Publications

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localized influence of 2'-hydroxyl groups and helix geometry on protein recognition in the rna major groove.the local geometry of a dna helix can influence protein recognition, but the sequence-specific features that contribute to helix structure are not fully understood, and even less is known about how rna helix geometry may affect protein recognition. to begin to understand how local or global helix structure may influence binding in an rna model system, we generated a series of dna analogues of hiv and biv tar rnas in which ribose sugars were systematically substituted in and around the known bind ...200515850388
characterization of biv env core: implication for mechanism of biv-mediated cell fusion.entry of lentiviruses, such as human immunodeficiency virus type 1 (hiv-1) and simian immunodeficiency virus (siv), requires folding of two heptad repeat regions (hr1 and hr2) of gp41 into a trimer-of-hairpins, which subsequently brings virus and cell membrane into fusion. this motif is a generalized feature of viral fusion proteins and has been exploited in generating antiviral fusion agents. in the present paper, we report structural characters of env protein from another lentivirus, bovine im ...200515737628
the bovine immunodeficiency virus: cloning of a tat/rev cdna encoding a novel tat protein with enhanced transactivation activity.previous studies have shown that biv may encode two types of tat proteins of 103 and 108 amino acids, respectively. here, we report the characterization of a new biv tat protein (tat236) derived from a tat/rev cdna. the tat/rev cdna was obtained by reverse transcription-pcr from rna extracted from cells infected with biv. biv was rescued by cell co-cultivation from the spleen of rabbits exposed for 3 years to the r29 isolate of biv. sequence analysis indicated that biv tat236 contains the first ...200515821973
cloning, expression, purification, crystallization and preliminary crystallographic study of the protein module (biv2-helix) in the fusion core of bovine immunodeficiency-like virus (biv) gp40.the fusion core of bovine immunodeficiency virus (biv) gp40 is proposed to be involved in membrane fusion. however, no crystal structures are yet available. a predicted protein module biv2-helix of bivgp40 has been expressed in escherichia coli and purified by chromatography. recombinant biv2-helix was crystallized using the hanging-drop vapour-diffusion technique at 291 k. the crystals were grown in mpd and belonged to the primitive rhombohedral space group r3, with unit-cell parameters a = 39. ...200516511008
a comparative binding study of biv tat peptide against its tar rna duplex, rna-dna heteroduplex and dna duplex.association between rna and dna strands to form rna-dna heteroduplex is important in many biological processes such as transcription, dna replication and reverse transcription. herein, binding affinities of a 17-mer biv tat peptide is compared with tar dna duplex, tar rna-dna heteroduplex and tar rna duplex. it was observed that binding affinities of tat peptide is comparable against dna-rna heteroduplex and rna duplex, whereas dna duplex binding is decidedly poor.200515582425
construction and characterization of chimeric bhiv (biv/hiv-1) viruses carrying the bovine immunodeficiency virus gag gene.to explore the possibility of the replacement of the gag gene between human immunodeficiency virus and bovine immunodeficiency virus, to achieve chimeric virions, and thereby gain a new kind of aids vaccine based on bhiv chimeric viruses.200515849820
the catalytic properties of the recombinant reverse transcriptase of bovine immunodeficiency virus.bovine immunodeficiency virus (biv) is a lentivirus with no proven pathogenesis in infected cattle. yet, in experimentally infected rabbits, it causes an aids-like disease. consequently, we expressed two recombinant isoforms of biv reverse transcriptase (rt), which differ in their c-termini, and studied their catalytic properties. both isoforms prefer mg(+2) over mn(+2) with most dna polymerase and ribonuclease-h substrates. the processivity of dna synthesis by the biv rts is higher than that of ...200616631225
from mice to macaques--animal models of hiv nervous system disease.lentiviral diseases of animals have been recognized for over a century, long before hiv was recognized as the cause of aids. all lentiviruses cause neurological disease and productive virus replication in the cns occurs exclusively in cells of macrophage lineage. the ability to molecularly engineer the inoculum virus, to sample the brain at many different time points from acute through terminal infection and to correlate in vivo with in vitro findings are significant advantages of animal models ...200616842082
