Publications

enhancement of sindbis virus self-replicating rna vaccine potency by linkage of mycobacterium tuberculosis heat shock protein 70 gene to an antigen gene.	recently, self-replicating rna vaccines (rna replicons) have emerged as an effective strategy for nucleic acid vaccine development. unlike naked dna vaccines, rna replicons eventually cause lysis of transfected cells and therefore do not raise the concern of integration into the host genome. we evaluated the effect of linking human papillomavirus type 16 e7 as a model ag to mycobacterium tuberculosis heat shock protein 70 (hsp70) on the potency of ag-specific immunity generated by a sindbis viru ...	2001	11342644
adaptation of tick-borne encephalitis virus to bhk-21 cells results in the formation of multiple heparan sulfate binding sites in the envelope protein and attenuation in vivo.	propagation of the flavivirus tick-borne encephalitis virus in bhk-21 cells selected for mutations within the large surface glycoprotein e that increased the net positive charge of the protein. in the course of 16 independent experiments, 12 different protein e mutation patterns were identified. these were located in all three of the structural domains and distributed over almost the entire upper and lateral surface of protein e. the mutations resulted in the formation of local patches of predom ...	2001	11356970
new immunochromatographic rapid test for diagnosis of acute puumala virus infection.	a new immunochromatographic rapid test, poc puumala (erilab ltd., kuopio, finland), for detection of acute-phase puumala virus (puuv) infection was developed based on a highly purified baculovirus-expressed puuv nucleocapsid protein antigen and lateral immunodiffusion techniques. after addition of sample (5 microl of serum, plasma, or fingertip blood) and buffer, puuv-specific immunoglobulin m (igm) antibodies, if present, together with the gold-conjugated anti-human igm, formed a specific color ...	2001	11376049
physicians' database searches as a tool for early detection of epidemics.	we analyzed retrospectively the use of physician desk reference database searches to identify epidemics of tularemia, nephropathy, pogosta disease, and lyme disease and compared the searches with mandatory laboratory reports to the national infectious diseases register in finland during 1995. continuous recording of such searches may be a tool for early detection of epidemics.	2001	11384534
deacylation of the transmembrane domains of sindbis virus envelope glycoproteins e1 and e2 does not affect low-ph-induced viral membrane fusion activity.	the envelope glycoproteins e1 and e2 of sindbis virus are palmitoylated at cysteine residues within their transmembrane domains (e1 at position 430, and e2 at positions 388 and 390). here, we investigated the in vitro membrane fusion activity of sindbis virus variants (derived from the toto 1101 infectious clone), in which the e1 c430 and/or e2 c388/390 residues had been substituted for alanines. both the e1 and e2 mutant viruses, as well as a triple mutant virus, fused with liposomes in a stric ...	2001	11389898
potential sources of the 1995 venezuelan equine encephalitis subtype ic epidemic.	venezuelan equine encephalitis viruses (veev) belonging to subtype ic have caused three (1962-1964, 1992-1993 and 1995) major equine epizootics and epidemics. previous sequence analyses of a portion of the envelope glycoprotein gene demonstrated a high degree of conservation among isolates from the 1962-1964 and the 1995 outbreaks, as well as a 1983 interepizootic mosquito isolate from panaquire, venezuela. however, unlike subtype iab veev that were used to prepare inactivated vaccines that prob ...	2001	11390583
trypsin cleavage stabilizes the rotavirus vp4 spike.	trypsin enhances rotavirus infectivity by an unknown mechanism. to examine the structural basis of trypsin-enhanced infectivity in rotaviruses, sa11 4f triple-layered particles (tlps) grown in the absence (nontrypsinized rotavirus [ntr]) or presence (trypsinized rotavirus [tr]) of trypsin were characterized to determine the structure, the protein composition, and the infectivity of the particles before and after trypsin treatment. as expected, vp4 was not cleaved in ntr particles and was cleaved ...	2001	11390607
stat1-independent regulation of gene expression in response to ifn-gamma.	although stat1 is essential for cells to respond fully to ifn-gamma, there is substantial evidence that, in the absence of stat1, ifn-gamma can still regulate the expression of some genes, induce an antiviral state and affect cell growth. we have now identified many genes that are regulated by ifn-gamma in serum-starved stat1-null mouse fibroblasts. the proteins induced by ifn-gamma in stat1-null cells can account for the substantial biological responses that remain. some genes are induced in bo ...	2001	11390994
biologic consequences of stat1-independent ifn signaling.	although stat1 is required for many ifn-dependent responses, recent work has shown that ifngamma functions independently of stat1 to affect the growth of tumor cells or immortalized fibroblasts. we now demonstrate that both ifngamma and ifnalpha/beta regulate proliferative responses in cells of the mononuclear phagocyte lineage derived from stat1-null mice. using both representational difference analysis and gene arrays, we show that ifngamma exerts its stat1-independent actions on mononuclear p ...	2001	11390995
dna vaccination against neu reduces breast cancer incidence and metastasis in mice.	the gene for her2/neu is overexpressed in 30-40% of breast and ovarian cancers, and this overexpression correlates with increased metastasis and poor prognosis. the her2/neu gene product, a transmembrane protein kinase member of the egf receptor family, has significant potential as a tumor antigen for vaccination. we inserted the sequence for neu into a novel plasmid called elvis containing a sindbis virus replicon that reproduces multiple copies of mrna. mice vaccinated one time intramuscularly ...	2001	11393278
virus-specific mrna capping enzyme encoded by hepatitis e virus.	hepatitis e virus (hev), a positive-strand rna virus, is an important causative agent of waterborne hepatitis. expression of cdna (encoding amino acids 1 to 979 of hev nonstructural open reading frame 1) in insect cells resulted in synthesis of a 110-kda protein (p110), a fraction of which was proteolytically processed to an 80-kda protein. p110 was tightly bound to cytoplasmic membranes, from which it could be released by detergents. immunopurified p110 catalyzed transfer of a methyl group from ...	2001	11413290
fidelity of leader and trailer sequence usage by the respiratory syncytial virus and avian pneumovirus replication complexes.	the specificity of usage of promoters for replication and transcription by the pneumoviruses human respiratory syncytial virus (hrsv) and avian pneumovirus (apv) was studied using minigenomes containing a reporter gene. when infectious hrsv or apv was used as helper virus, replication could occur only if both the leader and trailer regions (containing the replicative and transcriptional promoters) were derived from the helper virus. in contrast, when the hrsv replication complex was supplied fro ...	2001	11413292
