| [meningeal drainage of aura virus grown in the mouse brain]. | | 1976 | 1004206 |
| experimental myocarditis by adenoviruses. i. electron microscopy and infectivity of aura virus in the mouse heart. | | 1970 | 5501758 |
| aura virus is a new world representative of sindbis-like viruses. | aura virus is an alphavirus present in brazil and argentina that is serologically related to sindbis virus (present throughout the old world) and to western equine encephalitis (wee) virus (present in the americas). we have previously shown that wee is a recombinant virus whose glycoproteins and part of whose 3' nontranslated region (ntr) are derived from a sindbis-like virus, but the remainder of whose genome is derived from eastern equine encephalitis (eee) virus. we show here that aura virus ... | 1995 | 7747434 |
| aura alphavirus subgenomic rna is packaged into virions of two sizes. | the alphavirus genome is 11.8 kb in size. during infection, a 4.2-kb subgenomic rna is also produced. most alphaviruses package only the genomic rna into virions, which are enveloped particles with icosahedral symmetry, having a triangulation number (t) = 4. aura virus, however, packages both the genomic rna and the subgenomic rna into virions. the genomic rna is primarily packaged into a virion that has a diameter of 72 nm and which appears to be identical to the virions produced by other alpha ... | 1995 | 7853512 |
| subgenomic mrna of aura alphavirus is packaged into virions. | purified virions of aura virus, a south american alphavirus related to sindbis virus, were found to contain two rna species, one of 12 kb and the other of 4.2 kb. northern (rna) blot analysis, primer extension analysis, and limited sequencing showed that the 12-kb rna was the viral genomic rna, whereas the 4.2-kb rna present in virus preparations was identical to the 26s subgenomic rna present in infected cells. the subgenomic rna is the messenger for translation of the viral structural proteins ... | 1994 | 7902874 |
| recombinational history and molecular evolution of western equine encephalomyelitis complex alphaviruses. | western equine encephalomyelitis (wee) virus (togaviridae: alphavirus) was shown previously to have arisen by recombination between eastern equine encephalomyelitis (eee)- and sindbis-like viruses (c. s. hahn, s. lustig, e. g. strauss, and j. h. strauss, proc. natl. acad. sci. usa 85:5997-6001, 1988). we have now examined the recombinational history and evolution of all viruses belonging to the wee antigenic complex, including the buggy creek, fort morgan, highlands j, sindbis, babanki, ockelbo, ... | 1997 | 8985391 |
| 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 ... | 1998 | 9425157 |
| 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 ... | 1998 | 9557718 |
| 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- ... | 1999 | 10364277 |
| rainbow trout sleeping disease virus is an atypical alphavirus. | sleeping disease (sd) is currently a matter of concern for salmonid fish farmers in most parts of the world. a viral etiology of sd has recently been suspected, since virus-like particles have been observed in infected rainbow trout cells. in salmonid-derived cell lines, the maximal rate of virus production was observed at 10 degrees c, while little virus was produced at 14 degrees c. through biochemical, physicochemical, and morphological studies, sd virus (sdv) was shown to be an enveloped vir ... | 2000 | 10590104 |
| development of reverse transcription-pcr assays specific for detection of equine encephalitis viruses. | specific and sensitive reverse transcription-pcr (rt-pcr) assays were developed for the detection of eastern, western, and venezuelan equine encephalitis viruses (eee, wee, and vee, respectively). tests for specificity included all known alphavirus species. the eee-specific rt-pcr amplified a 464-bp region of the e2 gene exclusively from 10 different eee strains from south and north america with a sensitivity of about 3,000 rna molecules. in a subsequent nested pcr, the specificity was confirmed ... | 2000 | 10747138 |
| alphavirus nucleocapsid protein contains a putative coiled coil alpha-helix important for core assembly. | the alphavirus nucleocapsid core is formed through the energetic contributions of multiple noncovalent interactions mediated by the capsid protein. this protein consists of a poorly conserved n-terminal region of unknown function and a c-terminal conserved autoprotease domain with a major role in virion formation. in this study, an 18-amino-acid conserved region, predicted to fold into an alpha-helix (helix i) and embedded in a low-complexity sequence enriched with basic and pro residues, has be ... | 2001 | 11119567 |
| sequence requirements for sindbis virus subgenomic mrna promoter function in cultured cells. | the sindbis virus minimal subgenomic mrna promoter (spanning positions -19 to +5 relative to the subgenomic mrna start site) is approximately three- to sixfold less active than the fully active -98 to +14 promoter region. we identified two elements flanking the -19 to +5 region which increase its transcription to levels comparable to the -98 to +14 region. these elements span positions -40 to -20 and +6 to +14 and act synergistically to enhance transcription. nine different virus libraries were ... | 2001 | 11264340 |
