Academic literature on the topic 'HIV gag protein p17'
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Journal articles on the topic "HIV gag protein p17"
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Wong, S. B. Justin, and Robert F. Siliciano. "Contribution of Virus-Like Particles to the Immunogenicity of Human Immunodeficiency Virus Type 1 Gag-Derived Vaccines in Mice." Journal of Virology 79, no. 3 (February 1, 2005): 1701–12. http://dx.doi.org/10.1128/jvi.79.3.1701-1712.2005.
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ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Gag protein is a major target antigen for cytotoxic-T-lymphocyte-based vaccine strategies because of its high level of conservation. The murine model has been used extensively to evaluate potential HIV-1 vaccines. However, the biology of HIV-1 Gag is somewhat different in human and murine tissues. The ability of HIV-1 Gag to form virus-like particles (VLPs) in human cells is severely curtailed in murine cells. Hence, it is not known whether immunizing mice with expression vectors encoding HIV-1 Gag provides an accurate assessment of the immunogenicity of these candidate vaccines in primates. In this report, we made use of a chimeric Moloney murine leukemia virus (MMLV)-HIV-1 Gag in which the p17 matrix domain of HIV-1 was replaced with the p15 matrix and p12 domains from MMLV. Murine cells expressing this construct released significant amounts of VLPs. The construct preserved H-2 d -restricted antigenic determinants in the remaining portion of HIV-1 Gag, allowing immunogenicity studies to be performed with mice. We demonstrated that immunizing mice with plasmid DNA or adenoviral vectors encoding this chimeric Gag did not significantly increase the HIV-1 Gag-specific cellular or humoral immune response when compared to immunization with a myristoylation-incompetent version of the construct. Thus, the release of VLPs formed in vivo may not play a major role in the immunogenicity of vectors expressing HIV-1 Gag constructs.
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Koup, R. A., C. A. Pikora, K. Luzuriaga, D. B. Brettler, E. S. Day, G. P. Mazzara, and J. L. Sullivan. "Limiting dilution analysis of cytotoxic T lymphocytes to human immunodeficiency virus gag antigens in infected persons: in vitro quantitation of effector cell populations with p17 and p24 specificities." Journal of Experimental Medicine 174, no. 6 (December 1, 1991): 1593–600. http://dx.doi.org/10.1084/jem.174.6.1593.
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The presence of cytotoxic T lymphocytes (CTL) to the gag antigens of human immunodeficiency virus (HIV) has been described in infected populations. We found that the majority of this immune response as measured in bulk CTL assays of unstimulated peripheral blood mononuclear cells (PBMC) is directed against the p24 component of the p55 gag precursor protein. Using limiting dilution analysis of this effector cell population we confirm that the majority of activated gag-specific CTL circulating in the PBMC of infected hemophilic patients are directed at p24 determinants and are present at frequencies of 1/36,000 to 1/86,000 lymphocytes. By performing in vitro stimulation after limiting dilution, the precursor population of gag-specific CTL are characterized and quantitated. HIV gag-specific CTL precursors are identified at frequencies of 1/1700 to 1/17,000 lymphocytes and are made up of cells with both p17 and p24 specificities. No HIV gag-specific CTL precursor cells are identified in the PBMC of HIV-uninfected individuals. These studies demonstrate that CTL directed at both p17 and p24 determinants make up the cellular immune repertoire in HIV-infected individuals but that only the p24-specific CTL are routinely found in an activated state in the circulation.
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Eugen-Olsen, J. "Effect of HIV gag p17 protein on normal T cells." Immunology Letters 56, no. 1-3 (May 1997): 135. http://dx.doi.org/10.1016/s0165-2478(97)87377-4.
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Hofmann, B., P. Nishanian, J. Fan, T. Nguyen, and J. L. Fahey. "HIV Gag p17 protein impairs proliferation of normal lymphocytes in vitro." AIDS 8, no. 7 (July 1994): 1016. http://dx.doi.org/10.1097/00002030-199407000-00025.
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Carroll, Virginia A., Mark K. Lafferty, Luigi Marchionni, Joseph L. Bryant, Robert C. Gallo, and Alfredo Garzino-Demo. "Expression of HIV-1 matrix protein p17 and association with B-cell lymphoma in HIV-1 transgenic mice." Proceedings of the National Academy of Sciences 113, no. 46 (October 31, 2016): 13168–73. http://dx.doi.org/10.1073/pnas.1615258113.