an amino acid substitution in the coding region of the e2 glycoprotein adapts ross river virus to utilize heparan sulfate as an attachment moiety.	passage of ross river virus strain nb5092 in avian cells has been previously shown to select for virus variants that have enhanced replication in these cells. sequencing of these variants identified two independent sites that might be responsible for the phenotype. we now demonstrate, using a molecular cdna clone of the wild-type t48 strain, that an amino acid substitution at residue 218 in the e2 glycoprotein can account for the phenotype. substitutions that replaced the wild-type asparagine wi ...	2001	11413296
induction of caspase-dependent apoptosis in cultured cells by the avian coronavirus infectious bronchitis virus.	avian coronavirus infectious bronchitis virus (ibv) is the causative agent of chicken infectious bronchitis, an acute, highly contagious viral respiratory disease. replication of ibv in vero cells causes extensive cytopathic effects (cpe), leading to destruction of the entire monolayer and the death of infected cells. in this study, we investigated the cell death processes during acute ibv infection and the underlying mechanisms. the results show that both necrosis and apoptosis may contribute t ...	2001	11413307
a monoclonal antibody specific for reovirus outer-capsid protein sigma3 inhibits sigma1-mediated hemagglutination by steric hindrance.	reovirus virions are nonenveloped icosahedral particles consisting of two concentric protein shells, termed outer capsid and core. outer-capsid protein sigma1 is the viral attachment protein and binds carbohydrate molecules on the surface of host cells. monoclonal antibody (mab) 4f2, which is specific for outer-capsid protein sigma3, blocks the binding of sigma1 protein to sialic acid and inhibits reovirus-induced hemagglutination (ha). to determine whether mab 4f2 inhibits ha by altering sigma1 ...	2001	11413330
viral replicase gene products suffice for coronavirus discontinuous transcription.	we have used vaccinia virus as a vector to clone a 22.5-kbp cdna that represents the 5' and 3' ends of the human coronavirus 229e (hcov 229e) genome, the hcov 229e replicase gene, and a single reporter gene (coding for green fluorescent protein [gfp]) located downstream of a regulatory element for coronavirus mrna transcription. when rna transcribed from this cdna was transfected into bhk-21 cells, a small percentage of cells displayed strong fluorescence. a region of the mrna encoding gfp was a ...	2001	11413334
innate gastrointestinal immunity: characterization of broadly active viral inhibitors.	innate viral inhibitors that are broadly active have been characterized in the serum and the nervous system, but incompletely characterized in the gastrointestinal (gi) tract. gi preparations from porcine gastric mucosa, mouse intestine, and in neuramide (a pharmaceutical product), were examined for broad antiviral activity, molecular size and mechanism of action for comparison with the previously characterized, innate inhibitors in the serum and nervous system. the gi inhibitors were found to b ...	2001	11428242
sindbis virus-induced neuronal death is both necrotic and apoptotic and is ameliorated by n-methyl-d-aspartate receptor antagonists.	virus infection of neurons leads to different outcomes ranging from latent and noncytolytic infection to cell death. viruses kill neurons directly by inducing either apoptosis or necrosis or indirectly as a result of the host immune response. sindbis virus (sv) is an alphavirus that induces apoptotic cell death both in vitro and in vivo. however, apoptotic changes are not always evident in neurons induced to die by alphavirus infection. time lapse imaging revealed that sv-infected primary cortic ...	2001	11435592
pocket protein p130/rb2 is required for efficient herpes simplex virus type 1 gene expression and viral replication.	we have reported previously that herpes simplex virus type 1 (hsv-1) infection disrupts normal progression of the mammalian cell cycle, causing cells to enter a g(1)-like state. infected cells were characterized by a decline in cyclin-dependent kinase 2 (cdk2) activities, loss of hyperphosphorylated retinoblastoma protein (prb), accumulation of e2f-pocket protein complexes, and failure to initiate cellular dna replication. in the present study, we investigated the role of the pocket proteins prb ...	2001	11435596
sindbis virus-induced silencing of dengue viruses in mosquitoes.	aedes aegypti were injected intrathoracically with double subgenomic sindbis (dssin) viruses with inserted sequences derived from the genome of one or more of the four dengue (den) virus serotypes. mosquitoes were highly resistant to challenge with homologous den viruses from which the effector sequences were derived, and resistance to den viruses was independent of the orientation of the effector rna. dssin viruses designed to express rna derived from the premembrane coding region of den-2 prev ...	2001	11437918
role of antibodies in controlling alphavirus infection of neurons.		2001	11443874
interferon-gamma-mediated site-specific clearance of alphavirus from cns neurons.	recovery from viral encephalomyelitis requires immune-mediated noncytolytic clearance from neurons by mechanisms assumed to be the same for all neurons. in alphavirus encephalomyelitis, antibody clears infectious virus from neurons in all regions of the central nervous system (cns), but cd8 t cells contribute to elimination of viral rna. to understand the role of t cells in clearance, we infected antibody knockout mice with sindbis virus. virus was cleared from spinal cord and brain stem neurons ...	2001	11452126
characterization of new syncytium-inhibiting monoclonal antibodies implicates lipid rafts in human t-cell leukemia virus type 1 syncytium formation.	we have previously shown that erythroleukemia cells (k562) transfected with vascular adhesion molecule 1 (vcam-1) are susceptible to human t-cell leukemia virus type 1 (htlv-1)-induced syncytium formation. since expression of vcam-1 alone is not sufficient to render cells susceptible to htlv-1 fusion, k562 cells appear to express a second molecule critical for htlv-induced syncytium formation. by immunizing mice with k562 cells, we have isolated four monoclonal antibodies (mabs), k5.m1, k5.m2, k ...	2001	11462007
human herpesvirus 8 envelope glycoprotein k8.1a interaction with the target cells involves heparan sulfate.	human herpesvirus-8 (hhv-8) or kaposi's sarcoma-associated herpesvirus k8.1 gene encodes for two immunogenic glycoproteins, gpk8.1a and gpk8.1b, originating from spliced messages. the 228-amino-acid (aa) gpk8.1a is the predominant form associated with the virion envelope, consisting of a 167-aa region identical to gpk8.1b and a 61-aa unique region (l. zhu, v. puri, and b. chandran, virology 262:237-249, 1999). hhv-8 has a broad in vivo and in vitro cellular tropism, and our studies showed that t ...	2001	11462024
recombinant measles viruses expressing altered hemagglutinin (h) genes: functional separation of mutations determining h antibody escape from neurovirulence.	measles virus (mv) strain cam/rb, which was adapted to growth in the brain of newborn rodents, is highly neurovirulent. it has been reported earlier that experimentally selected virus variants escaping from the monoclonal antibodies (mabs) nc32 and l77 to hemagglutinin (h) preserved their neurovirulence, whereas mutants escaping mabs k71 and k29 were found to be strongly attenuated (u. g. liebert et al., j. virol. 68:1486-1493, 1994). to investigate the molecular basis of these findings, we have ...	2001	11462033
