1
|
Solution properties of murine leukemia virus gag protein: differences from HIV-1 gag. J Virol 2011; 85:12733-41. [PMID: 21917964 DOI: 10.1128/jvi.05889-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of ∼7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed.
Collapse
|
2
|
Yu JH, Schaffer DV. High-throughput, library-based selection of a murine leukemia virus variant to infect nondividing cells. J Virol 2006; 80:8981-8. [PMID: 16940510 PMCID: PMC1563944 DOI: 10.1128/jvi.00615-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gammaretroviruses, such as murine leukemia virus (MLV), are functionally distinguished from lentiviruses, such as human immunodeficiency virus, by their inability to infect nondividing cells. Attempts to engineer this property into MLV have been hindered by an incomplete understanding of early events in the viral life cycle. We utilized a transposon-based method to generate saturated peptide insertion libraries of MLV gag-pol variants with nuclear localization signals randomly incorporated throughout these overlapping genes. High-throughput selection of the libraries via iterative retroviral infection of nondividing cells led to the identification of a novel variant that successfully transduced growth-arrested cells. Vector packaging by cotransfection of the gag-pol.NLS variant with wild-type gag-pol produced high-titer virions capable of infecting neurons in vitro and in vivo. The capacity of mutant virions to transduce nondividing cells could help to elucidate incompletely understood mechanisms of the viral life cycle and greatly broaden the gene therapy applications of retroviral vectors. Furthermore, the ability to engineer key intracellular viral infection steps has potential implications for the understanding, design, and control of other post-entry events. Finally, this method of library generation and selection for a desired phenotype directly in a mammalian system can be readily expanded to address other challenges in protein engineering.
Collapse
Affiliation(s)
- Julie H Yu
- Department of Chemical Engineering, University of California-Berkeley, 201 Gilman Hall, Berkeley, CA 94720-1462, USA
| | | |
Collapse
|
3
|
Hübner W, Chen BK. Inhibition of viral assembly in murine cells by HIV-1 matrix. Virology 2006; 352:27-38. [PMID: 16750235 DOI: 10.1016/j.virol.2006.04.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 11/28/2005] [Accepted: 04/06/2006] [Indexed: 11/29/2022]
Abstract
In human cells, the N-terminal matrix (MA) domain of the human immunodeficiency virus type 1 (HIV-1) Gag targets assembly to specific membrane compartments. In murine fibroblasts, membrane targeting of Gag and assembly of HIV-1 are inefficient. These deficiencies are relieved by replacement of HIV-1 MA with murine leukemia virus (MLV) MA in chimeric proviruses. In this study, we examined chimeric HIV-1 carrying tandem MLV and HIV-1 MA domains and found that the addition of MLV MA to the N-terminus of HIV-1 Gag enhanced membrane binding in murine cells, but was not sufficient to stimulate virus production. Removal of HIV MA was required to observe more efficient Gag processing and increased virus production in murine cells. Deletion of the globular head of MA also alleviated the blocks to membrane binding and Gag processing in murine cells, yet did not lead to increased virus production. These MA-dependent, cell-type-specific phenotypes suggest that host factors interact with the globular head of MA to regulate membrane binding and additional membrane-independent step(s) required for assembly.
Collapse
Affiliation(s)
- Wolfgang Hübner
- Department of Pharmacology and Biological Chemistry, Center for Immunobiology, Mount Sinai School of Medicine, One Gustave Levy Place Box 1215, New York, NY 10029, USA
| | | |
Collapse
|
4
|
Yamashita M, Emerman M. Retroviral infection of non-dividing cells: old and new perspectives. Virology 2006; 344:88-93. [PMID: 16364740 DOI: 10.1016/j.virol.2005.09.012] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 09/10/2005] [Indexed: 12/16/2022]
Abstract
The dependence of retroviral replication on cell proliferation was described as early as 1958, although different classes of retroviruses are able to infect non-dividing cells with different efficiencies. For example, the human immunodeficiency virus (HIV) and other lentiviruses infect most non-dividing cells nearly as well as dividing cells, while the gammaretroviruses such as the murine leukemia virus (MLV) cannot infect non-dividing cells, and other retroviruses have intermediate phenotypes. One exception to the ability of HIV to infect non-dividing cells involves resting CD4+ T cells in vitro where there are multiple restrictions. However, recent data show that there is massive infection of non-activated CD4+ T cell during acute infection which suggests that the situation is different in vivo. Finally, much work trying to explain the difference between HIV and MLV in non-dividing cells has focused on describing the ability of HIV to enter the nucleus during interphase. However, we suggest that events in the viral life-cycle other than nuclear import may be more important in determining the ability of a given retrovirus to infect non-dividing cells.