| arbovirus of marine mammals: a new alphavirus isolated from the elephant seal louse, lepidophthirus macrorhini. | a novel alphavirus was isolated from the louse lepidophthirus macrorhini, collected from southern elephant seals, mirounga leonina, on macquarie island, australia. the virus displayed classic alphavirus ultrastructure and appeared to be serologically different from known australasian alphaviruses. nearly all macquarie island elephant seals tested had neutralizing antibodies against the virus, but no virus-associated pathology has been identified. antarctic division personnel who have worked exte ... | 2001 | 11287559 |
| evolutionary relationships and systematics of the alphaviruses. | partial e1 envelope glycoprotein gene sequences and complete structural polyprotein sequences were used to compare divergence and construct phylogenetic trees for the genus alphavirus. tree topologies indicated that the mosquito-borne alphaviruses could have arisen in either the old or the new world, with at least two transoceanic introductions to account for their current distribution. the time frame for alphavirus diversification could not be estimated because maximum-likelihood analyses indic ... | 2001 | 11581380 |
| comparison of two aquatic alphaviruses, salmon pancreas disease virus and sleeping disease virus, by using genome sequence analysis, monoclonal reactivity, and cross-infection. | cell culture isolates of salmon pancreas disease virus (spdv) of farmed atlantic salmon and sleeping disease virus (sdv) of rainbow trout were compared. excluding the poly(a) tracts, the genomic nucleotide sequences of spdv and sdv rnas include 11,919 and 11,900 nucleotides, respectively. phylogenetic analysis places spdv and sdv between the new world viruses of venezuelan equine encephalitis virus and eastern equine encephalitis virus and the old world viruses of aura virus and sindbis virus. w ... | 2002 | 12021349 |
| aura virus structure suggests that the t=4 organization is a fundamental property of viral structural proteins. | aura and sindbis viruses are closely related alphaviruses. unlike other alphaviruses, aura virus efficiently encapsidates both genomic rna (11.8 kb) and subgenomic rna (4.2 kb) to form virus particles. previous studies on negatively stained aura virus particles predicted that there were two major size classes with potential t=3 and t=4 capsid structures. we have used cryoelectron microscopy and three-dimensional image reconstruction techniques to examine the native morphology of different classe ... | 2002 | 12072523 |
| alphavirus minus-strand rna synthesis: identification of a role for arg183 of the nsp4 polymerase. | a partially conserved region spanning amino acids 142 to 191 of the sindbis virus (sin) nsp4 core polymerase is implicated in host restriction, elongation, and promoter recognition. we extended the analysis of this region by substituting ser, ala, or lys for a highly conserved arg183 residue immediately preceding its absolutely conserved ser184-ala-val-pro-ser188 sequence. in chicken cells, the nsp4 arg183 mutants had a nonconditionally lethal, temperature-sensitive (ts) growth phenotype caused ... | 2002 | 12163582 |
| modification of asn374 of nsp1 suppresses a sindbis virus nsp4 minus-strand polymerase mutant. | our recent study (c. l. fata, s. g. sawicki, and d. l. sawicki, j. virol. 76:8632-8640, 2002) found minus-strand synthesis to be temperature sensitive in vertebrate and invertebrate cells when the arg183 residue of the sindbis virus nsp4 polymerase was changed to ser, ala, or lys. here we report the results of studies identifying an interacting partner of the region of the viral polymerase containing arg183 that suppresses the ser183 codon mutation. large-plaque revertants were observed readily ... | 2002 | 12163583 |
| molecular genetic evidence that the hydrophobic anchors of glycoproteins e2 and e1 interact during assembly of alphaviruses. | chimeric alphaviruses in which the 6k and glycoprotein e1 moieties of sindbis virus are replaced with those of ross river virus grow very poorly, but upon passage, adapted variants arise that grow >100 times better. we have sequenced the entire domain encoding the e2, 6k, and e1 proteins of a number of these adapted variants and found that most acquired two amino acid changes, which had cumulative effects. in three independent passage series, amino acid 380 of e2, which is in the transmembrane d ... | 2002 | 12239293 |
| novel mutations that control the sphingolipid and cholesterol dependence of the semliki forest virus fusion protein. | the enveloped alphavirus semliki forest virus (sfv) infects cells via a membrane fusion reaction mediated by the e1 membrane protein. efficient sfv-membrane fusion requires the presence of cholesterol and sphingolipid in the target membrane. here we report on two mutants, srf-4 and srf-5, selected for growth in cholesterol-depleted cells. like the previously isolated srf-3 mutant (e1 proline 226 to serine), the phenotypes of the srf-4 and srf-5 mutants were conferred by single-amino-acid changes ... | 2002 | 12438597 |
| interactions between the transmembrane segments of the alphavirus e1 and e2 proteins play a role in virus budding and fusion. | the alphavirus envelope is built by heterodimers of the membrane proteins e1 and e2. the complex is formed as a p62e1 precursor in the endoplasmic reticulum. during transit to the plasma membrane (pm), it is cleaved into mature e1-e2 heterodimers, which are oligomerized into trimeric complexes, so-called spikes that bind both to each other and, at the pm, also to nucleocapsid (nc) structures under the membrane. these interactions drive the budding of new virus particles from the cell surface. th ... | 2003 | 12610119 |