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HIV-1 infection is associated with increased risk for B-cell lymphomas. How HIV infection promotes the development of lymphoma is unclear, but it may involve chronic B-cell activation, inflammation, and/or impaired immunity, possibly leading to a loss of control of oncogenic viruses and reduced tumor immunosurveillance. We hypothesized that HIV structural proteins may contribute to lymphomagenesis directly, because they can persist long term in lymph nodes in the absence of viral replication. The HIV-1 transgenic mouse Tg26 carries a noninfectious HIV-1 provirus lacking part of the gag-pol region, thus constituting a model for studying the effects of viral products in pathogenesis. Approximately 15% of Tg26 mice spontaneously develop leukemia/lymphoma. We investigated which viral proteins are associated with the development of leukemia/lymphoma in the Tg26 mouse model, and performed microarray analysis on RNA from spleen and lymph nodes to identify potential mechanisms of lymphomagenesis. Of the viral proteins examined, only expression of HIV-1 matrix protein p17 was associated with leukemia/lymphoma development and was highly expressed in bone marrow before disease. The tumor cells resembled pro-B cells, and were CD19+IgM−IgD−CD93+CD43+CD21−CD23−VpreB+CXCR4+. Consistent with the pro-B-cell stage of B-cell development, microarray analysis revealed enrichment of transcripts, including Rag1, Rag2, CD93, Vpreb1, Vpreb3, and Igll1. We confirmed RAG1 expression in Tg26 tumors, and hypothesized that HIV-1 matrix protein p17 may directly induce RAG1 in B cells. Stimulation of human activated B cells with p17 enhanced RAG1 expression in three of seven donors, suggesting that intracellular signaling by p17 may lead to genomic instability and transformation.
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Binley, James M., Xia Jin, Yaoxing Huang, Linqi Zhang, Yunzhen Cao, David D. Ho, and John P. Moore. "Persistent Antibody Responses but Declining Cytotoxic T-Lymphocyte Responses to Multiple Human Immunodeficiency Virus Type 1 Antigens in a Long-Term Nonprogressing Individual with a Defective p17 Proviral Sequence and No Detectable Viral RNA Expression." Journal of Virology 72, no. 4 (April 1, 1998): 3472–74. http://dx.doi.org/10.1128/jvi.72.4.3472-3474.1998.
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ABSTRACT Long-term nonprogressor AD-18 has been infected with human immunodeficiency virus type 1 (HIV-1) for at least 16 years. During the past 5 years, he has had undetectable levels of plasma viremia, and HIV-1 cannot be isolated from him. Sequencing of proviral DNA indicates that the only HIV-1 sequences that can be identified in AD-18 have gross defects in the p17-encoding regions of the gag gene (Y. Huang, L. Zhang, and D. D. Ho, Virology 240:36–49, 1998). However, AD-18 has strong, sustained antibody responses to several HIV-1 antigens, including p17. Cytotoxic T-lymphocyte responses to Env and Gag antigens have gradually diminished over the past 4 years, at a time when the titers of antibodies to the same proteins have remained stable. We discuss what these observations might mean for the generation and maintenance of immunological memory.
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Hantson, Anke, Valery Fikkert, Barbara Van Remoortel, Chistophe Pannecouque, Peter Cherepanov, Barry Matthews, George Holan, et al. "Mutations in Both env and gag genes are required for HIV-1 resistance to the polysulfonic dendrimer SPL2923, as corroborated by chimeric virus technology." Antiviral Chemistry and Chemotherapy 16, no. 4 (August 2005): 253–66. http://dx.doi.org/10.1177/095632020501600405.
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A drug-resistant NL4.3.SPL2923 strain has previously been generated by in vitro selection of HIV-1(NL4.3) in the presence of the polysulfonic dendrimer SPL2923 and mutations were reported in its gp120 gene (Witvrouw et al., 2000). Here, we further analysed the (cross) resistance profile of NL4.3/SPL2923. NL4.3.SPL2923 was found to contain additional mutations in gp41 and showed reduced susceptibility to SPL2923, dextran sulfate (DS) and enfuvirtide. To delineate to what extent the mutations in each env gene were accountable for the phenotypic (cross) resistance of NL4.3.SPL2923, the gp120-, gp41- and gp160-sequences derived from this strain were placed into a wild-type background using env chimeric virus technology (CVT). The cross resistance of NL4.3.SPL2923 towards DS was fully reproduced following gp160recombination, while it was only partially reproduced following gp120- or gp41-recombination. The mutations in gp41 of NL4.3/SPL2923 were sufficient to reproduce the cross resistance to enfuvirtide. Unexpectedly, the reduced sensitivity towards SPL2923 was not fully reproduced after gp160-recombination. The search for mutations in NL4.3.SPL2923 in viral genes other than env revealed several mutations in the gene encoding the HIV p17 matrix protein (MA) and one mutation in the gene encoding the p24 capsid protein (CA). In order to analyse the impact of the gag mutations alone and in combination with the mutations in env on the phenotypic resistance towards SPL2923, we developed a novel p17- and p17.gp160-CVT. Phenotypic analysis of the NL4.3.SPL2923 p17- and p17.gp160-recombined strains indicated that the mutations in both env and gag have to be present to fully reproduce the resistance of NL4.3.SPL2923 towards SPL2923.
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Eugen-Olsen, Jesper, Uffe Koppelhus, Lars Andresen, Jens O. Nielsen, and Bo Hofmann. "A recombinant HIV gag P17 protein suppresses the function of normal T cells." Biochemical Society Transactions 25, no. 2 (May 1, 1997): 220S. http://dx.doi.org/10.1042/bst025220s.
