Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| increased expression of the immediate-early gene arc/arg3.1 reduces ampa receptor-mediated synaptic transmission. | arc/arg3.1 is an immediate-early gene whose expression levels are increased by strong synaptic activation, including synapse-strengthening activity patterns. arc/arg3.1 mrna is transported to activated dendritic regions, conferring the distribution of arc/arg3.1 protein both temporal correlation with the inducing stimulus and spatial specificity. here, we investigate the effect of increased arc/arg3.1 levels on synaptic transmission. surprisingly, arc/arg3.1 reduces the amplitude of synaptic cur ... | 2006 | 17088212 |
| arc/arg3.1 mediates homeostatic synaptic scaling of ampa receptors. | homeostatic plasticity may compensate for hebbian forms of synaptic plasticity, such as long-term potentiation (ltp) and depression (ltd), by scaling neuronal output without changing the relative strength of individual synapses. this delicate balance between neuronal output and distributed synaptic weight may be necessary for maintaining efficient encoding of information across neuronal networks. here, we demonstrate that arc/arg3.1, an immediate-early gene (ieg) that is rapidly induced by neuro ... | 2006 | 17088213 |
| role of the amphipathic peptide of semliki forest virus replicase protein nsp1 in membrane association and virus replication. | semliki forest virus rna replication takes place in association with specific cytoplasmic vacuoles, derived from the endosomal apparatus. of the four virus-encoded replicase proteins, nsp1 serves as the membrane anchor of the replication complex. an amphipathic peptide segment, g245stlytesrkllrswhlpsv264, has been implicated in the membrane binding of nsp1. nsp1 variants with changes within the peptide were studied after protein expression and in the context of virus infection. proteins with mut ... | 2007 | 17093195 |
| chlorella viruses contain genes encoding a complete polyamine biosynthetic pathway. | two genes encoding the putative polyamine biosynthetic enzymes agmatine iminohydrolase (aih) and n-carbamoylputrescine amidohydrolase (cpa) were cloned from the chloroviruses pbcv-1, ny-2a and mt325. they were expressed in escherichia coli to form c-terminal (his)6-tagged proteins and the recombinant proteins were purified by ni2+-binding affinity chromatography. the biochemical properties of the two enzymes are similar to aih and cpa enzymes from arabidopsis thaliana and pseudomonas aeruginosa. ... | 2007 | 17101165 |
| the old world and new world alphaviruses use different virus-specific proteins for induction of transcriptional shutoff. | alphaviruses are widely distributed throughout the world. during the last few thousand years, the new world viruses, including venezuelan equine encephalitis virus (veev) and eastern equine encephalitis virus (eeev), evolved separately from those of the old world, i.e., sindbis virus (sinv) and semliki forest virus (sfv). nevertheless, the results of our study indicate that both groups have developed the same characteristic: their replication efficiently interferes with cellular transcription an ... | 2007 | 17108023 |
| selective repression of translation by the brome mosaic virus 1a rna replication protein. | differential expression of viral replication proteins is essential for successful infection. we report here that overexpression of the brome mosaic virus (bmv) 1a protein can repress viral rna replication in a dosage-dependent manner. using rna replication-incompetent reporter constructs, repression of translation from bmv rna1 and rna2 was observed, suggesting that the effect on translation of the bmv rna replication proteins is responsible for the decrease in rna levels. furthermore, repressio ... | 2007 | 17108036 |
| variable deficiencies in the interferon response enhance susceptibility to vesicular stomatitis virus oncolytic actions in glioblastoma cells but not in normal human glial cells. | with little improvement in the poor prognosis for humans with high-grade glioma brain tumors, alternative therapeutic strategies are needed. as such, selective replication-competent oncolytic viruses may be useful as a potential treatment modality. here we test the hypothesis that defects in the interferon (ifn) pathway could be exploited to enhance the selective oncolytic profile of vesicular stomatitis virus (vsv) in glioblastoma cells. two green fluorescent protein-expressing vsv strains, rec ... | 2007 | 17108037 |
| tumor necrosis factor (tnf) protects resistant c57bl/6 mice against herpes simplex virus-induced encephalitis independently of signaling via tnf receptor 1 or 2. | tumor necrosis factor (tnf) is a multifunctional cytokine that has a role in induction and regulation of host innate and adaptive immune responses. the importance of tnf antiviral mechanisms is reflected by the diverse strategies adopted by different viruses, particularly members of the herpesvirus family, to block tnf responses. tnf binds and signals through two receptors, tnfrsf1a (tnf receptor 1 [tnfr1], or p55) and tnfrsf1b (tnfr2, or p75). we report here that herpes simplex virus 1 (hsv-1) ... | 2007 | 17108044 |
| infection of ixodes scapularis ticks with rickettsia monacensis expressing green fluorescent protein: a model system. | ticks (acari: ixodidae) are ubiquitous hosts of rickettsiae (rickettsiaceae: rickettsia), obligate intracellular bacteria that occur as a continuum from nonpathogenic arthropod endosymbionts to virulent pathogens of both arthropod vectors and vertebrates. visualization of rickettsiae in hosts has traditionally been limited to techniques utilizing fixed tissues. we report epifluorescence microscopy observations of unfixed tick tissues infected with a spotted fever group endosymbiont, rickettsia m ... | 2007 | 17125789 |
| tyrosine 311 is phosphorylated by c-abl and promotes the apoptotic effect of pkcdelta in glioma cells. | in this study we characterized the phosphorylation of tyrosine 311 and its role in the apoptotic function of pkcdelta in glioma cells. we found that c-abl phosphorylated pkcdelta on tyrosine 311 in response to h2o2 and that this phosphorylation contributed to the apoptotic effect of h2o2. in contrast, src, lyn, and yes were not involved in the phosphorylation of tyrosine 311 by h2o2. a phosphomimetic pkcdelta mutant, in which tyrosine 311 was mutated to glutamic acid (pkcdeltay311e), induced a l ... | 2006 | 17126298 |
| genomic and metabolic studies of the impact of probiotics on a model gut symbiont and host. | probiotics are deliberately ingested preparations of live bacterial species that confer health benefits on the host. many of these species are associated with the fermentation of dairy products. despite their increasing use, the molecular details of the impact of various probiotic preparations on resident members of the gut microbiota and the host are generally lacking. to address this issue, we colonized germ-free mice with bacteroides thetaiotaomicron, a prominent component of the adult human ... | 2006 | 17132046 |
| ampar removal underlies abeta-induced synaptic depression and dendritic spine loss. | beta amyloid (abeta), a peptide generated from the amyloid precursor protein (app) by neurons, is widely believed to underlie the pathophysiology of alzheimer's disease. recent studies indicate that this peptide can drive loss of surface ampa and nmda type glutamate receptors. we now show that abeta employs signaling pathways of long-term depression (ltd) to drive endocytosis of synaptic ampa receptors. synaptic removal of ampa receptors is necessary and sufficient to produce loss of dendritic s ... | 2006 | 17145504 |