sindbis virus variant with a deletion in the 6k gene shows defects in glycoprotein processing and trafficking: lack of complementation by a wild-type 6k gene in trans.	a sindbis virus (sv) variant with a 6k gene partially deleted has been obtained. this sv del6k virus is defective in the proteolytic processing of virus glycoprotein precursor, transport of glycoproteins to the plasma membrane, and plaque phenotype. a revertant virus (sv del6k-revq21l) containing a point mutation in the deleted 6k gene was isolated and characterized. sv del6k-revq21l has corrected the defects of proteolytic processing and transport of virus glycoproteins to the plasma membrane, ...	2001	11462055
gene transfer: manipulating and monitoring function in cells and tissues.	1. the ectopic expression of genes has proven to be an extremely valuable tool for biologists. the most widely used systems involve electrically or chemically mediated transfer of genes to immortalized cell lines and, at the other end of the spectrum, transgenic animal models. as would be expected, there are compromises to be made when using either of these broad approaches. immortalized cell lines have limited "physiological relevance" and transgenic approaches are costly and out of the reach o ...	2001	11473537
genetic analysis of the pestivirus nonstructural coding region: defects in the ns5a unit can be complemented in trans.	the functional analysis of molecular determinants which control the replication of pestiviruses was considerably facilitated by the finding that subgenomic forms of the positive-strand rna genome of bvdv (bovine viral diarrhea virus) are capable of autonomous replication in transfected host cells. the prototype replicon, bvdv di9c, consists of the genomic 5' and 3' untranslated regions and a truncated open reading frame (orf) encoding mainly the nonstructural proteins ns3, ns4a, ns4b, ns5a, and ...	2001	11483722
salicylates inhibit flavivirus replication independently of blocking nuclear factor kappa b activation.	flaviviruses comprise a positive-sense rna genome that replicates exclusively in the cytoplasm of infected cells. whether flaviviruses require an activated nuclear factor(s) to complete their life cycle and trigger apoptosis in infected cells remains elusive. flavivirus infections quickly activate nuclear factor kappa b (nf-kappab), and salicylates have been shown to inhibit nf-kappab activation. in this study, we investigated whether salicylates suppress flavivirus replication and virus-induced ...	2001	11483726
antibody-directed targeting of retroviral vectors via cell surface antigens.	targeted stable transduction of specific cells is a highly desirable goal for gene therapy applications. we report an efficient and broadly applicable approach for targeting retroviral vectors to specific cells. we find that the envelope of the alphavirus sindbis virus can pseudotype human immunodeficiency virus type 1- and murine leukemia virus-based retroviral vectors. when modified to contain the fc-binding domain of protein a, this envelope gives a significant enhancement in specificity in c ...	2001	11483746
in vivo generation and characterization of a soluble form of the semliki forest virus fusion protein.	during infection of host cells, a number of enveloped animal viruses are known to produce soluble forms of viral membrane glycoproteins lacking the transmembrane domain. the roles of such soluble glycoproteins in viral life cycles are incompletely understood, but in several cases they are believed to modulate host immune response and viral pathogenesis. semliki forest virus (sfv) is an enveloped alphavirus that infects cells through low-ph-dependent fusion and buds from the plasma membrane. fusi ...	2001	11483778
abundant gfp expression and ltp in hippocampal acute slices by in vivo injection of sindbis virus.	virus-mediated gene transfer into neurons is a powerful tool for the analysis of neuronal structure and function. recombinant sindbis virus has been previously used to study protein function in hippocampal neuron cultures as well as in hippocampal organotypic slice cultures. nevertheless, some concern still exists about the physiological relevance of these cultured preparations. acute hippocampal slices are a widely used preparation for the study of synaptic transmission, but currently recombina ...	2001	11495971
n-methyl-d-aspartate-induced alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (ampa) receptor down-regulation involves interaction of the carboxyl terminus of glur2/3 with pick1. ligand-binding studies using sindbis vectors carrying ampa receptor decoys.	the dynamics of alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (ampa)-type glutamate receptors, as represented by their exocytosis, endocytosis and cytoskeletal linkage, has often been implicated in n-methyl-d-aspartate (nmda)-dependent synaptic plasticity. to explore the molecular mechanisms underlying the ampa receptor dynamics, cultured hippocampal neurons were stimulated with 100 microm nmda, and the biochemical and pharmacological changes in the ligand binding activity of ampa re ...	2001	11498531
characterization of the adomet-dependent guanylyltransferase activity that is associated with the n terminus of bamboo mosaic virus replicase.	bamboo mosaic virus (bamv), a member of the potexvirus group, infects primarily members of the bambusoideae. open reading frame 1 (orf1) of bamv encodes a 155-kda polypeptide that has long been postulated to be a replicase involved in the replication and formation of the cap structure at the 5' end of the viral genome. to identify and characterize the enzymatic activities associated with the n-terminal domain of the bamv orf1 protein, the intact replicase and two c-terminally truncated proteins ...	2001	11134291
recognition of nascent rna by the human la antigen: conserved and divergent features of structure and function.		2001	11134326
human immunodeficiency virus type 1 vpu protein affects sindbis virus glycoprotein processing and enhances membrane permeabilization.	the human immunodeficiency virus type 1 (hiv-1) vpu is an integral membrane protein that forms oligomeric structures in membranes. expression of vpu using sindbis virus (sv) as a vector leads to permeabilization of plasma membrane to hydrophilic molecules and impaired maturation of wild type sv glycoproteins in bhk cells. the 6k protein is a membrane protein encoded in the sv genome that facilitates budding of virus particles and regulates transport of viral glycoproteins through the secretory p ...	2001	11145902
sorting of marburg virus surface protein and virus release take place at opposite surfaces of infected polarized epithelial cells.	marburg virus, a filovirus, causes severe hemorrhagic fever with hitherto poorly understood molecular pathogenesis. we have investigated here the vectorial transport of the surface protein gp of marburg virus in polarized epithelial cells. to this end, we established an mdckii cell line that was able to express gp permanently (mdck-gp). the functional integrity of gp expressed in these cells was analyzed using vesicular stomatitis virus pseudotypes. further experiments revealed that gp is transp ...	2001	11152500