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Tamiya, Sadahiro, Sek Mardy, Mark F. Kavlick, Kazuhisa Yoshimura, and Hiroaki Mistuya. "Amino Acid Insertions near Gag Cleavage Sites Restore the Otherwise Compromised Replication of Human Immunodeficiency Virus Type 1 Variants Resistant to Protease Inhibitors." Journal of Virology 78, no. 21 (November 1, 2004): 12030–40. http://dx.doi.org/10.1128/jvi.78.21.12030-12040.2004.
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ABSTRACT A variety of amino acid substitutions in the protease and Gag proteins have been reported to contribute to the development of human immunodeficiency virus type 1 (HIV-1) resistance to protease inhibitors. In the present study, full-length molecular infectious HIV-1 clones were generated by using HIV-1 variants isolated from heavily drug-experienced and therapy-failed AIDS patients. Of six full-length infectious clones generated, four were found to have unique insertions (TGNS, SQVN, AQQA, SRPE, APP, and/or PTAPPA) near the p17/p24 and p1/p6 Gag cleavage sites, in addition to the known resistance-related multiple amino acid substitutions within the protease. The addition of such Gag inserts mostly compromised the replication of wild-type HIV-1, whereas the primary multidrug-resistant HIV infectious clones containing inserts replicated significantly better than those modified to lack the inserts. Western blot analyses revealed that the processing of Gag proteins by wild-type protease was impaired by the presence of the inserts, whereas that by mutant protease was substantially improved. The present study represents the first report clearly demonstrating that the inserts seen in the proximity of the Gag cleavage sites in highly multi-PI resistant HIV-1 variants restore the otherwise compromised enzymatic activity of mutant protease, enabling the multi-PI-resistant HIV-1 variants to remain replication competent.
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Mwau, Matilu, Inese Cebere, Julian Sutton, Priscilla Chikoti, Nicola Winstone, Edmund G. T. Wee, Tara Beattie, et al. "A human immunodeficiency virus 1 (HIV-1) clade A vaccine in clinical trials: stimulation of HIV-specific T-cell responses by DNA and recombinant modified vaccinia virus Ankara (MVA) vaccines in humans." Journal of General Virology 85, no. 4 (April 1, 2004): 911–19. http://dx.doi.org/10.1099/vir.0.19701-0.
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The immunogenicities of candidate DNA- and modified vaccinia virus Ankara (MVA)-vectored human immunodeficiency virus (HIV) vaccines were evaluated on their own and in a prime–boost regimen in phase I clinical trials in healthy uninfected individuals in the United Kingdom. Given the current lack of approaches capable of inducing broad HIV-neutralizing antibodies, the pTHr.HIVA DNA and MVA.HIVA vaccines focus solely on the induction of cell-mediated immunity. The vaccines expressed a common immunogen, HIVA, which consists of consensus HIV-1 clade A Gag p24/p17 proteins fused to a string of clade A-derived epitopes recognized by cytotoxic T lymphocytes (CTLs). Volunteers' fresh peripheral blood mononuclear cells were tested for HIV-specific responses in a validated gamma interferon enzyme-linked immunospot (ELISPOT) assay using four overlapping peptide pools across the Gag domain and three pools of known CTL epitopes present in all of the HIVA protein. Both the DNA and the MVA vaccines alone and in a DNA prime–MVA boost combination were safe and induced HIV-specific responses in 14 out of 18, seven out of eight and eight out of nine volunteers, respectively. These results are very encouraging and justify further vaccine development.
Dissertations / Theses on the topic "HIV gag protein p17"
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Dupont, Stefan A. "The Functional Roles of the Human Immunodeficiency Virus Type-1 Matrix Protein during Viral Life Cycle: A Dissertation." eScholarship@UMMS, 2000. http://escholarship.umassmed.edu/gsbs_diss/191.
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The human immunodeficiency virus type-1 matrix (HIV-1 MA) is best described as a multi-functional, structural protein. However, the multitude of functional activities ascribed to this viral component is not nearly as interesting as are its seemingly paradoxical and opposing roles during the viral life cycle.
At the time of virus infection, HIV-1 MA remains associated with the reverse transcription complex, in which viral nucleic acids are synthesized, and facilitates its translocation to the host cell nucleus (Bukrinsky, Sharova et al. 1992; Bukrinsky, Sharova et al. 1993). This activity of MA has been proposed to form the basis for the infection of non-dividing cells (Bukrinsky, Haggerty et al. 1993). An interaction between the C-terminally phosphorylated form of MA and HIV-1 integrase, an integral component of the complex, was initially proposed to mediate this association (Gallay, Swingler et al. 1995; Gallay, Swingler et al. 1995). However, conditions which promote dissociation of integrase from the reverse transcription complex do not reduce MA association (Miller, Farnet et al. 1997). The possibility of a direct interaction between MA and the viral genome is discussed in Chapter III.
