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Matthew A. Gonda - One of the best experts on this subject based on the ideXlab platform.
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Natural and experimental Bovine Immunodeficiency Virus infection in cattle.
The Veterinary clinics of North America. Food animal practice, 1997Co-Authors: T.g. Snider, Phillip G. Hoyt, D. Gene Luther, Bruce F. Jenny, Karen S. Coats, R. W. Storts, Jane K. Battles, Matthew A. GondaAbstract:The principal diseases associated with Bovine Immunodeficiency Virus (BlV) infection in a production dairy were bacterial infections. The infections were associated with histologic evidence of compromise of the immune system. The disease were most apparent after parturition and during early lactation. Two hundred twenty-seven different diseases were identified in 89 cows between 1989 and 1995. Fifty-two diseases were identified in 19 cows between 1995 and 1996. The primary lesions were encephalitis and lymphoid tissue hyperplasia followed by lymphoid tissue, exhaustion, and laminitis. Weight loss, decreased milk production, and reproductive inefficiency were secondary to the primary lesions. Many cows responded poorly to therapy. Epidemiologic and economic research are needed to clarify the association between BIV and Bovine diseases and the economic impact of the infection in beef and dairy production units.
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Serologic evidence for Bovine Immunodeficiency Virus infection in France
Veterinary microbiology, 1996Co-Authors: B. Polack, Matthew A. Gonda, I. Schwartz, M. Berthelemy, Catherine Belloc, G. Manet, A. Vuillaume, T. Baron, D. LevyAbstract:We report herein on the first serologic detection of antibodies to Bovine Immunodeficiency Virus (BIV) in France. Serum samples from dairy and beef cattle from southwestern and western France (Landes and Vendée) were tested using a western blot assay with a recombinant 53 kDa gag precursor derived from the Louisiana BIV R29 isolate. We performed our study on the oldest animals from 37 different herds that were under serologic follow up for previous Bovine leukemia Virus infection. Overall, 398 selected Bovine sera were assayed and 15 serum samples from 8 herds reacted with the recombinant 53 kDa BIV R29 gag. Interestingly, reactions obtained with French sera were weaker than with positive Louisiana sera, a finding that may indicate the occurrence of distinct French and Louisiana BIV variants.
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serologic evidence for Bovine Immunodeficiency Virus infection in france
Veterinary Microbiology, 1996Co-Authors: B. Polack, Matthew A. Gonda, I. Schwartz, M. Berthelemy, Catherine Belloc, G. Manet, A. Vuillaume, T. Baron, D. LevyAbstract:We report herein on the first serologic detection of antibodies to Bovine Immunodeficiency Virus (BIV) in France. Serum samples from dairy and beef cattle from southwestern and western France (Landes and Vendee) were tested using a western blot assay with a recombinant 53 kDa gag precursor derived from the Louisiana BIV R29 isolate. We performed our study on the oldest animals from 37 different herds that were under serologic follow up for previous Bovine leukemia Virus infection. Overall, 398 selected Bovine sera were assayed and 15 serum samples from 8 herds reacted with the recombinant 53 kDa BIV R29 gag. Interestingly, reactions obtained with French sera were weaker than with positive Louisiana sera, a finding that may indicate the occurrence of distinct French and Louisiana BIV variants.
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Inhibition of Bovine Immunodeficiency Virus by anti-HIV-1 compounds in a cell culture-based assay.