| diverse dengue type 2 virus populations contain recombinant and both parental viruses in a single mosquito host. | envelope (e) protein genes sampled from populations of dengue 2 (den-2) virus in individual aedes aegypti mosquitoes and in serum from dengue patients were copied to cdna, cloned, and sequenced. the nucleotide sequences of the e genes in more than 70% of the clones differed from the consensus sequence for the corresponding virus population at up to 11 sites, and 24 of the 94 clones contained at least one stop codon. virus populations recovered up to 2 years apart yielded clones with similar poly ... | 2003 | 12634407 |
| changes of the secondary structure of the 5' end of the sindbis virus genome inhibit virus growth in mosquito cells and lead to accumulation of adaptive mutations. | both the 5' end of the sindbis virus (sin) genome and its complement in the 3' end of the minus-strand rna synthesized during virus replication serve as parts of the promoters recognized by the enzymes that comprise the replication complex (rdrp). in addition to the 5' untranslated region (utr), which was shown to be critical for the initiation of replication, another 5' sequence element, the 51-nucleotide (nt) conserved sequence element (cse), was postulated to be important for virus replicatio ... | 2004 | 15113874 |
| sindbis virus with a tricomponent genome. | we established a system for propagation of sindbis virus (sin)-based replicons in tissue culture in the form of a tricomponent genome virus. three rna fragments containing complementing genetic information required for virus replication are packaged into separate viral particles, and each cell produces at least 1,000 packaged replicons and the number of packaged helpers sufficient to perform the next passage. this system can be used to generate large stocks of packaged replicons. the formation o ... | 2005 | 15596860 |
| heparin binding sites on ross river virus revealed by electron cryo-microscopy. | cell surface glycosaminoglycans play important roles in cell adhesion and viral entry. laboratory strains of two alphaviruses, sindbis and semliki forest virus, have been shown to utilize heparan sulfate as an attachment receptor, whereas ross river virus (rrv) does not significantly interact with it. however, a single amino acid substitution at residue 218 in the rrv e2 glycoprotein adapts the virus to heparan sulfate binding and expands the host range of the virus into chicken embryo fibroblas ... | 2005 | 15680416 |
| duplex reverse transcription-pcr followed by nested pcr assays for detection and identification of brazilian alphaviruses and flaviviruses. | a new approach was developed for the rapid detection and identification of brazilian alphaviruses and flaviviruses. the methodology involves the genus-specific detection of alphavirus and flavivirus by a duplex reverse transcription-pcr (d-rt-pcr), followed by multiplex nested pcr (m-n-pcr) or nested pcr (n-pcr) assays for species-specific identification. by this protocol, 25 arboviruses were specifically detected and identified. detection levels between 10(1.3) and 10(3.5) 50% tissue culture in ... | 2005 | 15695666 |
| mapping the structure and function of the e1 and e2 glycoproteins in alphaviruses. | the 9 a resolution cryo-electron microscopy map of sindbis virus presented here provides structural information on the polypeptide topology of the e2 protein, on the interactions between the e1 and e2 glycoproteins in the formation of a heterodimer, on the difference in conformation of the two types of trimeric spikes, on the interaction between the transmembrane helices of the e1 and e2 proteins, and on the conformational changes that occur when fusing with a host cell. the positions of various ... | 2006 | 16407066 |
| molecular determinants of substrate specificity for semliki forest virus nonstructural protease. | the c-terminal cysteine protease domain of semliki forest virus nonstructural protein 2 (nsp2) regulates the virus life cycle by sequentially cleaving at three specific sites within the virus-encoded replicase polyprotein p1234. the site between nsp3 and nsp4 (the 3/4 site) is cleaved most efficiently. analysis of semliki forest virus-specific cleavage sites with shuffled n-terminal and c-terminal half-sites showed that the main determinants of cleavage efficiency are located in the region prece ... | 2006 | 16699022 |
| morphogenesis of aura virus. | aura virus, a member of the western equine-encephalitis-whataroa subgroup of group a arboviruses, was studied by electron microscopy in suckling mouse brain and chick embryo cultured cells. virus precursors, budding particles, and complete virus particles were first detected 10 hr after infection in chick embryo cells and 24 hr after inoculation in mouse brain. virus precursors were generally seen aligned along cytomembranes, and were less frequently seen closely associated with viroplasm-like f ... | 1969 | 16789104 |
| reverse transcription-pcr-enzyme-linked immunosorbent assay for rapid detection and differentiation of alphavirus infections. | due to the lack of a rapid, simple, and inexpensive assay for detecting alphavirus infections, we combined a reverse transcription-pcr with an enzyme-linked immunosorbent assay (rt-pcr-elisa) to identify human pathogenic alphaviruses that are endemic in the new world. by combining the sensitivity of pcr, the detection simplicity of elisa, and the specificities of dna probes, this method rapidly detected and differentiated closely related species and subtypes of several medically important alphav ... | 2006 | 16957044 |