| thiol/disulfide exchange is required for membrane fusion directed by the newcastle disease virus fusion protein. | newcastle disease virus (ndv), an avian paramyxovirus, initiates infection with attachment of the viral hemagglutinin-neuraminidase (hn) protein to sialic acid-containing receptors, followed by fusion of viral and cell membranes, which is mediated by the fusion (f) protein. like all class 1 viral fusion proteins, the paramyxovirus f protein is thought to undergo dramatic conformational changes upon activation. how the f protein accomplishes extensive conformational rearrangements is unclear. sin ... | 2007 | 17151113 |
| alphavirus replicon approach to promoterless analysis of ires elements. | here we describe a system for promoterless analysis of putative internal ribosome entry site (ires) elements using an alphavirus (family togaviridae) replicon vector. the system uses the alphavirus subgenomic promoter to produce transcripts that, when modified to contain a spacer region upstream of an ires element, allow analysis of cap-independent translation of genes of interest (goi). if the ires element is removed, translation of the subgenomic transcript can be reduced >95% compared to the ... | 2007 | 17156813 |
| distinguishing reversible from irreversible virus capsid assembly. | capsids of spherical viruses may be constructed from hundreds or thousands of copies of the major capsid protein(s). these assembly reactions are poorly understood. here we consider the predicted behavior for assembly where the component reactions have weak association energy and are reversible and compare them to essentially irreversible reactions. the comparisons are based on mass action calculations and the behavior predicted from kinetic simulations where assembly is described as a cascade o ... | 2006 | 17157314 |
| herpes simplex virus type 2-mediated disease is reduced in mice lacking rnase l. | rnase l helps mediate the antiviral state induced by type i interferons (ifnalphabeta). although herpes simplex virus (hsv) encodes inhibitors of the ifnalphabeta-induced antiviral response, the ifnalphabeta system serves the body as a first line of defense against hsv. we investigated whether rnase l limits hsv-2 replication and virulence. rnasel(-/-) and wild-type c57bl/6 mice were infected intravaginally with hsv-2 strain 333. although initial replication in the genital epithelium was similar ... | 2007 | 17157346 |
| impact of protein kinase pkr in cell biology: from antiviral to antiproliferative action. | the double-stranded rna-dependent protein kinase pkr is a critical mediator of the antiproliferative and antiviral effects exerted by interferons. not only is pkr an effector molecule on the cellular response to double-stranded rna, but it also integrates signals in response to toll-like receptor activation, growth factors, and diverse cellular stresses. in this review, we provide a detailed picture on how signaling downstream of pkr unfolds and what are the ultimate consequences for the cell fa ... | 0 | 17158706 |
| metabotropic glutamate receptor 4-immunopositive terminals of medium-sized spiny neurons selectively form synapses with cholinergic interneurons in the rat neostriatum. | metabotropic glutamate receptor 4 (mglur4) is localized mainly to presynaptic membranes in the brain. rat neostriatum has been reported to contain two types of mglur4-immunoreactive axon varicosities: small, weakly immunoreactive varicosities that were distributed randomly (type 1) and large, intensely immunoreactive ones that were often aligned linearly (type 2). in the present study, most type 1 terminals formed asymmetric synapses on dendritic spines, whereas type 2 terminals made symmetric s ... | 2007 | 17177262 |
| a mouse cell-adapted ns4b mutation attenuates west nile virus rna synthesis. | an adaptive mutation (e249g) within west nile virus (wnv) ns4b gene was consistently recovered from replicon rnas in c3h/he mouse cells. the e249g is located at the c-terminal tail of ns4b predicted to be on the cytoplasmic side of the endoplasmic reticulum membrane. the e249g substitution reduced replicon rna synthesis. compared with the wild-type ns4b, the e249g mutant protein exhibited a similar efficiency in evasion of interferon-beta response. recombinant e249g virus exhibited smaller plaqu ... | 2007 | 17178141 |
| inhibition of filovirus replication by the zinc finger antiviral protein. | the zinc finger antiviral protein (zap) was recently shown to inhibit moloney murine leukemia virus and sindbis virus replication. we tested whether zap also acts against ebola virus (ebov) and marburg virus (marv). antiviral effects were observed after infection of cells expressing the n-terminal part of zap fused to the product of the zeocin resistance gene (nzap-zeo) as well as after infection of cells inducibly expressing full-length zap. ebov was inhibited by up to 4 log units, whereas marv ... | 2007 | 17182693 |
| long-distance rna-rna interactions between terminal elements and the same subset of internal elements on the potato virus x genome mediate minus- and plus-strand rna synthesis. | potexvirus genomes contain conserved terminal elements that are complementary to multiple internal octanucleotide elements. both local sequences and structures at the 5' terminus and long-distance interactions between this region and internal elements are important for accumulation of potato virus x (pvx) plus-strand rna in vivo. in this study, the role of the conserved hexanucleotide motif within sl3 of the 3' ntr and internal conserved octanucleotide elements in minus-strand rna synthesis was ... | 2007 | 17185361 |
| the zinc-finger antiviral protein recruits the rna processing exosome to degrade the target mrna. | zinc-finger antiviral protein (zap) is a host antiviral factor that specifically inhibits the replication of moloney murine leukemia virus (mlv) and sindbis virus (sin) by preventing accumulation of the viral mrna in the cytoplasm. in previous studies, we demonstrated that zap directly binds to its specific target mrnas. in this article, we provide evidence indicating that zap recruits the rna processing exosome to degrade the target rna. zap comigrated with the exosome in sucrose or glycerol ve ... | 2007 | 17185417 |
| caspase 3-dependent cell death of neurons contributes to the pathogenesis of west nile virus encephalitis. | west nile virus (wnv) is a neurotropic, arthropod-borne flavivirus that has become a significant global cause of viral encephalitis. to examine the mechanisms of wnv-induced neuronal death and the importance of apoptosis in pathogenesis, we evaluated the role of a key apoptotic regulator, caspase 3. wnv infection induced caspase 3 activation and apoptosis in the brains of wild-type mice. notably, congenic caspase 3(-/-) mice were more resistant to lethal wnv infection, although there were no sig ... | 2007 | 17192305 |
| the taming of the cell penetrating domain of the hiv tat: myths and realities. | protein transduction with cell penetrating peptides over the past several years has been shown to be an effective way of delivering proteins in vitro and now several reports have also shown valuable in vivo applications in correcting disease states. an impressive bioinspired phenomenon of crossing biological barriers came from hiv transactivator tat protein. specifically, the protein transduction domain of hiv tat has been shown to be a potent pleiotropic peptide in protein delivery. various app ... | 2007 | 17196289 |
| enzymatic defects of the nsp2 proteins of semliki forest virus temperature-sensitive mutants. | we have analyzed the biochemical consequences of mutations that affect viral rna synthesis in semliki forest virus temperature-sensitive (ts) mutants. of the six mutations mapping in the multifunctional replicase protein nsp2, three were located in the n-terminal helicase region and three were in the c-terminal protease domain. wild-type and mutant nsp2s were expressed, purified, and assayed for nucleotide triphosphatase (ntpase), rna triphosphatase (rtpase), and protease activities in vitro at ... | 2007 | 17202213 |