The nucleophilic nature of HIV-1 MA is paradoxical with its reported activity in targeting the viral precursor proteins to the cytoplasmic membrane (Krausslich and Welker 1996), during the particle production phase of the viral life cycle. Furthermore, MA when expressed in the absence of other viral proteins exhibits a cytoplasmic localization (Fouchier, Meyer et al. 1997); a result which does not support a nuclear translocation role for this protein. The work presented here resolves this seemingly controversial issue.
We demonstrate that MA exhibits a strong nuclear export activity. This newly discovered activity is designed to effectively counteract the protein's innate nucleophilic nature, thus maintaining a cytoplasmic localization. The nuclear export function of MA is sensitive to changes within the conformation of the protein as C- and N-terminal deletions, as well as point mutations in the protein, abolish the activity. Furthermore, the export activity is mediated by the Crm1 NES receptor (Fornerod, Ohno et al. 1997; Fukuda, Asano et al. 1997; Ossareh-Nazari, Bachelerie et al. 1997) despite the lack of a leucine-rich export signal within the matrix coding region. Therefore, the interaction between matrix protein and Crm1 is most likely to be mediated by another, perhaps cellular, protein. Any changes in matrix structure may lead to the disruption of this protein-protein interaction. We discuss a model implicating a phosphorylation event in the inactivation of this nuclear export signal.
An even more fascinating issue regards the role of this nuclear export activity, during the viral life cycle, and is detailed in Chapter II. In short, mutations in MA which impair its nuclear export activity result in nuclear accumulation of the precursor Gag polyprotein (Pr55) and the nucleocapsid-associated viral genomic RNA. As a result, non-infectious virions deficient in genomic viral RNA are produced. Therefore, drugs designed to block this export activity can undermine the carefully orchestrated course of events during HIV replication and can shut down the growth of the virus.
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Zeinolabediny, Yasmin. "The role of p17 protein in development of HIV associated neurocognitive disorder." Thesis, Manchester Metropolitan University, 2016. http://e-space.mmu.ac.uk/617800/.
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HIV-associated neurocognitive disorder in HIV patients substantially reduces their quality of life. We hypothesised that the HIV matrix protein, p17, already linked to tumour promotion and aberrant angiogenesis could contribute to neurological decline and cellular dysfunction within the brain and aimed here to confirm this. The experimental design was formulated to test the direct neurodegenerative capacity of p17 protein on relevant brain cells, both in vitro and in vivo to ascertain the potential of p17 within the brain to encourage neurodegenerative processes and to confirm that p17 was present in the brain of infected individuals. In vitro cell culture experiments identified cellular signalling induced by p17 within brain cells. I characterised the effects of hippocampal CA1 injection of p17 on histological appearance of brain sections following the analysis of the animals by our collaborators- behaviour, cognitive function and memory. Histological expression of p17 in tissue from three HIV patients who died from stroke was determined. Cell signalling pathways potentially associated with neurodegenerative signalling or aberrant angiogenesis were studied by Western blotting. p17 increased phosphorylation of ERK1/2, IRS-1 and EGFR in endothelial cells, blocking cell signalling and angiogenesis via an inhibitor peptide of EGFR. In neurons, p17 induced the phosphorylation of ERK1/2, Tau, FAK and IRS-1. Cognitive function and behavioural deficiencies after p17 injection were mimicked by demonstration that it localised in ventricular tracts, cortical microvessels and neurons. p17 formed β-amyloid/prion-like protein fibrillar aggregates, suggesting a pathogenic direct capability similar to that of β-amyloid. P17 was also identified in macrophages, microvessels, neurons and amyloid-beta (Aβ)-positive plaques in HIV-infected human brain sections. This work supports the involvement of p17 in initiating/perpetuating neurodegenerative pathophysiology associated with cognitive decline. Key words: P17, HIV-associated neurocognitive decline, angiogenesis, fibrillary, signalling.
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Lennard, Katherine Rachel. "Evolution of cyclic peptide Inhibitors of the Gag-TSG101 protein-protein interaction involved in HIV budding." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/418006/.
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Kim, Adonia Lee. "The Role of Adaptor Protein Complex-3 Delta-Mediated HIV-1 Gag Trafficking in HIV-1 Replication: A Dissertation." eScholarship@UMMS, 2012. https://escholarship.umassmed.edu/gsbs_diss/612.
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The process of HIV-1 particle production is a multi-step process directed by the viral structural protein Gag. As Gag is the only viral protein required to form virus-like particles, it presents a viable target for anti-viral therapeutics of which there are currently none. Although the functions of Gag during the particle assembly process have been well characterized, one of the least known parts of the assembly process is how Gag is targeted to the site of virus assembly.
Two main virus assembly sites have been identified in cells that support HIV-1 replication: the plasma membrane or multivesicular bodies (MVBs). However the mechanism by which Gag is targeted to either of these sites remains unknown. The δ subunit of Adaptor Protein Complex 3 has previously been identified as a cellular co-factor for HIV-1 Gag and was reported to mediate Gag trafficking to MVBs, providing a mechanism for Gag targeting to this assembly site. Additionally, AP-3δ was reported to be required for HIV-1 production, suggesting that Gag to MVB targeting is also required for HIV-1 production.