internalization of jembrana disease virus tat: possible pathway and implication.jembrana disease virus (jdv) is a lentivirus highly related to the bovine immunodeficiency virus (biv). it causes an acute disease with high mortality rate within 1-2 weeks. jdv encodes the most potent tat (jtat) of any of the lentiviruses. jtat can transactivate all ltrs and functionally substitute for hiv tat in the viral genome and may function as a pivotal regulator in the acute pathogenesis of jdv. the goal of this paper is to study jtat internalization by cells, the mechanisms involved in ...200616870296
the non-toxic a subunit of shiga toxin type 1 prevents replication of bovine immunodeficiency virus in infected cells.shiga toxins are ribosome-inactivating proteins many of which are antiviral. shiga toxin-producing escherichia coli (stec) may be pathogenic to humans, but are carried without ill effects by ruminants. we hypothesize that stec have antiviral activity in ruminants, and showed previously that the non-toxic subunit a of shiga toxin 1 (stxa1) acts selectively on cells infected with bovine leukemia virus, without harming normal cells, and that the numbers of intestinal stec are inversely correlated w ...200717197048
structure-guided peptidomimetic design leads to nanomolar beta-hairpin inhibitors of the tat-tar interaction of bovine immunodeficiency virus.the tat protein of immunodeficiency viruses is the main activator of viral gene expression. by binding specifically to its cognate site, the transactivator response element (tar), tat mediates a strong induction of the production of all viral transcripts. in seeking a new chemical solution to inhibiting viral protein-rna interactions, we recently identified inhibitors of the viral tat protein from the bovine immunodeficiency virus (biv) using conformationally constrained beta-hairpin peptidomime ...200717223695
[amplification of proviral dna of bovine immunodeficiency virus in experimentally infected animals].the primer set for detection of bovine immunodeficiency virus (biv) proviral dna, retrovirus of unknown pathology, by standard polymerase chain reaction was developed. amplicon of the expected size was detected in dna from peripheral blood mononuclear cells of seropositive experimentally biv infected sheep and cattle. primers targeted the short fragment of biv pol gene. sequences of biv proviral dna extracted from biv infected cell culture as well as from experimentally infected cows were taken ...200717427409
ledgf/p75 interacts with divergent lentiviral integrases and modulates their enzymatic activity in vitro.transcriptional co-activator ledgf/p75 is the major cellular interactor of hiv-1 integrase (in), critical to efficient viral replication. in this work, a series of ins from the betaretrovirus, gammaretrovirus, deltaretrovirus, spumavirus and lentivirus retroviral genera were tested for interaction with the host factor. none of the non-lentiviral ins possessed detectable affinity for ledgf in either pull-down or yeast two-hybrid assays. in contrast, all lentiviral ins examined, including those fr ...200717158150
differential sensitivity of viruses to the antiviral activity of shiga toxin 1 a subunit.the non-toxic enzymic a subunit of shiga toxin 1 (stxa1) reduces expression and replication of the bovine retroviruses, bovine leukemia virus and bovine immunodeficiency virus (biv). here, the impact of stxa1 on representative positive and negative stranded rna viruses was compared. biv and equine infectious anemia virus were sensitive to picomolar concentrations of stxa1 while poliovirus, rhinovirus, and vesicular stomatitis virus were only marginally sensitive to nanomolar concentrations of to ...200717197049
defibrinated bovine plasma inhibits retroviral transcription by blocking p52 activation of the nfkappab element in the long terminal repeat.bovine leukemia virus (blv) induces a persistent but latent infection in cattle. viral latency is invoked by a protein known as plasma blocking factor (pbf) that is found in both bovine and human plasma. we report here on pathways that mediate latency in the presence of pbf. reporter-gene constructs driven by the promoters of 6 retroviruses were used to measure the production of chloramphenicol acetyl transferase (cat) in cell lines cultured with or without defibrinated bovine plasma. plasma inh ...200717479775