| functions of the stem region of the semliki forest virus fusion protein during virus fusion and assembly. | membrane fusion of the alphaviruses is mediated by the e1 protein, a class ii virus membrane fusion protein. during fusion, e1 dissociates from its heterodimer interaction with the e2 protein and forms a target membrane-inserted e1 homotrimer. the structure of the homotrimer is that of a trimeric hairpin in which e1 domain iii and the stem region fold back toward the target membrane-inserted fusion peptide loop. the e1 stem region has a strictly conserved length and several highly conserved resi ... | 2006 | 16971447 |
| role of sindbis virus capsid protein region ii in nucleocapsid core assembly and encapsidation of genomic rna. | sindbis virus is an enveloped positive-sense rna virus in the alphavirus genus. the nucleocapsid core contains the genomic rna surrounded by 240 copies of a single capsid protein. the capsid protein is multifunctional, and its roles include acting as a protease, controlling the specificity of rna that is encapsidated into nucleocapsid cores, and interacting with viral glycoproteins to promote the budding of mature virus and the release of the genomic rna into the newly infected cell. the region ... | 2008 | 18305029 |
| the dynamic envelope of a fusion class ii virus. e3 domain of glycoprotein e2 precursor in semliki forest virus provides a unique contact with the fusion protein e1. | in alphaviruses, here represented by semliki forest virus, infection requires an acid-responsive spike configuration to facilitate membrane fusion. the creation of this relies on the chaperone function of glycoprotein e2 precursor (p62) and its maturation cleavage into the small external e3 and the membrane-anchored e2 glycoproteins. to reveal how the e3 domain of p62 exerts its control of spike functions, we determine the structure of a p62 cleavage-impaired mutant virus particle (sql) by elect ... | 2008 | 18596032 |
| discovery of frameshifting in alphavirus 6k resolves a 20-year enigma. | the genus alphavirus includes several potentially lethal human viruses. additionally, species such as sindbis virus and semliki forest virus are important vectors for gene therapy, vaccination and cancer research, and important models for virion assembly and structural analyses. the genome encodes nine known proteins, including the small '6k' protein. 6k appears to be involved in envelope protein processing, membrane permeabilization, virion assembly and virus budding. in protein gels, 6k migrat ... | 2008 | 18822126 |
| random insertion mutagenesis of sindbis virus nonstructural protein 2 and selection of variants incapable of downregulating cellular transcription. | sindbis virus nonstructural protein 2 (sinv nsp2) is an important determinant of virus pathogenesis and downregulation of virus-induced cell response. this protein efficiently inhibits transcription of cellular messenger and ribosomal rnas and, thus, is capable of inhibiting the activation of genes whose products are involved in development of the antiviral response. alphavirus nsp2 has a number of predicted functional domains, some of which were confirmed by crystal structure. our current study ... | 2009 | 19570872 |
| e1 mutants identify a critical region in the trimer interface of the semliki forest virus fusion protein. | the alphavirus semliki forest virus (sfv) uses a membrane fusion reaction to infect host cells. fusion of the virus and cell membranes is triggered by low ph in the endosome and is mediated by the viral membrane protein e1. during fusion, e1 inserts into the target membrane, trimerizes, and refolds into a hairpin conformation. formation of the e1 homotrimer is critical to membrane fusion, but the mechanism of trimerization is not understood. the crystal structure of the postfusion e1 trimer show ... | 2009 | 19692469 |
| a structural and functional perspective of alphavirus replication and assembly. | alphaviruses are small, spherical, enveloped, positive-sense ssrna viruses responsible for a considerable number of human and animal diseases. alphavirus members include chikungunya virus, sindbis virus, semliki forest virus, the western, eastern and venezuelan equine encephalitis viruses, and the ross river virus. alphaviruses can cause arthritic diseases and encephalitis in humans and animals and continue to be a worldwide threat. the viruses are transmitted by blood-sucking arthropods, and re ... | 2009 | 19722838 |
| replication cycle of chikungunya: a re-emerging arbovirus. | arboviruses (or arthropod-borne viruses), represent a threat for the new century. the 2005-2006 year unprecedented epidemics of chikungunya virus (chikv) in the french reunion island in the indian ocean, followed by several outbreaks in other parts of the world such as india, have attracted the attention of clinicians, scientists, and state authorities about the risks linked to this re-emerging mosquito-borne virus. chikv, which belongs to the alphaviruses genus, was not previously regarded as a ... | 2009 | 19732931 |
| novel functions of the alphavirus nonstructural protein nsp3 c-terminal region. | the functions of the alphavirus-encoded nonstructural protein nsp3 during infection are poorly understood. in contrast, nsp1, nsp2, and nsp4 have known enzymatic activities and functions. a functional analysis of the c-terminal region of nsp3 of semliki forest virus revealed the presence of a degradation signal that overlaps with a sequence element located between nsp3 and nsp4 that is required for proteolytic processing. this element was responsible for the short half-life (1 h) of individually ... | 2010 | 20015978 |
