes for the neutralization was investigated. the reaction patterns of sera induced by immunization with these antigens indicate that conformational epitopes do play the major role in neutralization of a ...19901694615
vector roles of fennoscandian mosquitoes attracted to mammals, birds and frogs.1. mosquitoes were sampled with five suction traps, from may to october 1983, at a forest site in south-central sweden. 2. twenty-three species of mosquitoes were identified among the total of 3108 females collected: 4% of them in an unbaited trap, 3% in a trap baited with two frogs, 24% with a guinea-pig, 28% with a hen and 40% in a trap baited with a rabbit. 3. the dominant species of culicidae trapped were 39% aedes communis (de geer), 21% ae. cinereus meigen, 14% coquillettidia richiardii (f ...19901983455
different pathogenicity of encephalitic togaviruses in organotypic cultures of spinal cord slices.the pathogenicity of two encephalitic togaviruses, sindbis virus (sv), an alphavirus, and west nile virus (wnv), a flavivirus, was studied in organotypic cultures of fetal mouse spinal cord slices grown in roller tubes. after about 3 weeks in vitro, during which time the cultures became abundantly myelinated, they were infected either by 5 x 10(5) pfu sv or by 5 x 10(6) pfu wnv per culture. the viruses caused different patterns of cytopathogenicity: sv induced severe cytotoxicity in all glia cel ...19901691307
defined mutations in the 5' nontranslated sequence of sindbis virus rna.we have constructed 24 deletion mutants which contain deletions of from 1 to 15 nucleotides in the 5' nontranslated region of sindbis virus rna and tested the effect of these mutations on virus replication. the results showed that the first 44 nucleotides, which are capable of forming a hairpin structure, are important for virus replication, as all deletions tested in this region were either lethal or resulted in virus that grew poorly in comparison to the parental virus. many of these deletions ...19902384916
proteolytic dissection of sindbis virus core protein.mild trypsin treatment of the sindbis virus nucleocapsid protein yields a fragment with a molecular mass of approximately 18.5 kilodaltons with its n terminus at residue 105. the fragment, which is stable to further digestion, appears by gel exclusion chromatography to be monomeric. these data are consistent with a model for the alphavirus core proteins, consisting of an extended and flexible n-terminal arm (residues 1 to 103) and a compactly folded c-terminal domain (residues 104 to 274), as pr ...19902370686
mutagenesis of the 3' nontranslated region of sindbis virus rna.a cdna clone from which infectious rna can be transcribed was used to construct 42 site-specific mutations in the 3' nontranslated region of the sindbis virus genome. the majority of these mutations were made in the 3'-terminal 19-nucleotide conserved sequence element and consisted of single nucleotide substitutions or of small (1 to 8) nucleotide deletions. an attempt was made to recover mutant viruses after transfection of sp6-transcribed rna into chicken cells. in most cases, viable virus was ...19902319643
brefeldin a arrests the intracellular transport of viral envelope proteins in primary cultured rat hepatocytes and hepg2 cells.we have studied the effect of brefeldin a (bfa) on the intracellular transport of the envelope proteins of vesicular stomatitis virus (vsv) and sindbis virus in primary cultured rat hepatocytes. bfa (2.5 micrograms/ml) inhibited not only the secretion of plasma proteins into the medium, but also the assembly of both g protein of vsv and e1 and e2 proteins (envelope proteins) of sindbis virus into respective virions. concomitantly, both the acquisition of endo-beta-n-acetylglucosaminidase h resis ...19902105715
temperature sensitive shut-off of alphavirus minus strand rna synthesis maps to a nonstructural protein, nsp4.minus strand rna synthesis by the positive strand alphaviruses, sindbis and semliki forest viruses, normally occurs early in infection, is coupled to synthesis of viral nonstructural proteins and to formation of viral replication complexes, and terminates and does not occur late in infection. previously, ts24 of the a complementation group of sindbis virus rna-negative mutants was found to possess, among its other temperature sensitive defects, a temperature sensitivity in the normal cessation o ...19902136781
synthesis and processing of the nonstructural polyproteins of several temperature-sensitive mutants of sindbis virus.we have examined the synthesis and processing of nonstructural polyproteins by several temperature-sensitive mutants of sindbis virus, representing the four known rna-minus complementation groups. four mutants that possess mutations in the c-terminal domain of nonstructural protein nsp2 all demonstrated aberrant processing patterns when cells infected with these mutants were shifted from a permissive (30 degrees) to a nonpermissive (40 degrees) temperature. mutants ts17, ts18, and ts24 showed se ...19902141204
cleavage between nsp1 and nsp2 initiates the processing pathway of sindbis virus nonstructural polyprotein p123.the cleavage between nsp1 and nsp2 and that between nsp2 and nsp3 in the sindbis virus nonstructural polyproteins was studied with respect to order of processing and enzyme-substrate relationships, using site-specific mutants in which the cleavage sites had been altered. the penultimate gly in nsp1 or nsp2 or both was substituted by ala, val, or glu, and processing was studied in vitro. substitution with ala resulted in partial cleavage whereas substitution with val or glu totally abolished clea ...19902141206