mutations in hepatitis c virus rnas conferring cell culture adaptation.	as an initial approach to studying the molecular replication mechanisms of hepatitis c virus (hcv), a major causative agent of acute and chronic liver disease, we have recently developed selectable self-replicating rnas. these replicons lacked the region encoding the structural proteins and instead carried the gene encoding the neomycin phosphotransferase. although the replication levels of these rnas within selected cells were high, the number of g418-resistant colonies was reproducibly low. in ...	2001	11152517
human papillomavirus infection requires cell surface heparan sulfate.	using pseudoinfection of cell lines, we demonstrate that cell surface heparan sulfate is required for infection by human papillomavirus type 16 (hpv-16) and hpv-33 pseudovirions. pseudoinfection was inhibited by heparin but not dermatan or chondroitin sulfate, reduced by reducing the level of surface sulfation, and abolished by heparinase treatment. carboxy-terminally deleted hpv-33 virus-like particles still bound efficiently to heparin. the kinetics of postattachment neutralization by antiseru ...	2001	11152531
ebola virus glycoprotein: proteolytic processing, acylation, cell tropism, and detection of neutralizing antibodies.	using the vesicular stomatitis virus (vsv) pseudotype system, we studied the functional properties of the ebola virus glycoprotein (gp). amino acid substitutions at the gp cleavage site, which reduce glycoprotein cleavability and viral infectivity in some viruses, did not appreciably change the infectivity of vsv pseudotyped with gp. likewise, removal of two acylated cysteine residues in the transmembrane region of gp showed no discernible effects on infectivity. although most filoviruses are be ...	2001	11152533
hostile takeovers: viral appropriation of the nf-kappab pathway.		2001	11160127
polarity of human parainfluenza virus type 3 infection in polarized human lung epithelial a549 cells: role of microfilament and microtubule.	human parainfluenza virus type 3 (hpiv-3) is an airborne pathogen that infects the epithelial cells of the respiratory tract. in the present study we investigated the interaction of hpiv-3 with the type ii alveolar human lung polarized epithelial a549 cells. although hpiv-3 entry and budding were bidirectional from both the apical and the basolateral domains, hpiv-3 exhibited preferential entry and release from the apical pole. while disruption of the cellular actin microfilament and microtubule ...	2001	11160698
exposure to low ph is not required for penetration of mosquito cells by sindbis virus.	it is widely held that the penetration of cells by alphaviruses is dependent on exposure to the acid environment of an endosome. the alphavirus sindbis virus replicates in both vertebrate and invertebrate cell cultures. we have found that exposure to an acid environment may not be required for infection of cells of the insect host. in this work, we investigated the effects of two agents (nh(4)cl and chloroquine), which raise the ph of intracellular compartments (lysosomotropic weak bases) on the ...	2001	11160702
yellow fever virus encephalitis: properties of the brain-associated t-cell response during virus clearance in normal and gamma interferon-deficient mice and requirement for cd4+ lymphocytes.	viral encephalitis caused by neuroadapted yellow fever 17d virus (pyf) was studied in parental and gamma interferon (ifn-gamma)-deficient (ifn-gamma knockout [gko]) c57bl/6 mice. the t-cell responses which enter the brain during acute fatal encephalitis of nonimmunized mice, as well as nonfatal encephalitis of immunized mice, were characterized for relative proportions of cd4+ and cd8+ cells, their proliferative responses, and antigen-specific expression of cytokines during stimulation in vitro. ...	2001	11160715
enhancement of sindbis virus self-replicating rna vaccine potency by linkage of herpes simplex virus type 1 vp22 protein to antigen.	recently, self-replicating and self-limiting rna vaccines (rna replicons) have emerged as an important form of nucleic acid vaccines. self-replicating rna eventually causes lysis of transfected cells and does not raise the concern associated with naked dna vaccines of integration into the host genome. this is particularly important for development of vaccines targeting proteins that are potentially oncogenic. however, the potency of rna replicons is significantly limited by their lack of intrins ...	2001	11160740
transmission of replication-defective sindbis helper vectors encoding capsid and envelope proteins.	a green fluorescent protein (gfp)-encoding derivative of the replication-defective sindbis helper vector dhbb was constructed in order to study the rate of packaging of the helper vector. the results show that despite lacking a 'packaging sequence', this vector is co-packaged about 1/300th the rate of packaging of single rnas containing a packaging sequence. this helps explain the frequent observation of recombinant, replication-competent viruses when using first generation sindbis packaging sys ...	2001	11164486
enhancement of sindbis virus self-replicating rna vaccine potency by targeting antigen to endosomal/lysosomal compartments.	self-replicating rna vaccines (rna replicons) have emerged as an attractive approach for tumor immunotherapy. rna replicons do not integrate into host chromosomes, eliminating the concern for oncogenicity associated with a dna vaccine. in this study, we used human papillomavirus type 16 (hpv-16) e7 as a model antigen and evaluated e7-specific immunity generated by a sindbis virus self-replicating rna vector, sin-rep5. three different constructs were created to target e7 antigen to different cell ...	2001	11177561
the effects of testosterone on a viral infection in greenfinches (carduelis chloris): an experimental test of the immunocompetence-handicap hypothesis.	the immunocompetence-handicap hypothesis suggests that the honesty of quality signals could be guaranteed if testosterone (t) suppresses immune function while enhancing male ornaments. in addition, it has been proposed that the cost of enhancing ornaments should be highest for males with small ornaments. recently, the assertion that t causes obligate immunosuppression has been questioned. in this study, we tested whether elevated t levels would increase susceptibility to a viral infection, and w ...	2001	11209893
measurement of rab5 protein kinase b/akt and regulation of ras-activated endocytosis.		2001	11210531
viral neuroinvasion as a marker for bbb integrity following exposure to cholinesterase inhibitors.	exposure to the nerve agent soman, an irreversible cholinesterase (che) inhibitor, results in changes in blood-brain barrier permeability attributed to its seizure-induced activity. however, smaller bbb changes may be independent of convulsions. such minor injury may escape detection. a nonneuroinvasive neurovirulent sindbis virus strain (svn) was used as a marker for bbb permeability. peripheral inoculation of mice with 2 x 10(3) plaque forming units (pfu) caused up to 10(5) pfu/ml viremia afte ...	2001	11212873
vaccines against hantaviruses.		2001	11217404
c-iap1 is cleaved by caspases to produce a proapoptotic c-terminal fragment.	although human c-iap1 and c-iap2 have been reported to possess antiapoptotic activity against a variety of stimuli in several mammalian cell types, we observed that full-length c-iap1 and c-iap2 failed to protect cells from apoptosis induced by bax overexpression, tumor necrosis factor alpha treatment or sindbis virus infection. however, deletion of the c-terminal ring domains of c-iap1 and c-iap2 restored antiapoptotic activity, indicating that this region negatively regulates the antiapoptotic ...	2001	11106668