| phylogeographic structure and evolutionary history of sindbis virus. | sindbis (sin) virus, alphavirus, is a mosquito-borne and bird-associated virus with large geographic distribution in the old world. we investigated the genetic diversity of 59 sin strains after limited sequencing of their e2 glycoprotein genes. the sin strains showed maximal diversity of 22.2% at the amino acid (aa) level, and formed five tentative genotypes. the sin-i genotype included strains from europe and africa. strains from australia and east asia formed sin-ii and sin-iii with about 12% ... | 2010 | 20420530 |
| structural basis for substrate specificity of alphavirus nsp2 proteases. | the alphavirus nsp2 protease is essential for correct processing of the alphavirus nonstructural polyprotein (nsp1234) and replication of the viral genome. we have combined molecular dynamics simulations with our structural studies to reveal features of the nsp2 protease catalytic site and s1'-s4 subsites that regulate the specificity of the protease. the catalytic mechanism of the nsp2 protease appears similar to the papain-like cysteine proteases, with the conserved catalytic dyad forming a th ... | 2010 | 20483643 |
| structure of the recombinant alphavirus western equine encephalitis virus revealed by cryoelectron microscopy. | western equine encephalitis virus (weev; togaviridae, alphavirus) is an enveloped rna virus that is typically transmitted to vertebrate hosts by infected mosquitoes. weev is an important cause of viral encephalitis in humans and horses in the americas, and infection results in a range of disease, from mild flu-like illnesses to encephalitis, coma, and death. in addition to spreading via mosquito vectors, human weev infections can potentially occur directly via aerosol transmission. due to its ae ... | 2010 | 20631130 |
| yellow fever virus in haemagogus leucocelaenus and aedes serratus mosquitoes, southern brazil, 2008. | yellow fever virus (yfv) was isolated from haemagogus leucocelaenus mosquitoes during an epizootic in 2001 in the rio grande do sul state in southern brazil. in october 2008, a yellow fever outbreak was reported there, with nonhuman primate deaths and human cases. this latter outbreak led to intensification of surveillance measures for early detection of yfv and support for vaccination programs. we report entomologic surveillance in 2 municipalities that recorded nonhuman primate deaths. mosquit ... | 2010 | 21122222 |
| pseudotyping lentiviral vectors with aura virus envelope glycoproteins for dc-sign-mediated transduction of dendritic cells. | abstract lentiviral vectors (lvs) pseudotyped with envelope proteins of alphaviruses have recently attracted considerable interest for their potential as gene delivery tools. we report the production of human immunodeficiency virus type 1 (hiv-1)-derived lvs pseudotyped with envelope glycoproteins derived from the aura virus (aura). we found that the aura-glycoprotein-pseudotyped lvs use c-type lectins (dc-sign and l-sign) as attachment factors. these interactions with dc-sign are specific as de ... | 2011 | 21452926 |
| stimulation of stop codon readthrough: frequent presence of an extended 3' rna structural element. | in sindbis, venezuelan equine encephalitis and related alphaviruses, the polymerase is translated as a fusion with other non-structural proteins via readthrough of a uga stop codon. surprisingly, earlier work reported that the signal for efficient readthrough comprises a single cytidine residue 3'-adjacent to the uga. however, analysis of variability at synonymous sites revealed strikingly enhanced conservation within the ∼150 nt 3'-adjacent to the uga, and rna folding algorithms revealed the po ... | 2011 | 21525127 |
| conservation of a packaging signal and the viral genome rna packaging mechanism in alphavirus evolution. | alphaviruses are a group of small, enveloped viruses which are widely distributed on all continents. in infected cells, alphaviruses display remarkable specificity in rna packaging by encapsidating only their genomic rna while avoiding packaging of the more abundant viral subgenomic (sg), cellular messenger and transfer rnas into released virions. in this work, we demonstrate that in spite of evolution in geographically isolated areas and accumulation of considerable diversity in the nonstructur ... | 2011 | 21680508 |
| Genome scale phylogeny of the Alphavirus genus suggests a marine origin. | The genus Alphavirus comprises a diverse group of viruses, including some that cause severe disease. Using full-length sequences of all known alphaviruses, we produced a robust and comprehensive phylogeny of the Alphavirus genus, presenting a more complete evolutionary history of these viruses compared to previous studies based on partial sequences. Our phylogeny suggests the origin of the alphaviruses occurred in the southern oceans and spread equally through the Old and New World. Since lice a ... | 2011 | 22190718 |
| 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 ... | 1999 | 10585969 |
| molecular detection of flaviviruses and alphaviruses in mosquitoes (diptera: culicidae) from coastal ecosystems in the colombian caribbean. | arboviruses belonging to the genera flavivirus and alphavirus were detected in mosquitoes in a rural area of san bernardo del viento (córdoba, colombia). a total of 22,180 mosquitoes were collected, sorted into 2,102 pools, and tested by generic/nested reverse transcription-polymerase chain reaction. venezuelan equine encephalitis virus, dengue virus, west nile virus, st. louis encephalitis virus, yellow fever virus, and culex flavivirus were detected and identified by sequencing. the detection ... | 2016 | 27706377 |