mutagenesis of the conserved 51-nucleotide region of sindbis virus.we have constructed 25 site-specific mutations in a domain of 51 nucleotides in sindbis virus that is highly conserved among all alphaviruses sequenced to date. these 51 nucleotides are capable of forming two hairpin structures and are found from nucleotides 155 to 205 in sindbis virus within the region encoding nsp1. of the mutations, 21 were silent and did not lead to a change in the amino acid sequence encoded. these silent mutations changed not only the linear sequence but also the stability ...19902319648
attenuating mutations in glycoproteins e1 and e2 of sindbis virus produce a highly attenuated strain when combined in vitro.alterations in either the e1 or the e2 glycoprotein of sindbis virus can affect pathogenesis in animals. previously, we identified two distinct e1 glycoprotein gene sequences which differed in their effect on pathogenesis. one had an attenuation phenotype following subcutaneous inoculation of neonatal mice (e1 ala-72, gly-75, and ser-237), while the other was virulent (e1 val-72, asp-75, and ala-237). in this study, we examined the basis for this difference in pathogenesis by using a full-length ...19902384921
anchorage-dependent surface distribution and partition during freeze-fracture of viral transmembrane glycoproteins.we have compared in the same cell type the surface distribution and partition in freeze-fractured plasma membranes of sindbis virus glycoproteins in three different situations: (i) in permanently transformed cells that express the glycoproteins as the only viral product; (ii) in cells in which prebound viruses were forced to fuse with the plasma membrane by low ph treatment; (iii) in virus-infected cells. we report here that the viral proteins expressed on the surface of transfected cells show a ...19902401782
cleavage-site preferences of sindbis virus polyproteins containing the non-structural proteinase. evidence for temporal regulation of polyprotein processing in vivo.the non-structural proteins of sindbis virus, nsp1, 2, 3 and 4, are produced upon cleavage of polyproteins p123 and p1234 by a proteinase residing in nsp2. we used cell free translation of sp6 transcripts to study the proteolytic activity of nsp2 and of nsp2-containing polyproteins. to generate polyprotein enzymes, a set of plasmids was made in which cleavage sites were eliminated and new initiation and termination codons introduced by in vitro mutagenesis. as a substrate, we used a polyprotein ...19902142454
phosphorylation of sindbis virus nsp3 in vivo and in vitro.nsp3 is one of four viral nonstructural proteins required for rna replication of sindbis virus. in this report, post-translational modifications of nsp3 which occur in both vertebrate and mosquito cell cultures have been examined. in pulse-chase experiments, analyzed by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, nsp3 was initially observed as a single species (termed nsp3a, approximately 76 kda) which was gradually converted to slower mobility forms rangin ...19902145690
the characterization of ia expression during sindbis virus encephalitis in normal and athymic nude mice.to characterize the expression of ia systemically and locally on mononuclear cells during acute viral encephalitis, weanling mice were inoculated intracerebrally with sindbis virus (sv), an alphavirus. peripheral blood mononuclear cells, splenocytes and perivascular inflammatory cells in frozen brain sections were examined immunocytochemically for the presence of ia. ia expression increased in the spleen, blood and brain during sv encephalitis. the majority of the cells in the central nervous sy ...19902153758
mutations which alter the level or structure of nsp4 can affect the efficiency of sindbis virus replication in a host-dependent manner.two mutants of sindbis virus have been isolated which grow inefficiently at 34.5 degrees c in mosquito cells yet replicate normally in chicken embryo fibroblast cells at the same temperature. in addition, these mutants exhibit temperature-sensitive growth in both cell types and are rna- at the nonpermissive temperatures (k.j. kowal and v. stollar, virology 114:140-148, 1981). to clarify the basis of this host restriction, we have mapped the causal mutations for these temperature-dependent, host- ...19902159558
both amino acid changes in nsp1 of sindbis viruslm21 contribute to and are required for efficient expression of the mutant phenotype.svlm21 is a mutant of sindbis virus which in contrast to the standard virus, svstd, is able to replicate in aedes albopictus mosquito cells deprived of methionine. previously, by making use of the infectious toto plasmids, we had constructed recombinant viruses containing various svlm21 sequences, and were thereby able to map the mutations associated with the svlm21 phenotype to the gene for the nonstructural protein nsp1. two mutations were found in the nsp1 gene of svlm21. these led to predict ...19902219702
promoter for sindbis virus rna-dependent subgenomic rna transcription.sindbis virus is a positive-strand rna enveloped virus, a member of the alphavirus genus of the togaviridae family. two species of mrna are synthesized in cells infected with sindbis virus; one, the 49s rna, is the genomic rna; the other, the 26s rna, is a subgenomic rna that is identical in sequence to the 3' one-third of the genomic rna. ou et al. (j.-h. ou, c. m. rice, l. dalgarno, e. g. strauss, and j. h. strauss, proc. natl. acad. sci. usa 79:5235-5239, 1982) identified a highly conserved r ...19902319651