| heparan sulfate binding can contribute to the neurovirulence of neuroadapted and nonneuroadapted sindbis viruses. | cell culture-adapted laboratory strains of sindbis virus (sb) exhibit efficient initial attachment to cell surface heparan sulfate (hs) receptors. in contrast, non-cell-adapted strains, such as the sb consensus sequence virus tr339, interact weakly with hs and cell surfaces. regardless of their hs binding phenotype, most sb strains do not cause fatal disease in adult mice, whether inoculated subcutaneously (s.c.) or intracranially (i.c.). however, laboratory strains of sb can be rendered neurovi ... | 2007 | 17215278 |
| a mouse-adapted sars-coronavirus causes disease and mortality in balb/c mice. | no single animal model for severe acute respiratory syndrome (sars) reproduces all aspects of the human disease. young inbred mice support sars-coronavirus (sars-cov) replication in the respiratory tract and are available in sufficient numbers for statistical evaluation. they are relatively inexpensive and easily accessible, but their use in sars research is limited because they do not develop illness following infection. older (12- to 14-mo-old) balb/c mice develop clinical illness and pneumoni ... | 2007 | 17222058 |
| negative regulation of isg15 e3 ligase efp through its autoisgylation. | the function of ubiquitin-like protein isg15 and protein modification by isg15 (isgylation) has been an enigma for many years. recently, the research of isgylation has been accelerated by the identification of the enzymes involved in the isg15 conjugation process. our previous study identified the interferon inducible protein efp as an isg15 isopeptide ligase (e3) for 14-3-3sigma. in this study, we show that isg15 e3 ligase efp can be modified by isg15. two ubiquitin e2 conjugating enzymes, ubch ... | 2007 | 17222803 |
| correlation between breakdown of the blood-brain barrier and disease outcome of viral encephalitis in mice. | changes in the permeability of the blood-brain barrier (bbb) were evaluated in two mouse models of viral encephalitis. the ability of sodium fluorescein (nafl) to cross the bbb from the serum into the central nervous system was assayed in animals inoculated with virulent strains of either banzi or semliki forest viruses. to test the hypothesis that increases in bbb permeability were associated with poor disease outcome subsequent experiments measured bbb permeability in conjunction with treatmen ... | 2007 | 17223204 |
| ifn-stimulated gene 15 functions as a critical antiviral molecule against influenza, herpes, and sindbis viruses. | type i interferons (ifns) play an essential role in the host response to viral infection through the induction of numerous ifn-stimulated genes (isgs), including important antiviral molecules such as pkr, rnase l, mx, and inos. yet, additional antiviral isgs likely exist. ifn-stimulated gene 15 (isg15) is a ubiquitin homolog that is rapidly up-regulated after viral infection, and it conjugates to a wide array of host proteins. although it has been hypothesized that isg15 functions as an antivira ... | 2007 | 17227866 |
| the glycoprotein cytoplasmic tail of uukuniemi virus (bunyaviridae) interacts with ribonucleoproteins and is critical for genome packaging. | we have analyzed the importance of specific amino acids in the cytoplasmic tail of the glycoprotein g(n) for packaging of ribonucleoproteins (rnps) into virus-like particles (vlps) of uukuniemi virus (uuk virus), a member of the bunyaviridae family. in order to study packaging, we added the g(n)/g(c) glycoprotein precursor (p110) to a polymerase i-driven minigenome rescue system to generate vlps that are released into the supernatant. these particles can infect new cells, and reporter gene expre ... | 2007 | 17229712 |
| early restriction of alphavirus replication and dissemination contributes to age-dependent attenuation of systemic hyperinflammatory disease. | severity of alphavirus infection in humans tends to be strongly age-dependent and several studies using laboratory-adapted sindbis virus (sb) ar339 strains have indicated that sb-induced disease in mice is similarly contingent upon host developmental status. in the current studies, the consensus wild-type sb, tr339, and in vivo imaging technology have been utilized to examine virus replication and disease manifestations in mice infected subcutaneously at 5 days of age (5d) vs 11d. initial virule ... | 2007 | 17251570 |
| dengue virus type 2: replication and tropisms in orally infected aedes aegypti mosquitoes. | to be transmitted by its mosquito vector, dengue virus (denv) must infect midgut epithelial cells, replicate and disseminate into the hemocoel, and finally infect the salivary glands, which is essential for transmission. the extrinsic incubation period (eip) is very relevant epidemiologically and is the time required from the ingestion of virus until it can be transmitted to the next vertebrate host. the eip is conditioned by the kinetics and tropisms of virus replication in its vector. here we ... | 2007 | 17263893 |
| capsid protein of eastern equine encephalitis virus inhibits host cell gene expression. | eastern equine encephalitis virus (eeev) causes sporadic but often severe cases of human and equine neurological disease in north america. to determine how eeev may evade innate immune responses, we screened individual eeev proteins for the ability to rescue the growth of a newcastle disease virus expressing green fluorescent protein (ndv-gfp) from the antiviral effects of interferon (ifn). only expression of the eeev capsid facilitated ndv-gfp replication. inhibition of the antiviral effects of ... | 2007 | 17267491 |
| synthesis and antiviral activities of new acyclic and "double-headed" nucleoside analogues. | to develop an understanding of the structure-activity relationships for the inhibition of orthopoxviruses by nucleoside analogues, a variety of novel chemical entities were synthesized. these included a series of pyrimidine 5-hypermodified acyclic nucleoside analogues based upon recently discovered new leads, and some previously unknown "double-headed" or "abbreviated" nucleosides. none of the synthetic products possessed significant activity against two representative orthopoxviruses; namely, v ... | 2007 | 17270235 |
| methylation: a regulator of hiv-1 replication? | recent characterizations of methyl transferases as regulators of cellular processes have spurred investigations into how methylation events might influence the hiv-1 life cycle. emerging evidence suggests that protein-methylation can positively and negatively regulate hiv-1 replication. how dna- and rna- methylation might impact hiv-1 is also discussed. | 2007 | 17274823 |
| the study transplacental chikungunya virus antibody kinetics, thailand. | antibodies to chikungunya virus were detected by hemagglutination-inhibition assay in 33.6% of 2,000 infants' cord sera at delivery. follow-up of 24 seropositive infants showed that the half-life of antibody persistence was 35.5 days. chikungunya virus infection is common in thailand, and routine use of diagnostic assays is needed. | 2006 | 17283634 |
| biochemical and genetic analysis of rna cap guanine-n2 methyltransferases from giardia lamblia and schizosaccharomyces pombe. | rna cap guanine-n2 methyltransferases such as schizosaccharomyces pombe tgs1 and giardia lamblia tgs2 catalyze methylation of the exocyclic n2 amine of 7-methylguanosine. here we performed a mutational analysis of giardia tgs2, entailing an alanine scan of 17 residues within the minimal active domain. alanine substitutions at phe18, thr40, asp76, asn103 and asp140 reduced methyltransferase specific activity to <3% of wild-type tgs2, thereby defining these residues as essential. alanines at pro14 ... | 2007 | 17284461 |
