Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
distinct biology of kaposi's sarcoma-associated herpesvirus from primary lesions and body cavity lymphomas.the dna sequence for kaposi's sarcoma-associated herpesvirus was originally detected in kaposi's sarcoma biopsy specimens. since its discovery, it has been possible to detect virus in cell lines established from aids-associated body cavity-based b-cell lymphoma and to propagate virus from primary kaposi's sarcoma lesions in a human renal embryonic cell line, 293. in this study, we analyzed the infectivity of kaposi's sarcoma-associated herpesvirus produced from these two sources. viral isolates ...19989811747
identification and characterization of the escherichia coli-expressed rna-dependent rna polymerase of bamboo mosaic virus.bamboo mosaic virus (bamv), a member of the potexvirus group, infects primarily members of the bambusoideae. the open reading frame 1 (orf1) of bamv encodes a 155-kda polypeptide that was postulated to be involved in the replication and the formation of cap structure at the 5' end of the viral genome. to characterize the activities associated with the 155-kda viral protein, it was expressed in escherichia coli bl21(de3) cells with thioredoxin, hexahistidine, and s. tag fused consecutively at its ...19989811749
alphavirus replicase protein nsp1 induces filopodia and rearrangement of actin filaments.expression of the nsp1 protein of semliki forest virus and sindbis virus in cultured cells induced filopodia-like extensions containing nsp1 but not f actin. the actin stress fibers disappeared, whereas vimentin, keratin, and tubulin networks remained intact. the effects of nsp1 were dependent on its palmitoylation but not on its enzymatic activities and were also observed in virus-infected cells.19989811773
capping and methylation of mrna by purified recombinant vp4 protein of bluetongue virus.the core of bluetongue virus (btv) is a multienzyme complex composed of two major proteins (vp7 and vp3) and three minor proteins (vp1, vp4, and vp6) in addition to the viral genome. the core is transcriptionally active and produces capped mrna from which all btv proteins are translated, but the relative role of each core component in the overall reaction process remains unclear. previously we showed that the 76-kda vp4 protein possesses guanylyltransferase activity, a necessary part of the rna ...19989811835
detection and quantitation of human respiratory syncytial virus (rsv) using minigenome cdna and a sindbis virus replicon: a prototype assay for negative-strand rna viruses.we describe here a novel approach for detecting and quantitating human respiratory syncytial virus (rsv) based on expression of a reporter gene from an rsv minigenome. bhk cells were cytoplasmically transformed with a noncytopathic sindbis virus replicon expressing t7 rna polymerase. these cells were then cotransfected with t7 expression plasmids that contain the cdna of an rsv minigenome and the genes for rsv nucleocapsid proteins n, p, and l. the minigenome contains a reporter gene such as lac ...19989813215
nuclear import and the evolution of a multifunctional rna-binding protein.la (ss-b) is a highly expressed protein that is able to bind 3'-oligouridylate and other common rna sequence/structural motifs. by virtue of these interactions, la is present in a myriad of nuclear and cytoplasmic ribonucleoprotein complexes in vivo where it may function as an rna-folding protein or rna chaperone. we have recently characterized the nuclear import pathway of the s. cerevisiae la, lhp1p. the soluble transport factor, or karyopherin, that mediates the import of lhp1p is kap108p/sxm ...19989817748
characterization of diverse viral vector preparations, using a simple and rapid whole-virion dot-blot method.a number of different viruses have been adapted as gene transfer vectors, including retroviruses, adenoviruses, adenoassociated viruses (aavs), herpes simplex virus, sv40 viruses, and alphaviruses (both semliki forest and sindbis viruses). one of the major rate-limiting and time-consuming steps in the characterization of these vectors is the process of determining the viral vector titers. in addition, there is no "universal" method that can be used to rapidly estimate the titer and the utility o ...19989829539
overexpression of chicken interferon regulatory factor-1 (ch-irf-1) induces constitutive expression of mhc class i antigens but does not confer virus resistance to a permanent chicken fibroblast cell line.the chicken fibroblast cell line c32 has been transfected with the chicken homolog (ch-irf-1) of the mammalian transcription factor irf-1. stable transfectants were generated, constitutively overexpressing ch-irf-1 mrna and protein. cells overexpressing ch-irf-1 showed enhanced constitutive expression of mhc class i (b-f, beta-microglobulin) antigens. with increasing number of passages cells with normal b-f iv surface antigen expression accumulated. in the revertants, the amount of ch-irf-1 mrna ...19989831662
a neuron-specific gene transfer by a recombinant defective sindbis virus.we examined the possibility that sindbis virus, an alpha virus with a single-stranded rna genome, would be applied for neuronal gene transfer. the recombinant defective sindbis viruses were constructed by replacing the structural genes of sindbis virus with genes encoding beta-galactosidase (rdsind-lacz) or enhanced green fluorescent protein (rdsind-egfp). in neuron-glia cocultures prepared from the neocortex, hippocampus, and striatum, egfp or beta-galactosidase was expressed selectively in neu ...19989838041
virus maturation by budding.enveloped viruses mature by budding at cellular membranes. it has been generally thought that this process is driven by interactions between the viral transmembrane proteins and the internal virion components (core, capsid, or nucleocapsid). this model was particularly applicable to alphaviruses, which require both spike proteins and a nucleocapsid for budding. however, genetic studies have clearly shown that the retrovirus core protein, i.e., the gag protein, is able to form enveloped particles ...19989841669
regulation of alphavirus 26s mrna transcription by replicase component nsp2.semliki forest virus (sfv) mutant ts4 has a reversible temperature-sensitive defect in the synthesis the subgenomic 26s mrna. the viral nonstructural protein nsp2 was identified as a regulator of 26s synthesis by transferring nsp2 coding sequences from ts4 into the infectious sfv cdna clone (sfoto) to create sfots4. sequencing identified the causal mutation as c4038u, predicting the amino acid change m781t in nsp2. a revertant was isolated in which a back mutation of u to c restored the wild-typ ...19989472615
a novel sialic acid binding site on factor h mediates serum resistance of sialylated neisseria gonorrhoeae.factor h (fh), a key alternative complement pathway regulator, is a cofactor for factor i-mediated cleavage of c3b. fh consists of 20 short consensus repeat (scr) domains. sialic acid binding domains have previously been localized to fh scrs 6-10 and 13. to examine fh binding on a sialylated microbial surface, we grew neisseria gonorrhoeae in the presence of 5'-cytidinemonophospho-n-acetylneuraminic acid, which sialylates lipooligosaccharide and converts to serum resistance gonococci previously ...19989480984
