Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| the predicted metal-binding region of the arterivirus helicase protein is involved in subgenomic mrna synthesis, genome replication, and virion biogenesis. | equine arteritis virus (eav), the prototype arterivirus, is a positive-stranded rna virus that expresses its replicase in the form of two large polyproteins of 1,727 and 3,175 amino acids. the functional replicase subunits (nonstructural proteins), which drive eav genome replication and subgenomic mrna transcription, are generated by extensive proteolytic processing. subgenomic mrna transcription involves an unusual discontinuous step and generates the mrnas for structural protein expression. pr ... | 2000 | 10799597 |
| infection of human cells by dengue virus is modulated by different cell types and viral strains. | although prior studies have investigated cellular infection by dengue virus (dv), many have used highly passaged strains. we have reassessed cellular infection by dv type 2 (dv2) using prototype and low-passage isolates representing genotypes from different geographic areas. we observed marked variation in the susceptibility to infection among cell types by different dv2 strains. hepg2 hepatoma cells were susceptible to infection by all dv2 strains assayed. although the prototype strain generate ... | 2000 | 10933688 |
| substitutions at the putative receptor-binding site of an encephalitic flavivirus alter virulence and host cell tropism and reveal a role for glycosaminoglycans in entry. | the flavivirus receptor-binding domain has been putatively assigned to a hydrophilic region (fg loop) in the envelope (e) protein. in some flaviviruses this domain harbors the integrin-binding motif arg-gly-asp (rgd). one of us has shown earlier that host cell adaptation of murray valley encephalitis virus (mve) can result in the selection of attenuated variants altered at e protein residue asp(390), which is part of an rgd motif. here, a full-length, infectious cdna clone of mve was constructed ... | 2000 | 10982329 |
| recombinant yellow fever viruses are effective therapeutic vaccines for treatment of murine experimental solid tumors and pulmonary metastases. | we have genetically engineered an attenuated yellow fever (yf) virus to carry and express foreign antigenic sequences and evaluated the potential of this type of recombinant virus to serve as a safe and effective tumor vaccine. live-attenuated yf vaccine is one of the most effective viral vaccines available today. important advantages include its ability to induce long-lasting immunity, its safety, its affordability, and its documented efficacy. in this study, recombinant live-attenuated (strain ... | 2000 | 10982366 |
| e2-p7 region of the bovine viral diarrhea virus polyprotein: processing and functional studies. | the genes encoding pestivirus e2 and ns2-3 are separated by a sequence that encodes a small hydrophobic polypeptide with an apparent molecular mass of 6 to 7 kda (p7). it has been shown that cleavage between e2 and p7 is incomplete, resulting in proteins e2-p7, e2, and p7. we found no precursor-product relationship between e2-p7 and e2, which indicates a stable nature of e2-p7. to study the function of the e2-p7 region of the polyprotein, mutations were introduced into an infectious cdna of bovi ... | 2000 | 11000219 |
| rubella virus replication and links to teratogenicity. | rubella virus (rv) is the causative agent of the disease known more popularly as german measles. rubella is predominantly a childhood disease and is endemic throughout the world. natural infections of rubella occur only in humans and are generally mild. complications of rubella infection, most commonly polyarthralgia in adult women, do exist; occasionally more serious sequelae occur. however, the primary public health concern of rv infection is its teratogenicity. rv infection of women during th ... | 2000 | 11023958 |
| development of a primary tamarin hepatocyte culture system for gb virus-b: a surrogate model for hepatitis c virus. | gb virus-b (gbv-b) causes an acute hepatitis in tamarins characterized by increased alanine transaminase levels that quickly return to normal as the virus is cleared. phylogenetically, gbv-b is the closest relative to hepatitis c virus (hcv), and thus gbv-b infection of tamarins represents a powerful surrogate model system for the study of hcv. in this study, the course of infection of gbv-b in tamarins was followed using a real-time 5' exonuclease (taqman) reverse transcription-pcr assay to det ... | 2000 | 11090176 |
| molecular basis for attenuation of neurovirulence of a yellow fever virus/japanese encephalitis virus chimera vaccine (chimerivax-je). | a yellow fever virus (yfv)/japanese encephalitis virus (jev) chimera in which the structural proteins prm and e of yfv 17d are replaced with those of the jev sa14-14-2 vaccine strain is under evaluation as a candidate vaccine against japanese encephalitis. the chimera (yfv/jev sa14-14-2, or chimerivax-je) is less neurovirulent than is yfv 17d vaccine in mouse and nonhuman primate models (f. guirakhoo et al., virology 257:363-372, 1999; t. p. monath et al., vaccine 17:1869-1882, 1999). attenuatio ... | 2001 | 11134306 |
| stable expression of noncytopathic kunjin replicons simulates both ultrastructural and biochemical characteristics observed during replication of kunjin virus. | this report focuses mainly on the characterization of a vero cell line stably expressing the flavivirus kunjin (kun) replicon c20sdrep (c20sdrepvero). we showed by immunofluorescence and cryoimmunoelectron microscopy that unique flavivirus-induced membrane structures, termed convoluted membranes/paracrystalline structures, were induced in the c20sdrepvero cells. these induced cytoplasmic foci were immunolabeled with kun virus anti-ns3 antibodies and with antibodies to the cellular markers ergic5 ... | 2001 | 11145899 |
| characterization of cell lines carrying self-replicating hepatitis c virus rnas. | subgenomic selectable rnas of the hepatitis c virus (hcv) have recently been shown to self-replicate to high levels in the human hepatoma cell line huh-7 (v. lohmann, f. körner, j. o. koch, u. herian, l. theilmann, and r. bartenschlager, science 285:110-113, 1999). taking advantage of this cell culture system that allows analyses of the interplay between hcv replication and the host cell, in this study we characterized two replicon-harboring cell lines that have been cultivated for more than 1 y ... | 2001 | 11152498 |
| biogenesis of the semliki forest virus rna replication complex. | the nonstructural (ns) proteins nsp1 to -4, the components of semliki forest virus (sfv) rna polymerase, were localized in infected cells by confocal microscopy using double labeling with specific antisera against the individual ns proteins. all ns proteins were associated with large cytoplasmic vacuoles (cpv), the inner surfaces of which were covered by small invaginations, or spherules, typical of alphavirus infection. all ns proteins were localized by immuno-electron microscopy (em) to the li ... | 2001 | 11264376 |