| synthesis of dioxane-based antiviral agents and evaluation of their biological activities as inhibitors of sindbis virus replication. | the crystal structure of the sindbis virus capsid protein contains one or two solvent-derived dioxane molecules in the hydrophobic binding pocket. a bis-dioxane antiviral agent was designed by linking the two dioxane molecules with a three-carbon chain having r,r connecting stereochemistry, and a stereospecific synthesis was performed. this resulted in an effective antiviral agent that inhibited sindbis virus replication with an ec(50) of 14 microm. the synthesis proceeded through an intermediat ... | 2007 | 17287124 |
| distinct sites on the sindbis virus rna-dependent rna polymerase for binding to the promoters for the synthesis of genomic and subgenomic rna. | sindbis virus-infected cells make two positive-strand rnas, a genomic (g) rna and a subgenomic (sg) rna. here we report the amino acid sequence in nonstructural protein 4 (nsp4), the viral rna-dependent rna polymerase, that binds to the promoter for the synthesis of g rna. in addition, using a cell-free system that makes both g and sg rna, we show that specific amino acid changes in nsp4 that abolish the synthesis of sg rna have no effect on the synthesis of g rna. our findings indicate that nsp ... | 2007 | 17287268 |
| superinfection exclusion in cells infected with hepatitis c virus. | superinfection exclusion is the ability of an established virus infection to interfere with infection by a second virus. in this study, we found that huh-7.5 cells acutely infected with hepatitis c virus (hcv) genotype 2a (chimeric strain j6/jfh) and cells harboring hcv genotype 1a, 1b, or 2a full-length or subgenomic replicons were resistant to infection with cell culture-produced hcv (hcvcc). replicon-containing cells became permissive for hcvcc infection after treatment with an hcv-specific p ... | 2007 | 17287280 |
| infection of cells by sindbis virus at low temperature. | sindbis virus, which belongs to the family togaviridae genus alphavirus infects a variety of vertebrate and invertebrate cells. the initial steps of sindbis virus infection involve attachment, penetration and uncoating. two different pathways of infection have been proposed for alphaviruses. one proposed mechanism involves receptor mediated virion endocytosis followed by membrane fusion triggered by endosome acidification. this virus-host membrane fusion model, well established by influenza viru ... | 2007 | 17289103 |
| isg15 modification of the eif4e cognate 4ehp enhances cap structure-binding activity of 4ehp. | the expression of the ubiquitin-like molecule isg15 and protein modification by isg15 (isgylation) are strongly activated by interferon, genotoxic stress, and pathogen infection, suggesting that isg15 plays an important role in innate immune responses. 4ehp is an mrna 5' cap structure-binding protein and acts as a translation suppressor by competing with eif4e for binding to the cap structure. here, we report that 4ehp is modified by isg15 and isgylated 4ehp has a much higher cap structure-bindi ... | 2007 | 17289916 |
| progranulin in frontotemporal lobar degeneration and neuroinflammation. | progranulin (pgrn) is a pleiotropic protein that has gained the attention of the neuroscience community with recent discoveries of mutations in the gene for pgrn that cause frontotemporal lobar degeneration (ftld). pathogenic mutations in pgrn result in null alleles, and the disease is likely the result of haploinsufficiency. little is known about the normal function of pgrn in the central nervous system apart from a role in brain development. it is expressed by microglia and neurons. in the per ... | 2007 | 17291356 |
| intranasal immunization with synthetic peptides corresponding to the e6 and e7 oncoproteins of human papillomavirus type 16 induces systemic and mucosal cellular immune responses and tumor protection. | the e6 and e7 oncoproteins of the high-risk hpv type16 represent ideal targets for hpv vaccine development, they being consistently expressed in cervical cancer lesions. since hpv-16 is primarily transmitted through genital mucosal route, mucosal immune responses constitute an essential feature for vaccination strategies against hpv-associated lesions. we present here evidence showing that mucosal immunization of mice by the intranasal route with a mixture of peptides e7(44-62) and e6(43-57) fro ... | 2007 | 17291642 |
| adaptation of venezuelan equine encephalitis virus lacking 51-nt conserved sequence element to replication in mammalian and mosquito cells. | replication of alphaviruses strongly depends on the promoters located in the plus- and minus-strands of virus-specific rnas. the most sophisticated promoter is encoded by the 5' end of the viral genome. this rna sequence is involved in the initiation of translation of viral nsps, and synthesis of both minus- and plus-strands of the viral genome. part of the promoter, the 51-nt conserved sequence element (cse), is located in the nsp1-coding sequence, and this limits the spectrum of possible mutat ... | 2007 | 17292936 |
| stability of a receptor-binding active human immunodeficiency virus type 1 recombinant gp140 trimer conferred by intermonomer disulfide bonding of the v3 loop: differential effects of protein disulfide isomerase on cd4 and coreceptor binding. | stable trimeric forms of human immunodeficiency virus recombinant gp140 (rgp140) are important templates for determining the structure of the glycoprotein to assist in our understanding of hiv infection and host immune response. such information will aid the design of therapeutic drugs and vaccines. here, we report the production of a highly stable and trimeric rgp140 derived from a hiv type 1 (hiv-1) subtype d isolate that may be suitable for structural studies. the rgp140 is functional in term ... | 2007 | 17301129 |
| analysis of hepatitis c virus superinfection exclusion by using novel fluorochrome gene-tagged viral genomes. | studies of the complete hepatitis c virus (hcv) life cycle have become possible with the development of an infectious cell culture system using the genotype 2a isolate jfh-1. taking advantage of this system in the present study, we investigated whether hcv infection leads to superinfection exclusion, a state in which hcv-infected cells are resistant to secondary hcv infection. to discriminate between viral genomes, we inserted genes encoding fluorescent proteins in frame into the 3'-terminal ns5 ... | 2007 | 17301154 |
| functional characterization of the sindbis virus e2 glycoprotein by transposon linker-insertion mutagenesis. | the glycoprotein envelope of alphaviruses consists of two proteins, e1 and e2. e1 is responsible for fusion and e2 is responsible for receptor binding. an atomic structure is available for e1, but one for e2 has not been reported. in this study, transposon linker-insertion mutagenesis was used to probe the function of different domains of e2. a library of mutants, containing 19 amino acid insertions in the e2 glycoprotein sequence of the prototype alphavirus, sindbis virus (sinv), was generated. ... | 2007 | 17306321 |
| complement contributes to inflammatory tissue destruction in a mouse model of ross river virus-induced disease. | arthritogenic alphaviruses, including ross river virus (rrv) and chikungunya virus, are mosquito-borne viruses that cause significant human disease worldwide, including explosive epidemics that can result in thousands to millions of infected individuals. similar to infection of humans, infection of c57bl/6 mice with rrv results in severe monocytic inflammation of bone, joint, and skeletal muscle tissues. we demonstrate here that the complement system, an important component of the innate immune ... | 2007 | 17314163 |