alphaviruses induce apoptosis in bcl-2-overexpressing cells: evidence for a caspase-mediated, proteolytic inactivation of bcl-2.bcl-2 oncogene expression plays a role in the establishment of persistent viral infection by blocking virus-induced apoptosis. this might be achieved by preventing virus-induced activation of caspase-3, an il-1beta-converting enzyme (ice)-like cysteine protease that has been implicated in the death effector phase of apoptosis. contrary to this model, we show that three cell types highly overexpressing functional bcl-2 displayed caspase-3 activation and underwent apoptosis in response to infectio ...19989482724
signal peptidase cleavage at the flavivirus c-prm junction: dependence on the viral ns2b-3 protease for efficient processing requires determinants in c, the signal peptide, and prm.signal peptidase cleavage at the c-prm junction in the flavivirus structural polyprotein is inefficient in the absence of the cytoplasmic viral protease, which catalyzes cleavage at the cooh terminus of the c protein. the signal peptidase cleavage occurs efficiently in circumstances where the c protein is deleted or if the viral protease complex is present. in this study, we used cdna of murray valley encephalitis virus (mve) to examine features of the structural polyprotein which allow this reg ...19989499070
chimeric measles viruses with a foreign envelope.measles virus (mv) and vesicular stomatitis virus (vsv) are both members of the mononegavirales but are only distantly related. we generated two genetically stable chimeric viruses. in mgv, the reading frames of the mv envelope glycoproteins h and f were substituted by a single reading frame encoding the vsv g glycoprotein; mg/fv is similar but encodes a g/f hybrid in which the vsv g cytoplasmic tail was replaced by that of mv f. in contrast to mg/fv, mgv virions do not contain the mv matrix (m) ...19989499071
a retention signal necessary and sufficient for endoplasmic reticulum localization maps to the transmembrane domain of hepatitis c virus glycoprotein e2.the hepatitis c virus (hcv) genome encodes two envelope glycoproteins (e1 and e2). these glycoproteins interact to formin a noncovalent heterodimeric complex which is retained in the endoplasmic reticulum (er). to identify whether e1 and/or e2 contains an er-targeting signal potentially involved in er retention of the e1-e2 complex, these proteins were expressed alone and their intracellular localization was studied. due to misfolding of e1 in the absence of e2, no conclusion on the localization ...19989499075
requirement for an aromatic amino acid or histidine at the n terminus of sindbis virus rna polymerase.the n terminal amino acid of nonstructural protein nsp4, the viral rna polymerase, is a tyrosine in all sequenced alphaviruses; this is a destabilizing amino acid for the n-end rule pathway and results in rapid degradation of nsp4 produced in infected cells or in reticulocyte lysates. we have constructed 11 mutants of sindbis virus bearing phe, ala, thr, cys, leu, met, asn, gln, glu, arg, or pro at the n terminus of nsp4. translation of rnas in reticulocyte lysates showed that cleavage at the ns ...19989499091
characterization of an autonomous subgenomic pestivirus rna replicon.as an initial approach to define the requirements for the replication of bovine viral diarrhea virus (bvdv), a member of the flaviviridae family with a positive-strand rna genome, full-length genomic and subgenomic rnas were originated by in vitro transcription of diverse bvdv cdna constructs and transfected into eucaryotic host cells. rna replication was measured either directly by an rnase protection method or by monitoring the synthesis of viral protein. when full-length bvdv crna was initial ...19989499097
characterization of defective viral rna produced during persistent infection of vero cells with murray valley encephalitis virus.defective interfering viral particles are readily produced in cell culture after a high multiplicity of infection with many animal rna viruses. due to defects that they carry in their genomes, their life cycle needs to be complemented by the helper functions provided by a parental virus which makes them both dependent on and competitive with the parental virus. in many instances, this may cause the abrogation of a lytic cycle of the parental virus, leading to a persistent infection. in this pape ...19989499109
effect of nitric oxide on poliovirus infection of two human cell lines.the role of nitric oxide after poliovirus infection of the human hela (carcinoma) and u937 (promonocytic) cell lines has been analyzed. both types of cells produced detectable levels of nitric oxide after poliovirus infection. however, this production was not sufficient to limit viral productivity. on the other hand, pretreatment with the nitric oxide donor glycerine trinitrate lengthened the course of poliovirus infection.19989499120
n-terminal protease of pestiviruses: identification of putative catalytic residues by site-directed mutagenesis.pestiviruses are the only members of the flaviviridae that encode a nonstructural protease at the n terminus of their polyproteins. this n-terminal protease (npro) cleaves itself off of the nascent polyprotein autocatalytically and thereby generates the n terminus of the adjacent viral capsid protein c. in previous reports, sequence similarities between npro and the catalytic residues of papain-like cysteine proteases were put forward. to test this hypothesis, substitutions of cysteine and histi ...19989499122
suppressors of cleavage-site mutations in the p62 envelope protein of semliki forest virus reveal dynamics in spike structure and function.the e2 spike glycoprotein of semliki forest virus is produced as a p62 precursor protein, which is cleaved by host proteases to its mature form, e2. cleavage is not necessary for particle formation or release but is necessary for infectivity. previous results had shown that phenotypic revertants of cleavage-deficient p62 mutants are generated, and here we show that these may contain second-site suppressor mutations in the vicinity of the cleavage site. these hot-spot sites were mutated to abolis ...19989525602
specific interactions between retrovirus env and gag proteins in rat neurons.in this work we have studied the intracellular localization properties of the gag and env proteins of moloney murine leukemia virus (mlv) and human immunodeficiency virus (hiv) in dorsal root ganglion (drg) neurons of rat. these neurons form thick bundles of axons, which facilitates protein localization studies by immunofluorescence analyses. when such neuron cultures were infected with recombinant semliki forest virus particles carrying the gag genes of either retrovirus, the expressed gag prot ...19989525603
role of actin microfilaments in black creek canal virus morphogenesis.we have investigated the involvement of cytoskeletal proteins in the morphogenesis of black creek canal virus (bccv), a new world hantavirus. immunofluorescent staining of bccv-infected cells revealed a filamentous pattern of virus antigen, the appearance of which was sensitive to treatment with cytochalasin d, an actin microfilament-depolymerizing drug. double immunofluorescence staining of bccv-infected vero cells with anti-bccv nucleocapsid (n) monoclonal antibody and phalloidin revealed a co ...19989525606
development of a chimeric sindbis virus with enhanced per os infection of aedes aegypti.the te/3'2j double subgenomic sindbis (dssin) viruses have been used to stably express genes in aedes aegypti nerve and salivary gland tissues. however, because these viruses inefficiently infect ae. aegypti when administered by the per os route, te/3'2j viruses must be intrathoracically inoculated into the mosquitoes to infect these tissues. a malaysian sindbis (sin) virus isolate (mre16) does efficiently infect ae. aegypti midgut tissues after ingestion, and approximately 95% of these mosquito ...19989527919