candidate vaccine against botulinum neurotoxin serotype a derived from a venezuelan equine encephalitis virus vector system.	a candidate vaccine against botulinum neurotoxin serotype a (bont/a) was developed by using a venezuelan equine encephalitis (vee) virus replicon vector. this vaccine vector is composed of a self-replicating rna containing all of the vee nonstructural genes and cis-acting elements and also a heterologous immunogen gene placed downstream of the subgenomic 26s promoter in place of the viral structural genes. in this study, the nontoxic 50-kda carboxy-terminal fragment (h(c)) of the bont/a heavy ch ...	2001	11500447
isolation and characterization of a mutant chinese hamster ovary cell line that is resistant to chlamydia trachomatis infection at a novel step in the attachment process.	host factors involved in chlamydia trachomatis pathogenesis were investigated by random chemical mutagenesis of chinese hamster ovary (cho-k1) cells followed by selection for clones resistant to chlamydial infection. a clonal mutant cell line, d4.1-3, refractory to infection by the c. trachomatis l2 serovar was isolated. the d4.1-3 cell line appears to be lacking in a previously undescribed temperature-dependent and heparin-resistant binding step that occurs subsequent to engagement of cell surf ...	2001	11500469
expression and functional characterization of bluetongue virus vp5 protein: role in cellular permeabilization.	segment 5 of bluetongue virus (btv) serotype 10, which encodes the outer capsid protein vp5, was tagged with glutathione s-transferase and expressed by a recombinant baculovirus. the recombinant protein was subsequently purified to homogeneity, and its possible biological role in virus infection was investigated. purified vp5 was able to bind mammalian cells but was not internalized, which indicates it is not involved in receptor-mediated endocytosis. the purified vp5 protein was shown to be abl ...	2001	11507181
pa subunit from influenza virus polymerase complex interacts with a cellular protein with homology to a family of transcriptional activators.	the pa subunit of the influenza virus polymerase complex is a phosphoprotein that induces proteolytic degradation of coexpressed proteins. point mutants with reduced proteolysis induction reconstitute viral ribonucleoproteins defective in replication but not in transcriptional activity. to look for cellular factors that could associate with pa protein, we have carried out a yeast two-hybrid screen. using a human kidney cdna library, we identified two different interacting clones. one of them was ...	2001	11507205
genetic control of neuroadapted sindbis virus replication in female mice maps to chromosome 2 and associates with paralysis and mortality.	neuroadapted sindbis virus (nsv) infection of mice causes hindlimb paralysis and 100% mortality in the c57bl/6 mouse strain, while adults of the balb/cby mouse strain are resistant to fatal encephalomyelitis. levels of viral rna are higher in the brains of infected c57bl/6 mice than in balb/cby mice (d. c. thach et al., j. virol. 74:6156-6161, 2000). these phenotypic differences between the two strains allowed us to map genetic loci involved in mouse susceptibility to nsv and to find relationshi ...	2001	11507212
effect of prophenoloxidase expression knockout on the melanization of microfilariae in the mosquito armigeres subalbatus.	melanization is an effective defence reaction used by mosquito hosts to kill malarial and filarial worm parasites. although phenoloxidase (po) has long been considered to be the key enzyme in the biosynthesis of melanotic material in insects, there is no direct evidence verifying its role in parasite melanization. to elucidate the role of po in the melanization of microfilariae (mf) by mosquitoes, a double subgenomic sindbis (dssin) recombinant virus was used to transduce armigeres subalbatus mo ...	2001	11520354
5'-nor carbocyclic 5'-deoxy-5'-(isobutylthio)adenosine and a 2',3'-dideoxy-2',3'-didehydro derivative.	the inhibition of biochemical processes requiring s-adenosylmethionine as a co-factor have led to many nucleoside-based medicinal agents. included in this group are 5'-deoxy-5'-(isobutylthio)adenosine (siba), a nucleoside with antiparasitic, antiviral and antiproliferative effects, and 5'-noraristeromycin, a carbocyclic-derived nucleoside with potent antiviral properties. this report brings together the structural components of these two compounds by describing both enantiomers of carbocyclic 5- ...	2001	11527043
mutant prion proteins are partially retained in the endoplasmic reticulum.	familial prion diseases are linked to point and insertional mutations in the prion protein (prp) gene that are presumed to favor conversion of the cellular isoform of prp to the infectious isoform. in this report, we have investigated the subcellular localization of prp molecules carrying pathogenic mutations using immunofluorescence staining, immunogold labeling, and prp-green fluorescent protein chimeras. to facilitate visualization of the mutant proteins, we have utilized a novel sindbis vira ...	2001	11527974
receptors and entry cofactors for retroviruses include single and multiple transmembrane-spanning proteins as well as newly described glycophosphatidylinositol-anchored and secreted proteins.	in the past few years, many retrovirus receptors, coreceptors, and cofactors have been identified. these molecules are important for some aspects of viral entry, although in some cases it remains to be determined whether they are required for binding or postbinding stages in entry, such as fusion. there are certain common features to the molecules that many retroviruses use to gain entry into the cell. for example, the receptors for most mammalian oncoretroviruses are multiple membrane-spanning ...	2001	11528001
cooperation of an rna packaging signal and a viral envelope protein in coronavirus rna packaging.	murine coronavirus mouse hepatitis virus (mhv) produces a genome-length mrna, mrna 1, and six or seven species of subgenomic mrnas in infected cells. among these mrnas, only mrna 1 is efficiently packaged into mhv particles. mhv n protein binds to all mhv mrnas, whereas envelope m protein interacts only with mrna 1. this m protein-mrna 1 interaction most probably determines the selective packaging of mrna 1 into mhv particles. a short cis-acting mhv rna packaging signal is necessary and sufficie ...	2001	11533169
high resistance of human parainfluenza type 2 virus protein-expressing cells to the antiviral and anti-cell proliferative activities of alpha/beta interferons: cysteine-rich v-specific domain is required for high resistance to the interferons.	human parainfluenza type 2 virus (hpiv-2)-infected hela (hela-ca) cells and hpiv-2 v-expressing hela (hela-v) cells show high resistance to alpha/beta interferons (ifn-alpha/beta) irrespective of whether vesicular stomatitis virus or sindbis virus is used as a challenge virus. when sindbis virus is used, these cells show high susceptibility to human ifn-gamma. furthermore, the multiplication of hela-v cells is not inhibited by ifn-alpha/beta. hela cells expressing the n-terminally truncated v pr ...	2001	11533180
