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Yamanaka MK, Yilma T. Altered plaque formation by recombinant vaccinia virus expressing simian immunodeficiency virus Nef. J Virol 1998; 72:5291-5. [PMID: 9573307 PMCID: PMC110127 DOI: 10.1128/jvi.72.6.5291-5295.1998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The nef gene of primate lentiviruses encodes a myristoylated protein that is important for pathogenicity and the maintenance of high virus loads. A deletion in nef leads to a significant reduction of the pathogenicity of simian immunodeficiency virus (SIV) in macaques. At the cellular and biochemical levels, Nef has been shown to down-regulate CD4 and major histocompatibility complex class I molecules and to interact with cellular protein kinases. The importance of these activities for Nef function remains uncertain. We have prepared vaccinia virus recombinants expressing different alleles of SIV nef. When grown on TK- 143 cells, recombinants constructed with the nef allele from SIVmac1A11 produced typical plaques while recombinants expressing the nef allele from SIVmac239-R1 gave rise to plaques with altered morphology. By using chimeric Nef proteins and site-directed mutagenesis, the amino acid responsible for altered plaque formation was mapped to a leucine at residue 211. In vitro phosphorylation of immunoprecipitates prepared from cells infected with the vaccinia virus recombinants resulted in labeled proteins of 62 and 90 kDa. The recombinants differed in the ability to stimulate phosphorylation, and the leucine at residue 211 was again found to be the determining amino acid. These results might help elucidate the role of nef in the pathogenesis of SIV.
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Affiliation(s)
- M K Yamanaka
- International Laboratory of Molecular Biology for Tropical Disease Agents, Department of Veterinary Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA
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2
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Vicenzi E, Turchetto L, Poli G. The nef gene of human immunodeficiency virus type-1 (HIV1) is required for optimal virus replication in fully activated primary T lymphocytes. RESEARCH IN VIROLOGY 1997; 148:38-43. [PMID: 9017832 DOI: 10.1016/s0923-2516(97)81911-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- E Vicenzi
- AIDS Immunopathogenesis Unit, DIBIT, San Raffaele Scientific Institute, Milan, Italy
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3
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Collette Y. Towards a consensus for a role of Nef in both viral replication and immunomodulation? RESEARCH IN VIROLOGY 1997; 148:23-30. [PMID: 9017829 DOI: 10.1016/s0923-2516(97)81908-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Y Collette
- Inserm U119, Institut Paoli Calmettes, Marseille, France
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4
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Whatmore AM, Cook N, Hall GA, Sharpe S, Rud EW, Cranage MP. Repair and evolution of nef in vivo modulates simian immunodeficiency virus virulence. J Virol 1995; 69:5117-23. [PMID: 7609080 PMCID: PMC189330 DOI: 10.1128/jvi.69.8.5117-5123.1995] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Experimental evidence from the simian immunodeficiency virus (SIV) model of AIDS has shown that the nef gene is critical in the pathogenesis of AIDS. Consequently, nef is of considerable interest in both antiviral drug and vaccine development. Preliminary findings in two rhesus macaques indicated that a deletion of only 12 bp found in the overlapping nef/3' long terminal repeat (LTR) region (9501 to 9512) of the SIVmacC8 molecular clone was associated with reduced virus isolation frequency. We show that this deletion can be repaired in vivo by a sequence duplication event and that sequence evolution continues until the predicted amino acid sequence of the repair is virtually indistinguishable from that of the virulent wild type. These changes occurred concomitantly with reversion to virulence, evidenced by a high virus isolation frequency and load, decline in anti-p27 antibody, substantial reduction in the CD4/CD8 ratio, and development of opportunistic infections associated with AIDS. These findings clearly illustrate the capacity for repair of small attenuating deletions in primate lentiviruses and also strongly suggest that the region from 9501 to 9512 in the SIV nef/3' LTR region is of biological relevance. In addition, the ability of attenuated virus to revert to virulence raises fundamental questions regarding the nature of superinfection immunity.