| sindbis and middelburg old world alphaviruses associated with neurologic disease in horses, south africa. | old world alphaviruses were identified in 52 of 623 horses with febrile or neurologic disease in south africa. five of 8 sindbis virus infections were mild; 2 of 3 fatal cases involved co-infections. of 44 middelburg virus infections, 28 caused neurologic disease; 12 were fatal. middelburg virus likely has zoonotic potential. | 0 | 26583836 |
| evolutionary genetics and vector adaptation of recombinant viruses of the western equine encephalitis antigenic complex provides new insights into alphavirus diversity and host switching. | western equine encephalitis virus (weev), highlands j virus (hjv), and fort morgan virus (fmv) are the sole representatives of the wee antigenic complex of the genus alphavirus, family togaviridae, that are endemic to north america. all three viruses have their ancestry in a recombination event involving eastern equine encephalitis virus (eeev) and a sindbis (sin)-like virus that gave rise to a chimeric alphavirus that subsequently diversified into the present-day weev, hjv, and fmv. here, we pr ... | 2014 | 25463613 |
| in- silico exploration of thirty alphavirus genomes for analysis of the simple sequence repeats. | the compilation of simple sequence repeats (ssrs) in viruses and its analysis with reference to incidence, distribution and variation would be instrumental in understanding the functional and evolutionary aspects of repeat sequences. present study encompasses the analysis of ssrs across 30 species of alphaviruses. the full length genome sequences, assessed from ncbi were used for extraction and analysis of repeat sequences using imex software. the repeats of different motif sizes (mono- to penta ... | 2014 | 25606453 |
| zoonotic encephalitides caused by arboviruses: transmission and epidemiology of alphaviruses and flaviviruses. | in this review, we mainly focus on zoonotic encephalitides caused by arthropod-borne viruses (arboviruses) of the families flaviviridae (genus flavivirus) and togaviridae (genus alphavirus) that are important in both humans and domestic animals. specifically, we will focus on alphaviruses (eastern equine encephalitis virus, western equine encephalitis virus, venezuelan equine encephalitis virus) and flaviviruses (japanese encephalitis virus and west nile virus). most of these viruses were origin ... | 2013 | 24427764 |
| a genome-wide analysis of rna pseudoknots that stimulate efficient -1 ribosomal frameshifting or readthrough in animal viruses. | programmed -1 ribosomal frameshifting (prf) and stop codon readthrough are two translational recoding mechanisms utilized by some rna viruses to express their structural and enzymatic proteins at a defined ratio. efficient recoding usually requires an rna pseudoknot located several nucleotides downstream from the recoding site. to assess the strategic importance of the recoding pseudoknots, we have carried out a large scale genome-wide analysis in which we used an in-house developed program to d ... | 2013 | 24298557 |
| adaptive changes in alphavirus mrna translation allowed colonization of vertebrate hosts. | members of the alphavirus genus are arboviruses that alternate replication in mosquitoes and vertebrate hosts. in vertebrate cells, the alphavirus resists the activation of antiviral rna-activated protein kinase (pkr) by the presence of a prominent rna structure (downstream loop [dlp]) located in viral 26s transcripts, which allows an eif2-independent translation initiation of these mrnas. this article shows that dlp structure is essential for replication of sindbis virus (sinv) in vertebrate ce ... | 2012 | 22761388 |
| cell-based analysis of chikungunya virus e1 protein in membrane fusion. | chikungunya fever is a pandemic disease caused by the mosquito-borne chikungunya virus (chikv). e1 glycoprotein mediation of viral membrane fusion during chikv infection is a crucial step in the release of viral genome into the host cytoplasm for replication. how the e1 structure determines membrane fusion and whether other chikv structural proteins participate in e1 fusion activity remain largely unexplored. | 2012 | 22520648 |
| ancient recombination events and the origins of hepatitis e virus. | hepatitis e virus (hev) is an enteric, single-stranded, positive sense rna virus and a significant etiological agent of hepatitis, causing sporadic infections and outbreaks globally. tracing the evolutionary ancestry of hev has proved difficult since its identification in 1992, it has been reclassified several times, and confusion remains surrounding its origins and ancestry. | 2016 | 27733122 |
| eilat virus host range restriction is present at multiple levels of the virus life cycle. | most alphaviruses are mosquito-borne and exhibit a broad host range, infecting many different vertebrates, including birds, rodents, equids, humans, and nonhuman primates. this ability of most alphaviruses to infect arthropods and vertebrates is essential for their maintenance in nature. recently, a new alphavirus, eilat virus (eilv), was described, and in contrast to all other mosquito-borne viruses, it is unable to replicate in vertebrate cell lines. investigations into the nature of its host ... | 2014 | 25392227 |
