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tracking and elucidating alphavirus-host protein interactions.viral infections cause profound alterations in host cells. here, we explore the interactions between proteins of the alphavirus sindbis and host factors during the course of mammalian cell infection. using a mutant virus expressing the viral nsp3 protein tagged with green fluorescent protein (gfp) we directly observed nsp3 localization and isolated nsp3-interacting proteins at various times after infection. these results revealed that host factor recruitment to nsp3-containing complexes was time ...200616895903
actin-associated neurabin-protein phosphatase-1 complex regulates hippocampal plasticity.protein phosphatase-1 (pp1) has been implicated in the control of long-term potentiation (ltp) and depression (ltd) in rat hippocampal ca1 neurons. pp1 catalytic subunits associate with multiple postsynaptic regulatory subunits, but the pp1 complexes that control hippocampal ltp and ltd in the rat hippocampus remain unidentified. the neuron-specific actin-binding protein, neurabin-i, is enriched in dendritic spines, and tethers pp1 to actin-rich postsynaptic density to regulate morphology and ma ...200616899074
transient low ph treatment enhances infection of lentiviral vector pseudotypes with a targeting sindbis envelope.efficient transduction of primary hematopoietic cell types by oncoretroviral vectors and lentiviral vectors with a variety of different envelope pseudotypes has proven to be difficult. we recently developed a lentiviral vector based upon a modified sindbis virus envelope that allows targeted transduction via antibody recognition to specific cells in unfractionated cell populations. however, similar to other envelope pseudotypes, the utility of this vector for some primary hematopoietic cells was ...200616905172
structural and functional basis for adp-ribose and poly(adp-ribose) binding by viral macro domains.macro domains constitute a protein module family found associated with specific histones and proteins involved in chromatin metabolism. in addition, a small number of animal rna viruses, such as corona- and toroviruses, alphaviruses, and hepatitis e virus, encode macro domains for which, however, structural and functional information is extremely limited. here, we characterized the macro domains from hepatitis e virus, semliki forest virus, and severe acute respiratory syndrome coronavirus (sars ...200616912299
rapid adaptation of a recombinant vesicular stomatitis virus to a targeted cell line.vesicular stomatitis virus (vsv) is being developed for cancer therapy. we created a recombinant replicating vsv (rrvsv) that preferentially infected her2/neu-expressing breast cancer cells. this rrvsv did not express the native vsv-g glycoprotein (gp). instead, it expressed a chimeric sindbis gp which included a single-chain antibody (sca) directed to the human her2/neu receptor. the virus infected mouse mammary carcinoma cells (d2f2/e2) expressing her2/neu 23-fold better than the parent cells ...200616912309
role of the low-density lipoprotein receptor in entry of bovine viral diarrhea virus.among several proposed cellular receptors for bovine viral diarrhea virus (bvdv), the low-density lipoprotein (ldl) receptor is of special interest because it is also considered a receptor for the related hepatitis c virus. it has been reported that an anti-ldl receptor monoclonal antibody blocked the infection of bovine cells by bvdv and that the resistance of bovine crib cells (cells resistant to infection with bvdv) (e. f. flores and r. o. donis, virology 208:565-575, 1995) to bvdv infection ...200616928760
rotavirus activates jnk and p38 signaling pathways in intestinal cells, leading to ap-1-driven transcriptional responses and enhanced virus replication.rotavirus infection is known to regulate transcriptional changes in many cellular genes. the transcription factors nf-kappab and ap-1 are activated by rotavirus infection, but the upstream processes leading to these events are largely unidentified. we therefore studied the activation state during rotavirus infection of c-jun nh2-terminal kinase (jnk) and p38, which are kinases known to activate ap-1. as assessed by western blotting using phospho-specific antibodies, infection with rhesus rotavir ...200616928761
phylogenetic analysis of buggy creek virus: evidence for multiple clades in the western great plains, united states of america.we present the first detailed phylogenetic analysis of buggy creek virus (bcrv), a poorly known alphavirus with transmission cycles involving a cimicid swallow bug (oeciacus vicarius) vector and cliff swallows (petrochelidon pyrrhonota) and house sparrows (passer domesticus) as the principal avian hosts. nucleotide sequences of a 2,075-bp viral envelope glycoprotein-coding region, covering the entire pe2 gene, were determined for 33 bcrv isolates taken from swallow bugs at cliff swallow colonies ...200616936062
c-e1 fusion protein synthesized by rubella virus di rnas maintained during serial passage.rubella virus (rub) replicons are derivatives of the rub infectious cdna clone that retain the nonstructural open reading frame (ns-orf) that encodes the replicase proteins but not the structural protein orf (sp-orf) that encodes the virion proteins. rub defective interfering (di) rnas contain deletions within the sp-orf and thus resemble replicons. di rnas often retain the 5' end of the capsid protein (c) gene that has been shown to modulate virus-specific rna synthesis. however, when replicons ...200616938325