| biophysical characterization and vector-specific antagonist activity of domain iii of the tick-borne flavivirus envelope protein. | the molecular determinants responsible for flavivirus host cell binding and tissue tropism are largely unknown, although domain iii of the envelope protein has been implicated in these functions. we examined the solution properties and antagonist activity of langat virus domain iii. our results suggest that domain iii adopts a stably folded structure that can mediate binding of tick-borne flaviviruses but not mosquito-borne flaviviruses to their target cells. three clusters of phylogenetically c ... | 2001 | 11264392 |
| outbreak of west nile virus infection, volgograd region, russia, 1999. | from july 25 to october 1, 1999, 826 patients were admitted to volgograd region, russia, hospitals with acute aseptic meningoencephalitis, meningitis, or fever consistent with arboviral infection. of 84 cases of meningoencephalitis, 40 were fatal. fourteen brain specimens were positive in reverse transcriptase-polymerase chain reaction assays, confirming the presence of west nile/kunjin virus. | 2001 | 11266303 |
| coupling between replication and packaging of flavivirus rna: evidence derived from the use of dna-based full-length cdna clones of kunjin virus. | in order to study whether flavivirus rna packaging is dependent on rna replication, we generated two dna-based kunjin virus constructs, pkun1 and pkun1dgdd, allowing continuous production of replicating (wild-type) and nonreplicating (with a deletion of the ns5 gene rna-polymerase motif gdd) full-length kunjin virus rnas, respectively, via nuclear transcription by cellular rna polymerase ii. as expected, transfection of pkun1 plasmid dna into bhk cells resulted in the recovery of secreted infect ... | 2001 | 11312333 |
| essential role of cyclization sequences in flavivirus rna replication. | a possible role in rna replication for interactions between conserved complementary (cyclization) sequences in the 5'- and 3'-terminal regions of flavivirus rna was previously suggested but never tested in vivo. using the m-fold program for rna secondary-structure predictions, we examined for the first time the base-pairing interactions between the covalently linked 5' genomic region (first ~160 nucleotides) and the 3' untranslated region (last ~115 nucleotides) for a range of mosquito-borne fla ... | 2001 | 11413342 |
| attenuation of murray valley encephalitis virus by site-directed mutagenesis of the hinge and putative receptor-binding regions of the envelope protein. | molecular determinants of virulence in flaviviruses cluster in two regions on the three-dimensional structure of the envelope (e) protein; the base of domain ii, believed to serve as a hinge during ph-dependent conformational change in the endosome, and the lateral face of domain iii, which contains an integrin-binding motif arg-gly-asp (rgd) in mosquito-borne flaviviruses and is believed to form the receptor-binding site of the protein. in an effort to better understand the nature of attenuatio ... | 2001 | 11462041 |
| genetic analysis of the pestivirus nonstructural coding region: defects in the ns5a unit can be complemented in trans. | the functional analysis of molecular determinants which control the replication of pestiviruses was considerably facilitated by the finding that subgenomic forms of the positive-strand rna genome of bvdv (bovine viral diarrhea virus) are capable of autonomous replication in transfected host cells. the prototype replicon, bvdv di9c, consists of the genomic 5' and 3' untranslated regions and a truncated open reading frame (orf) encoding mainly the nonstructural proteins ns3, ns4a, ns4b, ns5a, and ... | 2001 | 11483722 |
| mutagenesis of the dengue virus type 2 ns3 protein within and outside helicase motifs: effects on enzyme activity and virus replication. | the protein ns3 of dengue virus type 2 (den-2) is the second largest nonstructural protein specified by the virus and is known to possess multiple enzymatic activities, including a serine proteinase located in the n-terminal region and an ntpase-helicase in the remaining 70% of the protein. the latter region has seven conserved helicase motifs found in all members of the family flaviviridae. den-2 ns3 lacking the proteinase region was synthesized as a fusion protein with glutathione s-transferas ... | 2001 | 11559795 |
| development of dengue virus type 2 replicons capable of prolonged expression in host cells. | as part of a program to develop a dengue virus vaccine which avoids the deleterious effects of antibody dependent enhancement (ade) of infection mediated by antibodies to dengue virus structural proteins, we have begun to investigate the possibility of designing dengue vaccines based on non-structural proteins. | 2001 | 11580862 |
| host rna polymerase requirements for transcription of the human hepatitis delta virus genome. | replication of the genome of hepatitis delta virus (hdv) requires rna-directed rna synthesis using a host polymerase(s). this manuscript reviews the relevant published evidence. it also provides two new studies, both of which made use of transiently transfected huh7 cells undergoing hdv rna-directed rna synthesis. for the first study, rna transcription inhibitors were added to the transfected cells for periods of 1 to 2 days, after which assays of the effects on the accumulation of processed uni ... | 2001 | 11581384 |
| a case of kunjin virus encephalitis in a traveller returning from the northern territory. | 2001 | 11596722 | |
| assembly and maturation of the flavivirus kunjin virus appear to occur in the rough endoplasmic reticulum and along the secretory pathway, respectively. | the intracellular assembly site for flaviviruses in currently not known but is presumed to be located within the lumen of the rough endoplasmic reticulum (rer). building on previous studies involving immunofluorescence (if) and cryoimmunoelectron microscopy of kunjin virus (kun)-infected cells, we sought to identify the steps involved in the assembly and maturation of kun. thus, using antibodies directed against envelope protein e in if analysis, we found the accumulation of e within regions coi ... | 2001 | 11602720 |
| a phylogenetic approach to following west nile virus in connecticut. | the 1999 outbreak of west nile (wn) virus in the northeastern united states was the first known natural occurrence of this flavivirus in the western hemisphere. in 1999 and 2000, 82 independent connecticut wn virus isolates were cultured from nine species of birds, five species of mosquitoes, and one striped skunk. nucleotide sequences obtained from these isolates identified 30 genetic changes, compared with wn-ny99, in a 921-nt region of the viral genome beginning at nucleotide position 205 and ... | 2001 | 11606791 |
| flock house virus rna replicates on outer mitochondrial membranes in drosophila cells. | the identification and characterization of host cell membranes essential for positive-strand rna virus replication should provide insight into the mechanisms of viral replication and potentially identify novel targets for broadly effective antiviral agents. the alphanodavirus flock house virus (fhv) is a positive-strand rna virus with one of the smallest known genomes among animal rna viruses, and it can replicate in insect, plant, mammalian, and yeast cells. to investigate the localization of f ... | 2001 | 11689648 |