Collapse
Affiliation(s)
- Masahiro Yamashita
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109-1024, USA
| | | |
Collapse
|
5
|
Ako-Adjei D, Johnson MC, Vogt VM. The retroviral capsid domain dictates virion size, morphology, and coassembly of gag into virus-like particles. J Virol 2005; 79:13463-72. [PMID: 16227267 PMCID: PMC1262573 DOI: 10.1128/jvi.79.21.13463-13472.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The retroviral structural protein, Gag, is capable of independently assembling into virus-like particles (VLPs) in living cells and in vitro. Immature VLPs of human immunodeficiency virus type 1 (HIV-1) and of Rous sarcoma virus (RSV) are morphologically distinct when viewed by transmission electron microscopy (TEM). To better understand the nature of the Gag-Gag interactions leading to these distinctions, we constructed vectors encoding several RSV/HIV-1 chimeric Gag proteins for expression in either insect cells or vertebrate cells. We used TEM, confocal fluorescence microscopy, and a novel correlative scanning EM (SEM)-confocal microscopy technique to study the assembly properties of these proteins. Most chimeric proteins assembled into regular VLPs, with the capsid (CA) domain being the primary determinant of overall particle diameter and morphology. The presence of domains between matrix and CA also influenced particle morphology by increasing the spacing between the inner electron-dense ring and the VLP membrane. Fluorescently tagged versions of wild-type RSV, HIV-1, or murine leukemia virus Gag did not colocalize in cells. However, wild-type Gag proteins colocalized extensively with chimeric Gag proteins bearing the same CA domain, implying that Gag interactions are mediated by CA. A dramatic example of this phenomenon was provided by a nuclear export-deficient chimera of RSV Gag carrying the HIV-1 CA domain, which by itself localized to the nucleus but relocalized to the cytoplasm in the presence of wild type HIV-1 Gag. Wild-type and chimeric Gag proteins were capable of coassembly into a single VLP as viewed by correlative fluorescence SEM if, and only if, the CA domain was derived from the same virus. These results imply that the primary selectivity of Gag-Gag interactions is determined by the CA domain.
Collapse
Affiliation(s)
- Danso Ako-Adjei
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | | | |
Collapse
|
6
|
Yamashita M, Emerman M. The cell cycle independence of HIV infections is not determined by known karyophilic viral elements. PLoS Pathog 2005; 1:e18. [PMID: 16292356 PMCID: PMC1283251 DOI: 10.1371/journal.ppat.0010018] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 09/19/2005] [Indexed: 01/01/2023] Open
Abstract
Human immunodeficiency virus and other lentiviruses infect cells independent of cell cycle progression, but gammaretroviruses, such as the murine leukemia virus (MLV) require passage of cells through mitosis. This property is thought to be important for the ability of HIV to infect resting CD4+ T cells and terminally differentiated macrophages. Multiple and independent redundant nuclear localization signals encoded by HIV have been hypothesized to facilitate migration of viral genomes into the nucleus. The integrase (IN) protein of HIV is one of the HIV elements that targets to the nucleus; however, its role in nuclear entry of virus genomes has been difficult to describe because mutations in IN are pleiotropic. To investigate the importance of the HIV IN protein for infection of non-dividing cells, and to investigate whether or not IN was redundant with other viral signals for cell cycle-independent nuclear entry, we constructed an HIV-based chimeric virus in which the entire IN protein of HIV was replaced by that of MLV. This chimeric virus with a heterologous IN was infectious at a low level, and was able to integrate in an IN-dependent manner. Furthermore, this virus infected non-dividing cells as well as it infected dividing cells. Moreover, we used the chimeric HIV with MLV IN to further eliminate all of the other described nuclear localization signals from an HIV genome—matrix, IN, Viral Protein R, and the central polypurine tract—and show that no combination of the virally encoded NLS is essential for the ability of HIV to infect non-dividing cells. Human immunodeficiency virus can infect many cells irrespective of whether or not they are dividing, whereas some other retroviruses, such as the murine leukemia virus can only infect cells that are proliferating. This property is important for the ability of HIV to establish infections in critical cell types in infected people. Multiple and redundant signals encoded by HIV have been hypothesized to facilitate migration of viral genomes into the nucleus. However, here the authors eliminated all four described nuclear localizing signals from an HIV genome and show that no combination of these virally encoded signals is essential for the ability of HIV to infect non-dividing cells. They suggest that another step of the virus lifecycle, other than nuclear import, is the rate-limiting step that determines the cell cycle dependence/independence of retroviral infections.