The work presented in this thesis further investigates the role of AP-3δ in Gag trafficking to MVBs and its role in HIV-1 production in previously unexplored host environments. Through the use of RNA interference-mediated depletion of AP-3δ, we determined that AP-3δ is dispensible for virus replication in infected HeLa cells, chronically infected HeLa-LAV cells and infected primary human monocyte-derived macrophages. We concomitantly disrupted AP-3 function by disrupting its association with membranes and observed no effect on virus production. Collectively, these results demonstrate that AP-3δ is not required for HIV-1 replication. However, AP-3δ was demonstrated to be required for Gag targeting to MVBs thus presenting a new model for the function of AP-3δ in the context of HIV-1 replication.
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Zhang, Wei Hong. "Studies on structure and function of human immunodeficiency virus type one (HIV-1) Gag protein." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320175.
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Nadeem, Muhammad Faisal. "Chaperone mechanism of the HIV-1 Gag and its promotion by the RPL7 host protein." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ025.
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La protéine multidomaine Pr55Gag de VIH-1 joue un rôle crucial dans les étapes finales de la réplication virale, notamment lors de la reconnaissance et la sélection de l’ARN génomique ainsi que lors de la production de nouvelles particules virales. Outre son rôle structural, Pr55Gag chaperonne aussi les séquences d’acides nucléiques, une propriété cruciale pour la dimérisation de l’ARN génomique et l’hybridation de l’amorce ARNt à l’ARN génomique. Des partenaires cellulaires comme la protéine ribosomale RPL7 sont supposées être recrutées par Pr55Gag afin d’augmenter son potentiel chaperon. Afin d’étudier le mécanisme d’hybridation des acides nucléiques par Gag et RPL7, nous avons examiné leur effet sur la réaction d’hybridation entre dTAR, la version ADN de l’élément de transactivation virale et sa séquence complémentaire cTAR. Nos résultats révèlent que Gag et RPL7 présentent des mécanismes différents pour promouvoir l’hybridation cTAR/dTAR. Utilisés de concert, RPL7 peut aider Gag à chaperonner des séquences stables de l’ARN génomique que Gag seule pourrait difficilement chaperonner. Ce renforcement par RPL7 de l’activité chaperonne de Gag jouerait un rôle critique dans l’assemblage du virusThe multidomain Pr55 Gag protein of HIV-1 plays a crucial role during late stages of viral replication, notably for the recognition and selection of genomic RNA as well as for the production of new viral particles. In addition to its structural role, Pr55 Gag also chaperones nucleic acid sequences, a property which is crucial for genomic RNA dimerization and annealing of the primer tRNA to the genomic RNA. Cellular partners like ribosomal protein RPL7 are thought to be recruited by Pr55 Gag to enhance its chaperoning potential. To investigate the nucleic acid annealing mechanism of Gag and RPL7, we examined their effect on the annealing reaction between dTAR, the DNA version of the viral transactivation element and its complementary cTAR sequence taken as relevant model HIV-1 sequences. Our data show that Gag and RPL7 exhibit different mechanisms for promoting the cTAR/dTAR annealing. When used together, RPL7 can help Gag to chaperone stable sequences of the genomic RNA that Gag would hardly be able to chaperone alone. This RPL7-driven boost in Gag chaperone activity is thought to be critical in the viral assembly process
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Yandrapalli, Naresh. "Role of HIV-1 Gag protein multimerization in the generation of nanodomains in lipid membranes." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT097/document.