| nucleic acid sequence-based amplification assays for rapid detection of west nile and st. louis encephalitis viruses. | the development and application of nucleic acid sequence-based amplification (nasba) assays for the detection of west nile (wn) and st. louis encephalitis (sle) viruses are reported. two unique detection formats were developed for the nasba assays: a postamplification detection step with a virus-specific internal capture probe and electrochemiluminescence (nasba-ecl assay) and a real-time assay with 6-carboxyfluorescein-labeled virus-specific molecular beacon probes (nasba-beacon assay). the sen ... | 2001 | 11724870 |
| kunjin virus: an australian variant of west nile? | kunjin (kun) is a flavivirus in the japanese encephalitis antigenic complex that was first isolated from culex annulirostris mosquitoes captured in northern australia in 1960. it is the etiological agent of a human disease characterized by febrile illness with rash or mild encephalitis and, occasionally, of a neurological disease in horses. kun virus shares a similar epidemiology and ecology with the closely related murray valley encephalitis (mve) virus, the major causative agent of arboviral e ... | 2001 | 11797773 |
| biological significance of glycosylation of the envelope protein of kunjin virus. | 2001 | 11797800 | |
| capsid protein c of tick-borne encephalitis virus tolerates large internal deletions and is a favorable target for attenuation of virulence. | deletions ranging in size from 4 to 21 amino acid residues were introduced into the capsid protein of the flavivirus tick-borne encephalitis (tbe) virus. these deletions incrementally affected a hydrophobic domain which is present at the center of all flavivirus capsid protein sequences and part of which may form an amphipathic alpha-helix. in the context of the full-length tbe genome, the deletions did not measurably affect protein expression and up to a deletion length of 16 amino acid residue ... | 2002 | 11884577 |
| kunjin virus replicon vaccine vectors induce protective cd8+ t-cell immunity. | the ability of self-replicating rna (replicon) vaccine vectors derived from the australian flavivirus kunjin (kun) to induce protective alphabeta cd8+ t-cell responses was examined. kun replicons encoding a model immunogen were delivered by three different vaccine modalities: (i) as naked rna transcribed in vitro, (ii) as plasmid dna constructed to allow in vivo transcription of replicon rna by cellular rna polymerase ii (dna based), and (iii) as replicon rna encapsidated into virus-like particl ... | 2002 | 11907219 |
| hepatitis c virus-like particle morphogenesis. | although much is known about the hepatitis c virus (hcv) genome, first cloned in 1989, little is known about hcv structure and assembly due to the lack of an efficient in vitro culture system for hcv. using a recombinant semliki forest virus replicon expressing genes encoding hcv structural proteins, we observed for the first time the assembly of these proteins into hcv-like particles in mammalian cells. this system opens up new possibilities for the investigation of viral morphogenesis and viru ... | 2002 | 11907246 |
| reappearance of human cases due to murray valley encephalitis virus and kunjin virus in central australia after an absence of 26 years. | murray valley encephalitis (mve) and kunjin virus disease are endemic in the tropical parts of the northern territory and western australia, but have been absent from central australia since 1974. in 2000, 5 laboratory-confirmed cases of encephalitis occurred over a short period in the normally dry inland region of central australia. the sudden occurrence of cases in march and april 2000 followed unusually high rainfall in the preceding months and evidence of flavivirus activity in the endemic a ... | 2002 | 11950201 |
| mutations in the yellow fever virus nonstructural protein ns2a selectively block production of infectious particles. | little is known about the function of flavivirus nonstructural protein ns2a. two forms of ns2a are found in yellow fever virus-infected cells. full-length ns2a (224 amino acids) is the product of cleavage at the ns1/2a and ns2a/2b sites. ns2aalpha, a c-terminally truncated form of 190 amino acids, results from partial cleavage by the viral ns2b-3 serine protease at the sequence qk /t within ns2a. exchange of serine for lysine at this site (qkt-->qst) blocks the production of both ns2aalpha and i ... | 2002 | 11967294 |
| phylogenetic analysis of a human isolate from the 2000 israel west nile virus epidemic. | specimens from a patient of the 2000 israel west nile virus epidemic were analyzed by reverse transcription-polymerase chain reaction. products corresponding to e, ns3, and ns5 sequences were amplified from cerebellar but not from cortical samples. phylogenetic analyses indicated a closer relationship of this isolate to 1996 romanian and 1999 russian than to 1998-99 israeli or 1999 new york isolates. | 2002 | 11996693 |
| infectious cdna clone of the epidemic west nile virus from new york city. | we report the first full-length infectious clone of the current epidemic, lineage i, strain of west nile virus (wnv). the full-length cdna was constructed from reverse transcription-pcr products of viral rna from an isolate collected during the year 2000 outbreak in new york city. it was cloned into plasmid pbr322 under the control of a t7 promoter and stably amplified in escherichia coli hb101. rna transcribed from the full-length cdna clone was highly infectious upon transfection into bhk-21 c ... | 2002 | 12021317 |
| expression of hepatitis c virus proteins induces distinct membrane alterations including a candidate viral replication complex. | plus-strand rna viruses characteristically replicate their genome in association with altered cellular membranes. in the present study, the capacity of hepatitis c virus (hcv) proteins to elicit intracellular membrane alterations was investigated by expressing, in tetracycline-regulated cell lines, a comprehensive panel of hcv proteins individually as well as in the context of the entire hcv polyprotein. as visualized by electron microscopy (em), expression of the combined structural proteins co ... | 2002 | 12021330 |
| the ecology and epidemiology of kunjin virus. | 2002 | 12082993 | |
| replication and gene function in kunjin virus. | 2002 | 12082996 | |
| emergence of usutu virus, an african mosquito-borne flavivirus of the japanese encephalitis virus group, central europe. | during late summer 2001 in austria, a series of deaths in several species of birds occurred, similar to the beginning of the west nile virus (wnv) epidemic in the united states. we necropsied the dead birds and examined them by various methods; pathologic and immunohistologic investigations suggested a wnv infection. subsequently, the virus was isolated, identified, partially sequenced, and subjected to phylogenetic analysis. the isolates exhibited 97% identity to usutu virus (usuv), a mosquito- ... | 2002 | 12095429 |
| phylogenetic relationships of southern african west nile virus isolates. | phylogenetic relationships were examined for 29 southern african west nile virus (formal name west nile virus [wnv]) isolates from various sources in four countries from 1958 to 2001. in addition, sequence data were retrieved from genbank for another 23 wnv isolates and kunjin and japanese encephalitis viruses. all isolates belonged to two lineages. lineage 1 isolates were from central and north africa, europe, israel, and north america; lineage 2 isolates were from central and southern africa a ... | 2002 | 12141968 |