Antiviral research, 1996Co-Authors: Gregory J. Tobin, Willis H. Ennis, David J. Clanton, Matthew A. GondaAbstract:The Bovine Immunodeficiency Virus (BIV) and human Immunodeficiency Virus types 1 and 2 (HIV-1 and -2) are members of the lentiVirus genus of retroViruses. Although DNA sequences of these Viruses have diverged considerably, the BIV genome organization, function of structural and regulatory genes, and replication cycle are very similar to that of HIV-1, making BIV a potentially useful model to study compounds with anti-HIV-1 activity. A cell culture-based antiviral assay was developed to test compounds for inhibition of BIV replication. The assay uses an embryonic rabbit epithelial (EREp) cell line that is highly sensitive to BIV infection and cytopathology. The 50% effective concentrations (EC50) at which the Virus was inhibited in EREp cells were determined for 13 nucleoside analog, non-nucleoside, tumor-suppressive, or membrane-surface inhibitory compounds. The nucleoside analogs (3'-azido-2',3'-dideoxythymidine, 2',3'-dideoxyinosine and 2',3'-dideoxycytosine), surface-membrane inhibitors (dextran sulfate, hypericin, Chicago Sky Blue and quinobene), the nucleoside reductase inhibitor (hydroxyurea), and a tumor-suppressive phorbol ester (prostratin) inhibited BIV with EC50 values similar to those derived in HIV-1 lymphocyte (CD4+)-based assays. BIV was markedly more resistant to inhibition with HIV-1-specific non-nucleoside reverse transcriptase inhibitors (NNRTIs) (thiazolobenzimidazole, oxathiin carboxanilide and thiocarbamate) than was HIV-1, which parallels results with NNRTIs in HIV-2 assays.
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Encephalitis, lymphoid tissue depletion and secondary diseases associated with Bovine Immunodeficiency Virus in a dairy herd
Comparative immunology microbiology and infectious diseases, 1996Co-Authors: T.g. Snider, Phillip G. Hoyt, Jane K. Battles, Willis H. Ennis, D.g. Luther, B.f. Jenny, J. Balady, U. Blas-machado, T.x. Lemarchand, Matthew A. GondaAbstract:Encephalitis, lymphoid tissue depletion and secondary infections occurred over a 5-yr-period in Holstein cows infected with Bovine Immunodeficiency Virus (BIV). There were 59 cattle studied, the majority during 1991, when a severe environmental stress occurred, each with one or more primary causes of death, natural or by euthanasia, and most with several secondary diseases. The encephalitis was characterized by meningeal, perivascular and parenchymal infiltration with lymphocytes, occasional plasma cells and macrophages with perivascular edema in some cows. Affected areas included the cerebrum, cerebellum, and spinal cord with no particular distribution pattern recognized. The lymphoid depletion was primarily an absence of follicular development in nodes draining regions with secondary infections such as chronic mastitis and chronic suppurative pododermatitis. Paucity of lymphocytes in thymic-dependent regions of lymph nodes and the spleen suggested a primary depletion of T cells. Secondary infections were often multiple with each cow having several minor conditions, usually considered short-term and treatable. These included mastitis and pododermatitis, with many cows having non-responding abscesses, cellulitis and myositis attributed to injection site infections. A large number of the cattle had parturition difficulties such as dystocia, obturator paralysis, and metritis. Pulmonary, cardiovascular, and intestinal disease were recognized as both primary and secondary disease conditions. There was a high level of infection with Bovine leukemia Virus with 4 of the 59 cattle having lymphosarcoma. Under practical conditions, the infection with BIV has a different effect on the host than has been observed under experimental conditions. The presence of BIV combined with the stresses associated with parturition and a modern dairy production system were considered causal for the development of untreatable secondary diseases in immunocompromised cattle. The peak incidence in 1991 was attributed to increased environmental stress during renovation of the barn facility. During this time the cattle were kept on open pasture, exposed to an extremely wet winter, and spring weather conditions. The effect of co-infection with Bovine leukemia Virus, the influence of immunocompromise on the chronicity of mastitis, the relationship with laminitis and pododermatitis, and several questions related to viral transmission, complementarism with Bovine leukemia Virus, viral reactivation and immunoprophylaxis all remain as viable avenues for future investigations.
Denis Archambault - One of the best experts on this subject based on the ideXlab platform.