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La polyprotéine Gag du VIH-1 qui contient quatre principaux domaines (Matrix (MA), capside (CA), nucléocapside (NC), et P6) est l’orchestrateur privilégié de l'assemblage du virus HIV-1, assemblage qui a lieu pendant la phase tardive de la réplication. Il est bien connu que Gag interagit avec les lipides de la membrane plasmique de la cellule hôte et s’auto-assemble sur le feuillet interne de cette dernière afin de générer de nouvelles particules virales. Le bourgeonnement de ces particules virales hors de la cellule hôte est décrit comme étant dépendant de la machinerie cellulaire ESCRT. Différentes études structurales, fonctionnelles ainsi que des simulations de dynamique gros grain ont montré que la liaison de Gag à la membrane est médiée par une interaction duale. Une spécifique de nature éléctrostatique, qui associe une région hautement basique (HBR) du domaine MA de Gag au lipide acide,phosphatidyl inositol biphosphate (PI(4,5)P2) du feuillet interne de la membrane plasmique. Une de type hydrophobe, qui consiste en l’insertion du myristate de Gag dans la membrane plasmique. Savoir si Gag reconnait spécifiquement des domaines lipidiques pré-existants de type « rafts » ou si, au contraire, Gag tri ses lipides et les réorganise latéralement afin d’optimiser sa multimérisation et son bourgeonnement est une question à la fois fondamentale et d’actualité en virologie.Durant ma thèse, j’ai vérifié l’existence de la seconde hypothèse en utilisant des membranes modèles contenant du PI (4,5) P2 marqué de façon fluorescente et différent mutants et produits de la protéine Gag non-myristoylée. Ces expériences ont montré de fortes affinités de ces protéines pour les membranes contenant du PI (4,5) P2. S’appuyant sur les propriétés d’auto-extinction de fluorescence du marqueur choisit et à l’aide des différents variants de la protéine Gag, j'ai pu montré que la multimérisation de Gag génère l’existence de nanodomaines contenant du PI (4, 5) P2 et du cholestérol, la sphingomyéline étant au contraire exclue de ces domaines. En marquant la protéine Gag par un autre fluorophore, j’ai pu montrer par microscopie optique sur des vésicules lipidiques géantes (GUVs) que la protéine Gag partitionnait préférablement dans des microdomaines lipidiques de type liquide désordonnés (Ld). Par la suite, j’ai testé la capacité de la protéine Gag d’induire la formation de vésicules sur des membranes modèles (Bicouches supportés et GUVs) contenant du PI(4,5) P2 et de la phosphatidyl sérine (PS). En utilisant une microbalance à cristal de quartz (QCM-D) et des techniques de microscopie de fluorescence, j’ai suivi l'auto-assemblage de Gag dans le temps et ai montré que la protéine Gag était suffisante pour générer une courbure de la membrane et libérer des vésicules lipidiques. Grâce à différents produits de maturation de cette protéine, j’ai montré que la présence des domaines MA et CA est suffisante pour produire ces vésicules.L’ensemble de ces résultats suggèrent que la liaison et la multimérisation de la protéine Gag ne se produit pas dans des domaines lipidiques préexistants de type « raft », mais, au contraire, que la liaison et multimérisation de la protéine Gag génère l’existence de domaines lipidiques enrichis en PI (4,5) P2 et en cholestérol. La générescence de ces domaines lipidiques pourrait participer à la courbure de la membrane plasmique nécessaire au bourgeonnement du virusGag polyprotein of HIV-1 is made of four main domains Matrix (MA), Capsid (CA), Nucleocapsid (NC), and P6 and is the prime orchestrator of virus assembly that occurs during the late phase of replication. It is well known that Gag interacts with host cell lipids and self-assemble along the inner-leaflet of the plasma membrane in order to generate virus like particles (VLPs). Budding of these VLPs out of the living cell is described to be ESCRT dependent. Structural, functional and simulation based studies has shown that Gag membrane binding is mediated by a bipartite interaction. One specific electrostatic interaction, between the highly basic region (HBR) of its MA domain and the host cell acidic lipid phosphatidyl inositol bisphophate (PI(4,5)P2), plus a hydrophobic interaction through Gag’s myristate insertion in the plasma membrane. It is still an opened question whether Gag would specifically recognize pre-existing lipid domains such as rafts to optimize its multimerization or, on the contrary, would reorganize lipids during its multimerization. During my Ph.D. I explored the second hypothesis using purified myr(-) Gag protein and model membranes containing fluorescently labelled PI(4,5)P2.Bonding experiments have shown strong affinities of these purified proteins towards PI(4,5)P2 containing lipid bilayers. Using PI(4,5)P2 fluorescence self-quenching properties, I found that multimerization Gag generates PI(4,5)P2/Cholesterol enriched nanoclusters. On the opposite, sphingomyelin was excluded from these nanoclusters. In addition to this, using a fluorescently labelled myr(-) Gag, I have observed its preferable partitioning into lipid disordered (Ld) phases of giant unilamellar vesicles (GUVs). Further, possibility of whether HIV-1 Gag alone, as a minimal system, can induce the formation of vesicles on PI(4,5)P2/PS containing supported lipid bilayers (SLBs) & GUVs was tested. Using quartz crystal microbalance (QCM-D) and fluorescence microscopy techniques, I monitored the self-assembly of HIV-1 Gag with time and found that Gag was sufficient to generate membrane curvature and vesicle release. Moreover, using mutants of this protein, I found that having MA and CA domain is enough for Gag to produce vesicle like structures. Taken together, these results suggest that binding and multimerization of Gag protein does not occur in pre-existing lipid domains (such as “rafts”) but this multimerization is more likely to induce PI(4,5)P2/Cholesterol nanoclusters. This nanophase separation could locally play a role in the membrane curvature needed for the budding of the virus
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Person, Bridgette D. "An analysis of competition between gag-dependent transcripts and HIV-1 Rev protein in transient transfection assays." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2000. http://digitalcommons.auctr.edu/dissertations/2498.