| replication of a cytopathic strain of bovine viral diarrhea virus activates perk and induces endoplasmic reticulum stress-mediated apoptosis of mdbk cells. | endoplasmic reticulum (er) stress signaling is an adaptive cellular response to the loss of er ca(2+) homeostasis and/or the accumulation of misfolded, unassembled, or aggregated proteins in the er lumen. er stress-activated signaling pathways regulate protein synthesis initiation and can also trigger apoptosis through the er-associated caspase 12. viruses that utilize the host cell er as an integral part of their life cycle would be predicted to cause some level of er stress. bovine viral diarr ... | 2002 | 12208938 |
| complementation analysis of the flavivirus kunjin ns3 and ns5 proteins defines the minimal regions essential for formation of a replication complex and shows a requirement of ns3 in cis for virus assembly. | we have previously reported successful trans-complementation of defective kunjin virus genomic rnas with a range of large lethal deletions in the nonstructural genes ns1, ns3, and ns5 (a. a. khromykh et al., j. virol. 74:3253-3263, 2000). in this study we have mapped further the minimal region in the ns5 gene essential for efficient trans-complementation of genome-length rnas in repbhk cells to the first 316 of the 905 codons. to allow amplification and easy detection of complemented defective r ... | 2002 | 12368319 |
| cell-free replication of the hepatitis c virus subgenomic replicon. | the hepatitis c virus (hcv) contains a plus-strand rna genome. the 5' noncoding region (ncr) of the viral genome functions as an internal ribosome entry site, and its unique 3' ncr is required for the assembly of the replication complex during initiation of hcv rna replication. lohmann et al. (v. lohmann, f. korner, j.-o. koch, u. herian, l. theilman, and r. batenschlager, science 285:110-113, 1999) developed a subgenomic hcv replicon system, which represents an important tool in studying hcv re ... | 2002 | 12414942 |
| sentinel chicken surveillance programme in australia, 1 july 2001 to 30 june 2002. | detection of flavivirus seroconversions in sentinel chicken flocks located throughout australia is used to provide an early warning of increased levels of murray valley encephalitis (mve) and kunjin virus activity in the region. during the 2001/2002 season low levels of flavivirus activity were detected in northern australia compared to previous years. mve and kunjin virus activity was detected in the kimberley and pilbara regions of western australia and the northern territory but not in north ... | 2002 | 12416705 |
| induction of inflammation by west nile virus capsid through the caspase-9 apoptotic pathway. | west nile virus (wnv) is a member of the flaviviridae family of vector-borne pathogens. clinical signs of wnv infection include neurologic symptoms, limb weakness, and encephalitis, which can result in paralysis or death. we report that the wnv-capsid by itself induces rapid nuclear condensation and cell death in tissue culture. apoptosis is induced through the mitochondrial pathway resulting in caspase-9 activation and downstream caspase-3 activation. capsid gene delivery into the striatum of m ... | 2002 | 12498651 |
| fine mapping of a cis-acting sequence element in yellow fever virus rna that is required for rna replication and cyclization. | we present fine mapping of a cis-acting nucleotide sequence found in the 5' region of yellow fever virus genomic rna that is required for rna replication. there is evidence that this sequence interacts with a complementary sequence in the 3' region of the genome to cyclize the rna. replicons were constructed that had various deletions in the 5' region encoding the capsid protein and were tested for their ability to replicate. we found that a sequence of 18 nucleotides (residues 146 to 163 of the ... | 2003 | 12525663 |
| origin and evolution of japanese encephalitis virus in southeast asia. | since it emerged in japan in the 1870s, japanese encephalitis has spread across asia and has become the most important cause of epidemic encephalitis worldwide. four genotypes of japanese encephalitis virus (jev) are presently recognized (representatives of genotypes i to iii have been fully sequenced), but its origin is not known. we have determined the complete nucleotide and amino acid sequence of a genotype iv indonesian isolate (jkt6468) which represents the oldest lineage, compared it with ... | 2003 | 12584335 |
| epitope-blocking enzyme-linked immunosorbent assays for the detection of serum antibodies to west nile virus in multiple avian species. | we report the development of epitope-blocking enzyme-linked immunosorbent assays (elisas) for the rapid detection of serum antibodies to west nile virus (wnv) in taxonomically diverse north american avian species. a panel of flavivirus-specific monoclonal antibodies (mabs) was tested in blocking assays with serum samples from wnv-infected chickens and crows. selected mabs were further tested against serum samples from birds that represented 16 species and 10 families. serum samples were collecte ... | 2003 | 12624027 |
| hepatitis c virus rna replication occurs on a detergent-resistant membrane that cofractionates with caveolin-2. | the mechanism and machinery of hepatitis c virus (hcv) rna replication are still poorly understood. in this study, we labeled de novo-synthesized viral rna in situ with bromouridine triphosphate (brutp) in huh7 cells expressing an hcv subgenomic replicon. by immunofluorescence staining using an anti-brutp antibody and confocal microscopy, we showed that the newly synthesized hcv rna was localized to distinct speckle-like structures, which also contain all of the hcv nonstructural (ns) proteins. ... | 2003 | 12634374 |
| intracellular assembly and secretion of recombinant subviral particles from tick-borne encephalitis virus. | it is believed that flavivirus assembly occurs by intracellular budding of the nucleocapsid into the lumen of the endoplasmic reticulum (er). recombinant expression of tick-borne encephalitis (tbe) virus envelope proteins prm and e in mammalian cells leads to their incorporation into enveloped recombinant subviral particles (rsps), which have been used as a model system for studying assembly and entry processes and are also promising vaccine candidates. in this study, we analyzed the formation a ... | 2003 | 12634393 |
| cytoskeletal requirements for hepatitis c virus (hcv) rna synthesis in the hcv replicon cell culture system. | hepatitis c virus (hcv) induces microtubule aggregates in infected hepatocytes. to determine if cytoskeletal elements are important for hcv rna synthesis, we examined the effect of cytoskeleton inhibitors on hcv replicon transcription in huh7 cells. the data demonstrate that hcv replication complex-mediated rna synthesis requires microtubule and actin polymerization. | 2003 | 12634397 |
| topology of the membrane-associated hepatitis c virus protein ns4b. | hepatitis c virus (hcv) belongs to the hepacivirus genus in the flaviviridae family. among the least known viral proteins in this family is the nonstructural protein ns4b, which has been suggested to be a part of the replication complex. hydrophobicity plots indicate a common profile among the ns4b proteins from different members of the flaviviridae family, suggesting a common function. in order to gain a deeper understanding of the nature of hcv ns4b, we have determined localization and topolog ... | 2003 | 12692244 |