Collapse
Affiliation(s)
- Masahiro Yamashita
- Division of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Michael Emerman
- Division of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
7
|
Caron MC, Caruso M. A nuclear localization signal in the matrix of spleen necrosis virus (SNV) does not allow efficient gene transfer into quiescent cells with SNV-derived vectors. Virology 2005; 338:292-6. [PMID: 15961134 DOI: 10.1016/j.virol.2005.05.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 05/06/2005] [Accepted: 05/20/2005] [Indexed: 11/17/2022]
Abstract
A major limitation in gene therapy for vectors derived from Moloney murine leukemia virus (MLV) is that they only deliver genes into dividing cells. In this study, a careful comparison of spleen necrosis virus (SNV)-derived vectors with MLV and human immunodeficiency virus (HIV)-1 retroviral vectors indicated that SNV vectors can deliver genes 4-fold more efficiently than MLV vectors into aphidicolin-arrested cells, although at a 25-fold lower efficiency than HIV-1-derived vectors. Furthermore, the addition of a NLS in the SNV matrix (MA) that mimics the one located in HIV-1 MA did not increase the ability of SNV vectors to transfer genes into arrested cells. Also, we found that the RD114 envelope was able to pseudotype SNV viral particles in a very efficient manner.
Collapse
Affiliation(s)
- Marie-Christine Caron
- Le Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel Dieu de Québec, Centre Hospitalier Universitaire de Québec, 9 rue MacMahon, Québec, Canada
| | | |
Collapse
|
8
|
Marusich EI, Parveen Z, Strayer D, Mukhtar M, Dornburg RC, Pomerantz RJ. Spleen necrosis virus-based vector delivery of anti-HIV-1 genes potently protects human hematopoietic cells from HIV-1 infection. Virology 2005; 332:258-71. [PMID: 15661158 DOI: 10.1016/j.virol.2004.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 11/08/2004] [Accepted: 11/10/2004] [Indexed: 10/26/2022]
Abstract
In this study, we report on the efficacy of using a spleen necrosis virus (SNV)-based vector delivery system to block human immunodeficiency virus type I (HIV-1) replication in human hematopoietic cells. These efforts were directed towards the development of human immune system cell resistance to HIV-1 infection, based on the strategy of "intracellular immunization" via generation of a series of anti-HIV-1 therapeutic constructs carrying scFvs, single-chain variable fragments, against HIV-1 integrase and reverse transcriptase in combination with the trans-dominant mutant of HIV-1 Rev, RevM10. The efficiency of the anti-HIV-1 constructs were tested in viral challenge assays with different doses of HIV-1 NL4-3, Bal, 89.6 and R7-GFP strains. These experiments demonstrated the reduction of HIV-1 replication by these retroviral vector constructs in a range of 4- to 10-fold in CD4+ T-lymphocytes, human peripheral blood mononuclear cells (PBMCs), and primary human macrophages. We observed selective efficiency of SNV-based therapeutics in H9, C8166 and Jurkat T-lymphocytic cell lines, demonstrating the most efficient inhibition of HIV-1 replication in Jurkat T-cells. Thus, these data are the first demonstration of the ability of SNV-based retroviral vectors with select transgenes, which may have certain molecular advantages over other retroviral vector systems, to combat HIV-1 replication in human hematopoietic cells and support the potential for using SNV-expressed constructs in anti-HIV-1 molecular therapeutics.