functional role of hepatitis c virus chimeric glycoproteins in the infectivity of pseudotyped virus.the putative envelope glycoproteins of hepatitis c virus (hcv) likely play an important role in the initiation of viral infection. available information suggests that the genomic regions encoding the putative envelope glycoproteins, when expressed as recombinant proteins in mammalian cells, largely accumulate in the endoplasmic reticulum. in this study, genomic regions which include the putative ectodomain of the e1 (amino acids 174 to 359) and e2 (amino acids 371 to 742) glycoproteins were appe ...19989557633
coding sequences enhance internal initiation of translation by hepatitis a virus rna in vitro.hepatitis a virus (hav), unlike other picornaviruses, has a slow-growth phenotype in permissive cell lines and in general does not induce host cell cytopathology. although there are no published reports of productive infection of hela cells by hav, hav rna appears to be readily translated in hela cells when transcribed by t7 rna polymerase provided by a recombinant vaccinia virus. the 5' noncoding region of hav was fused to poliovirus (pv) coding sequences to determine the effect on translation ...19989557637
foot-and-mouth disease virus virulent for cattle utilizes the integrin alpha(v)beta3 as its receptor.adsorption and plaque formation of foot-and-mouth disease virus (fmdv) serotype a12 are inhibited by antibodies to the integrin alpha(v)beta3 (a. berinstein et al., j. virol. 69:2664-2666, 1995). a human cell line, k562, which does not normally express alpha(v)beta3 cannot replicate this serotype unless cells are transfected with cdnas encoding this integrin (k562-alpha(v)beta3 cells). in contrast, we found that a tissue culture-propagated fmdv, type o1bfs, was able to replicate in nontransfecte ...19989557639
mutations in rotavirus nonstructural glycoprotein nsp4 are associated with altered virus virulence.rotaviruses are major pathogens causing life-threatening dehydrating gastroenteritis in children and animals. one of the nonstructural proteins, nsp4 (encoded by gene 10), is a transmembrane, endoplasmic reticulum-specific glycoprotein. recently, our laboratory has shown that nsp4 causes diarrhea in 6- to 10-day-old mice by functioning as an enterotoxin. to confirm the role of nsp4 in rotavirus pathogenesis, we sequenced gene 10 from two pairs of virulent and attenuated porcine rotaviruses, the ...19989557647
collaboration of antibody and inflammation in clearance of rabies virus from the central nervous system.to investigate the involvement of various cellular and humoral aspects of immunity in the clearance of rabies virus from the central nervous system, (cns), we studied the development of clinical signs and virus clearance from the cns in knockout mice lacking either b and t cells, cd8+ cytotoxic t cells, b cells, alpha/beta interferon (ifn-alpha/beta) receptors, ifn-gamma receptors, or complement components c3 and c4. following intranasal infection with the attenuated rabies virus cvs-f3, normal ...19989557653
the transmembrane domains of sindbis virus envelope glycoproteins induce cell death.sindbis virus, the prototype alphavirus, kills cells by inducing apoptosis. to investigate potential mechanisms by which sindbis virus induces apoptosis, we examined whether specific viral gene products were able to induce cell death. genes encoding the three structural proteins--capsid, the precursor e1 (6k plus e1), and the precursor e2 (p62 or e3 plus e2)--were cotransfected with a beta-galactosidase reporter plasmid in transient-transfection assays in rat prostate adenocarcinoma at3 cells. c ...19989557679
two types of virus-related particles are found during transmissible gastroenteritis virus morphogenesis.the intracellular assembly of the transmissible gastroenteritis coronavirus (tgev) was studied in infected swine testis (st) cells at different postinfection times by using ultrathin sections of conventionally embedded infected cells, freeze-substitution, and methods for detecting viral proteins and rna at the electron microscopy level. this ultrastructural analysis was focused on the identification of the different viral components that assemble in infected cells, in particular the spherical, p ...19989557690
fus-1, a ph shift mutant of semliki forest virus, acts by altering spike subunit interactions via a mutation in the e2 subunit.semliki forest virus (sfv), an enveloped alphavirus, is a well-characterized paradigm for viruses that infect cells via endocytic uptake and low-ph-triggered fusion. the sfv spike protein is composed of a dimer of e1 and e2 transmembrane subunits, which dissociate upon exposure to low ph, liberating e2 and the fusogenic e1 subunit to undergo independent conformational changes. sfv fusion and infection are blocked by agents such as ammonium chloride, which act by raising the ph in the endosome an ...19989557718
deletion analysis of a defective interfering semliki forest virus rna genome defines a region in the nsp2 sequence that is required for efficient packaging of the genome into virus particles.the 1,244-nucleotide genome of semliki forest virus (sfv) defective interfering (di) rna 19 (di-19) is coterminal with the infectious genome and contains two major deletions. one deletion removes the end of the nsp1 gene and the beginning of the nsp2 gene, and the other removes the end of the nsp2 gene, the nsp3 and nsp4 genes, and all of the structural protein genes (m. thomson and n. j. dimmock, virology 199:354-365, 1994). like all di sfv rnas, di-19 contains three regions that are conserved. ...19989557722
a 68-nucleotide sequence within the 3' noncoding region of simian hemorrhagic fever virus negative-strand rna binds to four ma104 cell proteins.the 3' noncoding region (ncr) of the negative-strand rna [3'(-)ncr rna] of the arterivirus simian hemorrhagic fever virus (shfv) is 209 nucleotides (nt) in length. since this 3' region, designated 3'(-)209, is the site of initiation of full-length positive-strand rna and is the template for the synthesis of the 5' leader sequence, which is found on both full-length and subgenomic mrnas, it is likely to contain cis-acting signals for rna synthesis and to interact with cellular and viral proteins ...19989557724
functions of conserved motifs in the rna-dependent rna polymerase of a yeast double-stranded rna virus.at least eight conserved motifs are visible in the totivirus rna-dependent rna polymerase (rdrp). we have systematically altered each of these in the saccharomyces cerevisiae double-stranded rna virus scvl1 by substituting the conserved motifs from a giardiavirus. the results help define the conserved regions of the rdrp involved in polymerase function and those essential for other reasons.19989557735
the rubella virus nonstructural protease requires divalent cations for activity and functions in trans.the rubella virus (rub) nonstructural (ns) protease is a papain-like cysteine protease (pcp) located in the ns-protein open reading frame (nsp-orf) that cleaves the nsp-orf translation product at a single site to produce two products, p150 (the n-terminal product) and p90 (the c-terminal product). the rub ns protease was found not to function following translation in vitro in a standard rabbit reticulocyte lysate system, although all of the other viral pcps do so. however, in the presence of div ...19989557742