site-directed mutagenesis of the proposed catalytic amino acids of the sindbis virus capsid protein autoprotease.the structural proteins of sindbis virus are translated as a polyprotein precursor that is cleaved upon translation. the capsid protein is postulated to be a serine protease that releases itself from the n terminus of the nascent polyprotein by autoproteolysis. we have tested the importance in autoproteolysis of his-141, asp-147, and ser-215, previously postulated to form the catalytic triad of the protease, and of asp-163. several site-specific mutations were constructed at each of these positi ...19902335827
enhancement of the interferon-induced double-stranded rna-dependent protein kinase activity by sindbis virus infection and heat-shock stress.in extracts of fl cells that were infected with sindbis virus or treated with heat-shock stress, dsrna-dependent phosphorylation of 77k protein was markedly increased. the 77k phosphoprotein was indistinguishable from the autophosphorylated and activated form of interferon (ifn)-induced dsrna-dependent protein kinase (pk-i) by two-dimensional gel electrophoresis, and was immunologically related to p68 (galabru, j. and hovanessian, a., j. biol. chem. 262, 15538 (1987], the hela cell counterpart o ...19901963922
complete sequence of the genomic rna of o'nyong-nyong virus and its use in the construction of alphavirus phylogenetic trees.the alphaviruses are a group of about 25 positive-strand rna viruses that are important human and veterinary pathogens and that are geographically dispersed. we report here the complete nucleotide sequence of the genomic rna of the alphavirus, o'nyong-nyong virus. the rna is 11,835 nucleotides in length and the organization of the genome is typical of alphaviruses. phylogenetic trees were constructed from the protein sequences of o'nyong-nyong and six other alphaviruses. trees were constructed f ...19902155505
biochemical and physical properties of a solvent-detergent-treated fibrin glue.a fibrin glue preparation has been obtained from pooled human plasma using a procedure which includes a solvent-detergent (sd) treatment to inactivate lipid-enveloped viruses. the sd treatment inactivated greater than or equal to 5.5 log10 of hiv in less than 45 min, and greater than or equal to 5 log10 and greater than or equal to 6.5 log10 of vsv and sindbis virus, respectively, in less than 2 h. the product was found to contain high quantities of fibrinogen (116 +/- 2.49 g/l; n = 12), factor ...19902160146
[a comparative analysis of the polypeptides of the the sindbis and karelian fever viruses].in pulse-chase experiments with karelian fever virus-infected cells, proteins were found with molecular weights of 130, 98, 78, and 62 kd of which the first, second and fourth were classified as polypeptide precursors of the structural proteins of virion. the molecular weights of proteins e1, e2 and c of 52, 47 and 34 kd, respectively, as well as isoelectric points of isolated glycoproteins (pi e1 = 6.3, pi e2 = 8.4) were similar in kfv (strain leiv-9298) and sindbis virus (strain ar339). the an ...19902176422
the sindbis virus 6k protein can be detected in virions and is acylated with fatty acids.a small hydrophobic polypeptide is encoded within the genome of the alphaviruses by a set of 165 nucleotides which map between the sequences for the two virus glycoproteins. this polypeptide has been referred to as 6k and was previously found on membranes in virus-infected cells. we report here that this protein is heavily acylated with long chain fatty acids covalently attached in hydroxylamine-sensitive ester bonds and that the 6k protein can be detected in purified preparations of virions. a ...19902408229
antiviral effects of 2',5'oligoadenylates (2-5as), and related compounds.dephosphorylated "core" of 2',5'-oligoadenylate (2-5a) dimer (a2'p5'a), exogenously added to nonpermeabilized fl cells, inhibited the multiplication of sindbis virus and vesicular stomatitis virus (vsv). the compound was shown to inhibit viral protein synthesis. the addition of a2'p5'a at the early stage of viral replication was more effective than that at the late stage. in contrast with the core, phosphorylated 2-5a (p5'a2'p5'a and ppp5'a2'p5'a) and 2-5a analogs containing cordycepin (3'-deoxy ...19902178211
[the relationship of sindbis virus assembly and the viral protein 6k with intermediate filaments].the relationship of sindbis virus (sbv) assembly with intermediate filaments was studied by means of whole-mount and dgd embedment-free technique of em together with the procedure of gentle extraction. in the early stage of sbv infection, the "virus assembly center" was suspended in the intermediate filament network. in the late stage, the assembling and assembled virus nucleocapsids were associated with intermediate filaments. it is presumable that the virus nucleocapsids may move from the "vir ...19902270686
site-directed mutations in the sindbis virus 6k protein reveal sites for fatty acylation and the underacylated protein affects virus release and virion structure.a small hydrophobic polypeptide of 55 amino acids, noted as the 6k protein, is formed during processing of the polyprotein translated from the sindbis virus subgenomic 26 s mrna. in the accompanying paper we show that this 6k protein can be found in purified preparations of virions and that it is palmitoylated via thioester bonds with about four covalently bound fatty acids per molecule. to determine acylation sites on 6k and define a role for these fatty acids, we used site-directed mutagenesis ...19902309447