molecular basis of the internalization of bovine immunodeficiency virus tat protein.bovine immunodeficiency virus (biv) is a nonacute, pathogenic, and horizontally transmitted lentivirus. it shares the parallel properties in morphology and genetics with human immunodeficiency virus type 1 and other lentiviruses. biv encodes its own transactivator (btat), which transactivates its cognate long terminal repeat (ltr). however, the mechanism involved in the transactivation is different from that in hiv and other lentiviruses. we determined the mechanisms of btat internalization by c ...200817952584
prevalence of antibodies to bovine respiratory viruses in cattle infected with bovine immunodeficiency virus. 200818487588
evidence of bovine immunodeficiency virus (biv) infection: serological survey in argentina.this is the first report of serological evidence for bovine immunodeficiency virus (biv) infection in argentina. the analysis was performed in 589 dairy bovine sera samples, applying indirect enzyme-linked immunosorbent assay (i-elisa) using a synthetic antigen (transmembrane peptide, tm) and immunofluorescent assay (ifa). in this study, 9 dairy herds from 4 argentinian provinces were evaluated and 12% of the animals tested positive for biv. seven of the 9 herds tested were biv seropositive and ...200818037459
btat, a trans-acting regulatory protein, contributes to bovine immunodeficiency virus-induced apoptosis.bovine immunodeficiency virus (biv) is a member of the lentivirus subfamily of retroviruses highly related to human immunodeficiency virus in morphologic, antigenic and genomic features. biv is known to induce chronic pathological changes in infected hosts, which are often associated with the development of immune-mediated lesions. however, the molecular events underlying the cytopathic effect of biv remain poorly understood. in this study, biv was found to induce apoptotic cell death, and a sma ...200817645750
expression and characterization of the integrase of bovine immunodeficiency virus.in the pol gene of bovine immunodeficiency virus (biv) there is a sequence, located between the reverse-transcriptase and integrase (in)-encoding sequences, that is not found in hiv-1 pol gene and encodes a 74-residue polypeptide with homology to dutpases. we have expressed two biv in versions that differ in their amino termini. the longer version, containing the 74-residue sequence, did not show any detectable 3'-end processing and strand transfer in activities and performed only the in-associa ...200817976681
sequence analysis of mrna transcripts encoding jembrana disease virus tat-1 in vivo.jembrana disease virus (jdv) is a lentivirus which replicates to very high titres in vivo and its tat-1 protein has been shown to be a potent transactivator in vitro. analysis of tat mrna transcripts produced early in infection studies identified four predominant species which were generated by multiple splicing events. the use of a splice donor downstream of tat-1 was common indicating that a tat-1 protein of 97 amino acids is expressed during the acute phase of jembrana disease. the presence o ...200818096262
development of a capsid based competitive inhibition enzyme-linked immunosorbent assay for detection of bovine immunodeficiency virus antibodies in cattle and buffalo serum.the aim of this study was to develop a more specific and sensitive competitive inhibition elisa (ci-elisa) than the currently used indirect elisa for detection of antibodies to bovine immunodeficiency virus (biv) in cattle and buffaloes. murine monoclonal antibodies (mabs) were generated against a recombinant capsid (ca) protein of bovine immunodeficiency virus. of the 13 anti-ca mabs developed, mab-9g10 was selected for ci-elisa based on the maximum inhibition (98%) obtained with reference biv ...200818192030
comparison of immunoassay and real-time pcr methods for the detection of jembrana disease virus infection in bali cattle.a sensitive diagnostic assay for the detection of infections with the bovine lentivirus jembrana disease virus (jdv) is required in indonesia to control the spread of jembrana disease. immunoassays are used routinely but are compromised by cross-reactive epitopes in the capsid (ca) protein of jdv and the genetically related bovine immunodeficiency virus (biv). jdv gag-specific primers were tested in a real-time pcr assay to detect proviral dna in peripheral blood mononuclear cells from 165 cattl ...200919442849