alphavirus capsid protein helix i controls a checkpoint in nucleocapsid core assembly.the assembly of the alphavirus nucleocapsid core has been investigated using an in vitro assembly system. the c-terminal two-thirds of capsid protein (cp), residues 81 to 264 in sindbis virus (sinv), have been previously shown to have all the rna-cp and cp-cp contacts required for core assembly in vitro. helix i, which is located in the n-terminal dispensable region of the cp, has been proposed to stabilize the core by forming a coiled coil in the cp dimer formed by the interaction of residues 8 ...200616940497
altered central nervous system gene expression caused by congenitally acquired persistent infection with lymphocytic choriomeningitis virus.neonatal infection of most mouse strains with lymphocytic choriomeningitis virus (lcmv) leads to a life-long persistent infection characterized by high virus loads in the central nervous system (cns) in the absence of inflammation and tissue destruction. these mice, however, exhibit impaired learning and memory. the occurrence of cognitive defects in the absence of overt cns pathology led us to the hypothesis that chronic virus infection may contribute to neuronal dysfunction by altering the hos ...200616940520
modulation of the unfolded protein response by the severe acute respiratory syndrome coronavirus spike protein.perturbation of the function of endoplasmic reticulum (er) causes stress leading to the activation of cell signaling pathways known as the unfolded protein response (upr). severe acute respiratory syndrome (sars) coronavirus (sars-cov) uses er as a site for synthesis and processing of viral proteins. in this report, we demonstrate that infection with sars-cov induces the upr in cultured cells. a comparison with m, e, and nsp6 proteins indicates that sars-cov spike (s) protein sufficiently induce ...200616940539
acid sphingomyelinase deficiency increases susceptibility to fatal alphavirus encephalomyelitis.sindbis virus (sv), an enveloped virus with a single-stranded, plus-sense rna genome, is the prototype alphavirus in the togaviridae family. in mice, sv infects neurons and can cause apoptosis of immature neurons. sphingomyelin (sm) is the most prevalent cellular sphingolipid, is particularly abundant in the nervous systems of mammals, and is required for alphavirus fusion and entry. the level of sm is tightly regulated by sphingomyelinases. a defect in acid sphingomyelinase (asmase) results in ...200616943298
the effects of n-terminal insertion into vsv-g of an scfv peptide.recombinant retroviruses, including lentiviruses, are the most widely used vectors for both in vitro and in vivo stable gene transfer. however, the inability to selectively deliver transgenes into cells of interest limits the use of this technology. due to its wide tropism, stability and ability to pseudotype a range of viral vectors, vesicular stomatitis virus g protein (vsv-g) is the most commonly used pseudotyping protein. here, we attempted to engineer this protein for targeting purposes. ch ...200616948856
immunization with a low-dose replicon dna vaccine encoding phl p 5 effectively prevents allergic sensitization.replicase-based dna vaccines stimulate t(h)1-biased immune responses at ultralow doses and induce self-removal of transfected cells through apoptosis. both aspects are important requirements for efficient and safe dna-based immunotherapy of type i allergies.200616950295
detection of seroconversion to west nile virus, usutu virus and sindbis virus in uk sentinel chickens.we previously reported evidence of west nile virus (wnv) circulation in uk birds, probably introduced by migratory birds from overseas. we now demonstrate wnv-specific seroconversion in sentinel chickens raised on an english farm. maternal neutralizing antibodies to wnv in hatchlings declined within three weeks. during the following months, healthy chickens developed wnv neutralizing antibodies that were confirmed by immunoblotting and indirect immunofluorescence tests using wnv antigens. the pr ...200616952307
recombination and selection in the evolution of picornaviruses and other mammalian positive-stranded rna viruses.picornaviridae are a large virus family causing widespread, often pathogenic infections in humans and other mammals. picornaviruses are genetically and antigenically highly diverse, with evidence for complex evolutionary histories in which recombination plays a major part. to investigate the nature of recombination and selection processes underlying the evolution of serotypes within different picornavirus genera, large-scale analysis of recombination frequencies and sites, segregation by serotyp ...200616956935
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 ...200616957044
antiviral action of the tumor suppressor arf.oncogenic viruses frequently target the pathways controlled by tumor suppressor genes, suggesting an extra function for these proteins as antiviral factors. the control exerted by the tumor suppressor arf on cellular proliferation is crucial to restrict tumor development; however, a potential contribution of arf to prevent viral infectivity has remained unexplored. in the present study, we investigated the consequences of loss or increased expression of arf on viral infection. our results reveal ...200616957780