| expression of particulate-form of japanese encephalitis virus envelope protein in a stably transfected drosophila cell line. | japanese encephalitis virus (jev), a member of the family flaviviridae, is an important mosquito-borne human pathogen. its envelope glycoprotein (e) is the major determinant of the pathogenicity and host immune responses. in the present study, we explored the feasibility of producing recombinant jev e protein in the virus-free drosophila expression system. | 2007 | 17324254 |
| methamphetamine-induced structural plasticity in the dorsal striatum. | repeated exposure to psychostimulant drugs produces long-lasting changes in dendritic structure, presumably reflecting a reorganization in patterns of synaptic connectivity, in brain regions that mediate the psychomotor activating and incentive motivational effects of these drugs, including the nucleus accumbens and prefrontal cortex. however, repeated exposure to psychostimulant drugs also facilitates a transition in the control of some behaviors from action-outcome associations to behavior con ... | 2007 | 17328779 |
| development of sindbis viruses encoding nsp2/gfp chimeric proteins and their application for studying nsp2 functioning. | sindbis virus (sinv) is one of almost 30 currently known alphaviruses. in infected cells, it produces only a few proteins that function in virus replication and interfere with the development of the antiviral response. one of the viral nonstructural proteins, nsp2, not only exhibits protease and rna helicase activities that are directly involved in viral rna replication but also plays critical roles in the development of transcriptional and translational shutoffs in the sinv-infected cells. thes ... | 2007 | 17329335 |
| induction of t cell immunity by cutaneous genetic immunization with recombinant lentivector. | recent studies suggest that t cell-based cellular immunity plays an important role in preventing and delaying progression of infectious and neoplastic diseases. based on these findings, recent efforts in vaccine research are giving rise to a new generation of "t cell" vaccines. the development of t cell vaccines has been problematic. current investigations are focusing on gene-based immunization strategies, including the development of non-viral "naked" plasmid dna and recombinant viral vector-b ... | 2006 | 17337771 |
| uninfected mosquito bites confer protection against infection with malaria parasites. | despite decades of research and multiple initiatives, malaria continues to be one of the world's most debilitating infectious diseases. new insights for malaria control and vaccine development will be essential to thwart the staggering worldwide impact of this disease (a. bjorkman and a. bhattarai, acta trop. 94:163-169, 2005); ultimately successful vaccine strategies will undoubtedly be multifactorial, incorporating multiple antigens and targeting diverse aspects of the malaria parasites' biolo ... | 2007 | 17339356 |
| la crosse bunyavirus nonstructural protein nss serves to suppress the type i interferon system of mammalian hosts. | la crosse virus (lacv) is a mosquito-transmitted member of the bunyaviridae family that causes severe encephalitis in children. for the lacv nonstructural protein nss, previous overexpression studies with mammalian cells had suggested two different functions, namely induction of apoptosis and inhibition of rna interference (rnai). here, we demonstrate that mosquito cells persistently infected with lacv do not undergo apoptosis and mount a specific rnai response. recombinant viruses that either e ... | 2007 | 17344298 |
| sphingomyelinase restricts the lateral diffusion of cd4 and inhibits human immunodeficiency virus fusion. | previously, we reported that treatment of cells with sphingomyelinase inhibits human immunodeficiency virus type 1 (hiv-1) entry. here, we determined by measuring fluorescence recovery after photobleaching that the lateral diffusion of cd4 decreased 4-fold following sphingomyelinase treatment, while the effective diffusion rate of ccr5 remained unchanged. notably, sphingomyelinase treatment of cells did not influence gp120 binding, hiv-1 attachment, or fluid-phase and receptor-mediated endocytos ... | 2007 | 17344303 |
| hla-a2.1-restricted t cells react to serex-defined tumor antigen cml66l and are suppressed by cd4+cd25+ regulatory t cells. | the question of whether t cell responses to serex-defined tumor antigens are under regulation of naturally occurring cd4+cd25+ regulatory t cells (ntreg cells) has not been answered. to address this issue, we first identified an hla-a2.1-restricted t cell antigen epitope of serex-identified tumor antigen cml66l, 66pa. the hla-a2.1/66pa peptide complex in vitro stimulated the in vivo-primed t cells as shown by increased t cell proliferation, higher secretion of the t cell cytokine interferon-gamm ... | 2007 | 17346430 |
| junctophilin-mediated channel crosstalk essential for cerebellar synaptic plasticity. | functional crosstalk between cell-surface and intracellular ion channels plays important roles in excitable cells and is structurally supported by junctophilins (jps) in muscle cells. here, we report a novel form of channel crosstalk in cerebellar purkinje cells (pcs). the generation of slow afterhyperpolarization (sahp) following complex spikes in pcs required ryanodine receptor (ryr)-mediated ca(2+)-induced ca(2+) release and the subsequent opening of small-conductance ca(2+)-activated k(+) (s ... | 2007 | 17347645 |
| microarray analysis reveals that type i interferon strongly increases the expression of immune-response related genes in ubp43 (usp18) deficient macrophages. | type i interferon (ifn) contributes significantly to innate immune responses to pathogen infections in macrophages. our previous studies demonstrate that ubp43, an isg15-specific isopeptidase, is highly expressed in macrophages and noncatalytically inhibits type i ifn signaling. to understand the effect of type i ifn and ubp43 in macrophage activation, we analyzed the expression of ifn-beta stimulated genes in wild-type and ubp43(-/-) bone marrow derived macrophages (bmms). here, we show that ub ... | 2007 | 17349616 |
| differential inhibition of cellular and sindbis virus translation by brefeldin a. | brefeldin a is a macrolide compound that interferes with the secretory pathway and also affects protein synthesis in mammalian cells. as a result, this antibiotic impedes the maturation of viral glycoproteins of enveloped viruses and viral genome replication in several virus species. in the present work, we show that translation of subgenomic mrna from sindbis virus, which in contrast to cellular translation is resistant to brefeldin a after prolonged treatment. the phosphorylation of eif2alpha ... | 2007 | 17360015 |
| evolving the lock to fit the key to create a family of g protein-coupled receptors potently activated by an inert ligand. | we evolved muscarinic receptors in yeast to generate a family of g protein-coupled receptors (gpcrs) that are activated solely by a pharmacologically inert drug-like and bioavailable compound (clozapine-n-oxide). subsequent screening in human cell lines facilitated the creation of a family of muscarinic acetylcholine gpcrs suitable for in vitro and in situ studies. we subsequently created lines of telomerase-immortalized human pulmonary artery smooth muscle cells stably expressing all five famil ... | 2007 | 17360345 |