antigenic and genetic characterization of sindbis virus monoclonal antibody escape mutants which define a pathogenesis domain on glycoprotein e2.the sindbis virus mutant sb-rl, in contrast to its parent, sindbis strain ar339 (sb), is attenuated in neonatal mice, has an increased rate of penetration in tissue culture cells, and is more sensitive to neutralization by e2-specific monoclonal antibodies (mcabs) r6 and r13. these phenotypic differences are controlled by substitution of an arginine for serine at amino acid 114 of the e2 glycoprotein. to explore these relationships further, mcab r6 and r13 neutralization escape mutants of both s ...19902309450
efficient medium for impingement and storage of enveloped viruses.airborne infections with pathogenic viruses play an important role in the transmission of diseases amongst men and animals. we compared several media intended for impingement of viruses from virus-contaminated air and for their preserving effect for two enveloped viruses. sindbis (sinv) and vesicular stomatitis virus (vsv), members of the families toga- and rhabdoviridae, respectively, were chosen as indicator agents. amongst the media tested, a sampling fluid consisting of phosphate buffered sa ...19892548354
processing the nonstructural polyproteins of sindbis virus: nonstructural proteinase is in the c-terminal half of nsp2 and functions both in cis and in trans.the processing of the sindbis virus nonstructural polyprotein translated in vitro has been studied. when sindbis virus genomic rna was translated in a reticulocyte lysate, polyprotein p123 was cleaved efficiently to produce nsp1, nsp2, and nsp3. inhibition of this processing by anti-nsp2 antibodies, but not by antibodies specific for nsp1, nsp3, or nsp4, suggested that the viral proteinase was present in nsp2. to localize the proteolytic activity more precisely, deletions were made in a full-len ...19892529379
susceptibility of dogs to west nile virus: a survey and pathogenicity trial.a serological survey of dogs from the highveld region of south africa showed that 37 per cent (138 of 377) had neutralizing antibodies to west nile (wn) virus and only 2.7 per cent (10 of 377) had antibodies to sindbis virus. wn virus was isolated from one of the wn-antibody negative sera. because these results suggested that dogs may play an important part in the epidemiology of wn virus, a pathogenicity trial was carried out. two of three dogs infected with wn virus had a mild recurrent myopat ...19892537346
role of the immune response in sindbis virus-induced paralysis of sjl/j mice.the pathologic role of the specific immune and inflammatory responses to viral infections of the cns was investigated by using mice which are susceptible (sjl/j) and resistant (c57bl6 and balb/c) to the development of experimental autoimmune encephalomyelitis (eae). intracerebral inoculation of 10(4) pfu of sindbis virus (sv) into 6- to 8-wk-old sjl/j mice resulted in a severe and sometimes fatal encephalomyelitis. a mild to severe hind leg paralysis was observed around days 6 to 7 postinfection ...19892472447
abortive infection with sindbis virus of a chinese hamster ovary cell mutant defective in phosphatidylserine and phosphatidylethanolamine biosynthesis.the effects of phosphatidylserine starvation on the infection with sindbis virus (an enveloped rna virus) have been investigated in a chinese hamster ovary (cho) cell mutant (strain psa-3) which requires exogenously added phosphatidylserine for cell growth because it lacks the ability to synthesize this phospholipid. when psa-3 cells were grown in the absence of phosphatidylserine, the cellular contents of phosphatidylserine and also phosphatidylethanolamine produced through decarboxylation of p ...19892479418
evidence that sindbis virus nsp2 is an autoprotease which processes the virus nonstructural polyprotein.the four nonstructural proteins (nsp1-4) of sindbis virus, a member of the togaviridae family, are initially expressed from the 5' segment of the single-stranded genomic (+)rna as a polyprotein which is subsequently proteolytically processed. in attempts to identify the protease acting on this nonstructural polyprotein, we established a coupled in polyprotein, we established a coupled in vitro transcription-translation system which was able to faithfully process the major polyprotein when an mrn ...19892525839
comparison of three methods for determining transmission rates in vector competence studies with culex univittatus and west nile and sindbis viruses.culex univittatus mosquitoes were infected by ingesting west nile and sindbis viruses, respectively. after 13-19 days, comparative viral transmission rates were determined using 3 methods: 1) transmission to hamsters by bite, 2) in vitro transmission while feeding on suspensions in capillary tubes and 3) transmission while feeding on droplets of suspension. transmission rates were 59-100%, except for sindbis virus by droplet feeding when the rate was 9%. except for the latter, rates determined b ...19892540264