additive effects characterize the interaction of antibodies involved in neutralization of the primary dualtropic human immunodeficiency virus type 1 isolate 89.6.	human immunodeficiency virus-type i (hiv-1) infection elicits antibodies (abs) directed against several regions of the gp120 and gp41 envelope glycoproteins. many of these abs are able to neutralize t-cell-line-adapted strains (tcla) of hiv-1, but only a few effectively neutralize primary hiv-1 isolates. the nature of hiv-1 neutralization has been carefully studied using human monoclonal abs (mabs), and the ability of such mabs to act in synergy to neutralize hiv-1 has also been extensively stud ...	2001	11533181
chimeric bovine respiratory syncytial virus with attachment and fusion glycoproteins replaced by bovine parainfluenza virus type 3 hemagglutinin-neuraminidase and fusion proteins.	chimeric bovine respiratory syncytial viruses (brsv) expressing glycoproteins of bovine parainfluenza virus type 3 (bpiv-3) instead of brsv glycoproteins were generated from cdna. in the brsv antigenome cdna, the open reading frames of the major brsv glycoproteins, attachment protein g and fusion protein f, were replaced individually or together by those of the bpiv-3 hemagglutinin-neuraminidase (hn) and/or fusion (f) glycoproteins. recombinant virus could not be recovered from cdna when the brs ...	2001	11533200
venezuelan equine encephalomyelitis virus structure and its divergence from old world alphaviruses.	although alphaviruses have been extensively studied as model systems for the structural organization of enveloped viruses, no structures exist for the phylogenetically distinct eastern equine encephalomyelitis (eee)-venezuelan equine encephalomyelitis (vee) lineage of new world alphaviruses. here we report the 25-a structure of vee virus, obtained from electron cryomicroscopy and image reconstruction. the envelope spike glycoproteins of vee virus have a t=4 icosahedral arrangement, similar to th ...	2001	11533216
genetic selection and the lure of sin.		2001	11533637
a high-throughput alphavirus-based expression cloning system for mammalian cells.	we have developed a widely applicable functional genomics strategy based on alphavirus expression vectors. the technology allows for rapid identification of genes encoding a functional activity such as binding of a defined ligand. complementary dna (cdna) libraries were expressed in mammalian cells following infection with recombinant sindbis virus (sin replicon particles), a member of the alphavirus genus. virus-infected cells that specifically bound a ligand of choice were isolated using fluor ...	2001	11533644
membrane topography and topogenesis of prenylated rab acceptor (pra1).	the mouse prenylated rab acceptor (mpra1) is associated with the golgi membrane at steady state and interacts with rab proteins. it contains two internal hydrophobic domains (34 residues each) that have enough residues to form four transmembrane (tm) segments. in this study, we have determined the membrane topography of mpra1 in both intact cells and isolated microsomes. the putative tm segments of mpra1 were used to substitute for a known tm segment of a model membrane protein to determine whet ...	2001	11535589
complete, long-lasting protection against malaria of mice primed and boosted with two distinct viral vectors expressing the same plasmodial antigen.	we report that complete protection against malaria and total inhibition of liver stage development and parasitemia was obtained in 100% of balb/c mice primed with a replication-defective recombinant adenovirus expressing the circumsporozoite (cs) protein of plasmodium yoelii (adpycs), followed by a booster with an attenuated recombinant vaccinia virus, expressing the same malaria antigen, vacpycs. we found increased levels of activated cs-specific cd8(+) and cd4(+) t cells, higher anti-sporozoit ...	2001	11553779
interaction of classical swine fever virus with membrane-associated heparan sulfate: role for virus replication in vivo and virulence.	passage of native classical swine fever virus (csfv) in cultured swine kidney cells (sk6 cells) selects virus variants that attach to the surface of cells by interaction with membrane-associated heparan sulfate (hs). a ser-to-arg change in the c terminus of envelope glycoprotein e(rns) (amino acid 476 in the open reading frame of csfv) is responsible for selection of these hs-binding virus variants (m. m. hulst, h. g. p. van gennip, and r. j. m. moormann, j. virol. 74:9553-9561, 2000). in this i ...	2001	11559790
frequency of spontaneous mutations in an avian hepadnavirus infection.	in this study, we measured the frequency of revertants of a cytopathic strain of the duck hepatitis b virus that bears a single nucleotide substitution in the pre-s envelope protein open reading frame, resulting in the amino acid substitution g133e. cytopathic virus mixed with known amounts of a genetically marked wild-type virus was injected into ducklings. virus outgrowth was accompanied by a coselection of wild-type and spontaneous revertants during recovery of the ducklings from the acute li ...	2001	11559794
resistance to nucleoside analog reverse transcriptase inhibitors mediated by human immunodeficiency virus type 1 p6 protein.	resistance of human immunodeficiency virus type 1 (hiv-1) to antiretroviral agents results from target gene mutation within the pol gene, which encodes the viral protease, reverse transcriptase (rt), and integrase. we speculated that mutations in genes other that the drug target could lead to drug resistance. for this purpose, the p1-p6(gag)-p6(pol) region of hiv-1, placed immediately upstream of pol, was analyzed. this region has the potential to alter pol through frameshift regulation (p1), th ...	2001	11559796
murine gammaherpesvirus-68-induced interleukin-10 increases viral burden, but limits virus-induced splenomegaly and leukocytosis.	based on its genomic sequence and its pathogenesis, murine gammaherpesvirus-68 (gammahv-68) has been established as a tractable model for the study of viral infections caused by the human gammaherpesviruses, epstein-barr virus or human herpesvirus-8. despite significant advances, the mechanisms responsible for gammahv-68-induced alterations in the protective host response, and the accompanying virus-induced leukocytosis, are not clear. in the present study, we questioned whether viral infection ...	2001	11576228
phosphatidylinositol-4-phosphate 5-kinase-1beta is essential for epidermal growth factor receptor-mediated endocytosis.	phosphatidylinositol-4,5-bisphosphate (pip(2)) is known to play an important role in signal transduction and membrane trafficking. we show that one enzyme responsible for pip(2) production, phosphatidylinositol-4-phosphate 5-kinase type 1beta (pipkbeta), is essential for epidermal growth factor receptor (egfr)-mediated endocytosis. expression of murine pipkbeta in nr6 cells expressing egfr strikingly increased receptor internalization. moreover, the kinase was shown to form an immunoprecipitable ...	2001	11581249
evolutionary relationships and systematics of the alphaviruses.	partial e1 envelope glycoprotein gene sequences and complete structural polyprotein sequences were used to compare divergence and construct phylogenetic trees for the genus alphavirus. tree topologies indicated that the mosquito-borne alphaviruses could have arisen in either the old or the new world, with at least two transoceanic introductions to account for their current distribution. the time frame for alphavirus diversification could not be estimated because maximum-likelihood analyses indic ...	2001	11581380