venezuelan equine encephalitis virus transmission and effect on pathogenesis.quantifying the dose of an arbovirus transmitted by mosquitoes is essential for designing pathogenesis studies simulating natural infection of vertebrates. titration of saliva collected in vitro from infected mosquitoes may not accurately estimate titers transmitted during blood feeding, and infection by needle injection may affect vertebrate pathogenesis. we compared the amount of venezuelan equine encephalitis virus collected from the saliva of aedes taeniorhynchus to the amount injected into ...200616965696
o'nyong-nyong virus, chad.we report the first laboratory-confirmed human infection with o'nyong-nyong virus in chad. this virus was isolated from peripheral blood mononuclear cells of a patient with evidence of a seroconversion to a virus related to chikungunya virus. genome sequence was partly determined, and phylogenetic studies were conducted.200616965706
oligomerization of hepatitis c virus core protein is crucial for interaction with the cytoplasmic domain of e1 envelope protein.hepatitis c virus (hcv) contains two membrane-associated envelope glycoproteins, e1 and e2, which assemble as a heterodimer in the endoplasmic reticulum (er). in this study, predictive algorithms and genetic analyses of deletion mutants and glycosylation site variants of the e1 glycoprotein were used to suggest that the glycoprotein can adopt two topologies in the er membrane: the conventional type i membrane topology and a polytopic topology in which the protein spans the er membrane twice with ...200616971440
translation of the flavivirus kunjin ns3 gene in cis but not its rna sequence or secondary structure is essential for efficient rna packaging.our previous studies using trans-complementation analysis of kunjin virus (kun) full-length cdna clones harboring in-frame deletions in the ns3 gene demonstrated the inability of these defective complemented rnas to be packaged into virus particles (w. j. liu, p. l. sedlak, n. kondratieva, and a. a. khromykh, j. virol. 76:10766-10775). in this study we aimed to establish whether this requirement for ns3 in rna packaging is determined by the secondary rna structure of the ns3 gene or by the essen ...200616971441
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 ...200616971447
site-directed antibodies against the stem region reveal low ph-induced conformational changes of the semliki forest virus fusion protein.the e1 envelope protein of the alphavirus semliki forest virus (sfv) is a class ii fusion protein that mediates low ph-triggered membrane fusion during virus infection. like other class i and class ii fusion proteins, during fusion e1 inserts into the target membrane and rearranges to form a trimeric hairpin structure. the postfusion structures of the alphavirus and flavivirus fusion proteins suggest that the "stem" region connecting the fusion protein domain iii to the transmembrane domain inte ...200616973563
the 37/67-kilodalton laminin receptor is a receptor for adeno-associated virus serotypes 8, 2, 3, and 9.adeno-associated virus serotype 8 (aav8) is currently emerging as a powerful gene transfer vector, owing to its capability to efficiently transduce many different tissues in vivo. while this is believed to be in part due to its ability to uncoat more readily than other aav serotypes such as aav2, understanding all the processes behind aav8 transduction is important for its application and optimal use in human gene therapy. here, we provide the first report of a cellular receptor for aav8, the 37 ...200616973587
template requirements for recognition and copying by sindbis virus rna-dependent rna polymerase.the sindbis virus (sin) nonstructural protein nsp4 possesses the rna-dependent rna polymerase activity required for the replication of the sin genome and transcription of a subgenomic mrna during infection. isolation of this protein from other viral components of the rna synthetic complex allowed the characterization of template requirements for nsp4-mediated genome replication. the major findings of this study are: (i) in the absence of other viral proteins nsp4 is capable of copying sin plus- ...200716979682
ab initio random model method facilitates 3d reconstruction of icosahedral particles.model-based, three-dimensional (3d) image reconstruction procedures require a starting model to initiate data analysis. we have designed an ab initio method, which we call the random model (rm) method, that automatically generates models to initiate structural analysis of icosahedral viruses imaged by cryo-electron microscopy. the robustness of the rm procedure was demonstrated on experimental sets of images for five representative viruses. the rm method also provides a straightforward way to ge ...200716979906
replicase-based dna vaccines for allergy treatment.replicase-based vaccines were introduced to overcome some of the deficiencies of conventional dna- and rna-based vaccines, including poor efficiency and low stability. at ultra-low doses, these alphavirus-derived vectors elicit cellular as well as humoral immune responses. additionally, replicase-based vectors induce "self-removal" of the vaccine via apoptosis of transfected cells. this chapter describes the construction of a replicon-based dna vaccine vector from commercially available plasmids ...200616988457