Collapse
Affiliation(s)
- Elena I Marusich
- Division of Infectious Diseases and Environmental Medicine, Department of Medicine, Center for Human Virology and Biodefense, Thomas Jefferson University, 1020 Locust Street, Suite 329, Philadelphia, PA 19107, USA
| | | | | | | | | | | |
Collapse
|
9
|
Rayne F, Kajava AV, Lalanne J, Mamoun RZ. In vivo homodimerisation of HTLV-1 Gag and MA gives clues to the retroviral capsid and TM envelope protein arrangement. J Mol Biol 2004; 343:903-16. [PMID: 15476809 DOI: 10.1016/j.jmb.2004.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 09/08/2004] [Accepted: 09/08/2004] [Indexed: 10/26/2022]
Abstract
During retroviral particle formation, the capsid precursors (Gag) associate with the cell membrane via their matrix (MA) domain to form viral assembling particles. After budding, Gag and its proteolytically matured MA, form a shell in the released immature and mature particles, respectively. Although the arrangement of Gag domains in vitro and their radial organisation in retroviral particles have been extensively studied, little is known concerning Gag inter-subunit interactions in authentic retroviruses. We report that human T-cell leukemia virus type 1 Gag homodimerises in the cell via a disulphide bonding at cysteine 61 in the MA domain. Most Gags are homodimeric after budding and MAs are also dimeric in mature authentic virions. Molecular modelling of the MA domain indicates that non-covalent interactions at the MA dimer interface may also be important for Gag (and MA) dimerisation. In addition, all amino acids previously reported to be involved in MA-transmembrane (TM) interactions are located on the MA face opposite to the dimer interface. The model reveals that homodimerisation is compatible with a hexameric network of Gag and MA dimers that look like the hexameric networks observed for other retroviruses. These data, together with previous studies, lead us to propose a supra-molecular arrangement model in which the transmembrane glycoproteins of the virion envelope are anchored in a hexameric cage hole formed by the MA.
Collapse
Affiliation(s)
- Fabienne Rayne
- INSERM U443, Equipe Rétrovirus et Transfert génique, 146, rue Léo Saignat, F-33076 Bordeaux Cedex, France
| | | | | | | |
Collapse
|
10
|
Manrique ML, González SA, Affranchino JL. Functional relationship between the matrix proteins of feline and simian immunodeficiency viruses. Virology 2004; 329:157-67. [PMID: 15476883 DOI: 10.1016/j.virol.2004.07.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 06/22/2004] [Accepted: 07/29/2004] [Indexed: 11/16/2022]
Abstract
To investigate the functional relationship between the matrix (MA) proteins of feline and simian immunodeficiency viruses (FIV and SIV, respectively), we generated chimeric proviruses in which the MA-coding region of an SIV infectious molecular clone was partially or fully replaced by its FIV counterpart. Chimeric SIV proviruses containing the amino-terminal 36 residues or the central and carboxy-terminal regions of the FIV MA assembled into virions as efficiently as wild-type SIV. However, the resulting virions were noninfectious in single-cycle infectivity assays. Furthermore, a chimeric SIV provirus containing the entire FIV MA was found to be severely impaired in virion production due to inefficient membrane binding of the chimeric Gag polyprotein. Interestingly, the assembly defective phenotype of this chimeric Gag precursor could be reversed either by introducing the G31K/G33K double amino acid substitution in the FIV-derived MA domain or by coexpression with wild-type SIV Gag. Of note, a chimeric FIV provirus expressing the SIV MA not only assembled into particles as efficiently as wild-type FIV, but also replicated in feline T cells with wild-type kinetics. Our results thus provide novel information about the functional homology between the MA proteins of distantly related lentiviruses.
Collapse
Affiliation(s)
- Mariana L Manrique
- Centro de Virología Animal (CEVAN-CONICET), C1414DEM Buenos Aires, Argentina
| | | | | |
Collapse
|
11
|
Abstract
A major difference between lentiviruses such as human immunodeficiency virus (HIV) and most other retroviruses is their ability to productively infect nondividing cells. We present here genetic evidence for involvement of the capsid protein (CA) in the infectious phenotype in nondividing cells. A chimeric HIV type 1 (HIV-1) in which the MA and CA of HIV-1 are replaced with the MA, p12, and CA encoding sequences from murine leukemia virus (MLV) loses the ability to efficiently infect nondividing cells. Analysis of the accumulation of two-long-terminal-repeat circles implies that the impairment of nuclear transport of preintegration complexes is responsible for the restricted infection of this chimeric virus in nondividing cells. Incorporation of MLV MA and MLV p12 into HIV virions alone does not exert any adverse effects on viral infection in interphase cells. These results suggest that CA is the dominant determinant for the difference between HIV and MLV in the ability to transduce nondividing cells.