verapamil and chlorpromazine inhibit the budding of sindbis and vesicular stomatitis viruses from infected chicken embryo fibroblasts.two agents, verapamil and chlorpromazine, which affect calcium levels in cells were tested as inhibitors of sindbis and vesicular stomatitis virus replication in chicken embryo fibroblasts. at levels which did not greatly inhibit general protein synthesis, both drugs appeared to selectively block virus formation at the final stages of virus assembly and budding. viral nucleoprotein synthesis and transport of viral glycoproteins to the cell plasma membrane were not inhibited under conditions that ...19892535903
most alphaviruses share a conserved epitopic region on their nucleocapsid protein.fourteen hybridoma cell lines secreting antibodies against the semliki forest virus nucleocapsid protein were established and employed for identification of conserved epitopes among 27 alphavirus types and subtypes. using an antibody capture test, the antibodies were found to cross-react to variable degree with alphaviruses belonging to the semliki forest, western encephalitis and eastern encephalitis complexes, as well as middelburg and ndumu. none of the antibodies reacted with either venezuel ...19892471798
isolation, culture and main characteristics of mouse fat-storing cells: interaction with viruses.fat-storing cells were isolated from 15-day-old mouse sinusoidal cell cultures (kupffer or endothelial cells), where they had multiplied abundantly; they were then purified by a negative selection method based on the fact that they do not possess fc receptors, as do both other types of cells. the fat-storing cells, which could be subcultured for at least 10 passages, have the main morphological characteristics already described in vivo, in particular, the rough endoplasmic reticulum and the lipi ...19892465986
the effect of interferon on cells persistently infected with hiv.in this study the effect of interferon (ifn) on uninfected cells (h9-) and cells infected (h9+) with hiv-1 was investigated. in both h9- and h9+, ifn was unable to inhibit sindbis virus replication. hiv-1 replication was inhibited by a maximum of 22% at 1000 u/ml of ifn. in both h9- and h9+ cells ifn exhibited a limited antiproliferative effect. there was activation of the 2'-5' oligo-a-synthetase (e enzyme) and the protein kinase enzyme systems, but low activation of the ribonuclease f was seen ...19892496710
mapping of rna- temperature-sensitive mutants of sindbis virus: complementation group f mutants have lesions in nsp4.temperature-sensitive (ts) mutants of sindbis virus belonging to complementation group f, ts6, ts110, and ts118, are defective in rna synthesis at the nonpermissive temperature. cdna clones of these group f mutants, as well as of ts+ revertants, have been constructed. to assign the ts phenotype to a specific region in the viral genome, restriction fragments from the mutant cdna clones were used to replace the corresponding regions of the full-length clone toto1101 of sindbis virus. these hybrid ...19892521674
a cis-acting mutation in the sindbis virus junction region which affects subgenomic rna synthesis.the synthesis of sindbis virus minus-strand and genomic and subgenomic rnas is believed to require specific cis-acting sequences or structures in the template rnas and a combination of virus-specific proteins and host components which act in trans. a conserved sequence of about 21 nucleotides in the junction region and encompassing the start site for the subgenomic rna has been proposed to function as the promoter on the minus-strand template for synthesis of the subgenomic rna (j.-h. ou, c. m. ...19892685355
evidence for specificity in the encapsidation of sindbis virus rnas.we investigated the interaction of the capsid protein of sindbis virus with sindbis viral rnas and defined a region of the genome that is required for binding in vitro and for packaging in vivo. the binding studies were performed with purified capsid protein immobilized on nitrocellulose and 32p-labeled rnas transcribed in vitro from viral and nonspecific cdnas. genomic and defective interfering (di) rnas bound capsid protein significantly better than either the subgenomic (26s) rna or nonspecif ...19892585607
possible involvement of virus-induced protein kinase in the antiviral state induced with interferon-gamma against sindbis virus.the kinetics of induction of the antiviral state against two rna viruses, vesicular stomatitis virus (vsv) and sindbis virus, by human interferons (ifns)-alpha, -beta, and -gamma was measured and compared with that of 2',5'-oligoadenylate (2-5a) synthetase and protein kinase in cells treated with ifns. both enzymes were induced in similar time courses and the induction by ifn-gamma was slower than ifn-alpha or beta. the time course of the induction of antiviral state against vsv almost parallele ...19892541209
intracellular transport and processing of sindbis virus glycoproteins.the intracellular transport and processing of sindbis virus envelope glycoproteins were studied in cells infected with sindbis virus using the mannose-specific enzyme, endoglycosidase h (endo h). in pulse/chase labeling experiments of hamster cells with [35s]methionine, sindbis glycoproteins pe2 and e1 became endo h resistant in two steps at 12.5 and 20.0 min after a 5-min pulse, suggesting that the glycoproteins required this period of time to be transported to the golgi compartments containing ...19892718376
rna viruses as gene expression vectors. 19892815597