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b23 nucleophosmin interacts with Bovine Immunodeficiency Virus rev protein and facilitates viral replication
Virology, 2018Co-Authors: Ana Maria Passoscastilho, Claude Marchand, Denis ArchambaultAbstract:The Bovine Immunodeficiency Virus (BIV) Rev shuttling protein contains nuclear/nucleolar localization signals and nuclear import/export mechanisms that are novel among lentiVirus Rev proteins. Several viral proteins localize to the nucleolus, which may play a role in processes that are essential to the outcome of viral replication. Although BIV Rev localizes to the nucleoli of transfected/infected cells and colocalizes with one of its major proteins, nucleophosmin (NPM1, also known as B23), the role of the nucleolus and B23 in BIV replication remains to be determined. Here, we demonstrate for the first time that BIV Rev interacts with nucleolar phosphoprotein B23 in cells. Using small interfering RNA (siRNA) technology, we show that depletion of B23 expression inhibits Virus production by BIV-infected cells, indicating that B23 plays an important role in BIV replication. The interaction between Rev and B23 may represent a potential new target for the development of antiviral drugs against lentiViruses.
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B23/nucleophosmin interacts with Bovine Immunodeficiency Virus Rev protein and facilitates viral replication.
Virology, 2017Co-Authors: Ana Maria Passos-castilho, Claude Marchand, Denis ArchambaultAbstract:The Bovine Immunodeficiency Virus (BIV) Rev shuttling protein contains nuclear/nucleolar localization signals and nuclear import/export mechanisms that are novel among lentiVirus Rev proteins. Several viral proteins localize to the nucleolus, which may play a role in processes that are essential to the outcome of viral replication. Although BIV Rev localizes to the nucleoli of transfected/infected cells and colocalizes with one of its major proteins, nucleophosmin (NPM1, also known as B23), the role of the nucleolus and B23 in BIV replication remains to be determined. Here, we demonstrate for the first time that BIV Rev interacts with nucleolar phosphoprotein B23 in cells. Using small interfering RNA (siRNA) technology, we show that depletion of B23 expression inhibits Virus production by BIV-infected cells, indicating that B23 plays an important role in BIV replication. The interaction between Rev and B23 may represent a potential new target for the development of antiviral drugs against lentiViruses.
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Molecular and biological aspects of the Bovine Immunodeficiency Virus.
Current HIV research, 2010Co-Authors: Andrea Gomez Corredor, Marie-claude St-louis, Denis ArchambaultAbstract: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/accessory genes encoding proteins, some of which are involved in the regulation of Virus gene expression. This manuscript aims to review biological and molecular aspects of BIV, with emphasis on regulatory/accessory viral genes/proteins which are involved in Virus expression.
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The Bovine Immunodeficiency Virus Rev Protein: Identification of a Novel Lentiviral Bipartite Nuclear Localization Signal Harboring an Atypical Spacer Sequence
Journal of virology, 2009Co-Authors: Andrea Gomez Corredor, Denis ArchambaultAbstract: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 fluorescence microscopy analyses, we were able to map the NLS region between aa 71 and 110 of the protein. Remarkably, by conducting alanine substitution of basic residues within the aa 71 to 110 sequence, we demonstrated that the BIV Rev NLS is bipartite, maps to aa 71 to 74 and 95 to 101, and is predominantly composed of arginine residues. This is the first report of a bipartite Rev (or Rev-like) NLS in a lentiVirus/retroVirus. Moreover, this NLS is atypical, as the length of the sequence between the motifs composing the bipartite NLS, e.g., the spacer sequence, is 20 aa. Further mutagenesis experiments also identified the NoLS region of BIV Rev. It localizes mainly within the NLS spacer sequence. In addition, the BIV Rev NoLS sequence differs from the consensus sequence reported for other viral and cellular nucleolar proteins. In summary, we conclude that the nucleolar and nuclear localizations of BIV Rev are mediated via novel NLS and NoLS motifs.
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Bovine Immunodeficiency Virus: identification of a long terminal repeat sequence with enhanced promoter activity.
Archives of Virology, 2009Co-Authors: M. Cojocariu, Marie-claude St-louis, Denis ArchambaultAbstract: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 sequence. Reporter gene assays indicated that LTRn promotes basal and Tat-mediated transactivation activity to levels significantly higher than those obtained with the wild-type LTR. Restoration experiments to the wild-type genotype indicated that both the −135 and −114 nucleic acid substitutions were responsible for the enhanced promoter activity of BIV LTRn.