Collapse
Affiliation(s)
- Masahiro Yamashita
- Division of Human Biology, Mail Stop C2-023, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | | |
Collapse
|
12
|
Steidl S, Schüle S, Mühlebach MD, Stitz J, Boller K, Cichutek K, Schweizer M. Genetic engineering of onco/lentivirus hybrids results in formation of infectious but not of replication-competent viruses. J Gen Virol 2004; 85:665-678. [PMID: 14993652 DOI: 10.1099/vir.0.19479-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To achieve specific gene transfer into human CD4(+) cells, murine leukaemia virus (MLV)-based pseudotype vector particles were generated employing Env variants derived from human or simian immunodeficiency virus (HIV-1 or SIVagm). Here, we describe the generation of full-length onco/lentivirus hybrid genomes comprising components of MLV and HIV-1 or SIVagm, respectively, to assess the possibility of replication-competent hybrid virus formation. The env reading frame of an infectious molecular clone of MLV was replaced with the analogous coding regions of HIV-1 or SIVagm encompassing the env gene and accessory genes. Resulting MLV/HIV-1 or MLV/SIVagm hybrid genomes were transfected into 293T cells. Expression of viral proteins and budding of retroviral particles was shown by specific immunostaining and electron microscopy. The viral particles mediated CD4- and co-receptor-specific infection of human cells as demonstrated by PCR and immunostaining in the respective target cells. However, no productive infection resulting in the generation of infectious virus was detected in these cells. Thus, these onco/lentivirus hybrids, although able to initiate single-round infection, were not replication competent. Thus, MLV-based pseudotype vectors carrying Env variants of HIV-1 or SIVagm are not prone to form replication-competent retroviruses, suggesting a favourable safety profile for MLV-based CD4-specific pseudotype vectors.
Collapse
Affiliation(s)
- Stefanie Steidl
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Silke Schüle
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Michael D Mühlebach
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Jörn Stitz
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Klaus Boller
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Klaus Cichutek
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| | - Matthias Schweizer
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany
| |
Collapse
|
13
|
Liu B, Yu X, Luo K, Yu Y, Yu XF. Influence of primate lentiviral Vif and proteasome inhibitors on human immunodeficiency virus type 1 virion packaging of APOBEC3G. J Virol 2004; 78:2072-81. [PMID: 14747572 PMCID: PMC369424 DOI: 10.1128/jvi.78.4.2072-2081.2004] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Vif protein of human immunodeficiency virus type 1 (HIV-1) is essential for viral evasion of the host antiviral protein APOBEC3G, also known as CEM15. Vif mutant but not wild-type HIV-1 viruses produced in the presence of APOBEC3G have been shown to undergo hypermutations in newly synthesized viral DNA upon infection of target cells, presumably resulting from C-to-U modification during minus-strand viral DNA synthesis. We now report that HIV-1 Vif could induce rapid degradation of human APOBEC3G that was blocked by the proteasome inhibitor MG132. The efficiency of Vif-induced downregulation of APOBEC3G expression depended on the level of Vif expression. A single amino acid substitution in the conserved SLQXLA motif reduced Vif function. Vif proteins from distantly related primate lentiviruses such as SIVagm were unable to suppress the antiviral activity of human APOBEC3G or the packaging of APOBEC3G into HIV-1 Vif mutant virions, due to a lack of interaction with human APOBEC3G. In the presence of the proteasome inhibitor MG132, virion-associated Vif increased dramatically. However, increased virion packaging of Vif did not prevent virion packaging of APOBEC3G when proteasome function was impaired, and the infectivity of these virions was significantly reduced. These results suggest that Vif function is required during virus assembly to remove APOBEC3G from packaging into released virions. Once packaged, virion-associated Vif could not efficiently block the antiviral activity of APOBEC3G.