risk of equine infectious anemia virus disease transmission through in vitro embryo production using somatic cell nuclear transfer.prevention and regulation of equine infectious anemia virus (eiav) disease transmission solely depend on identification, isolation, and elimination of infected animals because of lack of an effective vaccine. embryo production via the somatic cell nuclear transfer (scnt) technology uses oocytes collected mainly from untested animals, which creates a potential risk of eiav transmission through infected embryos. the current review examines the risk of eiav disease transmission through scnt embryo ...200919482352
the bovine immunodeficiency virus rev protein: identification of a novel lentiviral bipartite nuclear localization signal harboring an atypical spacer sequence.the bovine immunodeficiency virus (biv) rev protein (186 amino acids [aa] in length) is involved in the nuclear exportation of partially spliced and unspliced viral rnas. previous studies have shown that biv rev localizes in the nucleus and nucleolus of infected cells. here we report the characterization of the nuclear/nucleolar localization signals (nls/nols) of this protein. through transfection of a series of deletion mutants of biv rev fused to enhanced green fluorescent protein and fluoresc ...200919828621
comparative functional analysis of jembrana disease virus tat protein on lentivirus long terminal repeat promoters: evidence for flexibility at its n-terminus.jembrana disease virus (jdv) encodes a potent regulatory protein tat that strongly stimulates viral expression by transactivating the long terminal repeat (ltr) promoter. jdv tat (jtat) promotes the transcription from its own ltr as well as non-cognate ltrs, by recruiting host transcription factors and facilitating transcriptional elongation. here, we compared the sequence requirements of jtat for transactivation of jdv, bovine immunodeficiency virus (biv) and human immunodeficiency virus (hiv) ...200919860923
rna detection using peptide-inserted renilla luciferase.a novel complementation system with short peptide-inserted-renilla luciferase (pi-rluc) and split-rna probes was constructed for noninvasive rna detection. the rna binding peptides hiv-1 rev and biv tat were used as inserted peptides. they display induced fit conformational changes upon binding to specific rnas and trigger complementation or discomplementation of rluc. split-rna probes were designed to reform the peptide binding site upon hybridization with arbitrarily selected target rna. this ...200918979090
bovine immunodeficiency virus: identification of a long terminal repeat sequence with enhanced promoter activity.we previously identified a new bovine immunodeficiency virus (biv) trans-activator factor of transcription (tat236) that was derived from a variant of biv. here, we report a new biv long terminal repeat (ltr) sequence (ltrn) that was obtained by pcr from the dna of cells infected with the biv variant mentioned above. sequence analysis indicated that the ltrn u3 region harbors three nucleic acid mutations at residue positions -194, -135 and -114 when compared to the original (wild-type) ltr seque ...200919547911
simultaneous recognition of hiv-1 tar rna bulge and loop sequences by cyclic peptide mimics of tat protein.the interaction of the hiv-1 transactivator protein tat with its transactivation response (tar) rna is an essential step in viral replication and therefore an attractive target for developing antivirals with new mechanisms of action. numerous compounds that bind to the 3-nt bulge responsible for binding tat have been identified in the past, but none of these molecules had sufficient potency to warrant pharmaceutical development. we have discovered conformationally-constrained cyclic peptide mime ...200919584251
[distribution of potentially hairpin-loop structures in the genome of bovine retroviruses].inverted repeats which can form hairpin-loop structures in the genomic rna and cruciform structures in the proviral dna of bovine leukemia virus (blv) and bovine immunodeficiency virus (biv) have been determined. localization diagrams have been made up for hairpins (one of the elements of signaling genome function). the retroviruses blv and biv, about 8.5 kbp in length, are characterized by the varying quantitative and qualitative composition of hairpin-loop structures. the blv and biv genomes h ...200919708552
bovine immunodeficiency virus produces a transient viraemic phase soon after infection in bos javanicus.infection of bali cattle (bos javanicus) in indonesia with a non-pathogenic bovine lentivirus similar to bovine immunodeficiency virus (biv) is suspected but efforts to detect the virus have been unsuccessful. to define the kinetics of biv infection in bali cattle, 13 were infected with the r-29 strain of biv and monitored for 60 days. no clinical effects were detected. proviral dna was detected in peripheral blood mononuclear cells from 4 to 60 days with peak titres 20 days post-infection (dpi) ...201019766411