[regulation of expression of human fibroblast interferon gene by human leukocyte interferon and cytopathogenic alpha-virus]. 19989559136
mutations in the sindbis virus capsid gene can partially suppress mutations in the cytoplasmic domain of the virus e2 glycoprotein spike.assembly and budding of alphaviruses are postulated to occur by protein-protein interactions between sites on the cytoplasmic domain of the transmembranal envelope e2 glycoprotein and on the surface of the nucleocapsid protein subunits. genetic data to support this model have been obtained by isolating revertants of two slow-growth mutants of sindbis virus and analyzing the sequences of the genes encoding their structural proteins. the slow-growth phenotypes of the mutants were previously shown ...19989568036
antibody-mediated neutralization of human rhinovirus 14 explored by means of cryoelectron microscopy and x-ray crystallography of virus-fab complexes.the structures of three different human rhinovirus 14 (hrv14)-fab complexes have been explored with x-ray crystallography and cryoelectron microscopy procedures. all three antibodies bind to the nim-ia site of hrv14, which is the beta-b-beta-c loop of the viral capsid protein vp1. two antibodies, fab17-ia (fab17) and fab12-ia (fab12), bind bivalently to the virion surface and strongly neutralize viral infectivity whereas fab1-ia (fab1) strongly aggregates and weakly neutralizes virions. the stru ...19989573224
evaluation of the galalpha1-3gal epitope as a host modification factor eliciting natural humoral immunity to enveloped viruses.human sera contain high levels of natural antibody (ab) to galalpha1-3gal, a terminal glycosidic structure expressed on the surface of cells of mammals other than old world primates. incorporation of this determinant onto retroviral membranes by passage of viruses in cells encoding alpha-1-3-galactosyltransferase (gt) renders retroviruses sensitive to lysis by natural ab and complement in normal human serum (nhs). plasma membrane-budding viruses representing four additional virus groups were exa ...19989573228
infectious bovine viral diarrhea virus (strain nadl) rna from stable cdna clones: a cellular insert determines ns3 production and viral cytopathogenicity.bovine viral diarrhea virus (bvdv), strain nadl, was originally isolated from an animal with fatal mucosal disease. this isolate is cytopathic in cell culture and produces two forms of ns3-containing proteins: uncleaved ns2-3 and mature ns3. for bvdv nadl, the production of ns3, a characteristic of cytopathic bvdv strains, is believed to be a consequence of an in-frame insertion of a 270-nucleotide cellular mrna sequence (called cins) in the ns2 coding region. in this study, we constructed a sta ...19989573238
transmissible gastroenteritis coronavirus induces programmed cell death in infected cells through a caspase-dependent pathway.in this report, we show that apoptosis (or programmed cell death) is induced in different cell lines infected with a coronavirus, the porcine transmissible gastroenteritis virus (tgev). kinetic analysis of internucleosomal dna cleavage by agarose gel electrophoresis and flow cytometry or cytometric monitoring of the mitochondrial transmembrane potential showed that, for st cells infected with tgev, the first overt signs of apoptosis appeared from 10 to 12 h postinfection on. they preceded morpho ...19989573259
induction of protective immunity against japanese encephalitis in mice by immunization with a plasmid encoding japanese encephalitis virus premembrane and envelope genes.a dna vaccine plasmid containing the japanese encephalitis (je) virus premembrane (prm) and envelope (e) genes (designated pcdna3jeme) was evaluated for immunogenicity and protective efficacy in mice. two immunizations of 4-week-old female icr mice with pcdna3jeme by intramuscular or intradermal injections at a dose of 10 or 100 microg per mouse elicited neutralizing (neut) antibodies at titers of 1:10 to 1:20 (90% plaque reduction), and all immunized mice survived a challenge with 10,000 50% le ...19989573260
alphavirus-specific cytotoxic t lymphocytes recognize a cross-reactive epitope from the capsid protein and can eliminate virus from persistently infected macrophages.persistent alphavirus infections in synovial and neural tissues are believed to be associated with chronic arthritis and encephalitis, respectively, and represent likely targets for cd8+ alphabeta cytotoxic t lymphocytes (ctl). here we show that the capsid protein is a dominant target for alphavirus-specific ctl in balb/c mice and that capsid-specific ctl from these mice recognize an h-2kd restricted epitope, qysggrfti. this epitope lies in the highly conserved region of the capsid protein, and ...19989573286
purification of a multipotent antideath activity from bovine liver and its identification as arginase: nitric oxide-independent inhibition of neuronal apoptosis.catalase is an antioxidant enzyme that has been shown to inhibit apoptotic or necrotic neuronal death induced by hydrogen peroxide. we report the purification of a contaminating antiapoptotic activity from a commercial bovine liver catalase preparation by following its ability to inhibit apoptosis when applied extracellularly in multiple death paradigms. the antiapoptotic activity was identified by protein microsequencing as arginase, a urea cycle and nitric oxide synthase-regulating enzyme, and ...19989592089
engineered resistance in aedes aegypti to a west african and a south american strain of yellow fever virus.double subgenomic sindbis (dssin) viruses were engineered to transduce mosquito cells with antisense rna derived either from the premembrane (prm) or polymerase (ns5) coding regions of the 17d vaccine strain of yellow fever virus (yfv). aedes albopictus c6/36 cells were infected at high multiplicities of infection (moi) with each dssin virus. forty-eight hours later, the transduced cells were challenged with an moi of 0.1 of the asibi strain of yfv. at 72-hr postchallenge, the cells were assayed ...19989598458
the serine proteinase inhibitor (serpin) plasminogen activation inhibitor type 2 protects against viral cytopathic effects by constitutive interferon alpha/beta priming.the serine proteinase inhibitor (serpin) plasminogen activator inhibitor type 2 (pai-2) is well characterized as an inhibitor of extracellular urokinase-type plasminogen activator. here we show that intracellular, but not extracellular, pai-2 protected cells from the rapid cytopathic effects of alphavirus infection. this protection did not appear to be related to an effect on apoptosis but was associated with a pai-2-mediated induction of constitutive low-level interferon (ifn)-alpha/beta produc ...19989607921
genes required for replication of the 15.5-kilobase rna genome of a plant closterovirus.a full-length cdna clone of beet yellows closterovirus (byv) was engineered and used to map functions involved in the replication of the viral rna genome and subgenomic rna formation. among 10 open reading frames (orfs) present in byv, orfs 1a and 1b suffice for rna replication and transcription. the proteins encoded in these orfs harbor putative methyltransferase, rna helicase, and rna polymerase domains common to sindbis virus-like viruses and a large interdomain region that is unique to clost ...19989621048