molecular pathogenesis of sindbis virus encephalitis in experimental animals.in general, the analysis of a number of strains of sindbis virus has revealed amino acid differences of potential importance for virulence at relatively few positions in the e2-glycoprotein. only 10 amino acid changes are potentially implicated, and 9 of these 10 lie in the n-terminal half of the protein (fig. 1.). currently, there is strong evidence to implicate 3 of these positions (e2-55, -114, and -172) in virulence (table v). as more recombinant viruses are prepared and analyzed, the eviden ...19892544083
palmitylation of viral membrane glycoproteins takes place after exit from the endoplasmic reticulum.palmitylation of vesicular stomatitis virus g and sindbis virus e1 glycoproteins has been studied in relation to the transport from the endoplasmic reticulum (er) to the golgi complex. incubation of infected cells at 15 degrees c prevents the transport of newly synthesized membrane proteins from the er to the golgi (saraste, j., and kuismanen, e. (1984) cell 38, 535-549). in these conditions, also palmitylation of g protein and of e1 glycoprotein is blocked. when the transport is restored by inc ...19892545712
characterization of the local and systemic b cell response of normal and athymic nude mice with sindbis virus encephalitis.during sindbis virus (sv) encephalitis in mice b cells are an important component of the mononuclear inflammatory response and recovery depends primarily on the development of antiviral antibody. to begin to characterize various parameters of the local b cell response during sv encephalitis we have defined b cell isotype expression in brain sections, splenocytes and peripheral blood mononuclear cells (pbmc) in normal and athymic nude mice using an immunoperoxidase technique. early (days 3-5) in ...19892553771
comparison of an antibody-capture igm enzyme-linked immunosorbent assay with igm-indirect immunofluorescence for the diagnosis of acute sindbis and west nile infections.the development and evaluation of an antibody-capture elisa for the detection of igm antibodies to sindbis (sin) and west nile (wn) viruses are described. comparison of the elisa results with those obtained by indirect immunofluorescence (iif) antibody tests using both fluorescein and biotinylated anti-human igm conjugates, showed that the former technique was both more sensitive and specific than the iif methods. there were no false positives by the elisa whereas with the igm-iif assays a high ...19892555380
the role of monovalent cation transport in sindbis virus maturation and release.alterations in intracellular monovalent cation concentrations in sindbis virus-infected avian cells result, in part, from a reduction in na+/k+ atpase (na+ pump) activity. inhibition of na+ pump activity was shown previously to temporally correlate with the appearance of viral envelope proteins on the cell surface and the release of virus particles. cells infected with envelope-defective temperature-sensitive mutants exhibited reduced na+ pump activity at the nonpermissive temperature, where vir ...19892549721
defective response to interferons in cells transfected with the hepatitis b virus genome.the interferon responsiveness of two cell lines transfected with the hepatitis b virus genome was investigated. a cosmid vector containing multiple copies of the hepatitis b virus genome was transfected into fl5-1 cells; it reduced their sensitivity to interferons as measured by inhibition of the cytopathic effect of sindbis virus challenge. similar vectors transfected into hela cells reduced their sensitivity to interferon as measured by production of beta 2-microglobulin. this resistance to in ...19892461895
the antiviral action of lignans.a total of 18 purified lignans was evaluated for antiviral activity against murine cytomegalovirus (cmv) and sindbis virus, by means of different treatment regimens. podophyllotoxin and alpha-peltatin were the most potent compounds, and they apparently inhibited murine cmv at an essential early step in the replication cycle after the adsorption of virus to the cells. on the other hand, justicidin b and the diphyllin derivatives were much more effective against sindbis virus, and 12 of the lignan ...19892559420
enhanced full-length transcription of sindbis virus rna by effective denaturation with methylmercury hydroxide.49-s sindbis virus rna was reverse transcribed into a complementary dna. the rna templates were denatured by three different methods prior to dna synthesis. efficient full-length transcription was only achieved after treatment with methylmercury hydroxide.19892570517
svlm21, a sindbis virus mutant resistant to methionine deprivation, encodes an altered methyltransferase.the replication of sindbis virus (svstd) in cultured aedes albopictus mosquito cells is sensitive to methionine deprivation. we have suggested from earlier work that this sensitivity is primarily because of a decreased pool of s-adenosyl methionine (ado met) and the resultant failure to methylate the 5' cap of the viral mrnas. svlm21, a strain of sindbis virus derived in our laboratory from svstd by serial passage on mosquito cells maintained after infection in low concentrations of methionine, ...19892596021
mapping of rna- temperature-sensitive mutants of sindbis virus: assignment of complementation groups a, b, and g to nonstructural proteins.four complementation groups of temperature-sensitive (ts) mutants of sindbis virus that fail to make rna at the nonpermissive temperature are known, and we have previously shown that group f mutants have defects in nsp4. here we map representatives of groups a, b, and g. restriction fragments from a full-length clone of sindbis virus, toto1101, were replaced with the corresponding fragments from the various mutants. these hybrid plasmids were transcribed in vitro by sp6 rna polymerase to produce ...19892724421