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Retroviruses express their repertoire of products from a single primary transcript. However, it appears that the default condition for posttranscriptional processing in a normal cell is to completely splice any intron-containing transcripts. Consequently, the dilemma for the retroviruses is how to export the full length, unspliced and partially spliced transcript which both code for structural proteins, as well as serves as the genome to be packaged into mature virus particles. Many retroviruses (HIV-1, HTLV-l, EIAV, visna) exploit posttranscriptional mechanisms, by which their intron-containing mRNAs circumvent nuclear retention, and are exported to the cytoplasm. For example, HIV-1 RNAs contain at least one functional intron that must enter the cytoplasm to act as templates for the synthesis of proteins. HIV-l regulates expression of its genome through the interaction of a virally encoded trans-acting factor, Rev, with a cis-acting Rev responsive element (RRE). Rev binds unspliced and singly spliced nuclear transcripts containing the RE and shuttles them into the cytoplasm. Other retroviruses (MPMV, SRV) lack Rev-like trans-acting viral proteins. Their transcripts contain a cis-acting element, termed the constitutive transport element (CTE), that allows transport of intron-containing mRNAs. CTE-like elements have also been identified in DNA viruses (Hepatitis B, HSV~1). Retroviral CTEs have been shown to be able to substitute for the Rev/RRE system to allow efficient regulatory control of HIV expression. Although a number of studies have examined what cellular cofactors are involved in Rev/RRE and CTE-mediated transport, it is not clear if common cellular cofactor(s) exist. In these studies we have used a transfection/competition assay to investigate whether Rev/RRE-, SRVCTE~, and MPMVCTE-containing transcripts utilize similar cofactors for nucleocytoplasmic transport. Coexpression of gagMPMVCTE and pCwtRev at various concentrations in the same cell demonstrated that Rev inhibited CTE- mediated transport from the nucleus. Using the same assay we further demonstrated that GTE-mediated export was not inhibited by cotransfection with a pCΔRev(-) mutant clone, a Rev point mutant clone, or luciferase, a non-specific marker protein. Our data suggest that this inhibition is specific for Rev, and for a specific region of the Rev protein. We propose that Rev and the CTEs interact with a common cellular cofactor(s), or that Rev directly interacts with the CTEs.
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Davi, Eliza Vieira. "Clonagem de fragmentos dos genes gag e env do HIV-1 e HTLV-1, expressão em Escherichia coli das proteínas gp21, p24 e gp46 do HTLV-1 e imunodetecção." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/60/60135/tde-01072015-103417/.
Full textAbstract:
O HIV-1 é o agente etiológico da síndrome da imunodeficiência adquirida (AIDS) e o HTLV-I da leucemia/linfoma de célula T no adulto (ATL) e da paraparesia espástica tropical ou mielopatia associada ao HTLV (HAM/TSP), principalmente. Ambos são retrovírus com genoma RNA e possuem o gene gag que codifica as proteínas p24 (HIV-1 e HTLV-1) e p19 (HTLV-1) que formam o capsídeo e a matriz do vírus, respectivamente, e o gene env que codifica as proteínas gp41 e gp120 (HIV-1) e gp21 e gp46 (HTLV-1) que compõem o envelope viral. Os primeiros anticorpos produzidos nas infecções por ambos os vírus são destinados a essas proteínas e os diferentes testes diagnósticos disponíveis no mercado usam uma combinação dessas proteínas virais. O diagnóstico precoce é de extrema importância para o controle da epidemia, tratamento dos indivíduos e planejamento dos gastos com saúde pública. Os kits diagnósticos usados em laboratórios clínicos, bancos de sangue e hospitais brasileiros para o diagnóstico destas viroses são na sua maioria de empresas estrangeiras e o Brasil despende milhares de reais importando esses materiais. No Brasil, há a necessidade e incentivo para a produção de sistemas de diagnóstico com tecnologia nacional. Neste trabalho, os genes das proteínas p24, gp41 e gp120 do HIV-1 e p19 do HTLV-1 foram clonados com sucesso em diferentes vetores e em diferentes linhagens de E. coli, porém essas proteínas não foram expressas. As proteínas gp21, p24 e gp46 do HTLV-1 foram produzidas em bactérias BL21(DE3) com vetor pET28a(+). Essas três proteínas foram solubilizadas dos corpos de inclusão, purificadas por IMAC e identificadas pelas técnicas de Western Blotting e por espectrometria de massas. As proteínas recombinantes gp21, p24 e gp46 foram reconhecidas pelos soros de indivíduos com HTLV-1 e não foram reconhecidas por soros de indivíduos com HIV-1 e saudáveis, o que confere a elas especificidade e grande potencial diagnóstico. Os resultados deste trabalho são os primeiros passos para atingir o objetivo maior de produzir todas as sete proteínas em maior escala e, por fim, chegar a produção de um kit diagnóstico sensível, específico e barato com tecnologia nacional, diminuindo os gastos com a importação destes produtos e fomentando a indústria biotecnológica nacional.HIV-1 is the etiologic agent of acquired immunodeficiency syndrome (AIDS) and HTLV-I is the cause of adult T-cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy or tropical spastic paraparesis (HAM/TSP). Both are retroviruses with RNA genome and possess the gene gag and env. The gag gene encodes for p24 protein (HTLV-1 and HIV-1) and p19 (HTLV-1) forming the viral capsid and matrix, respectively, and the env gene encodes for proteins gp120 and gp41 (HIV-1) and gp21 and gp46 (HTLV-1) making the viral envelope. The first antibodies produced in infections by both viruses are against these proteins and the various diagnostic tests on the market use a combination of those viral proteins. Early diagnosis is extremely important to control the epidemia, treatment of individuals and planning of public health expenditures. The diagnostic kits used in clinical laboratories, blood banks and in Brazilian hospitals for the diagnosis of these viruses are mostly from foreign companies. Brazil spends thousands of reais importing these materials. In Brazil, there is a need and incentive for the production of diagnostic systems with national technology. In this study, the genes of p24, gp41 and gp120 of HIV-1 and p19 of HTLV-1 have been successfully cloned in different vectors and different strains of E. coli, but these proteins were not expressed. The proteins gp21, gp46 and p24 of HTLV-1 were produced in bacteria BL21 (DE3) with vector pET28a (+). These three proteins were solubilized from inclusion bodies, purified by IMAC and identified by Western blotting techniques and mass spectrometry. The recombinant proteins gp21, p24 and gp46 were recognized by sera from patients with HTLV-1 and were not recognized by sera from individuals with HIV-1 and healthy people, which gives them great specificity and diagnostic potential. These results are the first steps to achieve the ultimate goal of producing all seven proteins on a larger scale and finally get the production of a diagnostic kit sensitive, specific and cheap with national technology, reducing spending on imports of these products and fostering the national biotechnology industry.