| sindbis virus vectors designed to express a foreign protein as a cleavable component of the viral structural polyprotein. | alphavirus-based expression vectors commonly use a duplicated 26s promoter to drive expression of a foreign gene. here we describe an expression strategy in which the foreign sequences are linked to the gene encoding the 2a protease of foot-and-mouth disease virus and then inserted in frame between the capsid and e3 genes of sindbis virus. during replication, the 2a fusion protein is synthesized as a component of the viral structural polyprotein that is then released by intramolecular cleavages ... | 2003 | 12719552 |
| australia's notifiable diseases status, 2001: annual report of the national notifiable diseases surveillance system. | in 2001 there were 104,187 notifications of communicable diseases in australia reported to the national notifiable diseases surveillance system (nndss). the number of notifications in 2001 was an increase of 16 per cent of those reported in 2000 (89,740) and the largest annual total since the nndss commenced in 1991. in 2001, nine new diseases were added to the list of diseases reported to nndss and four diseases were removed. the new diseases were cryptosporidiosis, laboratory-confirmed influen ... | 2003 | 12725505 |
| flavivirus capsid is a dimeric alpha-helical protein. | the capsid proteins of two flaviviruses, yellow fever virus and dengue virus, were expressed in escherichia coli and purified to near homogeneity suitable for biochemical characterization and structure determination by nuclear magnetic resonance. the oligomeric properties of the capsid protein in solution were investigated. in the absence of nucleic acid, both proteins were predominantly dimeric in solution. further analysis of both proteins with far-uv circular dichroism spectroscopy indicated ... | 2003 | 12768036 |
| tick-borne encephalitis with hemorrhagic syndrome, novosibirsk region, russia, 1999. | eight fatal cases of tick-borne encephalitis with an unusual hemorrhagic syndrome were identified in 1999 in the novosibirsk region, russia. to study these strains, we sequenced cdna fragments of protein e gene from six archival formalin-fixed brain samples. phylogenetic analysis showed tick-borne encephalitis variants clustered with a far eastern subtype (homology 94.7%) but not with the siberian subtype (82%). | 2003 | 12781020 |
| epitope-blocking enzyme-linked immunosorbent assays for detection of west nile virus antibodies in domestic mammals. | we evaluated the ability of epitope-blocking enzyme-linked immunosorbent assays (elisas) to detect west nile virus (wnv) antibodies in domestic mammals. sera were collected from experimentally infected horses, cats, and pigs at regular intervals and screened in elisas and plaque reduction neutralization tests. the diagnostic efficacies of these techniques were similar. | 2003 | 12791902 |
| kunjin virus replicon vectors for human immunodeficiency virus vaccine development. | we have previously demonstrated the ability of the vaccine vectors based on replicon rna of the australian flavivirus kunjin (kun) to induce protective antiviral and anticancer cd8+ t-cell responses using murine polyepitope as a model immunogen (i. anraku, t. j. harvey, r. linedale, j. gardner, d. harrich, a. suhrbier, and a. a. khromykh, j. virol. 76:3791-3799, 2002). here we showed that immunization of balb/c mice with kun replicons encoding hiv-1 gag antigen resulted in induction of both gag- ... | 2003 | 12829819 |
| molecular and functional analyses of kunjin virus infectious cdna clones demonstrate the essential roles for ns2a in virus assembly and for a nonconservative residue in ns3 in rna replication. | a number of full-length cdna clones of kunjin virus (kun) were previously prepared; it was shown that two of them, pakun and flsdx, differed in specific infectivities of corresponding in vitro transcribed rnas by approximately 100,000-fold (a. a. khromykh et al., j. virol. 72:7270-7279, 1998). in this study, we analyzed a possible genetic determinant(s) of the observed differences in infectivity initially by sequencing the entire cdnas of both clones and comparing them with the published sequenc ... | 2003 | 12829820 |
| nonstructural protein precursor ns4a/b from hepatitis c virus alters function and ultrastructure of host secretory apparatus. | the nonstructural proteins of hepatitis c virus (hcv) have been shown previously to localize to the endoplasmic reticulum (er) when expressed singly or in the context of other hcv proteins. to determine whether the expression of hcv nonstructural proteins alters er function, we tested the effect of expression of ns2/3/4a, ns4a, ns4b, ns4a/b, ns4b/5a, ns5a, and ns5b from genotype 1b hcv on anterograde traffic from the er to the golgi apparatus. only the nominal precursor protein ns4a/b affected t ... | 2003 | 12829824 |
| west nile virus encephalomyelitis in horses in ontario: 28 cases. | west nile virus encephalomyelitis was diagnosed in 28 horses presented to the ontario veterinary college veterinary teaching hospital between august 20 and october 15, 2002. the age range of affected horses was 5 months to 20 years (mean 6.9 years, median 6 years). clinical signs were highly variable. duration of hospitalization ranged from < 1 to 12 days (mean 5 days, median 5.4 days). overall, 16 of the 28 (57%) horses were discharged and, of the 14 from which follow-up information was availab ... | 2003 | 12839240 |
| dynamics of hepatitis c virus replication in human liver. | hepatitis c virus (hcv) replication at the cellular level is not fully understood. this study describes an optimized system for quantifying replication of hcv in hepatocytes and in liver tissues. a digital image analysis method was developed to quantify signal intensities of hcv genomic and replicative-intermediate rnas in infected human liver tissues and to examine their spatial distribution. the average number of viral genomes per productively infected hepatocyte ranged from 7 to 64 rna molecu ... | 2003 | 12875965 |
| de novo synthesis of negative-strand rna by dengue virus rna-dependent rna polymerase in vitro: nucleotide, primer, and template parameters. | by using a purified dengue virus rna-dependent rna polymerase and a subgenomic 770-nucleotide rna template, it was shown previously that the ratio of the de novo synthesis product to hairpin product formed was inversely proportional to increments of assay temperatures (20 to 40 degrees c). in this study, the components of the de novo preinitiation complex are defined as atp, a high concentration of gtp (500 micro m), the polymerase, and the template rna. even when the 3'-terminal sequence of tem ... | 2003 | 12885902 |
| incorporation of tick-borne encephalitis virus replicons into virus-like particles by a packaging cell line. | rna replicons derived from flavivirus genomes show considerable potential as gene transfer and immunization vectors. a convenient and efficient encapsidation system is an important prerequisite for the practical application of such vectors. in this work, tick-borne encephalitis (tbe) virus replicons and an appropriate packaging cell line were constructed and characterized. a stable cho cell line constitutively expressing the two surface proteins prm/m and e (named cho-me cells) was generated and ... | 2003 | 12885909 |