the requirement for cellular transportin 3 (tnpo3 or trn-sr2) during infection maps to human immunodeficiency virus type 1 capsid and not integrase.recent genome-wide screens have highlighted an important role for transportin 3 in human immunodeficiency virus type 1 (hiv-1) infection and preintegration complex (pic) nuclear import. moreover, hiv-1 integrase interacted with recombinant transportin 3 protein under conditions whereby moloney murine leukemia virus (mlv) integrase failed to do so, suggesting that integrase-transportin 3 interactions might underscore active retroviral pic nuclear import. here we correlate infectivity defects in t ...201019846519
bovine isg15: an antiviral and inducible protein in biv infected fetal bovine lung cells.bovine isg15 (bisg15) is an interferon inducible ubiquitin-like protein that is responsible for the establishment of early pregnancy in ruminant, understanding the properties of bisg15 capable of being inducible in fetal bovine lung (fbl) cells upon infection of bovine immunodeficiency virus (biv) is of significant importance. in this study, we investigated the expression of bisg15 in poly i:c treated fbl cells. the increased expression of bisg15 was observed, and the inhibition of biv replicati ...201020569475
establishment of an indicator cell line for monitoring bovine immunodeficiency virus infection and inhibitor susceptibility.indicator cell lines are useful biological tools for monitoring virus infection. in order to monitor infection with bovine immunodeficiency virus (biv) in vitro, an indicator cell line derived from baby hamster kidney cells which contains integrated copies of an enhanced green fluorescent protein gene driven by the biv long terminal repeat was constructed. the biv indicator cell line, designated bive, can detect biv infection more easily and effectively than the established method, which involve ...201019643140
microtubule-dependent retrograde transport of bovine immunodeficiency virus.microtubules are essential components of the cytoskeleton that participate in a variety of cellular processes such as cell division and migration. in addition, there is a growing body of evidence implicating a role for microtubules in intracellular viral transport. in this study, we found that pharmacological disruption of microtubules remarkably blocked bovine immunodeficiency virus (biv) movement from the cell periphery to the perinuclear region, a process known as retrograde transport. a simi ...201020148896
[polypurine/polypyrimidine sequences with potential of forming triplexes in the proviral dna of bovine retroviruses].perfect interstranded triplexes that can potentially arise in the proviral dna of wide-spread bovine retroviruses like as bovine leukemia virus (blv) and bovine immunodeficiency virus (biv) have been determined. in the blv and biv genomes 2 and 5 fragments respectively were found to form triple helixes under acidic conditions. one of those fragments that is localized on the blv gag gene can exist as cruciform structure too. experimentally the existence of triplexes is confirmed by atomic force m ...201020201407
molecular and biological aspects of the bovine immunodeficiency virus.the bovine immunodeficiency virus (biv) was isolated in 1969 from a cow, r-29, with a wasting syndrome suggesting bovine leucosis. the virus, first designated bovine visna-like virus, remained unstudied until hiv was discovered in 1983. then, it was demonstrated in 1987 that the bovine r-29 isolate was a lentivirus with striking similarity to the human immunodeficiency virus (hiv). moreover, biv has the most complex genomic structure among all identified lentiviruses shown by several regulatory/ ...201020210777
jembrana disease virus: host responses, viral dynamics and disease control.jembrana disease virus (jdv) is the most recently discovered member of the lentivirus family and causes an acute clinical disease in bali cattle with a fatality rate of approximately 15%. it is genetically related to bovine immunodeficiency virus (biv) to the extent that infections cannot yet be differentially diagnosed using serological assays due to cross-reacting epitopes. despite their close genetic relationship the pathogenesis of jdv infection in bali cattle is very different to that of bi ...201020210780