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Serriere, Jennifer. "Études fonctionnelles et structurales de protéines rétrovirales, Gag du FIV et Tat du VIH-1, à des fins thérapeutiques et vaccinales." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10167.
Full textAbstract:
Depuis sa découverte il y a plus de 30 ans, le Virus de l’Immunodéficience Humaine est à l’origine d’une importante mortalité dans le monde. De par la difficulté de tester l’efficacité de formulations thérapeutiques et/ou vaccinales directement chez l’homme, des études d’infections modèles du VIH, comme celle du Virus de l’Immunodéficience Féline (FIV), ont été entreprises ces dernières années. Au-delà de son intérêt vétérinaire, l’étude du FIV représente un avantage important pour trouver un moyen de contrôler les infections par les lentivirus tel que le VIH. Elle peut permettre de développer et surtout de tester l’efficacité des vaccins et/ou thérapies spécifiques chez le chat, dont le SIDA mime les symptômes et les modifications hématologiques rencontrés chez l’homme. Ce manuscrit s’est intéressé à l’étude structurale de deux familles de protéines virales de ces virus, les protéines lentivirales précoces (protéine Tat du VIH) et tardives (domaines Capside CA et Matrice MA de Gag du FIV). L’étude structurale de ces protéines et leur compréhension fonctionnelle au sein de l’hôte pourront à l’avenir ouvrir de nouvelles voies thérapeutiques et/ou vaccinales contre les lentivirus, palliant ainsi les problèmes existants de résistances viralesSince its discovery 30 years ago, the Human Immunodeficiency Virus is the cause of an important mortality worldwide. Because of the difficulty to test the efficiency of therapeutical and/or vaccinal formulations directly in humans, studies of models of HIV infections, such as the Feline Immunodeficiency Virus (FIV), have been performed in recent years. In addition to its veterinary interest, the study of FIV is an important issue to find a way to control infections by lentiviruses such as HIV. It can help to develop and test the efficiency of specific therapies and/or vaccines for cats, where AIDS mimics the symptoms and hematologic changes observed in humans. This manuscript describes the structural study of two types of viral proteins of these viruses, early lentiviral proteins (HIV Tat protein) and late lentiviral proteins (CA capsid and MA Matrix domains of FIV Gag). The structural study of these proteins and their functional understanding into the host will open new therapeutic and/or vaccine strategies against these lentiviruses in the future, in order to overcome the existing problems of viral resistance
Book chapters on the topic "HIV gag protein p17"
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Peng, Cheng, Karin Moelling, Nancy T. Chang, and Tse Wen Chang. "Functional Characterisation of HIV-1 gag-pol Fusion Protein." In Retroviral Proteases, 55–62. London: Macmillan Education UK, 1990. http://dx.doi.org/10.1007/978-1-349-11907-3_7.
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Deshpande, Milind S., and Susan P. Manly. "HIV-1 protease substrate based on the p17/p24 cleavage site of gag-pol polyprotein: Synthesis and assay." In Peptides, 725–26. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2264-1_291.
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Datta, Siddhartha A. K., and Alan Rein. "Preparation of Recombinant HIV-1 Gag Protein and Assembly of Virus-Like Particles In Vitro." In Methods in Molecular Biology, 197–208. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-59745-170-3_14.
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Koelsch, Gerald, Jeff Loy, Xinli Lin, and Jordan Tang. "Activation Mechanism of Pepsinogen as Compared to the Processing of HIV Protease gag-pol Precursor Protein." In Aspartic Proteinases, 245–52. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5373-1_34.
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