antiapoptotic activity of the herpesvirus saimiri-encoded bcl-2 homolog: stabilization of mitochondria and inhibition of caspase-3-like activity.viruses have evolved different strategies to interfere with host cell apoptosis. herpesvirus saimiri (hvs) and other lymphotropic herpesviruses code for proteins that are homologous to the cellular antiapoptotic bcl-2. in this study hvs-bcl-2 was stably expressed in the human leukemia cell line jurkat and in the murine t-cell hybridoma do to assess its antiapoptotic spectrum and to gain further insight into its mode of action. hvs- bcl-2 prevented apoptosis that occurs as a result of a disturban ...19989621051
encapsidation of the flavivirus kunjin replicon rna by using a complementation system providing kunjin virus structural proteins in trans.kunjin virus (kun) replicon rna was encapsidated by a procedure involving two consecutive electroporations of bhk-21 cells, first with kun replicon rna c20dxrep (with prme and most of c deleted) and about 24 h later with a recombinant semliki forest virus (sfv) replicon rna(s) expressing kun structural proteins. the presence of kun replicon rna in encapsidated particles was demonstrated by its amplification and expression in newly infected bhk-21 cells, detected by northern blotting with a kun-s ...19989621059
his...asp catalytic dyad of ribonuclease a: structure and function of the wild-type, d121n, and d121a enzymes.the side chains of histidine and aspartate residues form a hydrogen bond in the active sites of many enzymes. in serine proteases, the his...asp hydrogen bond of the catalytic triad is known to contribute greatly to catalysis, perhaps via the formation of a low-barrier hydrogen bond. in bovine pancreatic ribonuclease a (rnase a), the his...asp dyad is composed of his119 and asp121. previously, site-directed mutagenesis was used to show that his119 has a fundamental role, to act as an acid during ...19989636030
suppression of steady-state, but not stimulus-induced nf-kappab activity inhibits alphavirus-induced apoptosis.recent studies have established cell type- specific, proapoptotic, or antiapoptotic functions for the transcription factor nf-kappab. in each of these studies, inhibitors of nf-kappab activity have been present before the apoptotic stimulus, and so the role of stimulus- induced nf-kappab activation in enhancing or inhibiting survival could not be directly assessed. sindbis virus, an alphavirus, induces nf-kappab activation and apoptosis in cultured cell lines. to address whether sindbis virus- i ...19989647642
template-dependent initiation of sindbis virus rna replication in vitro.recent insights into the early events in sindbis virus rna replication suggest a requirement for either the p123 or p23 polyprotein, as well as mature nsp4, the rna-dependent rna polymerase, for initiation of minus-strand rna synthesis. based on this observation, we have succeeded in reconstituting an in vitro system for template-dependent initiation of sin rna replication. extracts were isolated from cells infected with vaccinia virus recombinants expressing various sin proteins and assayed by ...19989658098
steady-state plasma membrane expression of human cytomegalovirus gb is determined by the phosphorylation state of ser900.human cytomegalovirus (hcmv) infection of an astrocytoma cell line (u373) or human fibroblast (hf) cells results in a differential cell distribution of the major envelope glycoprotein gb (ul55). this 906-amino-acid type i glycoprotein contains an extracellular domain with a signal sequence, a transmembrane domain, and a 135-amino-acid cytoplasmic tail with a consensus casein kinase ii (ckii) site located at ser900. since phosphorylation of proteins in the secretory pathway is an important determ ...19989658112
coronavirus particle assembly: primary structure requirements of the membrane protein.coronavirus-like particles morphologically similar to normal virions are assembled when genes encoding the viral membrane proteins m and e are coexpressed in eukaryotic cells. using this envelope assembly assay, we have studied the primary sequence requirements for particle formation of the mouse hepatitis virus (mhv) m protein, the major protein of the coronavirion membrane. our results show that each of the different domains of the protein is important. mutations (deletions, insertions, point ...19989658133
recombinant sindbis viruses expressing a cytotoxic t-lymphocyte epitope of a malaria parasite or of influenza virus elicit protection against the corresponding pathogen in mice.subcutaneous administration in mice of recombinant sindbis viruses expressing a class i major histocompatibility complex-restricted 9-mer epitope of the plasmodium yoelii circumsporozoite protein or the nucleoprotein of influenza virus induces a large epitope-specific cd8(+) t-cell response. this immunization also elicits a high degree of protection against infection with malaria or influenza a virus.19989658144
rapid, high level protein production using dna-based semliki forest virus vectors.semliki forest virus (sfv) vectors can be produced faster, and have a wider host range, than baculovirus vectors. however, the original sfv system requires in vitro manipulation of rna. we have generated a system that is wholly dna-based. both the replicon vector, encoding sfv polymerase and the protein of interest, and the helper vector, encoding viral structural proteins, were modified so that expression was rna polymerase ii-dependent. transfection of the modified replicon plasmid alone gener ...19989660762
inducible nitric oxide synthase and nitrotyrosine are found in monocytes/macrophages and/or astrocytes in acute, but not in chronic, multiple sclerosis.we have examined the localization of inducible nitric oxide synthase (inos) and nitrotyrosine (the product of nitration of tyrosine by peroxynitrite, a highly reactive derivative of nitric oxide [no]) in demyelinating lesions from (i) two young adult patients with acute multiple sclerosis (ms), (ii) a child with ms (consistent with diffuse sclerosis), and (iii) five adult patients with chronic ms. previous reports have suggested a possible correlation between inos, peroxynitrite, related nitroge ...19989665945
acute infection of sindbis virus induces phosphorylation and intracellular translocation of small heat shock protein hsp27 and activation of p38 map kinase signaling pathway.in general, viral infection is supposed to induce stress responses in the host cell. however, very few detailed observations about virus-induced stress responses have been reported. here we investigated specific stress responses in vero cells infected with sindbis virus (sv), a single-stranded rna virus, acute infection with which is known to cause apoptotic cell death in the host cells. prior to the onset of apoptosis, p38 mitogen-activated protein kinase (mapk) and c-jun nh2-terminal kinases ( ...19989875220
broad-spectrum antiviral activity and mechanism of antiviral action of the fluoroquinolone derivative k-12.the fluoroquinolone derivatives have been shown to inhibit human immunodeficiency virus (hiv) replication at the transcriptional level. we confirmed the anti-hiv activity of the most potent congener, 8-difluoromethoxy-1-ethyl-6-fluoro-1,4-dihydro-7-[4-(2- methoxyphenyl)-1-piperazinyl]-4-quinolone-3-carboxylic acid (k-12), in both acutely and chronically infected cells. k-12 was active against different strains of hiv-1 (including azt- and ritonavir-resistant hiv-1 strains), hiv-2 and simian immu ...19989875393