single-chain fragment variable antibody against the capsid protein of bovine immunodeficiency virus and its use in elisa.recombinant antibody specific for the capsid (ca) protein of bovine immunodeficiency virus (biv) was generated in the form of single-chain fragment variable (scfv) using the phage display technique for affinity selection. the variable heavy (v(h)) and variable light (v(l)) chain gene fragments were recovered from cells of ca-specific hybridoma (9g10) described previously. the v(h) and v(l) dna fragments were assembled through a flexible linker dna to generate scfv fragment which was cloned in a ...201020304014
lentiviral vif degrades the apobec3z3/apobec3h protein of its mammalian host and is capable of cross-species activity.all lentiviruses except equine infectious anemia virus (eiav) use the small accessory protein vif to counteract the restriction activity of the relevant apobec3 (a3) proteins of their host species. prior studies have suggested that the vif-a3 interaction is species specific. here, using the apobec3h (z3)-type proteins from five distinct mammals, we report that this is generally not the case: some lentiviral vif proteins are capable of triggering the degradation of both the a3z3-type protein of t ...201020519393
crystal structures of catalytic core domain of biv integrase: implications for the interaction between integrase and target dna.integrase plays a critical role in the recombination of viral dna into the host genome. therefore, over the past decade, it has been a hot target of drug design in the fight against type 1 human immunodeficiency virus (hiv-1). bovine immunodeficiency virus (biv) integrase has the same function as hiv-1 integrase. we have determined crystal structures of the biv integrase catalytic core domain (ccd) in two different crystal forms at a resolution of 2.45 å and 2.2 å, respectively. in crystal form ...201021203948
a quantitative assay for measuring of bovine immunodeficiency virus using a luciferase-based indicator cell line.in order to quantitate the bovine immunodeficiency virus (biv) infection in vitro, a biv indicator cell line (bivl) was established by transfecting baby hamster kidney cells with reporter plasmids containing the firefly luciferase gene driven by a biv long terminal repeat promoter. the biv activates promoter activity of the ltr to express luciferase upon infection. biv infection could therefore by quantified by detection of luciferase activity. compared to standard assays used to detect biv infe ...201020960311
prior bovine immunodeficiency virus infection does not inhibit subsequent superinfection by the acutely pathogenic jembrana disease virus.in cattle the interaction between the two genetically and antigenically related bovine lentiviruses, the acutely pathogenic jembrana disease virus (jdv) and the non-pathogenic bovine immunodeficiency virus (biv) has not been reported although both jdv and a biv-like virus have been reported in the bali cattle (bos javanicus) population in indonesia. the outcome of infection of bali cattle with the r29 strain of biv prior to superinfection 42 days later with jdv(tab/87) was determined. all biv-in ...201020570311
bovine immunodeficiency virus and bovine leukemia virus and their mixed infection in iranian holstein cattle.bovine immunodeficiency virus (biv) and bovine leukemia virus (blv) have worldwide distributions, but their prevalences in iran are unknown. we investigated the presence of infections in iranian holstein cattle and determined changes in hematological values for infected animals.201021045371
serological survey for bovine immunodeficiency virus in dairy cattle from poland.a seroprevalence study of bovine immunodeficiency virus (biv) was undertaken on 1,541 serum samples from holstein cattle from 23 herds, located in different geographical regions of poland. the analysis was performed using elisa, with recombinant gag protein of biv as antigen. the average biv prevalence was 4.9% in individual cattle, while the percentage of herds harboring at least one seropositive animal, was 82.6%. to demonstrate the correlation of biv and bovine leukemia virus infection, all s ...201122439328
role of cullin-elonginb-elonginc e3 complex in bovine immunodeficiency virus and maedi-visna virus vif-mediated degradation of host a3z2-z3 proteins.all lentiviruses except equine infectious anemia virus (eiva) antagonize antiviral family apobec3 (a3) proteins of the host through viral vif proteins. the mechanism by which vif of human, simian or feline immunodeficiency viruses (hiv/siv/fiv) suppresses the corresponding host a3s has been studied extensively.201425213124
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