| panmicrobial oligonucleotide array for diagnosis of infectious diseases. | to facilitate rapid, unbiased, differential diagnosis of infectious diseases, we designed greenechippm, a panmicrobial microarray comprising 29,455 sixty-mer oligonucleotide probes for vertebrate viruses, bacteria, fungi, and parasites. methods for nucleic acid preparation, random primed pcr amplification, and labeling were optimized to allow the sensitivity required for application with nucleic acid extracted from clinical materials and cultured isolates. analysis of nasopharyngeal aspirates, b ... | 2007 | 17370518 |
| insertion of egfp into the replicase gene of semliki forest virus results in a novel, genetically stable marker virus. | alphavirus-based vector and replicon systems have been extensively used experimentally and are likely to be used in human and animal medicine. whilst marker genes can be inserted easily under the control of a duplicated subgenomic promoter, these constructs are often genetically unstable. here, a novel alphavirus construct is described in which an enhanced green fluorescent protein (egfp) marker gene is inserted into the virus replicase open reading frame between nsp3 and nsp4, flanked by nsp2 p ... | 2007 | 17374766 |
| synergistic roles of antibody and interferon in noncytolytic clearance of sindbis virus from different regions of the central nervous system. | sindbis virus (sinv) is an alphavirus that causes infection of neurons and encephalomyelitis in adult immunocompetent mice. recovery can occur without apparent neurological damage. to better define the factors facilitating noncytolytic clearance of sinv in different regions of the central nervous system (cns) and the roles of innate and adaptive immune responses at different times during infection, we have characterized sinv infection and clearance in the brain, brain stem, and spinal cords of s ... | 2007 | 17376910 |
| structure of immature west nile virus. | the structure of immature west nile virus particles, propagated in the presence of ammonium chloride to block virus maturation in the low-ph environment of the trans-golgi network, was determined by cryo-electron microscopy (cryo-em). the structure of these particles was similar to that of immature west nile virus particles found as a minor component of mature virus samples (naturally occurring immature particles [noips]). the structures of mature infectious flaviviruses are radically different ... | 2007 | 17376919 |
| ubp43 gene expression is required for normal isg15 expression and fetal development. | isg15 covalently modifies murine endometrial proteins in response to early pregnancy. isg15 can also be severed from targeted proteins by a specific protease called ubp43 (usp18). mice lacking ubp43 (null) form increased conjugated isg15 in response to interferon. the isg15 system has not been examined in chorioallantoic placenta (cp) or mesometrial (mm) components of implantation sites beyond 9.5 days post coitum (dpc). it was hypothesized that deletion of ubp43 would cause disregulation of isg ... | 2007 | 17381847 |
| homer 1a uncouples metabotropic glutamate receptor 5 from postsynaptic effectors. | metabotropic glutamate receptors (mglurs) and homer proteins play critical roles in neuronal functions including plasticity, nociception, epilepsy, and drug addiction. furthermore, homer proteins regulate mglur1/5 function by acting as adapters and facilitating coupling to effectors such as the inositol triphosphate receptor. however, although homer proteins and their interaction with mglurs have been the subject of intense study, direct measurements of homer-induced changes in postsynaptic mglu ... | 2007 | 17389377 |
| viral vector-induced amygdala npy overexpression reverses increased alcohol intake caused by repeated deprivations in wistar rats. | acute administration of neuropeptide y (npy) modulates alcohol intake in genetic and chemical models of high intake, while leaving intake unaffected during 'normal' or baseline conditions. in non-selected, normal rat lines, alcohol consumption can be increased by prolonged exposure to alcohol, and it is unclear what effect a constitutive increase in npy function will have on alcohol intake. the purpose of the present study was to examine the effects on alcohol intake of an inducible, constitutiv ... | 2007 | 17405766 |
| therapy with minocycline aggravates experimental rabies in mice. | minocycline is a tetracycline derivative with antiapoptotic and anti-inflammatory properties, and the drug has been shown to have beneficial effects in a variety of models of neurological disorders. the potentially neuroprotective role of minocycline was assessed in experimental in vitro and in vivo models of rabies virus infection. in this study, 5 nm minocycline did not improve the viability of embryonic mouse cortical and hippocampal neurons infected in vitro with the attenuated sad-d29 strai ... | 2007 | 17409147 |
| location and role of free cysteinyl residues in the sindbis virus e1 and e2 glycoproteins. | sindbis virus is a single-stranded positive-sense rna virus. it is composed of 240 copies of three structural proteins: e1, e2, and capsid. these proteins form a mature virus particle composed of two nested t=4 icosahedral shells. a complex network of disulfide bonds in the e1 and e2 glycoproteins is developed through a series of structural intermediates as virus maturation occurs (m. mulvey and d. t. brown, j. virol. 68:805-812, 1994; m. carleton et al., j. virol. 71:1558-1566, 1997). to better ... | 2007 | 17409163 |
| genetic determinants of sindbis virus strain tr339 affecting midgut infection in the mosquito aedes aegypti. | mosquito midgut epithelial cells (mec) play a major role in determining whether an arbovirus can successfully infect and be transmitted by mosquitoes. the sindbis virus (sinv) strain tr339 efficiently infects aedes aegypti mec but the sinv strain te/5'2j poorly infects mec. sinv determinants for mec infection have been localized to the e2 glycoprotein. the e2 amino acid sequences of tr339 and te/5'2j differ at two sites, e2-55 and e2-70. we have altered the te/5'2j virus genome by site-directed ... | 2007 | 17412985 |
| a conserved region between the heptad repeats of paramyxovirus fusion proteins is critical for proper f protein folding. | paramyxoviruses are a diverse family that utilizes a fusion (f) protein to enter cells via fusion of the viral lipid bilayer with a target cell membrane. although certain regions of the f protein are known to play critical roles in membrane fusion, the function of much of the protein remains unclear. sequence alignment of a set of paramyxovirus f proteins and analysis utilizing block maker identified a region of conserved amino acid sequence in a large domain between the heptad repeats of f1, de ... | 2007 | 17417875 |
| synthesis of some novel heterocyclic compounds derived from diflunisal hydrazide as potential anti-infective and anti-inflammatory agents. | three novel series of 2',4'-difluoro-4-hydroxybiphenyl-3-carboxylic acid derivatives namely 4-substituted-1,2,4-triazoline-3-thiones (4a-g); 2-substituted-1,3,4-thiadiazoles (5a-g) and 2-substituted-1,3,4-oxadiazoles (6a-g) have been synthesized. twenty-one of the newly synthesized compounds were tested against various bacteria, fungi, yeast species and virus. in addition, we have replaced the carboxylic acid group of diflunisal with heterocycles and the anti-inflammatory activity of heterocycle ... | 2007 | 17418454 |
| transcriptional activation of interferon-stimulated genes but not of cytokine genes after primary infection of rhesus macaques with dengue virus type 1. | macaques are the only animal model used to test dengue virus (denv) vaccine candidates. nevertheless, the pathogenesis of denv in macaques is not well understood. in this work, by using affymetrix oligonucleotide microarrays, we studied the broad transcriptional modifications and cytokine expression profile after infecting rhesus macaques with denv serotype 1. five days after infection, these animals produced a potent, innate antiviral immune response by inducing the transcription of signature g ... | 2007 | 17428947 |