| the alphavirus e3 glycoprotein functions in a clade-specific manner. | the 80 trimeric, glycoprotein spikes that cover the surface of alphavirus particles are required for mediating viral entry into a host cell. spike assembly is a regulated process that requires interactions between five structural proteins, e3, e2, 6k and its translational frameshift product tf, and e1. e3 is a small, ∼65-amino-acid glycoprotein that has two known functions: e3 serves as the signal sequence for translocation of the e3-e2-6k-e1 polyprotein into the endoplasmic reticulum (er), and ... | 2012 | 23035234 |
| biological transmission of arboviruses: reexamination of and new insights into components, mechanisms, and unique traits as well as their evolutionary trends. | among animal viruses, arboviruses are unique in that they depend on arthropod vectors for transmission. field research and laboratory investigations related to the three components of this unique mode of transmission, virus, vector, and vertebrate host, have produced an enormous amount of valuable information that may be found in numerous publications. however, despite many reviews on specific viruses, diseases, or interests, a systematic approach to organizing the available information on all f ... | 0 | 16223950 |
| an rna trapping mechanism in alphavirus mrna promotes ribosome stalling and translation initiation. | during translation initiation, eukaryotic initiation factor 2 (eif2) delivers the met-trna to the 40s ribosomal subunit to locate the initiation codon (augi) of mrna during the scanning process. stress-induced eif2 phosphorylation leads to a general blockade of translation initiation and represents a key antiviral pathway in mammals. however, some viral mrnas can initiate translation in the presence of phosphorylated eif2 via stable rna stem-loop structures (dlp; downstream loop) located in thei ... | 2016 | 26984530 |
| bed bugs and infectious disease: a case for the arboviruses. | | 2013 | 23966852 |
| a fully attenuated recombinant salmonid alphavirus becomes pathogenic through a single amino acid change in the e2 glycoprotein. | a recombinant sleeping disease virus (rsdv) was previously shown to be totally attenuated and provide long-term protection in trout (c. moriette, m. leberre, a. lamoureux, t. l. lai, m. brémont, j. virol. 80:4088-4098, 2006). sequence comparison of the rsdv to wild-type genomes exhibited a number of nucleotide changes. in the current study, we demonstrate that the virulent phenotype of sdv was essentially associated with two amino acid changes, v8a and m136t, in the e2 glycoprotein, with the v8a ... | 2013 | 23449806 |
| eilat virus, a unique alphavirus with host range restricted to insects by rna replication. | most alphaviruses and many other arboviruses are mosquito-borne and exhibit a broad host range, infecting many different vertebrates including birds, rodents, equids, humans, and nonhuman primates. consequently, they can be propagated in most vertebrate and insect cell cultures. this ability of arboviruses to infect arthropods and vertebrates is usually essential for their maintenance in nature. however, several flaviviruses have recently been described that infect mosquitoes but not vertebrates ... | 2012 | 22908261 |
| crystal structure of aura virus capsid protease and its complex with dioxane: new insights into capsid-glycoprotein molecular contacts. | the nucleocapsid core interaction with endodomains of glycoproteins plays a critical role in the alphavirus life cycle that is essential to virus budding. recent cryo-electron microscopy (cryo-em) studies provide structural insights into key interactions between capsid protein (cp) and trans-membrane glycoproteins e1 and e2. cp possesses a chymotrypsin-like fold with a hydrophobic pocket at the surface responsible for interaction with glycoproteins. in the present study, crystal structures of th ... | 2012 | 23251484 |
| kinetic characterization of trans-proteolytic activity of chikungunya virus capsid protease and development of a fret-based hts assay. | chikungunya virus (chikv) capsid protein (cvcp) is a serine protease that possesses cis-proteolytic activity essential for the structural polyprotein processing and plays a key role in the virus life cycle. chikv being an emerging arthropod-borne pathogenic virus, is a public health concern worldwide. no vaccines or specific antiviral treatment is currently available for chikungunya disease. thus, it is important to develop inhibitors against chikv enzymes to block key steps in viral reproductio ... | 2015 | 26439734 |
| alphavirus rna synthesis and non-structural protein functions. | the members of the genus alphavirus are positive-sense rna viruses, which are predominantly transmitted to vertebrates by a mosquito vector. alphavirus disease in humans can be severely debilitating, and depending on the particular viral species, infection may result in encephalitis and possibly death. in recent years, alphaviruses have received significant attention from public health authorities as a consequence of the dramatic emergence of chikungunya virus in the indian ocean islands and the ... | 2015 | 26219641 |
| ifit1 differentially interferes with translation and replication of alphavirus genomes and promotes induction of type i interferon. | alphaviruses are a group of widely distributed human and animal pathogens. it is well established that their replication is sensitive to type i ifn treatment, but the mechanism of ifn inhibitory function remains poorly understood. using a new experimental system, we demonstrate that in the presence of ifn-β, activation of interferon-stimulated genes (isgs) does not interfere with either attachment of alphavirus virions to the cells, or their entry and nucleocapsid disassembly. however, it strong ... | 2015 | 25927359 |