properties of a highly purified human plasma factor ix:c therapeutic concentrate prepared by conventional chromatography.we have characterized a highly purified (hp) factor ix concentrate intended for therapy of hemophilia b. the product has been prepared from pooled human plasma using a large-scale procedure combining three conventional chromatographic steps based on deae ion exchange and affinity on immobilized heparin. the specific activity of the product was 119 +/- 10 iu factor ix:c/mg protein (n = 15), corresponding to a purification factor of about 9,000. the concentrate was free of the vitamin k-dependent ...19892617959
mutagenesis of the in-frame opal termination codon preceding nsp4 of sindbis virus: studies of translational readthrough and its effect on virus replication.sindbis virus (sin) contains an in-frame opal termination codon in the nonstructural protein-coding region separating nsp3 and nsp4 and provides a useful tool to study the readthrough phenomenon of the termination codon in host cells and its role in viral replication. we have changed the opal codon by site-directed mutagenesis of a full-length sin cdna clone to either sense amino acids (serine, tryptophan, or arginine) or the other two translation termination codons (amber or ochre). transcripts ...19892521676
ecologic studies of mosquitoes and birds as hosts of ockelbo virus in sweden and isolation of inkoo and batai viruses from mosquitoes.field studies were conducted in central sweden from 1983 through 1985 to obtain information on the etiologic agent of ockelbo disease, described in sweden in the 1960s and probably identical to pogosta disease in finland and to karelian fever in the western ussr. mosquitoes (63,644) collected during this 3 year period yielded 21 virus strains. ockelbo virus isolations were from culiseta morsitans (5 strains), culex pipiens and/or cx. torrentium (6 strains), and aedes cinereus (3 strains). inkoo ...19892572178
the proteolytic cleavage of pe2 to envelope glycoprotein e2 is not strictly required for the maturation of sindbis virus.the ionophore monensin has been shown previously to block the maturation of sindbis virus as well as prevent the cleavage of pe2 to e2 when applied to cells in high concentration. we found that a moderate dose of monensin reduced virus titer and inhibited the cleavage of pe2 to e2. under these conditions, pe2 appeared on the cell surface in a form susceptible to lactoperoxidase-mediated iodination. this pe2 was incorporated into virions, replacing e2. pe2-containing virions had a normal pfu-to-p ...19892704073
low ph-dependent sindbis virus-induced fusion of bhk cells: differences between strains correlate with amino acid changes in the e1 glycoprotein.expression of alphavirus glycoproteins on the surface of infected cells leads to cell fusion after exposure to acidic ph. two strains of sindbis virus, ar339 (sv) and neuroadapted sindbis virus (nsv), which differ in virulence for weanling mice, were found to differ in ph-dependent fusion. bhk-21 cells infected with sv fused maximally after shifting to ph 5.4, whereas cells infected with nsv required a lower ph, ph 4.8, for maximal fusion. no difference was noted in the optimal ph for agglutinat ...19892705310
association of the sindbis virus rna methyltransferase activity with the nonstructural protein nsp1.svlm21 is a mutant of sindbis virus, which in contrast to svstd, is able to replicate in aedes albopictus mosquito cells deprived of methionine. we have obtained evidence that the basis of this low methionine-resistance (lmr) phenotype is the generation of an altered rna methyltransferase with an increased affinity for s-adenosylmethionine (ado met). we now report that following the substitution of the nucleotide sequence, 126-504, from svlm21 cdna for the corresponding sequence of the toto 1101 ...19892728344
[use of probes containing cloned genes of the karelian fever virus in detecting viral genetic material in infected cells by a molecular hybridization method].two plasmid dna-probes containing dna-replicas of kfv genes (clone 1-protein e1 gene, clone 9--proteins e1 and p1 genes of kfv) were used for detection of the genetic material of karelian fever virus (kfv) in the infected cells and study of the time course of accumulation of virus-specific rnas in the process of infection. the detection was performed by the method of rna:dna dot-hybridization. both probes were hybridized with kfv and sindbis virus rna in equal amounts--5 x 10(2) infected cells a ...19892728408
expression of sindbis virus 26s cdna in spodoptera frugiperda (sf9) cells, using a baculovirus expression vector.to study protein processing in an insect spodoptera frugiperda (fall armyworm; sf9) cell line, a 26s cdna encoding the sequence of sindbis virus structural proteins (capsid protein, of 30 kilodaltons [kda]; p62 [the precursor of e3 and e2], of 62 kda; a 6-kda peptide; and the e1 protein, of 56 kda) was inserted into the genome of autographa californica nuclear polyhedrosis virus (acnpv) adjacent to the polyhedrin promoter. by immunoblot analysis with antisera directed against whole sindbis virus ...19892644447
sindbis virus core protein crystals.the core protein of sindbis virus has been crystallized. three different crystal forms have been observed. they diffract variously from 2.5 a to 3.5 a resolution.19892769756