| antiviral activity of oxidized polyamines. | polyamines, oxidized by serum amine oxidase, yield aminoaldehydes and hydrogen peroxide. acrolein may be formed from the aminoaldehydes by a spontaneous beta-elimination process. these oxidation products "oxidized polyamines" inhibit bacterial growth and exhibit anticancer activity. the antimicrobial activity of oxidized polyamines is not limited to bacteria; and the inactivation of bacterial viruses, plant viruses and animal viruses, was also reported. bacteriophages of the t-odd series are per ... | 2007 | 17429570 |
| retrospective survey of chikungunya disease in réunion island hospital staff. | réunion island (indian ocean) has been suffering from its first known chikungunya virus (chikv) epidemic since february 2005. to achieve a better understanding of the disease, a questionnaire was drawn up for hospital staff members and their household. chikv infected about one-third of the studied population, the proportion increasing with age and being higher in women. presence of a garden was associated with chikv infection. the geographical distribution of cases was concordant with insect vec ... | 2008 | 17433130 |
| synaptic scaffolding molecule alpha is a scaffold to mediate n-methyl-d-aspartate receptor-dependent rhoa activation in dendrites. | synaptic scaffolding molecule (s-scam) interacts with a wide variety of molecules at excitatory and inhibitory synapses. it comprises three alternative splicing variants, s-scamalpha, -beta, and -gamma. we generated mutant mice lacking specifically s-scamalpha. s-scamalpha-deficient mice breathe and feed normally but die within 24 h after birth. primary cultured hippocampal neurons from mutant mice have abnormally elongated dendritic spines. exogenously expressed s-scamalpha corrects this abnorm ... | 2007 | 17438139 |
| viral translation is coupled to transcription in sindbis virus-infected cells. | during the late phase of sindbis virus infection, the viral subgenomic mrna is translated efficiently in bhk cells, whereas host protein synthesis is inhibited. however, transfection of in vitro-generated sindbis virus subgenomic mrna leads to efficient translation in uninfected bhk cells, whereas it is a poor substrate in infected cells. therefore, the structure of the subgenomic mrna itself is not sufficient to confer its translatability in infected cells. in this regard, translation of the su ... | 2007 | 17442713 |
| cellular and humoral immune responses to alphavirus replicon vaccines expressing cytomegalovirus pp65, ie1, and gb proteins. | development of vaccines against cytomegalovirus (cmv) is an important public health priority. we used a propagation-defective, single-cycle rna replicon vector system derived from an attenuated strain of an alphavirus, venezuelan equine encephalitis virus, to produce virus-like replicon particles (vrp) expressing various combinations of pp65, ie1, or gb proteins of human cmv. protein expression in vrp-infected cells was highest with single-promoter replicons expressing pp65, ie1, a pp65/ie1 fusi ... | 2007 | 17442845 |
| emerging zoonoses and vector-borne infections affecting humans in europe. | the purpose of this study was to assess and describe the current spectrum of emerging zoonoses between 2000 and 2006 in european countries. a computerized search of the medline database from january 1966 to august 2006 for all zoonotic agents in european countries was performed using specific criteria for emergence. fifteen pathogens were identified as emerging in europe from 2000 to august 2006: rickettsiae spp., anaplasma phagocytophilum, borrelia burgdorferi, bartonella spp., francisella tula ... | 2007 | 17445320 |
| [ockelbo disease: stinging fly transmitted polyarthritis in scandinavia]. | 2007 | 17447272 | |
| rapid membrane fusion of individual virus particles with supported lipid bilayers. | many enveloped viruses employ low-ph-triggered membrane fusion during cell penetration. solution-based in vitro assays in which viruses fuse with liposomes have provided much of our current biochemical understanding of low-ph-triggered viral membrane fusion. here, we extend this in vitro approach by introducing a fluorescence assay using single particle tracking to observe lipid mixing between individual virus particles (influenza or sindbis) and supported lipid bilayers. our single-particle exp ... | 2007 | 17449662 |
| the opioid receptor antagonist, naloxone, protects spinal motor neurons in a murine model of alphavirus encephalomyelitis. | spread of neuroadapted sindbis virus (nsv) to motor neurons (mn) of the spinal cord (sc) causes severe hind limb weakness in c57bl/6 mice and models the paralysis that can accompany alphavirus and flavivirus encephalomyelitis in humans. the fate of spinal mn dictates the severity of nsv-induced paralysis, and recent data suggest that mn damage can occur indirectly via the actions of activated microglial cells. because the opioid receptor antagonist, naloxone (nal), blocks microglial-mediated neu ... | 2007 | 17459376 |
| viral alteration of cellular translational machinery increases defective ribosomal products. | here we show that cells expressing genes inserted into semliki forest virus (sfv) vectors generate a large fraction of defective ribosomal products (drips) due to frequent initiation on downstream met residues. in monopolizing the host cell translational machinery, sfv reduces levels of translation eukaryotic initiation factor 4e (eif4e), diminishes phosphorylation of ribosome subunit s6, and phosphorylates translation initiation factor eif2alpha. we show that the last event is required for sfv ... | 2007 | 17459927 |
| changes in the structural complexity of the aged brain. | structural changes of neurons in the brain during aging are complex and not well understood. neurons have significant homeostatic control of essential brain functions, including synaptic excitability, gene expression, and metabolic regulation. any deviations from the norm can have severe consequences as seen in aging and injury. in this review, we present some of the structural adaptations that neurons undergo throughout normal and pathological aging and discuss their effects on electrophysiolog ... | 2007 | 17465981 |
| pick1 interacts with alpha7 neuronal nicotinic acetylcholine receptors and controls their clustering. | central to synaptic function are protein scaffolds associated with neurotransmitter receptors. alpha7 neuronal nicotinic acetylcholine receptors (nachrs) modulate network activity, neuronal survival and cognitive processes in the cns, but protein scaffolds that interact with these receptors are unknown. here we show that the pdz-domain containing protein pick1 binds to alpha7 nachrs and plays a role in their clustering. pick1 interacted with the alpha7 cytoplasmic loop in yeast in a pdz-dependen ... | 2007 | 17467288 |
| seco-pregnane steroids target the subgenomic rna of alphavirus-like rna viruses. | plants have evolved multiple mechanisms to selectively suppress pathogens by production of secondary metabolites with antimicrobial activities. therefore, direct selections for antiviral compounds from plants can be used to identify new agents with potent antiviral activity but not toxic to hosts. here, we provide evidence that a class of compounds, seco-pregnane steroid glaucogenin c and its monosugar-glycoside cynatratoside a of strobilanthes cusia and three new pantasugar-glycosides of glauco ... | 2007 | 17470783 |