Alan D. Frankel - One of the best experts on this subject based on the ideXlab platform.
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Molecular Dynamics and Binding Specificity Analysis of the Bovine Immunodeficiency Virus BIV Tat-TAR Complex
Biophysical journal, 2001Co-Authors: Carolina M. Reyes, Alan D. Frankel, Riccardo Nifosì, Peter A. KollmanAbstract:We have performed molecular dynamics (MD) simulations, with particle-mesh Ewald, explicit waters, and counterions, and binding specificity analyses using combined molecular mechanics and continuum solvent (MM-PBSA) on the Bovine Immunodeficiency Virus (BIV) Tat peptide-TAR RNA complex. The solution structure for the complex was solved independently by Patel and co-workers and Puglisi and co-workers. We investigated the differences in both structures and trajectories, particularly in the formation of the U-A-U base triple, the dynamic flexibility of the Tat peptide, and the interactions at the binding interface. We observed a decrease in RMSD in comparing the final average RNA structures and initial RNA structures of both trajectories, which suggests the convergence of the RNA structures to a MD equilibrated RNA structure. We also calculated the relative binding of different Tat peptide mutants to TAR RNA and found qualitative agreement with experimental studies.
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Solution Structure of a Bovine Immunodeficiency Virus Tat-TAR Peptide-RNA Complex
Science (New York N.Y.), 1995Co-Authors: Joseph D. Puglisi, Lily Chen, Scott C. Blanchard, Alan D. FrankelAbstract:The Tat protein of Bovine Immunodeficiency Virus (BIV) binds to its target RNA, TAR, and activates transcription. A 14-amino acid arginine-rich peptide corresponding to the RNA-binding domain of BIV Tat binds specifically to BIV TAR, and biochemical and in vivo experiments have identified the amino acids and nucleotides required for binding. The solution structure of the RNA-peptide complex has now been determined by nuclear magnetic resonance spectroscopy. TAR forms a virtually continuous A-form helix with two unstacked bulged nucleotides. The peptide adopts a beta-turn conformation and sits in the major groove of the RNA. Specific contacts are apparent between critical amino acids in the peptide and bases and phosphates in the RNA. The structure is consistent with all biochemical data and demonstrates ways in which proteins can recognize the major groove of RNA.
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solution structure of a Bovine Immunodeficiency Virus tat tar peptide rna complex
Science, 1995Co-Authors: Joseph D. Puglisi, Lily Chen, Scott C. Blanchard, Alan D. FrankelAbstract:The Tat protein of Bovine Immunodeficiency Virus (BIV) binds to its target RNA, TAR, and activates transcription. A 14-amino acid arginine-rich peptide corresponding to the RNA-binding domain of BIV Tat binds specifically to BIV TAR, and biochemical and in vivo experiments have identified the amino acids and nucleotides required for binding. The solution structure of the RNA-peptide complex has now been determined by nuclear magnetic resonance spectroscopy. TAR forms a virtually continuous A-form helix with two unstacked bulged nucleotides. The peptide adopts a β-turn conformation and sits in the major groove of the RNA. Specific contacts are apparent between critical amino acids in the peptide and bases and phosphates in the RNA. The structure is consistent with all biochemical data and demonstrates ways in which proteins can recognize the major groove of RNA.
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An RNA-binding peptide from Bovine Immunodeficiency Virus Tat protein recognizes an unusual RNA structure.
Biochemistry, 1994Co-Authors: Lily Chen, Alan D. FrankelAbstract:The human Immunodeficiency Virus (HIV) Tat protein binds specifically to an RNA hairpin, TAR, located at the 5' end of its mRNA. Tat uses a single arginine residue within a short region of basic amino acids to recognize a bulge region in TAR. Here we show that a 17 amino acid arginine-rich peptide from the Bovine Immunodeficiency Virus (BIV) Tat protein also binds to an RNA hairpin at the 5' end of its mRNA (BIV TAR), but recognizes different structural features of the RNA. Mutagenesis, RNase mapping, and chemical interference experiments indicate that bulge and stem regions of BIV TAR are recognized simultaneously by the BIV peptide and that the RNA adopts an unusual structure. BIV Tat binds to its TAR site with high affinity and specificity and, unlike HIV Tat, does not appear to use cellular proteins to stabilize RNA binding in vivo. Thus, two related viral activators have evolved rather distinct ways to recognize their RNA targets.