| dna vaccine coding for the full-length infectious kunjin virus rna protects mice against the new york strain of west nile virus. | a plasmid dna directing transcription of the infectious full-length rna genome of kunjin (kun) virus in vivo from a mammalian expression promoter was used to vaccinate mice intramuscularly. the kun viral cdna encoded in the plasmid contained the mutation in the ns1 protein (pro-250 to leu) previously shown to attenuate kun virus in weanling mice. kun virus was isolated from the blood of immunized mice 3-4 days after dna inoculation, demonstrating that infectious rna was being transcribed in vivo ... | 2003 | 12917491 |
| functional analysis of mosquito-borne flavivirus conserved sequence elements within 3' untranslated region of west nile virus by use of a reporting replicon that differentiates between viral translation and rna replication. | we have developed a reporting replicon of west nile virus (wnv) that could be used to quantitatively distinguish viral translation and rna replication. a renilla luciferase (rluc) gene was fused in-frame with the open reading frame of a subgenomic replicon in the position where the viral structural region was deleted, resulting in rlucrep. transfection of bhk cells with rlucrep rna yielded two distinctive rluc signal peaks, one between 2 and 10 h and the other after 26 h posttransfection. by con ... | 2003 | 12941911 |
| significance in replication of the terminal nucleotides of the flavivirus genome. | point mutations that resulted in a substitution of the conserved 3'-penultimate cytidine in genomic rna or the rna negative strand of the self-amplifying replicon of the flavivirus kunjin virus completely blocked in vivo replication. similarly, substitutions of the conserved 3'-terminal uridine in the rna negative or positive strand completely blocked replication or caused much-reduced replication, respectively. the same preference for cytidine in the 3'-terminal dinucleotide was noted in report ... | 2003 | 12970446 |
| association of japanese encephalitis virus ns3 protein with microtubules and tumour susceptibility gene 101 (tsg101) protein. | previously reported findings by our group showed that non-structural protein 3 (ns3) of japanese encephalitis virus (jev) was localized mainly in the jev-induced convoluted membrane (cm), which has been proposed to originate from rough endoplasmic reticulum (rer), golgi apparatus or the trans-golgi network (tgn), and serves as a reservoir for viral proteins during virus assembly. earlier findings indicated that ns3 of kunjin virus interacts with microtubules. in addition, one of the golgi-associ ... | 2003 | 13679614 |
| cytopathic and noncytopathic interferon responses in cells expressing hepatitis c virus subgenomic replicons. | hepatitis c virus (hcv) is the only known positive-stranded rna virus that causes persistent lifelong infections in humans. accumulation of hcv rna can be inhibited with alpha interferon (ifn-alpha) in vivo and in culture cells. we used cell-based assay systems to investigate the mechanisms responsible for the cytokine-induced inhibition of hcv replication. the results showed that ifn-alpha could suppress the accumulation of viral rna by a noncytopathic pathway and could also induce apoptosis of ... | 2003 | 14512527 |
| a system of protein target sequences for anti-rna-viral chemotherapy by a vitamin b6-derived zinc-chelating trioxa-adamantane-triol. | the synthesis of the structurally unusual heterotricyclic compound 1-[3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridinyl]-2,8,9-trioxaadamantane-3,5,7-triol (trivially named bananin, bn) from pyridoxylidenephloroglucinol and a theoretical prospect on possible biological activities of bn are presented in this report. pyridoxylidenephloroglucinol is synthesized by knoevenagel condensation of the vitamin b6 aldehyde pyridoxal with phloroglucinol. pyridoxylidenephloroglucinol rearranges to light-yello ... | 2003 | 14527557 |
| dengue 2 pdk-53 virus as a chimeric carrier for tetravalent dengue vaccine development. | attenuation markers of the candidate dengue 2 (d2) pdk-53 vaccine virus are encoded by mutations that reside outside of the structural gene region of the genome. we engineered nine dengue virus chimeras containing the premembrane (prm) and envelope (e) genes of wild-type d1 16007, d3 16562, or d4 1036 virus within the genetic backgrounds of wild-type d2 16681 virus and the two genetic variants (pdk53-e and pdk53-v) of the d2 pdk-53 vaccine virus. expression of the heterologous prm-e genes in the ... | 2003 | 14557629 |
| potential high-throughput assay for screening inhibitors of west nile virus replication. | prevention and treatment of infection by west nile virus (wnv) and other flaviviruses are public health priorities. we describe a reporting cell line that can be used for high-throughput screening of inhibitors against all targets involved in wnv replication. dual reporter genes, encoding renilla luciferase (rluc) and neomycin phosphotransferase (neo), were engineered into a wnv subgenomic replicon, resulting in rluc/neorep. geneticin selection of bhk-21 cells transfected with rluc/neorep yielde ... | 2003 | 14610212 |
| inefficient signalase cleavage promotes efficient nucleocapsid incorporation into budding flavivirus membranes. | the mechanism for efficient nucleocapsid (nc) uptake into flavivirus particles which form by budding through the membranes of the endoplasmic reticulum (er) was investigated by using murray valley encephalitis virus as a model. budding of flavivirus membranes is driven by the viral transmembrane proteins prm and e independently of nc interaction. we show that control of signalase cleavage of the multimembrane-spanning flavivirus polyprotein by the catalytic function of the viral protease is crit ... | 2004 | 14671099 |
| tetracycline-inducible packaging cell line for production of flavivirus replicon particles. | we have previously developed replicon vectors derived from the australian flavivirus kunjin that have a unique noncytopathic nature and have been shown to direct prolonged high-level expression of encoded heterologous genes in vitro and in vivo and to induce strong and long-lasting immune responses to encoded immunogens in mice. to facilitate further applications of these vectors in the form of virus-like particles (vlps), we have now generated a stable bhk packaging cell line, tetkuncprme, carr ... | 2004 | 14671135 |
| kunjin rna replication and applications of kunjin replicons. | the kunjin virus (kunv) has provided a useful laboratory model for flavivirus rna replication. the synthesis of progeny rna(+) strands occurs via asymmetric and semiconservative replication on a template of recycling double-stranded rna (dsrna) or replicative form (rf). kinetics of viral rna synthesis indicated a cycle period of about 15 min during which, on average, a single nascent rna (+) strand displaces the pre-existing rna(+) strand in the replicative intermediate. data on the composition ... | 2003 | 14696328 |
| flavivirus isolations from mosquitoes collected from western cape york peninsula, australia, 1999-2000. | after the 1st appearance of japanese encephalitis virus (je) on mainland australia in 1998, a study was undertaken to investigate whether je had become established in enzootic transmission cycles on western cape york peninsula. adult mosquitoes were collected during the late wet season from kowanyama and pormpuraaw in april 1999, and pormpuraaw and barr's yard in april 2000. despite processing 269,270 mosquitoes for virus isolation, no isolates of je were obtained. however, other flaviviruses co ... | 2003 | 14710742 |
| sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine. | sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications. | 2004 | 14720306 |
| mimicking live flavivirus immunization with a noninfectious rna vaccine. | flaviviruses are human pathogens of world-wide medical importance. they have recently received much additional attention because of their spread to new regions (such as west nile virus to north america), highlighting their potential as newly emerging disease agents. using tick-borne encephalitis virus, we have developed and evaluated in mice a new genetic vaccine based on self-replicating but noninfectious rna. this rna contains all of the necessary genetic information for establishing its repli ... | 2004 | 14769933 |
| alterations of pr-m cleavage and virus export in pr-m junction chimeric dengue viruses. | during the export of flavivirus particles through the secretory pathway, a viral envelope glycoprotein, prm, is cleaved by the proprotein convertase furin; this cleavage is required for the subsequent rearrangement of receptor-binding e glycoprotein and for virus infectivity. similar to many furin substrates, prm in vector-borne flaviviruses contains basic residues at positions p1, p2, and p4 proximal to the cleavage site; in addition, a number of charged residues are found at position p3 and be ... | 2004 | 14963133 |
| recombinant kunjin virus replicon vaccines induce protective t-cell immunity against human papillomavirus 16 e7-expressing tumour. | the persistence of the e7 oncoprotein in transformed cells in human papillomavirus (hpv)-associated cervical cancer provides a tumour-specific antigen to which immunotherapeutic strategies may be directed. self-replicating rna (replicon) vaccine vectors derived from the flavivirus kunjin (kun) have recently been reported to induce t-cell immunity. here, we report that inclusion of a ctl epitope of hpv16 e7 protein into a polyepitope encoded by a kun vector induced e7-directed t-cell responses an ... | 2004 | 14980484 |
| detection of australasian flavivirus encephalitic viruses using rapid fluorogenic taqman rt-pcr assays. | the development of single, sensitive, fluorogenic reverse transcriptase-polymerase chain reaction (taqman) assays were required for the rapid and specific detection of three encephalitic viruses found in the australasian region, namely; japanese encephalitis virus (jev), murray valley encephalitis virus (mvev), and kunjin virus (kunv). primers and a fluorogenic probe were individually designed to be complementary to a nucleotide region encompassing the 3' terminus of the nonstructural (ns) 5 gen ... | 2004 | 15041213 |
| sybr green-based real-time quantitative pcr assay for detection of west nile virus circumvents false-negative results due to strain variability. | real-time quantitative pcr is used routinely for the high-throughput diagnosis of viral pathogens, such as west nile virus (wnv). rapidly evolving rna viruses present a challenge for diagnosis because they accumulate mutations that may render them undetectable. to explore the effect of sequence variations on assay performance, we generated every possible single point mutation within the target region of the widely used taqman assay for wnv and found that the taqman assay failed to detect 47% of ... | 2004 | 15070997 |
| polymerase chain reaction tests for the identification of ross river, kunjin and murray valley encephalitis virus infections in horses. | to develop and validate specific, sensitive and rapid diagnostic tests using rt-pcr for the detection of ross river virus (rrv), kunjin virus (kv) and murray valley encephalitis virus (mvev) infections in horses. | 2003 | 15084017 |
| west nile virus: a growing concern? | west nile virus was first detected in north america in 1999 and has subsequently spread throughout the united states and canada and into mexico and the caribbean. this review describes the epidemiology and ecology of west nile virus in north america and the prospects for effective treatments and vaccines. | 2004 | 15085186 |
| enzyme-linked immunosorbent assays using recombinant envelope protein expressed in cos-1 and drosophila s2 cells for detection of west nile virus immunoglobulin m in serum or cerebrospinal fluid. | humans infected with west nile virus (wnv) develop immunoglobulin m (igm) antibodies soon after infection. the microtiter-based assays for wnv igm antibody detection used by most state public health and reference laboratories utilize wnv antigen isolated from infected vero cells or recombinant envelope protein produced in cos-1 cells. recombinant antigen produced in cos-1 cells was used to develop a wnv igm capture enzyme immunoassay (eia). a supplementary eia using wnv envelope protein expresse ... | 2004 | 15242936 |
| common e protein determinants for attenuation of glycosaminoglycan-binding variants of japanese encephalitis and west nile viruses. | natural isolates and laboratory strains of west nile virus (wnv) and japanese encephalitis virus (jev) were attenuated for neuroinvasiveness in mouse models for flavivirus encephalitis by serial passage in human adenocarcinoma (sw13) cells. the passage variants displayed a small-plaque phenotype, augmented affinity for heparin-sepharose, and a marked increase in specific infectivity for sw13 cells relative to the respective parental viruses, while the specific infectivity for vero cells was not ... | 2004 | 15254199 |
| west nile virus vaccines. | west nile virus (wnv) is a mosquito-borne flavivirus that is emerging as a global pathogen. in the last decade, virulent strains of the virus have been associated with significant outbreaks of human and animal disease in europe, the middle east and north america. efforts to develop human and veterinary vaccines have taken both traditional and novel approaches. a formalin-inactivated whole virus vaccine has been approved for use in horses. dna vaccines coding for the structural wnv proteins have ... | 2004 | 15268663 |
| comparisons of physical separation methods of kunjin virus-induced membranes. | the two sets of connected membranes induced in kunjin virus-infected cells are characterized by the presence of ns3 helicase/protease in both, and by rna-dependent rna polymerase (rdrp) activity plus the associated double-stranded rna (dsrna) template in vesicle packets (vp), or by the absence of both the vp-specific markers in the convoluted membranes/paracrystalline arrays (cm/pc). attempts were made to separate flavivirus-induced membranes by sedimentation or flotation analyses in density gra ... | 2004 | 15288961 |
| phylogenetic analysis of west nile virus, nuevo leon state, mexico. | west nile virus rna was detected in brain tissue from a horse that died in june 2003 in nuevo leon state, mexico. nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to west nile virus isolates collected in texas in 2002. | 2004 | 15324558 |