| novel strategy for treatment of viral central nervous system infection by using a cell-permeating inhibitor of c-jun n-terminal kinase. | viral encephalitis is a major cause of morbidity and mortality worldwide, yet there is no proven efficacious therapy for most viral infections of the central nervous system (cns). many of the viruses that cause encephalitis induce apoptosis and activate c-jun n-terminal kinase (jnk) following infection. we have previously shown that reovirus infection of epithelial cell lines activates jnk-dependent apoptosis. we now show that reovirus infection resulted in activation of jnk and caspase-3 in the ... | 2007 | 17475657 |
| influenza virus hemagglutinin and neuraminidase, but not the matrix protein, are required for assembly and budding of plasmid-derived virus-like particles. | for influenza virus, we developed an efficient, noncytotoxic, plasmid-based virus-like particle (vlp) system to reflect authentic virus particles. this system was characterized biochemically by analysis of vlp protein composition, morphologically by electron microscopy, and functionally with a vlp infectivity assay. the vlp system was used to address the identity of the minimal set of viral proteins required for budding. combinations of viral proteins were expressed in cells, and the polypeptide ... | 2007 | 17475660 |
| the alphavirus 6k protein activates endogenous ionic conductances when expressed in xenopus oocytes. | the alphavirus sindbis 6k protein is involved in several functions. it contributes to the processing and membrane insertion of e1 and pe2 viral envelope glycoproteins and to virus budding. it also permeabilizes escherichia coli and mammalian cells. these viroporin-like properties have been proposed to help virus budding by modifying membrane permeabilities. we expressed sindbis virus 6k crna in xenopus oocytes to further characterize the effect of 6k on membrane conductances and permeabilization ... | 2007 | 17483865 |
| poliovirus induces bax-dependent cell death mediated by c-jun nh2-terminal kinase. | poliovirus (pv) is the causal agent of paralytic poliomyelitis, a disease that involves the destruction of motor neurons associated with pv replication. in pv-infected mice, motor neurons die through an apoptotic process. however, mechanisms by which pv induces cell death in neuronal cells remain unclear. here, we demonstrate that pv infection of neuronal imr5 cells induces cytochrome c release from mitochondria and loss of mitochondrial transmembrane potential, both of which are evidence of mit ... | 2007 | 17494073 |
| enucleated l929 cells support invasion, differentiation, and multiplication of trypanosoma cruzi parasites. | cell infection with trypanosoma cruzi, the agent of chagas' disease, begins with the uptake of infective trypomastigotes within phagosomes and their release into the cytosol, where they transform into replicating amastigotes; the latter, in turn, differentiate into cytolytically released and infective trypomastigotes. we ask here if the t. cruzi infection program can develop in enucleated host cells. monolayers of l929 cells, enucleated by centrifugation in the presence of cytochalasin b and kep ... | 2007 | 17502387 |
| interaction of tia-1/tiar with west nile and dengue virus products in infected cells interferes with stress granule formation and processing body assembly. | the west nile virus minus-strand 3' terminal stem loop (sl) rna was previously shown to bind specifically to cellular stress granule (sg) components, t cell intracellular antigen-1 (tia-1) and the related protein tiar. in vitro tiar binding was 10 times more efficient than tia-1. the 3'(-)sl functions as the promoter for genomic rna synthesis. colocalization of tiar and tia-1 with the viral replication complex components dsrna and ns3 was observed in the perinuclear regions of west nile virus- a ... | 2007 | 17502609 |
| comparative analysis of the alphavirus-based vectors expressing rift valley fever virus glycoproteins. | during the last decade, alphaviruses became widely used for expression of heterologous genetic information and development of recombinant vaccines against a variety of human and animal pathogens. in this study, we compared a number of vectors based on the genome of sindbis (sinv) and venezuelan equine encephalitis (veev) viruses for their ability to express the rift valley fever virus (rvfv) envelope glycoprotein gn and induce a protective immune response against rvfv infection. our results sugg ... | 2007 | 17507072 |
| lipid rafts of primary endothelial cells are essential for kaposi's sarcoma-associated herpesvirus/human herpesvirus 8-induced phosphatidylinositol 3-kinase and rhoa-gtpases critical for microtubule dynamics and nuclear delivery of viral dna but dispensable for binding and entry. | early during de novo infection of human microvascular dermal endothelial (hmvec-d) cells, kaposi's sarcoma-associated herpesvirus (kshv) (human herpesvirus 8 [hhv-8]) induces the host cell's preexisting fak, src, phosphatidylinositol 3-kinase (pi3-k), rho-gtpases, diaphanous-2 (dia-2), ezrin, protein kinase c-zeta, extracellular signal-regulated kinase 1/2 (erk1/2), and nf-kappab signal pathways that are critical for virus entry, nuclear delivery of viral dna, and initiation of viral gene expres ... | 2007 | 17507466 |
| restricted tissue tropism and acquired resistance to sindbis viral vector expression in the absence of innate and adaptive immunity. | our previous studies suggest that replication-defective sindbis vectors might be promising agents for specific tumor targeting and detection. however, the effects of innate and/or adaptive anti-viral immunity, in particular, the ifn-i/stat1 signaling pathway, may impact their therapeutic potential. using a bioluminescent imaging system, we demonstrate that although most normal cells are not permissively transduced by replication-defective sindbis vector, transduction of liver non-sinusoidal endo ... | 2007 | 17508007 |
| virus inactivation by protein denaturants used in affinity chromatography. | virus inactivation by a number of protein denaturants commonly used in gel affinity chromatography for protein elution and gel recycling has been investigated. the enveloped viruses sindbis, herpes simplex-1 and vaccinia, and the non-enveloped virus polio-1 were effectively inactivated by 0.5 m sodium hydroxide, 6 m guanidinium thiocyanate, 8 m urea and 70% ethanol. however, ph 2.6, 3 m sodium thiocyanate, 6 m guanidinium chloride and 20% ethanol, while effectively inactivating the enveloped vir ... | 2007 | 17517521 |
| the neuregulin-1 receptor erbb4 controls glutamatergic synapse maturation and plasticity. | neuregulin-1 (nrg1) signaling participates in numerous neurodevelopmental processes. through linkage analysis, nrg1 has been associated with schizophrenia, although its pathophysiological role is not understood. the prevailing models of schizophrenia invoke hypofunction of the glutamatergic synapse and defects in early development of hippocampal-cortical circuitry. here, we show that the erbb4 receptor, as a postsynaptic target of nrg1, plays a key role in activity-dependent maturation and plast ... | 2007 | 17521571 |
| functional requirements of the yellow fever virus capsid protein. | although it is known that the flavivirus capsid protein is essential for genome packaging and formation of infectious particles, the minimal requirements of the dimeric capsid protein for virus assembly/disassembly have not been characterized. by use of a trans-packaging system that involved packaging a yellow fever virus (yfv) replicon into pseudo-infectious particles by supplying the yfv structural proteins using a sindbis virus helper construct, the functional elements within the yfv capsid p ... | 2007 | 17526891 |