Qi Min Chen - One of the best experts on this subject based on the ideXlab platform.
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Bovine HEXIM1 inhibits Bovine Immunodeficiency Virus replication through regulating BTat-mediated transactivation
Veterinary research, 2013Co-Authors: Hongyan Guo, Qi Min Chen, Yuan-ming Gai, Zhibin Liang, Qicheng Zhang, Juan TanAbstract:The Bovine Immunodeficiency Virus (BIV) transactivator (BTat) recruits the Bovine cyclin T1 (B-cyclin T1) to the LTR to facilitate the transcription of BIV. Here, we demonstrate that Bovine hexamethylene bisacetamide (HMBA)-induced protein 1 (BHEXIM1) inhibits BTat-mediated BIV LTR transcription. The results of in vivo and in vitro assays show direct binding of BHEXIM1 to the B-cyclin T1. These results suggest that the repression arises from BHEXIM1-BTat competition for B-cyclin T1, which allows BHEXIM1 to displace BTat from B-cyclin T1. Furthermore, we found that the C-terminal region and the centrally located region of BHEXIM1 are required for BHEXIM1 to associate with B-cyclin T1. Knockdown of BHEXIM1 enhances BIV replication. Taken together, our study provides the first clear evidence that BHEXIM1 is involved in BIV replication through regulating BTat-mediated transactivation.
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Microtubule-dependent retrograde transport of Bovine Immunodeficiency Virus.
Cellular microbiology, 2010Co-Authors: Wentao Qiao, Tingting Guo, Juan Tan, Yan Chen, Li Xin, Jun Zhou, Qi Min ChenAbstract: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 similar effect was observed by inhibiting function of the microtubule-associated motor protein dynein. By yeast two-hybrid assay, we found that the capsid protein (CA) of BIV interacted with the dynein light-chain component LC8. Immunoprecipitation and GST-pulldown assays further demonstrated an interaction between CA and LC8 in mammalian cells. In addition, our data revealed LC8 as a linker between BIV particles and microtubules. Retrograde transport of BIV was significantly inhibited by knockdown of LC8 expression. Our findings present the first evidence that incoming BIV particles employ host microtubule/dynein machinery for transport towards the perinuclear region. In addition, our data indicate that the LC8-CA interaction is a potential target for the design of antiviral strategies.
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Molecular basis of the internalization of Bovine Immunodeficiency Virus Tat protein.
Virus genes, 2007Co-Authors: Gang Deng, Wentao Qiao, Yun-qi Geng, Rina Sha, Qi Min ChenAbstract: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 cells and the effect of BTat on neighboring cells. The green fluorescent protein fusion analysis indicated that the internalization of extracellular BTat was a time and dose-dependent, but endocytosis and energy-independent manner. Arginine residues in the arginine-rich motif (ARM) of BTat were definitively responsible for the internalization. Internalized BTat is predominantly present in the nucleus, resulting in LTR activation and NF-kappaB induction. These results propose that the secretion and internalization of BTat facilitates BIV in influencing neighboring cells and makes the cellular environment propitious to viral replication.
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BTat, a trans-acting regulatory protein, contributes to Bovine Immunodeficiency Virus-induced apoptosis.
Cellular microbiology, 2007Co-Authors: Chenghao Xuan, Qi Min Chen, Wentao Qiao, Jun Zhou, Guoyuan Peng, Min Liu, Yun-qi GengAbstract:Summary 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 small trans-acting regulatory protein encoded by BIV, BTat, was found to participate in the pro-apoptotic action of BIV. Introduction of exogenous BTat to cells triggered apoptosis dramatically, as revealed by assays such as terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling, nuclear morphology analysis, flow cytometry, and cleavages of caspases and poly(ADP-ribose)polymerase. Interestingly, the pro-apoptotic effect of BTat was found to be mediated through its interaction with cellular microtubules and its interference with microtubule dynamics. These results provide the first evidence that induction of apoptosis may contribute to the cytopathic effect of BIV. In addition, these results uncover a novel role for BTat in regulating microtubule dynamics in addition to its conventional role in regulating gene transcription.