cyclophosphamide increases transgene expression mediated by an oncolytic adenovirus in glioma-bearing mice monitored by bioluminescence imaging.approaches to improve the oncolytic potency of replication-competent adenoviruses include the insertion of therapeutic transgenes into the viral genome. little is known about the levels and duration of in vivo transgene expression by cells infected with such "armed" viruses. using a tumor-selective adenovirus encoding firefly luciferase (addelta24cmv-luc) we investigated these questions in an intracranial mouse model for malignant glioma. luciferase expression was detected by bioluminescence ima ...200616996314
in vivo packaging of brome mosaic virus rna3, but not rnas 1 and 2, is dependent on a cis-acting 3' trna-like structure.the four encapsidated rnas of brome mosaic virus (bmv; b1, b2, b3, and b4) contain a highly conserved 3' 200-nucleotide (nt) region encompassing the trna-like structure (tls) which is required for packaging in vitro (y. g. choi, t. w. dreher, and a. l. n. rao, proc. natl. acad. sci. usa 99:655-660, 2002). to validate these observations in vivo, we performed packaging assays using agrobacterium-mediated transient expression of rnas and coat protein (cp) (p. annamalai and a. l. n. rao, virology 33 ...200717005656
characterization of a novel 5' subgenomic rna3a derived from rna3 of brome mosaic bromovirus.the synthesis of 3' subgenomic rna4 (sgrna4) by initiation from an internal sg promoter in the rna3 segment was first described for brome mosaic bromovirus (bmv), a model tripartite positive-sense rna virus (w. a. miller, t. w. dreher, and t. c. hall, nature 313:68-70, 1985). in this work, we describe a novel 5' sgrna of bmv (sgrna3a) that we propose arises by premature internal termination and that encapsidates in bmv virions. cloning and sequencing revealed that, unlike any other bmv rna segme ...200617005659
catalytic core of alphavirus nonstructural protein nsp4 possesses terminal adenylyltransferase activity.the rna-dependent rna polymerase nsp4 is an integral part of the alphavirus replication complex. to define the role of nsp4 in viral rna replication and for a structure-function analysis, we expressed sindbis virus nsp4 in escherichia coli. the core catalytic domain of nsp4 (delta97nsp4, a deletion of the n-terminal 97 amino acids), which consists of the predicted polymerase domain containing the gdd amino acid motif required for viral rna synthesis, was stable against proteolytic degradation du ...200617005674
trans regulation of cap-independent translation by a viral subgenomic rna.many positive-strand rna viruses generate 3'-coterminal subgenomic mrnas to allow translation of 5'-distal open reading frames. it is unclear how viral genomic and subgenomic mrnas compete with each other for the cellular translation machinery. translation of the uncapped barley yellow dwarf virus genomic rna (grna) and subgenomic rna1 (sgrna1) is driven by the powerful cap-independent translation element (bte) in their 3' untranslated regions (utrs). the bte forms a kissing stem-loop interactio ...200617005682
rabies virus infection of primary neuronal cultures and adult mice: failure to demonstrate evidence of excitotoxicity.cultures derived from the cerebral cortices and hippocampi of 17-day-old mouse fetuses infected with the cvs strain of rabies virus showed loss of trypan blue exclusion, morphological apoptotic features, and activated caspase 3 expression, indicating apoptosis. the nmda (n-methyl-d-aspartate acid) antagonists ketamine (125 microm) and mk-801 (60 microm) were found to have no significant neuroprotective effect on cvs-infected neurons, while the caspase inhibitor ac-asp-glu-val aspartic acid aldeh ...200617005706
pkcdelta alternatively spliced isoforms modulate cellular apoptosis in retinoic acid-induced differentiation of human nt2 cells and mouse embryonic stem cells.nt2 cells are a human teratocarcinoma cell line that, upon treatment with retinoic acid (ra), begin differentiating into a neuronal phenotype. the transformation of undifferentiated nt2 cells into hnt neurons presents an opportunity to investigate the mechanisms involved in neurogenesis because a key component is cell apoptosis, which is essential for building neural networks. protein kinase cdelta (pkcdelta) plays an important role as a mediator of cellular apoptosis in response to various stim ...200617017122
indolopyridones inhibit human immunodeficiency virus reverse transcriptase with a novel mechanism of action.we have discovered a novel class of human immunodeficiency virus (hiv) reverse transcriptase (rt) inhibitors that block the polymerization reaction in a mode distinct from those of the nucleoside or nucleotide rt inhibitors (nrtis) and nonnucleoside rt inhibitors (nnrtis). for this class of indolopyridone compounds, steady-state kinetics revealed competitive inhibition with respect to the nucleotide substrate. despite substantial structural differences with classical chain terminators or natural ...200617020946