recombination of nonreplicative rna precursors of sindbis virus in infected cells overexpressing murine-inducible nitric oxide synthase.the sindbis virus-based sinrep5 expression system is one of the most efficient vectors for gene transfer leading to fast and high expression of the gene of interest. this system was used to transfect vascular endothelial and smooth muscle cells using murine inducible nitric oxide synthase (minos) as a reporter gene. infection of both cell types leads to high expression levels of minos. in addition, the harvested supernatant of these infected cells was used for further rounds of infections, demon ...19989878569
inhibition versus induction of apoptosis by proteasome inhibitors depends on concentration.we previously established that nf-kappab dna binding activity is required for sindbis virus (sv)-induced apoptosis. to investigate whether sv induces nuclear translocation of nf-kappab via the proteasomal degradation pathway, we utilized mg132, a peptide aldehyde inhibitor of the catalytic subunit of the proteasome. 20 microm mg132 completely abrogated sv-induced nf-kappab nuclear activity at early time points after infection. parallel measures of cell viability 48 h after sv infection revealed ...199810200512
expression of foreign proteins by poliovirus polyprotein fusion: analysis of genetic stability reveals rapid deletions and formation of cardioviruslike open reading frames.using a strategy developed by r. andino, d. silvera, s. d. suggett, p. i. achacoso, c. j. miller, d. baltimore, and m. b. feinberg (science 265:1448-1451, 1994), we constructed recombinant polioviruses by fusing the open reading frame (orf) of the green fluorescent protein gene (gfp) of aequorea victoria or the gag gene (encoding p17-p24) of human immunodeficiency virus type 1 (hiv-1) to the n terminus of the poliovirus polyprotein. all poliovirus expression vectors constructed by us and those o ...19989420196
the papillomavirus minor capsid protein, l2, induces localization of the major capsid protein, l1, and the viral transcription/replication protein, e2, to pml oncogenic domains.we have used immunofluorescent staining and confocal microscopy to examine the subcellular localization of structural and nonstructural bovine papillomavirus (bpv) proteins in cultured cells that produce infectious virions. when expressed separately, l1, the major capsid protein, showed a diffuse nuclear distribution while l2, the minor capsid protein, was found to localize to punctate nuclear regions identified as promonocytic leukemia protein (pml) oncogenic domains (pods). coexpression of l1 ...19989420209
dna immunization with japanese encephalitis virus nonstructural protein ns1 elicits protective immunity in mice.japanese encephalitis virus (jev), a mosquito-borne flavivirus, is a zoonotic pathogen that is prevalent in some southeast asian countries and causes acute encephalitis in humans. to evaluate the potential application of gene immunization to jev infection, we characterized the immune responses from mice intramuscularly injected with plasmid dna encoding jev glycoproteins, including the precursor membrane (prm) plus envelope (e) proteins and the nonstructural protein ns1. when injected with the p ...19989420215
infectious transcripts from cloned genome-length cdna of porcine reproductive and respiratory syndrome virus.the 5'-terminal end of the genomic rna of the lelystad virus isolate (lv) of porcine reproductive and respiratory syndrome virus was determined. to construct full-length cdna clones, the 5'-terminal sequence was ligated to cdna clones covering the complete genome of lv. when rna that was transcribed in vitro from these full-length cdna clones was transfected into bhk-21 cells, infectious lv was produced and secreted. the virus was rescued by passage to porcine alveolar lung macrophages or cl2621 ...19989420236
sindbis virus induces apoptosis through a caspase-dependent, crma-sensitive pathway.sindbis virus infection of cultured cells and of neurons in mouse brains leads to programmed cell death exhibiting the classical characteristics of apoptosis. although the mechanism by which sindbis virus activates the cell suicide program is not known, we demonstrate here that sindbis virus activates caspases, a family of death-inducing proteases, resulting in cleavage of several cellular substrates. to study the role of caspases in virus-induced apoptosis, we determined the effects of specific ...19989420245
a defective interference-like phenomenon of human hepatitis b virus in chronic carriers.defective interfering (di) particles have been found in many rna and dna viruses of bacteria, plants, and animals since their first discovery in influenza virus. however, this fundamental phenomenon has not been demonstrated in human natural infections. using a new approach, here we provide the first experimental evidence for the existence of di-like viruses in human chronic carriers of hepatitis b virus (hbv). functional characterization of naturally occurring core internal deletion (cid) varia ...19989420261
effects of defined mutations in the 5' nontranslated region of rubella virus genomic rna on virus viability and macromolecule synthesis.the 5' end of the genomic rna of rubella virus (rub) contains a 14-nucleotide (nt) single-stranded leader (ss-leader) followed by a stem-and-loop structure [5'(+)sl] (nt 15 to 65), the complement of which at the 3' end of the minus-strand rna [3'(-)sl] has been proposed to function as a promoter for synthesis of genomic plus strands. a second intriguing feature of the 5' end of the rub genomic rna is the presence of a short (17 codons) open reading frame (orf) located between nt 3 and 54; the or ...19989420269
apoptosis in the mouse central nervous system in response to infection with mouse-neurovirulent dengue viruses.apoptosis has been suggested as a mechanism by which dengue (den) virus infection may cause neuronal cell death (p. desprès, m. flamand, p.-e. ceccaldi, and v. deubel, j. virol. 70:4090-4096, 1996). in this study, we investigated whether apoptotic cell death occurred in the central nervous system (cns) of neonatal mice inoculated intracerebrally with den virus. we showed that serial passage of a wild-type human isolate of den virus in mouse brains selected highly neurovirulent variants which rep ...19989420294
identification of the leader-body junctions for the viral subgenomic mrnas and organization of the simian hemorrhagic fever virus genome: evidence for gene duplication during arterivirus evolution.simian hemorrhagic fever virus (shfv) was recently reclassified and assigned to the new virus family arteriviridae. during replication, arteriviruses produce a 3' coterminal, nested set of subgenomic mrnas (sgrnas). these sgrnas arise by discontinuous transcription, and each contains a 5' leader sequence which is joined to the body of the mrna through a conserved junction sequence. only the 5'-most open reading frame (orf) is believed to be transcribed from each sgrna. the shfv genome encodes ni ...19989420301
a single point mutation controls the cholesterol dependence of semliki forest virus entry and exit.membrane fusion and budding are key steps in the life cycle of all enveloped viruses. semliki forest virus (sfv) is an enveloped alphavirus that requires cellular membrane cholesterol for both membrane fusion and efficient exit of progeny virus from infected cells. we selected an sfv mutant, srf-3, that was strikingly independent of cholesterol for growth. this phenotype was conferred by a single amino acid change in the e1 spike protein subunit, proline 226 to serine, that increased the cholest ...19989425157