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Construction and characterization of chimeric BHIV (BIV/HIV-1) Viruses carrying the Bovine Immunodeficiency Virus gag gene.
World journal of gastroenterology, 2005Co-Authors: Yi-xin Zhu, Qi Min Chen, Yi Zeng, Wentao Qiao, Chang Liu, Xin-lei Liu, Yun-qi GengAbstract:AIM: 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. METHODS: A series of chimeric BHIV proviral DNAs differing in the replacement regions in gag gene were constructed, and then were transfected into 293T cells. The expression of chimeric viral genes was detected at the RNA and protein level. The supernatant of 293T cell was ultra centrifuged to detect the probable chimeric virion. Once the chimeric virion was detected, its biological activities were also assayed by infecting HIV-sensitive MT4 cells. RESULTS: Four chimeric BHIV proviral DNAs were constructed. Genes in chimeric Viruses expressed correctly in transfected 293T cells. All four constructs assembled chimeric virions with different degrees of efficiency. These virions had complete structures common to retroViruses and packaged genomic RNAs, but the cleavages of the precursor Gag proteins were abnormal to some extent. Three of these virions tested could attach and enter into MT4 cells, and one of them could complete the course of reverse transcription. Yet none of them could replicate in MT4 cells. CONCLUSION: The replacement of partial gag gene of HIV with BIV gag gene is feasible. Genes in chimeric BHIVs are accurately expressed, and virions are assembled. These chimeric BHIVs (proviral DNA together with Virus particles) have the potential to become a new kind of HIV/AIDS vaccine.
Reuben S Harris - One of the best experts on this subject based on the ideXlab platform.
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cellular requirements for Bovine Immunodeficiency Virus vif mediated inactivation of Bovine apobec3 proteins
Journal of Virology, 2014Co-Authors: Wenyan Zhang, Hong Wang, Xin Liu, Guanchen Liu, Reuben S HarrisAbstract:ABSTRACT Human Immunodeficiency Virus type 1 (HIV-1) and simian Immunodeficiency Virus (SIV) viral infectivity factor (Vif) form a CRL5 E3 ubiquitin ligase complex to suppress Virus restriction by host APOBEC3 (A3) proteins. The primate lentiviral Vif complex is composed of the unique cofactor core binding factor β (CBF-β) and canonical ligase components Cullin 5 (CUL5), Elongin B/C (ELOB/C), and RBX2. However, the mechanism by which the Vif protein of the related lentiVirus Bovine Immunodeficiency Virus (BIV) overcomes its host A3 proteins is less clear. In this study, we show that BIV Vif interacts with Cullin 2 (CUL2), ELOB/C, and RBX1, but not with CBF-β or CUL5, to form a CRL2 E3 ubiquitin ligase and degrade the restrictive Bovine A3 proteins (A3Z2Z3 and A3Z3). RNA interference-mediated knockdown of ELOB or CUL2 inhibited BIV Vif-mediated degradation of these A3 proteins, whereas knockdown of CUL5 or CBF-β did not. BIV Vif with mutations in the BC box (Vif SLQ-AAA) or putative VHL box (Vif YI-AA), which cannot interact with ELOB/C or CUL2, respectively, lost the ability to counteract Bovine A3 proteins. Moreover, CUL2 and UBE2M dominant negative mutants competitively inhibited the BIV Vif-mediated degradation mechanism. Thus, although the general strategy for inhibiting A3 proteins is conserved between HIV-1/SIV and BIV, the precise mechanisms can differ substantially, with only the HIV-1/SIV Vif proteins requiring CBF-β as a cofactor, HIV-1/SIV Vif using CUL5-RBX2, and BIV Vif using CUL2-RBX1. IMPORTANCE Primate lentiVirus HIV-1 and SIV Vif proteins form a ubiquitin ligase complex to target host antiviral APOBEC3 proteins for degradation. However, the mechanism by which the nonprimate lentiVirus BIV Vif inhibits Bovine APOBEC3 proteins is unclear. In the present study, we determined the mechanism for BIV Vif-mediated degradation of Bovine APOBEC3 proteins and found that it differs from the mechanism of HIV-1/SIV Vif by being CBF-β independent and requiring different ubiquitin ligase scaffolding proteins (CUL2-RBX1 instead of CUL5-RBX2). BIV Vif is the only known retroviral protein that can interact with CUL2. This information broadens our understanding of the distinct mechanisms by which the Vif proteins of different lentiViruses facilitate viral infection. This novel mechanism for assembly of the BIV Vif-APOBEC3 ubiquitin ligase complex advances our understanding of viral hijacking of host E3 ubiquitin ligases and illustrates the evolutionary flexibility of lentiViruses.