identification of genes involved in the host response to neurovirulent alphavirus infection.	single-amino-acid mutations in sindbis virus proteins can convert clinically silent encephalitis into uniformly lethal disease. however, little is known about the host gene response during avirulent and virulent central nervous system (cns) infections. to identify candidate host genes that modulate alphavirus neurovirulence, we utilized genechip expression analysis to compare cns gene expression in mice infected with two strains of sindbis virus that differ by one amino acid in the e2 envelope g ...	2001	11581411
cd8(+) t lymphocytes mediate borna disease virus-induced immunopathology independently of perforin.	perforin-mediated lysis of target cells is the major antiviral effector mechanism of cd8(+) t lymphocytes. we have analyzed the role of perforin in a mouse model for cd8(+) t-cell-mediated central nervous system (cns) immunopathology induced by borna disease virus. when a defective perforin gene was introduced into the genetic background of the borna disease-susceptible mouse strain mrl, the resulting perforin-deficient mice developed strong neurological disease in response to infection indistin ...	2001	11581414
the synthetic peptide p-197 inhibits human t-cell leukemia virus type 1 envelope-mediated syncytium formation by a mechanism that is independent of hsc70.	entry of human t-cell leukemia virus type 1 (htlv-1) into cells is mediated by the viral envelope glycoproteins gp46 and gp21. the gp46 surface glycoprotein binds to a poorly characterized cell surface receptor, thereby promoting the gp21-dependent fusion of the viral and cellular membranes. interestingly, a synthetic peptide (p-197) simulating amino acids 197 to 216 of gp46 strongly inhibits envelope-dependent membrane fusion with molt-4 target cells. it has been suggested that this peptide act ...	2001	11581416
ross river virus transmission, infection, and disease: a cross-disciplinary review.	ross river virus (rrv) is a fascinating, important arbovirus that is endemic and enzootic in australia and papua new guinea and was epidemic in the south pacific in 1979 and 1980. infection with rrv may cause disease in humans, typically presenting as peripheral polyarthralgia or arthritis, sometimes with fever and rash. rrv disease notifications in australia average 5,000 per year. the first well-described outbreak occurred in 1928. during world war ii there were more outbreaks, and the name ep ...	2001	11585790
poliovirus 5'-terminal cloverleaf rna is required in cis for vpg uridylylation and the initiation of negative-strand rna synthesis.	chimeric poliovirus rnas, possessing the 5' nontranslated region (ntr) of hepatitis c virus in place of the 5' ntr of poliovirus, were used to examine the role of the poliovirus 5' ntr in viral replication. the chimeric viral rnas were incubated in cell-free reaction mixtures capable of supporting the sequential translation and replication of poliovirus rna. using preinitiation rna replication complexes formed in these reactions, we demonstrated that the 3' ntr of poliovirus rna was insufficient ...	2001	11602711
c terminus of infectious bursal disease virus major capsid protein vp2 is involved in definition of the t number for capsid assembly.	infectious bursal disease virus (ibdv), a member of the birnaviridae family, is a double-stranded rna virus. the ibdv capsid is formed by two major structural proteins, vp2 and vp3, which assemble to form a t=13 markedly nonspherical capsid. during viral infection, vp2 is initially synthesized as a precursor, called vpx, whose c end is proteolytically processed to the mature form during capsid assembly. we have computed three-dimensional maps of ibdv capsid and virus-like particles built up by v ...	2001	11602723
neuroadapted yellow fever virus 17d: genetic and biological characterization of a highly mouse-neurovirulent virus and its infectious molecular clone.	a neuroadapted strain of yellow fever virus (yfv) 17d derived from a multiply mouse brain-passaged virus (porterfield yf17d) was additionally passaged in scid and normal mice. the virulence properties of this virus (spyf) could be distinguished from nonneuroadapted virus (yf5.2iv, 17d infectious clone) by decreased average survival time in scid mice after peripheral inoculation, decreased average survival time in normal adult mice after intracerebral inoculation, and occurrence of neuroinvasiven ...	2001	11602731
human immunodeficiency virus type 1 entry into macrophages mediated by macropinocytosis.	whereas human immunodeficiency virus (hiv) infects various cell types by fusion at the plasma membrane, we observed a different entry route in human primary macrophages, in which macropinocytosis is active. shortly after exposure of macrophages to hiv-1 and irrespective of viral envelope-receptor interactions, particles were visible in intracellular vesicles, which were identified as macropinosomes. most virions appeared subsequently degraded. however, fusion leading to capsid release in the cyt ...	2001	11602756
pe2 cleavage mutants of sindbis virus: correlation between viral infectivity and ph-dependent membrane fusion activation of the spike heterodimer.	the spike glycoprotein e2 of sindbis virus (sin) is synthesized in the infected cell as a pe2 precursor protein, which matures through cleavage by a cellular furin-like protease. previous work has shown that sin mutants impaired in pe2 cleavage are noninfectious on bhk-21 cells, the block in infection being localized at a step after virus-receptor interaction but prior to rna replication. here, we studied the membrane fusion properties of sin pe2 cleavage mutants and observed that these viruses ...	2001	11602759
visualization of ip(3) dynamics reveals a novel ampa receptor-triggered ip(3) production pathway mediated by voltage-dependent ca(2+) influx in purkinje cells.	ip(3) signaling in purkinje cells is involved in the regulation of cell functions including ltd. we have used a gfp-tagged pleckstrin homology domain to visualize ip(3) dynamics in purkinje cells. surprisingly, ip(3) production was observed in response not only to mglur activation, but also to ampa receptor activation in purkinje cells in culture. ampa-induced ip(3) production was mediated by depolarization-induced ca(2+) influx because it was mimicked by depolarization and was blocked by inhibi ...	2001	11604143
expression of serum amyloid a genes in mouse brain: unprecedented response to inflammatory mediators.	serum amyloid a (saa) proteins were originally identified as prominent acute-phase serum proteins synthesized predominantly by hepatocytes. these small proteins are remarkably lipophilic, and we have sought evidence for their synthesis in mouse brain. rt-pcr showed constitutive expression of the murine saa1 gene in the brains of normal balb/cj mice. after intracerebral inoculation with sindbis virus, these mice predictably increase brain expression of tumor necrosis factor alpha (tnf-alpha), int ...	2001	11641251