activity- and mtor-dependent suppression of kv1.1 channel mrna translation in dendrites.mammalian target of rapamycin (mtor) is implicated in synaptic plasticity and local translation in dendrites. we found that the mtor inhibitor, rapamycin, increased the kv1.1 voltage-gated potassium channel protein in hippocampal neurons and promoted kv1.1 surface expression on dendrites without altering its axonal expression. moreover, endogenous kv1.1 mrna was detected in dendrites. using kv1.1 fused to the photoconvertible fluorescence protein kaede as a reporter for local synthesis, we obser ...200617023663
manipulating kv4.2 identifies a specific component of hippocampal pyramidal neuron a-current that depends upon kv4.2 expression.the somatodendritic a-current, i(sa), in hippocampal ca1 pyramidal neurons regulates the processing of synaptic inputs and the amplitude of back propagating action potentials into the dendritic tree, as well as the action potential firing properties at the soma. in this study, we have used rna interference and over-expression to show that expression of the kv4.2 gene specifically regulates the i(sa) component of a-current in these neurons. in dissociated hippocampal pyramidal neuron cultures, or ...200617026528
mutagenesis of the la crosse virus glycoprotein supports a role for gc (1066-1087) as the fusion peptide.the la crosse virus (lacv) m segment encodes two glycoproteins (gn and gc), and plays a critical role in the neuropathogenesis of lacv infection as the primary determinant of neuroinvasion. a recent study from our group demonstrated that the region comprising the membrane proximal two-thirds of gc, amino acids 860-1442, is critical in mediating lacv fusion and entry. furthermore, computational analysis identified structural similarities between a portion of this region, amino acids 970-1350, and ...200717027056
identification of japanese encephalitis virus-inducible genes in mouse brain and characterization of garg39/ifit2 as a microtubule-associated protein.several mouse central nervous system genes have been identified that are differentially regulated during japanese encephalitis virus (jev) infection, including those which have not been reported to be induced by any other neurotropic virus. interestingly, approximately 80 % of jev-inducible genes identified in this study are also induced by sindbis virus, indicating activation of common host signalling pathways by these two viruses, despite their diverse life cycles. one of these, the glucocorti ...200617030862
antilipopolysaccharide factor interferes with white spot syndrome virus replication in vitro and in vivo in the crayfish pacifastacus leniusculus.in a study of genes expressed differentially in the freshwater crayfish pacifastacus leniusculus infected experimentally with the white spot syndrome virus (wssv), one protein, known as antilipopolysaccharide factor (alf), was chosen, among those whose transcript levels increased upon viral infection, for further studies. alf rna interference (rnai) experiments in whole animals and in cell cultures indicated that alf can protect against wssv infection, since knockdown of alf by rnai specifically ...200617041217
identification of linear heparin-binding peptides derived from human respiratory syncytial virus fusion glycoprotein that inhibit infectivity.it has been shown previously that the fusion glycoprotein of human respiratory syncytial virus (rsv-f) interacts with cellular heparan sulfate. synthetic overlapping peptides derived from the f-protein sequence of rsv subtype a (strain a2) were tested for their ability to bind heparin using heparin-agarose affinity chromatography (haac). this evaluation identified 15 peptides representing eight linear heparin-binding domains (hbds) located within f1 and f2 and spanning the protease cleavage acti ...200717050595
a chimeric alphavirus rna replicon gene-based vaccine for human parainfluenza virus type 3 induces protective immunity against intranasal virus challenge.parainfluenza virus type 3 (piv3) infections continue to be a significant health risk for infants, young children, and immunocompromised adults. we describe a gene-based vaccine strategy against piv3 using replication-defective alphavirus vectors. these rna replicon vectors, delivered as virus-like particles and expressing the piv3 hemagglutinin-neuraminidase glycoprotein, were shown to be highly immunogenic in mice and hamsters, inducing piv3-specific neutralizing antibody responses. importantl ...200717052811
antibody responses against hiv in rhesus macaques following combinations of mucosal and systemic immunizations with chimeric alphavirus-based replicon particles.mucosal and systemic transmission of hiv is prevalent. therefore, mucosal followed by parenteral immunizations with chimeric vs. complete alphavirus-based replicon particles, encoding an hiv envelope glycoprotein, were tested. female rhesus macaques were immunized intranasally and then intramuscularly. following the immunizations, enhanced mucosal and systemic antibody responses were detected with the chimeric compared to the complete replicon particles. although similar proportions of the same ...200617067269