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Cellular Requirements for Bovine Immunodeficiency Virus Vif-Mediated Inactivation of Bovine APOBEC3 Proteins
Journal of virology, 2014Co-Authors: Wenyan Zhang, Hong Wang, Xin Liu, Guanchen Liu, Reuben S HarrisAbstract:Human Immunodeficiency Virus type 1 (HIV-1) and simian Immunodeficiency Virus (SIV) viral infectivity factor (Vif) form a CRL5 E3 ubiquitin ligase complex to suppress Virus restriction by host APOBEC3 (A3) proteins. The primate lentiviral Vif complex is composed of the unique cofactor core binding factor β (CBF-β) and canonical ligase components Cullin 5 (CUL5), Elongin B/C (ELOB/C), and RBX2. However, the mechanism by which the Vif protein of the related lentiVirus Bovine Immunodeficiency Virus (BIV) overcomes its host A3 proteins is less clear. In this study, we show that BIV Vif interacts with Cullin 2 (CUL2), ELOB/C, and RBX1, but not with CBF-β or CUL5, to form a CRL2 E3 ubiquitin ligase and degrade the restrictive Bovine A3 proteins (A3Z2Z3 and A3Z3). RNA interference-mediated knockdown of ELOB or CUL2 inhibited BIV Vif-mediated degradation of these A3 proteins, whereas knockdown of CUL5 or CBF-β did not. BIV Vif with mutations in the BC box (Vif SLQ-AAA) or putative VHL box (Vif YI-AA), which cannot interact with ELOB/C or CUL2, respectively, lost the ability to counteract Bovine A3 proteins. Moreover, CUL2 and UBE2M dominant negative mutants competitively inhibited the BIV Vif-mediated degradation mechanism. Thus, although the general strategy for inhibiting A3 proteins is conserved between HIV-1/SIV and BIV, the precise mechanisms can differ substantially, with only the HIV-1/SIV Vif proteins requiring CBF-β as a cofactor, HIV-1/SIV Vif using CUL5-RBX2, and BIV Vif using CUL2-RBX1. Primate lentiVirus HIV-1 and SIV Vif proteins form a ubiquitin ligase complex to target host antiviral APOBEC3 proteins for degradation. However, the mechanism by which the nonprimate lentiVirus BIV Vif inhibits Bovine APOBEC3 proteins is unclear. In the present study, we determined the mechanism for BIV Vif-mediated degradation of Bovine APOBEC3 proteins and found that it differs from the mechanism of HIV-1/SIV Vif by being CBF-β independent and requiring different ubiquitin ligase scaffolding proteins (CUL2-RBX1 instead of CUL5-RBX2). BIV Vif is the only known retroviral protein that can interact with CUL2. This information broadens our understanding of the distinct mechanisms by which the Vif proteins of different lentiViruses facilitate viral infection. This novel mechanism for assembly of the BIV Vif-APOBEC3 ubiquitin ligase complex advances our understanding of viral hijacking of host E3 ubiquitin ligases and illustrates the evolutionary flexibility of lentiViruses. Copyright © 2014, American Society for Microbiology. All Rights Reserved.