the 37-kda/67-kda laminin receptor acts as the cell-surface receptor for the cellular prion protein.	recently, we identified the 37-kda laminin receptor precursor (lrp) as an interactor for the prion protein (prp). here, we show the presence of the 37-kda lrp and its mature 67-kda form termed high-affinity laminin receptor (lr) in plasma membrane fractions of n2a cells, whereas only the 37-kda lrp was detected in baby hamster kidney (bhk) cells. prp co-localizes with lrp/lr on the surface of n2a cells and semliki forest virus (sfv) rna transfected bhk cells. cell-binding assays reveal the lrp/l ...	2001	11689427
functional interactions of human immunodeficiency virus type 1 integrase with human and yeast hsp60.	integration of human immunodeficiency virus type 1 (hiv-1) proviral dna in the nuclear genome is catalyzed by the retroviral integrase (in). in addition to in, viral and cellular proteins associated in the high-molecular-weight preintegration complex have been suggested to be involved in this process. in an attempt to define host factors interacting with in, we used an in vitro system to identify cellular proteins in interaction with hiv-1 in. the yeast saccharomyces cerevisiae was chosen since ...	2001	11689615
palmitoylation of the rous sarcoma virus transmembrane glycoprotein is required for protein stability and virus infectivity.	the rous sarcoma virus (rsv) transmembrane (tm) glycoprotein is modified by the addition of palmitic acid. to identify whether conserved cysteines within the hydrophobic anchor region are the site(s) of palmitoylation, and to determine the role of acylation in glycoprotein function, cysteines at residues 164 and 167 of the tm protein were mutated to glycine (c164g, c167g, and c164g/c167g). in cv-1 cells, palmitate was added to env gene products containing single mutations but was absent in the d ...	2001	11689636
cell surface heparan sulfate is a receptor for human herpesvirus 8 and interacts with envelope glycoprotein k8.1.	an immunodominant envelope glycoprotein is encoded by the human herpesvirus 8 (hhv-8) (also termed kaposi's sarcoma-associated herpesvirus) k8.1 gene. the functional role of glycoprotein k8.1 is unknown, and recognizable sequence homology to k8.1 is not detectable in the genomes of most other closely related gammaherpesviruses, such as herpesvirus saimiri or epstein-barr virus. in search for a possible function for k8.1, we expressed the ectodomain of k8.1 fused to the fc part of human immunoglo ...	2001	11689640
flock house virus rna replicates on outer mitochondrial membranes in drosophila cells.	the identification and characterization of host cell membranes essential for positive-strand rna virus replication should provide insight into the mechanisms of viral replication and potentially identify novel targets for broadly effective antiviral agents. the alphanodavirus flock house virus (fhv) is a positive-strand rna virus with one of the smallest known genomes among animal rna viruses, and it can replicate in insect, plant, mammalian, and yeast cells. to investigate the localization of f ...	2001	11689648
construction and analysis of mouse strains lacking the ubiquitin ligase ubr1 (e3alpha) of the n-end rule pathway.	the n-end rule relates the in vivo half-life of a protein to the identity of its n-terminal residue. in the yeast saccharomyces cerevisiae, the ubr1-encoded ubiquitin ligase (e3) of the n-end rule pathway mediates the targeting of substrate proteins in part through binding to their destabilizing n-terminal residues. the functions of the yeast n-end rule pathway include fidelity of chromosome segregation and the regulation of peptide import. our previous work described the cloning of cdna and a g ...	2001	11689692
biological activity of guatteria cardoniana fractions.	methanolic extract of leaves and twigs of guatteria cardoniana r.e. fries (annonaceae), a plant from the venezuelan rain forest, was separated in alkaloid rich fractions and their biological effect on baby hamster kidney (bhk) cell line was studied. the initial plant extract (fa) induced cell proliferation, cytotoxicity as well as antiviral activity, depending on the concentration used. further separation of this methanolic extract allowed us to separate these biological activities. the fraction ...	2001	11694356
prolonged arthritis associated with sindbis-related (pogosta) virus infection.		2001	11709622
molecular determinants of virulence, cell tropism, and pathogenic phenotype of infectious bursal disease virus.	infectious bursal disease viruses (ibdvs), belonging to the family birnaviridae, exhibit a wide range of immunosuppressive potential, pathogenicity, and virulence for chickens. the genomic segment a encodes all the structural (vp2, vp4, and vp3) and nonstructural proteins, whereas segment b encodes the viral rna-dependent rna polymerase (vp1). to identify the molecular determinants for the virulence, pathogenic phenotype, and cell tropism of ibdv, we prepared full-length cdna clones of a virulen ...	2001	11711587
the helicase-like domain of plant potexvirus replicase participates in formation of rna 5' cap structure by exhibiting rna 5'-triphosphatase activity.	open reading frame 1 (orf1) of potexviruses encodes a viral replicase comprising three functional domains: a capping enzyme at the n terminus, a putative helicase in the middle, and a polymerase at the c terminus. to verify the enzymatic activities associated with the putative helicase domain, the corresponding cdna fragment from bamboo mosaic virus (bamv) was cloned into vector pet32 and the protein was expressed in escherichia coli and purified by metal affinity chromatography. an activity ass ...	2001	11711602
functional specialization and evolution of leader proteinases in the family closteroviridae.	members of the closteroviridae and potyviridae families of the plant positive-strand rna viruses encode one or two papain-like leader proteinases. in addition to a c-terminal proteolytic domain, each of these proteinases possesses a nonproteolytic n-terminal domain. we compared functions of the several leader proteinases using a gene swapping approach. the leader proteinase (l-pro) of beet yellows virus (byv; a closterovirus) was replaced with l1 or l2 proteinases of citrus tristeza virus (ctv; ...	2001	11711606
matrix protein and another viral component contribute to induction of apoptosis in cells infected with vesicular stomatitis virus.	the induction of apoptosis in host cells is a prominent cytopathic effect of vesicular stomatitis virus (vsv) infection. the viral matrix (m) protein is responsible for several important cytopathic effects, including the inhibition of host gene expression and the induction of cell rounding in vsv-infected cells. this raises the question of whether m protein is also involved in the induction of apoptosis. hela or bhk cells were transfected with m mrna to determine whether m protein induces apopto ...	2001	11711608
intracellular trafficking of the ul11 tegument protein of herpes simplex virus type 1.	growing evidence indicates that herpes simplex virus type 1 (hsv-1) acquires its final envelope in the trans-golgi network (tgn). during the envelopment process, the viral nucleocapsid as well as the envelope and tegument proteins must arrive at this site in order to be incorporated into assembling virions. to gain a better understanding of how these proteins associate with cellular membranes and target to the correct compartment, we have been studying the intracellular trafficking properties of ...	2001	11711612