[the relationship between protein synthesis of sindbis virus and host cytoskeletons].in our experiments, protein synthesis of host cells were inhibited quickly at the early stage of infection by sindbis virus. polysome and mrna of host cell fell off from cytoskeletons, whereas virus rna bound up. we also found it was via 3'-terminal that virus rna bound with cytoskeleton. after studying on the virus nonstructural proteins, we found the synthesis and processing of virus protein in vitro were far slowly than in vivo, and most of proteins were premature. so, the cytoskeletons may p ...199812016969
directed changes in the number of double-stranded rna genomic segments in bacteriophage phi6.bacteriophage phi6 has a genome of three segments of double-stranded rna. the segments are designated s, m, and l. each segment has a unique packaging site, pac, near the 5' end of the plus strand. the plus strands of the segments are normally packaged in the order s, m, l. chimeras of segment m and s in which segment m is at the 5' end of the plus strand can be stably incorporated into the virion; however, an independent segment s must be included along with normal segment l, even if it contain ...19989520468
adding the third dimension to virus life cycles: three-dimensional reconstruction of icosahedral viruses from cryo-electron micrographs.viruses are cellular parasites. the linkage between viral and host functions makes the study of a viral life cycle an important key to cellular functions. a deeper understanding of many aspects of viral life cycles has emerged from coordinated molecular and structural studies carried out with a wide range of viral pathogens. structural studies of viruses by means of cryo-electron microscopy and three-dimensional image reconstruction methods have grown explosively in the last decade. here we revi ...199910585969
vaccines timeline. interview by philip cohen. 199910559053
construction of recombinant sindbis-based expression vectors for the study of hcv genes and their products.there are currently no methods for propogating hepatitis c virus (hcv) in culture useful for the analysis of viral proteins. therefore, we have utilized sindbis virus-based vectors to express and study hcv genes and their products.199921374397
non-viral amplification systems for gene transfer: vectors based on alphaviruses.non-viral self-replicating vectors based on defective viral genomes have been developed for a number of different alphaviruses including semliki forest virus (sfv), sindbis virus (sin) and venezuelan equine encephalitis virus (vee). these vectors can be used for gene delivery as naked rna or dna. recombinant alphavirus rna can be synthesized in vitro from plasmids containing the alphavirus replicon under the control of a prokaryotic promoter such as sp6 or t7. these self-replicating rnas have be ...199911715947
use of vegetable-derived tween 80 for virus inactivation by solvent/detergent treatment. 199910652181
[complete nucleotide sequence of the nonstructural gene of alphavirus yn87448 strain isolated in china and its relationship to other sindbis viruses].to determine the complete nucleotide sequence of the nonstructural gene of yn87448 virus stain which was firstly isolated from a female patient with fever in yunnan province in 1986, and identified as a member of alphavirus by the serological method.199912759966
virus reduction in the preparation of intravenous immune globulin: in vitro experiments.while immune globulins for intravenous administration (igiv) have an excellent record with respect to virus safety, concern regarding these preparations has been raised by reports of transmission of hepatitis c virus (hcv) to patients treated with igiv and the presence of genetic material for hcv in igiv preparations.199910204586
packaging of aednv-gfp transducing virus by expression of densovirus structural proteins from a sindbis virus expression system.genetic recombination resulting in the production of wild-type infectious virus is an obstacle in the current system for producing densovirus transducing particles. in order to eliminate this problem, a double subgenomic sindbis virus (te/3'2j/vp) was engineered that expresses the structural proteins (vps) of aedes densonucleosis virus (aednv) from the second subgenomic promoter. expression of aednv vps from te/3'2j/vp was confirmed by northern analysis of rna from infected c6/36 (aedes albopict ...199910208920
binding of tumour necrosis factor-alpha (tnf-alpha) to tnf-ri induces caspase(s)-dependent apoptosis in human cholangiocarcinoma cell lines.cholangiocarcinoma (cca), a tumour of the bile duct epithelium, occurs with a higher incidence in south-east asian countries than in europe and north america. the prognosis is poor, due to the unavailability of early diagnosis and the tumours being relatively resistant to chemotherapy. in the present study one of the fatal routes of this tumour was studied. this death was stimulated by tnf-alpha. tnf-alpha at a concentration of 760 pg/ml and 100 pg/ml in the presence of 1 microgram/ml actinomyci ...199910209503
endoprotease pace4 is ca2+-dependent and temperature-sensitive and can partly rescue the phenotype of a furin-deficient cell strain.pace4 is a member of the eukaryotic subtilisin-like endoprotease family. the expression of human pace4 in rpe.40 cells (furin-null mutants derived from chinese hamster ovary k1 cells) resulted in the rescue of a number of wild-type characteristics, including sensitivity to sindbis virus and the ability to process the low-density-lipoprotein receptor-related protein. expression of pace4 in these cells failed to restore wild-type sensitivity to pseudomonas exotoxin a. co-expression of human pace4 ...199910215603
seroprevalence of dengue, chikungunya and sindbis virus infections in german aid workers.vector-borne virus infections were studied in 670 german overseas aid workers who had spent an average of 37.7 months in tropical areas of africa and asia. antibodies to dengue viruses (den) were detected by indirect immunofluorescence assay in 43/670 (6.4%) aid workers. of these 43, 41 (95.3%) were also positive for antibodies to dengue by haemagglutination inhibition assay. the highest seroprevalence was in aid workers returning from thailand (19.4%), benin (14.8%) and burkina faso (9.2%). ant ...199910219635
decreased intracellular superoxide levels activate sindbis virus-induced apoptosis.infection of many cultured cell types with sindbis virus (sv), an alphavirus, triggers apoptosis through a commonly utilized caspase activation pathway. however, the upstream signals by which sv activates downstream apoptotic effectors, including caspases, remain unclear. here we report that in at-3 prostate carcinoma cells, sv infection decreases superoxide (o-2) levels within minutes of infection as monitored by an aconitase activity assay. this sv-induced decrease in o-2 levels appears to act ...199910224137
genetic interaction of flavivirus nonstructural proteins ns1 and ns4a as a determinant of replicase function.nonstructural protein 1 (ns1) of yellow fever virus (yf) is a glycoprotein localized to extracytoplasmic compartments within infected cells. we have previously shown that ns1 can be supplied in trans and is required for viral rna replication, a process thought to occur in membrane-bound cytoplasmic complexes. here we report that the ns1 gene from a related virus, dengue virus (den), is unable to function in the process of yf rna replication. this virus-specific incompatibility leads to a lack of ...199910233920