monoclonal antibodies that cross-react with the e1 glycoprotein of different alphavirus serogroups: characterization including passive protection in vivo.a panel of four monoclonal antibodies (mab) were produced that cross-react with representatives of two different togavirus serogroups, namely sindbis (sin) and semliki forest (sf) viruses, by elisa and adcmc assays. three of these mab, igg2a and igg2b isotypes, passively protected c3h/hej mice against 10 and 100 ld50 of sf challenge and one, igm, did not protect against either challenge dose, or even at 1 ld50. all these mab were cross-reactive with the e1 glycoprotein of the viruses by immunobl ...19892773592
biosynthesis, membrane translocation, and surface expression of sindbis virus e1 glycoprotein.sindbis virus glycoproteins pe2 (precursor of e2) and e1 are coded in this order by the same monocistronic mrna, cotranslationally inserted in the endoplasmic reticulum membrane and then transported to the cell surface where the progeny virus is released by budding. in the virion, three e1 plus three e2 molecules form hexameric spike complexes. previous work (s. bonatti, g. migliaccio, g. blobel, and p. walter (1984), eur. j. biochem. 140, 499-502) revealed a single signal sequence for cotransla ...19892806407
form-determining functions in sindbis virus nucleocapsids: nucleosomelike organization of the nucleocapsid.purified intact sindbis virus nucleocapsids were treated at different ph values or with various concentrations of divalent cations, cation chelators, salt, or formamide. the resulting structures were examined by velocity sedimentation, electron microscopy, and protein-protein cross-linking. changes in each of the test conditions led to alterations in the sedimentation profile of treated nucleocapsids. appropriate concentrations of formamide or divalent cations generated beaded strandlike structu ...19892911124
sindbis virus ts103 has a mutation in glycoprotein e2 that leads to defective assembly of virions.sindbis virus mutant ts103 is aberrant in the assembly of virus particles. during virus budding, proper nucleocapsid-glycoprotein interactions fail to occur such that particles containing many nucleocapsids are formed, and the final yield of virus is low. we have determined that a mutation in the external domain of glycoprotein e2, ala-344----val, is the change that leads to this phenotype. mapping was done by making recombinant viruses between ts103 and a parental strain of the virus, using a f ...19892746736
localization of epstein-barr virus envelope glycoproteins on the inner nuclear membrane of virus-producing cells.epstein-barr virus-producing cells were used as a model to analyze, with a fracture-immunolabel technique, the distribution, behavior on fracture, and extent of glycosylation of viral transmembrane glycoproteins at the inner nuclear membrane. surface and fracture immunolabeling with two monoclonal antibodies directed against the carbohydrate or polypeptide portions of the major viral envelope glycoproteins gp350/220 showed the following. (i) the glycoproteins present on the inner and outer nucle ...19892536106
effect of sindbis virus infection on induction of heat shock proteins in aedes albopictus cells.when aedes albopictus cells (clone c7) were infected with sindbis virus, the production of cytopathic effect cpe depended largely on the conditions under which the cells were cultured. we observed marked inhibition of cellular rna and protein synthesis, as well as a loss of the ability to induce heat shock proteins, e.g., hsp70, under conditions which led to cytopathic effect. infected cells in which heat shock proteins could no longer be induced contained much lower amounts of hsp70 mrna after ...19892911128
sindbis virus: an efficient, broad host range vector for gene expression in animal cells.sindbis virus, an enveloped virus with a single-stranded rna genome, was engineered to express a bacterial protein, chloramphenicol acetyltransferase (cat), in cultured insect, avian, and mammalian cells. the vectors were self-replicating and gene expression was efficient and rapid; up to 10(8) cat polypeptides were produced per infected cell in 16 to 20 hours. cat expression could be made temperature-sensitive by means of a derivative that incorporated a temperature-sensitive mutation in viral ...19892922607
sindbis virus mutations which coordinately affect glycoprotein processing, penetration, and virulence in mice.rapid penetration of baby hamster kidney cells was used as a selective pressure for the isolation of pathogenesis mutants of the s.a.ar86 strain of sindbis virus. unlike most sindbis virus strains, s.a.ar86 is virulent in adult as well as neonatal mice. two classes of mutants were defined. one class was attenuated in adult mice inoculated intracerebrally as well as in neonatal mice inoculated either intracerebrally or subcutaneously. sequence analysis of the glycoprotein genes of the parent viru ...19892926866
involvement of lipids in the interaction of sindbis virus with goose erythrocytes.the chemical nature of sindbis virus receptors on goose erythrocytes was investigated by means of two different experimental approaches: by testing the capacity of human serum lipoproteins (hdl, ldl, vldl) to compete with erythrocytes for virus binding and by enzymatic and chemical modifications of the cell membrane. each class of lipoproteins was separated into its protein and lipid components which were tested for hemagglutination and hemolysis inhibiting activity. only the lipid moieties were ...19892747550
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