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Affiliation(s)
- A M Whatmore
- Centre for Applied Microbiology and Research, Wiltshire, United Kingdom
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5
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Benichou S, Bomsel M, Bodéus M, Durand H, Douté M, Letourneur F, Camonis J, Benarous R. Physical interaction of the HIV-1 Nef protein with beta-COP, a component of non-clathrin-coated vesicles essential for membrane traffic. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)43773-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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6
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Robertson MN, Buseyne F, Schwartz O, Rivière Y. Efficient antigen presentation to cytotoxic T lymphocytes by cells transduced with a retroviral vector expressing the HIV-1 Nef protein. AIDS Res Hum Retroviruses 1993; 9:1217-23. [PMID: 7511396 DOI: 10.1089/aid.1993.9.1217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In the classic model of antigen processing and presentation, viral antigens must be synthesized within the cytoplasm of infected cells to be processed and presented to CD8+, MHC class I-restricted cytotoxic T lymphocytes (CTLs). We have examined the utility of a retroviral vector (pNeoNef) expressing the human immunodeficiency virus type (HIV-1)Lai Nef protein for the development of target cells to study HIV-specific CTLs. Autologous Epstein-Barr-transformed B cell lines (EBV-B cells) transduced with pNeoNef were efficiently lysed by CTL lines from donors capable of lysing EBV-B cells infected with a recombinant vaccinia virus (rVV) expressing Nef. Also, the transduced cells were efficient stimulator cells for the generation of Nef-specific CTL lines. The CTL lines thus generated recognized the same epitopes as CTL lines from the same donor generated by nonspecific stimulation. The use of similar cell lines transduced with retroviral vectors expressing HIV proteins may be useful in the study of CTLs in HIV-infected donors and in the study of the ability of candidate vaccines, including rVV, to induce HIV-specific CTLs. As antigen-presenting cells, the cell lines may be useful in the generation of antigen-specific CTL lines.
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Affiliation(s)
- M N Robertson
- Unité de Virologie et Immunologie Cellulaire, Institut Pasteur, Paris
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7
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Mustafa F, Robinson HL. Context-dependent role of human immunodeficiency virus type 1 auxiliary genes in the establishment of chronic virus producers. J Virol 1993; 67:6909-15. [PMID: 8411397 PMCID: PMC238142 DOI: 10.1128/jvi.67.11.6909-6915.1993] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Two molecularly cloned viruses, human immunodeficiency virus type 1 (HIV-1)-NL4-3 (NL4-3) and HIV-1-HXB-2 (HXB-2), have been used to study the role of HIV-1 auxiliary genes in the establishment of chronic virus producers. NL4-3 encodes all known HIV-1 proteins, whereas HXB-2 is defective for three auxiliary genes: vpr, vpu, and nef. Studies were done in H9 cells, a T-cell line unusually permissive for the establishment of chronic virus producers. NL4-3 and HXB-2 undergo lytic phases of infection in H9 cultures with HXB-2, but not NL4-3, supporting the efficient establishment of chronic virus producers. Tests of mutant NL4-3 genomes containing various combinations of defective auxiliary genes revealed that both vpr and nef limited the ability of NL4-3 to establish chronic virus producers. Tests of a series of recombinants between NL4-3 and HXB-2 revealed that 5' internal sequences as well as fragments containing defective auxiliary genes affected the establishment of chronic virus producers. Viral envelope sequences and levels of virus production did not correlate with the ability to establish chronic virus producers. These results suggest that complex interactions of viral auxiliary and nonauxiliary gene functions with the host cell determine the ability to establish chronic virus producers.
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Affiliation(s)
- F Mustafa
- Department of Molecular Genetics, University of Massachusetts Medical Center, Worcester 01655
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8
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Shugars DC, Smith MS, Glueck DH, Nantermet PV, Seillier-Moiseiwitsch F, Swanstrom R. Analysis of human immunodeficiency virus type 1 nef gene sequences present in vivo. J Virol 1993; 67:4639-50. [PMID: 8043040 PMCID: PMC237849 DOI: 10.1128/jvi.67.8.4639-4650.1993] [Citation(s) in RCA: 210] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The nef genes of the human immunodeficiency viruses type 1 and 2 (HIV-1 and HIV-2) and the related simian immunodeficiency viruses (SIVs) encode a protein (Nef) whose role in virus replication and cytopathicity remains uncertain. As an attempt to elucidate the function of nef, we characterized the nucleotide and corresponding protein sequences of naturally occurring nef genes obtained from several HIV-1-infected individuals. A consensus Nef sequence was derived and used to identify several features that were highly conserved among the Nef sequences. These features included a nearly invariant myristylation signal, regions of sequence polymorphism and variable duplication, a region with an acidic charge, a (Pxx)4 repeat sequence, and a potential protein kinase C phosphorylation site. Clustering of premature stop codons at position 124 was noted in 6 of the 54 Nef sequences. Further analysis revealed four stretches of residues that were highly conserved not only among the patient-derived HIV-1 Nef sequences, but also among the Nef sequences of HIV-2 and the SIVs, suggesting that Nef proteins expressed by these retroviruses are functionally equivalent. The "Nef-defining" sequences were used to evaluate the sequence alignments of known proteins reported to share sequence similarity with Nef sequences and to conduct additional computer-based searches for similar protein sequences. A gene encoding the consensus Nef sequence was also generated. This gene encodes a full-length Nef protein that should be a valuable tool in further studies of Nef function.