mutational analysis, using a full-length rubella virus cdna clone, of rubella virus e1 transmembrane and cytoplasmic domains required for virus release.we report on the construction of a full-length cdna clone, pbrm33, derived from wild-type rubella virus m33 strain. the rna transcripts synthesized in vitro from pbrm33 are highly infectious, and the viruses produced retain the phenotypic characteristics of the parental m33 virus in growth rate and plaque size. this cdna clone was used to study the role of e1 transmembrane and cytoplasmic domains in virus assembly by site-directed mutagenesis. three different alanine substitutions were introduce ...199910233921
dengue virus structural differences that correlate with pathogenesis.the understanding of dengue virus pathogenesis has been hampered by the lack of in vitro and in vivo models of disease. the study of viral factors involved in the production of severe dengue, dengue hemorrhagic fever (dhf), versus the more common dengue fever (df), have been limited to indirect clinical and epidemiologic associations. in an effort to identify viral determinants of dhf, we have developed a method for comparing dengue type 2 genomes (reverse transcriptase pcr in six fragments) dir ...199910233934
human cd46 enhances nitric oxide production in mouse macrophages in response to measles virus infection in the presence of gamma interferon: dependence on the cd46 cytoplasmic domains.cd46 is a transmembrane complement regulatory protein widely expressed on nucleated human cells. laboratory-adapted strains of measles virus (mv) bind to the extracellular domains of cd46 to enter human cells. the cytoplasmic portion of cd46 consists of a common juxtamembrane region and different distal sequences called cyt1 and cyt2. the biological functions of these cytoplasmic sequences are unknown. in this study, we show that expression of human cd46 with the cyt1 cytoplasmic domain in mouse ...199910233938
characterization of a chinese hamster ovary cell line developed by retroviral insertional mutagenesis that is resistant to sindbis virus infection.the alphavirus sindbis virus (sv) has a wide host range and infects many types of cultured cells in vitro. the outcome of infection is dependent on the strain of virus used for infection and the properties of the cells infected. to identify cellular determinants of susceptibility to sv infection we mutagenized chinese hamster ovary (cho) cells by retroviral insertion with a vector containing the neomycin resistance gene that allowed selection for integration into transcriptionally active genes. ...199910233953
oligomerization within virions and subcellular localization of human immunodeficiency virus type 1 integrase.previous biochemical and genetic evidence indicated that the functional form of retroviral integrase protein (in) is a multimer. a direct demonstration of in oligomerization during the infectious cycle was, however, missing, due to the absence of a sensitive detection method. we describe here the generation of infectious human immunodeficiency virus type 1 (hiv-1) viral clones carrying in protein tagged with highly antigenic epitopes. in this setting, we could readily visualize in both in produc ...199910233971
infection of primary cultures of human kupffer cells by dengue virus: no viral progeny synthesis, but cytokine production is evident.we investigated the ability of dengue virus to invade human primary kupffer cells and to complete its life cycle. the virus effectively penetrated kupffer cells, but the infection did not result in any viral progeny. dengue virus-replicating kupffer cells underwent apoptosis and were cleared by phagocytosis. infected kupffer cells produced soluble mediators that could intervene in dengue virus pathogenesis.199910233989
reducing cytotoxicity induced by sindbis viral vectors.sindbis virus has been recognized as a potentially useful virus vector for gene therapy. in an effort to improve its utility and provide cell-targeting capability to gene therapy vectors, we recently developed sindbis virus vectors possessing chimeric envelopes with cell-specific targeting ability [k. ohno et al. nature biotechnol 15:763-767, 1997; k. sawai et al. biochem biophys res commun 248:315-323, 1998]. however, a residual problem associated with sindbis virus vectors is the apoptotic eff ...199910329021
mechanisms of t-cell activation by human t-cell lymphotropic virus type i.the interactions between human t-cell lymphotropic virus type i (htlv-i) and the cellular immune system can be divided into viral interference with functions of the infected host t cell and the subsequent interactions between the infected t cell and the cellular immune system. htlv-i-mediated activation of the infected host t cell is induced primarily by the viral protein tax, which influences transcriptional activation, signal transduction pathways, cell cycle control, and apoptosis. these prop ...199910357853
recombinant semliki forest virus and sindbis virus efficiently infect neurons in hippocampal slice cultures.gene transfer into nervous tissue is a powerful tool for the analysis of gene function. by using a rat hippocampal slice culture preparation, we show here that semliki forest virus (sfv) and sindbis virus (sin) vectors are useful for the effective infection of neurons. the stratum pyramidale and/or the granular cell layer were injected with recombinant virus encoding beta-galactosidase (lacz) or green fluorescent protein (gfp). by using low concentrations of injected sfv-lacz or sin-lacz, we det ...199910359835
the african swine fever virus prenyltransferase is an integral membrane trans-geranylgeranyl-diphosphate synthase.in a previous study, it was shown that the protein encoded by the gene b318l of african swine fever virus (asfv) is a trans-prenyltransferase that catalyzes in vitro the condensation of farnesyl diphosphate and isopentenyl diphosphate to synthesize geranylgeranyl diphosphate and longer chain prenyl diphosphates (alejo, a., yáñez, r. j., rodríguez, j. m., viñuela, e., and salas, m. l. (1997) j. biol. chem. 272, 9417-9423). to investigate the in vivo function of the viral enzyme, we have determine ...199910364254
characterization of an equine arteritis virus replicase mutant defective in subgenomic mrna synthesis.equine arteritis virus (eav) is a positive-stranded rna virus that synthesizes a 5'- and 3'-coterminal nested set of six subgenomic mrnas. these mrnas all contain a common leader sequence which is derived from the 5' end of the genome. subgenomic mrna transcription and genome replication are directed by the viral replicase, which is expressed in the form of two polyproteins and subsequently processed into smaller nonstructural proteins (nsps). during the recent construction of an eav infectious ...199910364273
in vitro assembly of alphavirus cores by using nucleocapsid protein expressed in escherichia coli.the production of the alphavirus virion is a multistep event requiring the assembly of the nucleocapsid core in the cytoplasm and the maturation of the glycoproteins in the endoplasmic reticulum and the golgi apparatus. these components associate during the budding process to produce the mature virion. the nucleocapsid proteins of sindbis virus and ross river virus have been produced in a t7-based escherichia coli expression system and purified. in the presence of single-stranded but not double- ...199910364277
Displaying items 1801 - 1900 of 5405