| involvement of a bovine viral diarrhea virus ns5b locus in virion assembly. | a novel mutant of bovine viral diarrhea virus (bvdv) was found with a virion assembly phenotype attributable to an insertion into the ns5b polymerase locus. this mutant, termed 5b-741, was engineered by reverse genetics to express ns5b with a c-terminal peptide tag of 22 amino acids. electroporation of bovine cells with genomic rna from this mutant showed levels rna synthesis which were regarded as sufficient for infectivity, yet infectious virions were not produced. pseudorevertants of mutant 5 ... | 2004 | 15331694 |
| trans-packaged west nile virus-like particles: infectious properties in vitro and in infected mosquito vectors. | a trans-packaging system for west nile virus (wnv) subgenomic replicon rnas (reprnas), deleted for the structural coding region, was developed. wnv reprnas were efficiently encapsidated by the wnv c/prm/e structural proteins expressed in trans from replication-competent, noncytopathic sindbis virus-derived rnas. infectious virus-like particles (vlps) were produced in titers of up to 10(9) infectious units/ml. wnv vlps established a single round of infection in a variety of different cell lines w ... | 2004 | 15479801 |
| genetic interactions between hepatitis c virus replicons. | to investigate interactions between hepatitis c virus (hcv) rna replication complexes, a system was developed to simultaneously select different hcv subgenomic replicons within the same cell. transcomplementation of defective replicons was not observed, suggesting an isolated and independent nature of the hcv rna replication complex. in contrast, a high level of competition between replicons was observed, such that the presence and increased fitness of one replicon reduced the capacity of a seco ... | 2004 | 15479852 |
| analysis of adaptive mutations in kunjin virus replicon rna reveals a novel role for the flavivirus nonstructural protein ns2a in inhibition of beta interferon promoter-driven transcription. | the establishment of persistent noncytopathic replication by replicon rnas of a number of positive-strand rna viruses usually leads to generation of adaptive mutations in nonstructural genes. some of these adaptive mutations (e.g., in hepatitis c virus) increase the ability of rna replication to resist the antiviral action of alpha/beta interferon (ifn-alpha/beta); others (e.g., in sindbis virus) may also lead to more efficient ifn production. using puromycin-selectable kunjin virus (kun) replic ... | 2004 | 15507609 |
| the transmembrane domains of the prm and e proteins of yellow fever virus are endoplasmic reticulum localization signals. | the immature flavivirus particle contains two envelope proteins, prm and e, that are associated as a heterodimer. virion morphogenesis of the flaviviruses occurs in association with endoplasmic reticulum (er) membranes, suggesting that there should be accumulation of the virion components in this compartment. this also implies that er localization signals must be present in the flavivirus envelope proteins. in this work, we looked for potential subcellular localization signals in the yellow feve ... | 2004 | 15507646 |
| identification of residues in the dengue virus type 2 ns2b cofactor that are critical for ns3 protease activation. | proteolytic processing of the dengue virus polyprotein is mediated by host cell proteases and the virus-encoded ns2b-ns3 two-component protease. the ns3 protease represents an attractive target for the development of antiviral inhibitors. the three-dimensional structure of the ns3 protease domain has been determined, but the structural determinants necessary for activation of the enzyme by the ns2b cofactor have been characterized only to a limited extent. to test a possible functional role of t ... | 2004 | 15564480 |
| development and evaluation of fluorogenic taqman reverse transcriptase pcr assays for detection of dengue virus types 1 to 4. | the fluorogenic taqman reverse transcriptase pcr (rt-pcr) assay was developed for detecting each of the dengue virus (dv) types 1 to 4. dv genome was detected in all the 35 serum samples from confirmed dengue cases by the taqman rt-pcr, although it was not detected in 13 and 21% by conventional type-specific and cross-reactive rt-pcr, respectively. | 2004 | 15583346 |
| kissing-loop interaction in the 3' end of the hepatitis c virus genome essential for rna replication. | the hepatitis c virus (hcv) is a positive-strand rna virus belonging to the flaviviridae. its genome carries at either end highly conserved nontranslated regions (ntrs) containing cis-acting rna elements that are crucial for replication. in this study, we identified a novel rna element within the ns5b coding sequence that is indispensable for replication. by using secondary structure prediction and nuclear magnetic resonance spectroscopy, we found that this rna element, designated 5bsl3.2 by ana ... | 2005 | 15596831 |
| efficient rescue of hepatitis c virus rna replication by trans-complementation with nonstructural protein 5a. | studies of hepatitis c virus (hcv) rna replication have become possible with the development of subgenomic replicons. this system allows the functional analysis of the essential components of the viral replication complex, which so far are poorly defined. in the present study we wanted to investigate whether lethal mutations in hcv nonstructural genes can be rescued by trans-complementation. therefore, a series of replicon rnas carrying mutations in ns3, ns4b, ns5a, and ns5b that abolish replica ... | 2005 | 15613318 |
| west nile virus inhibits the signal transduction pathway of alpha interferon. | west nile virus (wnv) is a human pathogen that can cause neurological disorders, including meningoencephalitis. experiments with mice and mammalian cell cultures revealed that wnv exhibited resistance to the innate immune program induced by alpha interferon (ifn-alpha). we have investigated the nature of this inhibition and have found that wnv replication inhibited the activation of many known ifn-inducible genes, because it prevented the phosphorylation and activation of the janus kinases jak1 ... | 2005 | 15650160 |
| differential induction of antiviral effects against west nile virus in primary mouse macrophages derived from flavivirus-susceptible and congenic resistant mice by alpha/beta interferon and poly(i-c). | a cell model of primary macrophages isolated from the peritoneal cavity of flavivirus-susceptible and congenic resistant mice has been used to study the extent and kinetics of antiviral effects against west nile virus upon priming with alpha/beta interferon (ifn-alpha/beta) or poly(i-c) (pic). the pattern of flavivirus resistance expressed after priming of cells in this model was in good agreement with the pattern of flavivirus resistance described in the brains of the corresponding mouse strain ... | 2005 | 15650200 |
| inhibition of interferon signaling by the new york 99 strain and kunjin subtype of west nile virus involves blockage of stat1 and stat2 activation by nonstructural proteins. | the interferon (ifn) response is the first line of defense against viral infections, and the majority of viruses have developed different strategies to counteract ifn responses in order to ensure their survival in an infected host. in this study, the abilities to inhibit ifn signaling of two closely related west nile viruses, the new york 99 strain (ny99) and kunjin virus (kun), strain mrm61c, were analyzed using reporter plasmid assays, as well as immunofluorescence and western blot analyses. w ... | 2005 | 15650219 |