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MESH Headings
- Acquired Immunodeficiency Syndrome/blood
- Acquired Immunodeficiency Syndrome/microbiology
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Viral/blood
- DNA, Viral/genetics
- DNA, Viral/isolation & purification
- Databases, Factual
- Gene Products, nef/analysis
- Gene Products, nef/biosynthesis
- Gene Products, nef/genetics
- Genes, nef
- Genetic Vectors
- HIV-1/genetics
- HIV-1/isolation & purification
- HIV-1/metabolism
- HeLa Cells
- Humans
- Immunoblotting
- Molecular Sequence Data
- Moloney murine leukemia virus/genetics
- Oligodeoxyribonucleotides
- Polymerase Chain Reaction/methods
- Proviruses/genetics
- Proviruses/isolation & purification
- Proviruses/metabolism
- Sequence Homology, Amino Acid
- Transduction, Genetic
- Transfection
- nef Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- D C Shugars
- Department of Microbiology and Immunology, UNC School of Dentistry, Chapel Hill
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9
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Kienzle N, Freund J, Kalbitzer HR, Mueller-Lantzsch N. Oligomerization of the Nef protein from human immunodeficiency virus (HIV) type 1. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 214:451-7. [PMID: 8513795 DOI: 10.1111/j.1432-1033.1993.tb17941.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The nef genes, derived from two different human immunodeficiency-virus-type-1 (HIV-1) strains, were expressed in procaryotic cells (Escherichia coli) and in eucaryotic cells (insect cells infected with nef-containing baculovirus). The oligomerization of recombinant Nef protein was studied by NMR spectroscopy and immunoblotting under various experimental conditions. 1H-NMR spectroscopy shows that native folded protein has the tendency to polymerize under low-salt conditions. These oligomers become covalently linked by disulfide bonds after decreasing the reduction potential, a process which is fully reversible. Cross-linking studies with bis(sulfo-succinimidyl)suberate and alkylation with iodoacetic acid under non-reducing and reducing conditions document for the first time that Nef can also form homomeric structures including monomers, dimers, trimers and tetramers in cell lysates and intact cells. We found disulfide-linked as well as non-covalently associated oligomers. Since the Nef molecules are not exclusively found in the cytoplasm of HIV infected cells and since the reduced glutathione concentration in lymphocytes of virus infected persons is known to be unusually low, it might be possible that these Nef oligomers have a biological function in vivo as well.
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Affiliation(s)
- N Kienzle
- University of the Saarland, Dept. Virology, Homburg/Saar, FRG
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Garcia JV, Alfano J, Miller AD. The negative effect of human immunodeficiency virus type 1 Nef on cell surface CD4 expression is not species specific and requires the cytoplasmic domain of CD4. J Virol 1993; 67:1511-6. [PMID: 8437228 PMCID: PMC237521 DOI: 10.1128/jvi.67.3.1511-1516.1993] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The nef gene product of human immunodeficiency virus type 1 has been shown to induce CD4 downregulation from the surface of human cells. To determine if this effect is species specific, we used a retroviral vector to transduce the human immunodeficiency virus type 1 nef gene into murine cells expressing human, chimpanzee, or murine CD4. Our results indicate that Nef induces cell surface downregulation of all three molecules. We also determined that Nef is functional in murine T cells and induces downregulation of both murine CD4 and CD8 (Ly-2) from the cell surface. In contrast, Nef does not downregulate cell surface expression of human CD8 in either murine or human cells. By using a mutant of human CD4 lacking its cytoplasmic domain and a human CD4/CD8 chimera, we determined that the cytoplasmic domain of CD4 is required for its downregulation by Nef. Transduction with a control vector had no effect on CD4 cell surface levels, indicating that retroviral transduction by itself has no significant effect on the cell surface levels of CD4. These results show that the observed downregulation of CD4 by Nef is independent of human-specific factors, is not species specific, and requires the cytoplasmic domain of CD4.
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Affiliation(s)
- J V Garcia
- Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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11
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Blumberg BM, Epstein LG, Saito Y, Chen D, Sharer LR, Anand R. Human immunodeficiency virus type 1 nef quasispecies in pathological tissue. J Virol 1992; 66:5256-64. [PMID: 1501274 PMCID: PMC289079 DOI: 10.1128/jvi.66.9.5256-5264.1992] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The role of the nef gene in human immunodeficiency virus type 1 (HIV-1) infection is poorly understood. To provide a basis for studies on the role of nef in AIDS, we used targeted polymerase chain reaction amplification and DNA sequencing to determine the structure of nef genes in pathologic tissue from HIV-1-infected children and adults. We find that the nef reading frame is open in 92% of clones derived from both brain and lymphocytic tissue of children, suggesting that nef is expressed in these tissues. One HIV-1 clone, BRVA, obtained by coculture from the brain of an adult AIDS patient with progressive dementia, was previously shown to contain a duplicated region in nef. We show here that similar duplications are widespread in both adults and children with AIDS. However, coculture strongly selects against the broad spectrum of nef quasispecies found in tissue. These findings suggest functional selection for nef quasispecies in pathologic tissues during HIV-1 infection of the human host.
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Affiliation(s)
- B M Blumberg
- Department of Neurology, University of Rochester Medical Center, New York 14642
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