| trans-protease activity and structural insights into the active form of the alphavirus capsid protease. | the alphavirus capsid protein (cp) is a serine protease that possesses cis-proteolytic activity essential for its release from the nascent structural polyprotein. the released cp further participates in viral genome encapsidation and nucleocapsid core formation, followed by its attachment to glycoproteins and virus budding. thus, protease activity of the alphavirus capsid is a potential antialphaviral target to arrest capsid release, maturation, and structural polyprotein processing. however, th ... | 2014 | 25100849 |
| crystallization, high-resolution data collection and preliminary crystallographic analysis of aura virus capsid protease and its complex with dioxane. | the c-terminal protease domain of capsid protein from aura virus expressed in a bacterial expression system has been purified to homogeneity and crystallized. crystals suitable for x-ray diffraction analysis were obtained by the vapour-diffusion method using 0.1 m bis-tris and polyethylene glycol monomethyl ether 2000. crystals of the c-terminal protease domain of capsid protein in complex with dioxane were also produced and crystal data were obtained. both crystals belonged to space group c2, w ... | 2011 | 22102240 |
| a viral mrna motif at the 3'-untranslated region that confers translatability in a cell-specific manner. implications for virus evolution. | sindbis virus (sinv) mrnas contain several motifs that participate in the regulation of their translation. we have discovered a motif at the 3' untranslated region (utr) of viral mrnas, constituted by three repeated sequences, which is involved in the translation of both sinv genomic and subgenomic mrnas in insect, but not in mammalian cells. these data illustrate for the first time that an element present at the 3'-utr confers translatability to mrnas from an animal virus in a cell-specific man ... | 2016 | 26755446 |
| neutralising antibodies for mayaro virus in pantanal, brazil. | the pantanal hosts diverse wildlife species and therefore is a hotspot for arbovirus studies in south america. a serosurvey for mayaro virus (mayv), eastern (eeev), western (weev) and venezuelan (veev) equine encephalitis viruses was conducted with 237 sheep, 87 free-ranging caimans and 748 equids, including 37 collected from a ranch where a neurologic disorder outbreak had been recently reported. sera were tested for specific viral antibodies using plaque-reduction neutralisation test. from a t ... | 2015 | 25742272 |
| mayaro virus and dengue virus 1 and 4 natural infection in culicids from cuiabá, state of mato grosso, brazil. | this study aimed to verify the diversity of culicidae species and their frequency of infection with flaviviruses and alphaviruses in cuiabá, state of mato grosso, brazil. mosquitoes were captured with nasci aspirators and hand net in 200 census tracts, identified alive at species level and pooled in one-20 (11,090 mosquitoes, 14 species). female pools (n = 610) were subjected to multiplex seminested-reverse transcription-polymerase chain reaction (rt-pcr) for 11 flavivirus and five alphavirus. p ... | 0 | 26784852 |
| molecular detection of mayaro virus during a dengue outbreak in the state of mato grosso, central-west brazil. | mayaro virus (mayv) is frequently reported in pan-amazonia. the aim of this study was to investigate the circulation of alphaviruses during a dengue outbreak in the state of mato grosso, brazil. serum samples from dengue-suspected patients were subjected to multiplex semi-nested reverse transcriptase polymerase chain reaction for 11 flaviviruses and five alphaviruses, to nucleotide sequencing and to viral isolation. mayv was detected in 15 (2.5%) of 604 patients. twelve were co-infected with den ... | 2014 | 25141284 |
| alphavirus protease inhibitors from natural sources: a homology modeling and molecular docking investigation. | alphaviruses such as chikungunya virus (chikv), o'nyong-nyong virus (onnv), ross river virus (rrv), eastern equine encephalitis virus (eeev), venezuelan equine encephalitis virus (veev), and western equine encephalitis virus (weev), are mosquito-transmitted viruses that can cause fevers, rash, and rheumatic diseases (chikv, onnv, rrv) or potentially fatal encephalitis (eeev, veev, weev) in humans. these diseases are considered neglected tropical diseases for which there are no current antiviral ... | 2016 | 27387412 |
| effect of dimethylsulfoxide on the infectivity of aura virus ribonucleic acid. brief report. | | 1970 | 5457238 |
| evaluation of antiviral activity of piperazine against chikungunya virus targeting hydrophobic pocket of alphavirus capsid protein. | small heterocyclic molecules such as piperazine are potential pharmacotherapeutic agents and binding of these molecules to the hydrophobic pocket of capsid protein (cp) offers a new perspective for therapeutic intervention. here, we report the crystal structure of cp from aura virus (avcp) in complex with piperazine at 2.2 å resolution. piperazine binds to the conserved hydrophobic pocket of cp where dioxane based antivirals bind. comparative structural studies of the piperazine-bound avcp struc ... | 2017 | 28842264 |