characterization of immune responses elicited in macaques immunized sequentially with chimeric vee/sin alphavirus replicon particles expressing sivgag and/or hivenv and with recombinant hivgp140env protein.in the present study, macaques were coimmunized with veerep/sinenv chimeric alphavirus replicon particles expressing sivp55gag and hivdeltav2gp140env or only with replicon particles expressing hivdeltav2gp140env. all animals were subsequently immunized with recombinant trimeric hivdeltav2gp140env protein. during alphavirus immunization, anti-sivgag and anti-hivenv-specific interferon (ifn)-gamma responses, as well as high titers of anti-hivenv binding (gp120 but not gp41 specific) and anti-hiv n ...200617067273
differential induction of type i interferon responses in myeloid dendritic cells by mosquito and mammalian-cell-derived alphaviruses.dendritic cells (dcs) are an important early target cell for many mosquito-borne viruses, and in many cases mosquito-cell-derived arboviruses more efficiently infect dcs than viruses derived from mammalian cells. however, whether mosquito-cell-derived viruses differ from mammalian-cell-derived viruses in their ability to induce antiviral responses in the infected dendritic cell has not been evaluated. in this report, alphaviruses, which are mosquito-borne viruses that cause diseases ranging from ...200717079324
arc/arg3.1 interacts with the endocytic machinery to regulate ampa receptor trafficking.arc/arg3.1 is an immediate-early gene whose mrna is rapidly transcribed and targeted to dendrites of neurons as they engage in information processing and storage. moreover, arc/arg3.1 is known to be required for durable forms of synaptic plasticity and learning. despite these intriguing links to plasticity, arc/arg3.1's molecular function remains enigmatic. here, we demonstrate that arc/arg3.1 protein interacts with dynamin and specific isoforms of endophilin to enhance receptor endocytosis. arc ...200617088211
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 ...200617088212
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 ...200617088213
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 ...200717093195
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. ...200717101165
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 ...200717108023
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 ...200717108036
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 ...200717108037
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) ...200717108044
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 ...200717125789
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 ...200617132046
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 ...200617145504
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 ...200717151113
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 ...200717156813
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 ...200717157346
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 ...200717177262
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 ...200717178141
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 ...200717182693
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 ...200717185361
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 ...200717185417
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 ...200717192305
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 ...200717196289
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 ...200717202213
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 ...200717215278
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 ...200717222058
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 ...200717222803
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 ...200717223204
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 ...200717227866
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 ...200717251570
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 ...200717263893
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 ...200717267491
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 ...200717270235
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.200717274823
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.200617283634
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 ...200717284461
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 ...200717287124
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 ...200717287268
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 ...200717287280
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 ...200717289103
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 ...200717289916
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 ...200717291356
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 ...200717291642
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 ...200717292936
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 ...200717301129
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 ...200717301154
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. ...200717306321
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 ...200717314163
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.200717324254
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 ...200717328779
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 ...200717329335
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 ...200617337771
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 ...200717339356
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 ...200717344298
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