Collapse
Affiliation(s)
- Bindong Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
| | | | | | | | | |
Collapse
|
14
|
Brunelle MN, Brakier-Gingras L, Lemay G. Replacement of murine leukemia virus readthrough mechanism by human immunodeficiency virus frameshift allows synthesis of viral proteins and virus replication. J Virol 2003; 77:3345-50. [PMID: 12584361 PMCID: PMC149774 DOI: 10.1128/jvi.77.5.3345-3350.2003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Retroviruses use unusual recoding strategies to synthesize the Gag-Pol polyprotein precursor of viral enzymes. In human immunodeficiency virus, ribosomes translating full-length viral RNA can shift back by 1 nucleotide at a specific site defined by the presence of both a slippery sequence and a downstream stimulatory element made of an extensive secondary structure. This so-called frameshift mechanism could become a target for the development of novel antiviral strategies. A different recoding strategy is used by other retroviruses, such as murine leukemia viruses, to synthesize the Gag-Pol precursor; in this case, a stop codon is suppressed in a readthrough process, again due to the presence of a specific structure adopted by the mRNA. Development of antiframeshift agents will greatly benefit from the availability of a simple animal and virus model. For this purpose, the murine leukemia virus readthrough region was rendered inactive by mutagenesis and the frameshift region of human immunodeficiency virus was inserted to generate a chimeric provirus. This substitution of readthrough by frameshift allows the synthesis of viral proteins, and the chimeric provirus sequence was found to generate infectious viruses. This system could be a most interesting alternative to study ribosomal frameshift in the context of a virus amenable to the use of a simple animal model.
Collapse
|
15
|
Sakalian M, Dittmer SS, Gandy AD, Rapp ND, Zábranský A, Hunter E. The Mason-Pfizer monkey virus internal scaffold domain enables in vitro assembly of human immunodeficiency virus type 1 Gag. J Virol 2002; 76:10811-20. [PMID: 12368324 PMCID: PMC136644 DOI: 10.1128/jvi.76.21.10811-10820.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The Mason-Pfizer monkey virus (M-PMV) Gag protein possesses the ability to assemble into an immature capsid when synthesized in a reticulocyte lysate translation system. In contrast, the human immunodeficiency virus (HIV) Gag protein is incapable of assembly in parallel assays. To enable the assembly of HIV Gag, we have combined or inserted regions of M-PMV Gag into HIV Gag. By both biochemical and morphological criteria, several of these chimeric Gag molecules are capable of assembly into immature capsid-like structures in this in vitro system. Chimeric species containing large regions of M-PMV Gag fused to HIV Gag sequences failed to assemble, while species consisting of only the M-PMV p12 region, and its internal scaffold domain (ISD), fused to HIV Gag were capable of assembly, albeit at reduced kinetics compared to M-PMV Gag. The ability of the ISD to induce assembly of HIV Gag, which normally assembles at the plasma membrane, suggests a common requirement for a concentrating factor in retrovirus assembly. Despite the dramatic effect of the ISD on chimera assembly, the function of HIV Gag domains in that process was found to remain essential, since an assembly-defective mutant of HIV CA, M185A, abolished assembly when introduced into the chimera. This continued requirement for HIV Gag domain function in the assembly of chimeric molecules will allow this in vitro system to be used for the analysis of potential inhibitors of HIV immature particle assembly.
Collapse
Affiliation(s)
- Michael Sakalian
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA.
| | | | | | | | | | | |
Collapse
|
16
|
Katz RA, Greger JG, Darby K, Boimel P, Rall GF, Skalka AM. Transduction of interphase cells by avian sarcoma virus. J Virol 2002; 76:5422-34. [PMID: 11991971 PMCID: PMC137034 DOI: 10.1128/jvi.76.11.5422-5434.2002] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
It has been generally believed that oncoretroviruses are dependent on mitosis for efficient nuclear entry of viral DNA. We previously identified a nuclear localization signal in the integrase protein of an oncoretrovirus, avian sarcoma virus (ASV), suggesting an active import mechanism for the integrase-DNA complex (G. Kukolj, R. A. Katz, and A. M. Skalka, Gene 223:157-163, 1998). Here, we have evaluated the requirement for mitosis in nuclear import and integration of ASV DNA. Using a modified ASV encoding a murine leukemia virus amphotropic env gene and a green fluorescent protein (GFP) reporter gene, DNA nuclear import was measured in cell cycle-arrested avian (DF-1) as well as human (HeLa) and mouse cells. The results showed efficient accumulation of nuclear forms of ASV DNA in gamma-irradiation-arrested cells. Efficient transduction of a GFP reporter gene was also observed after infection of cells that were arrested with gamma-irradiation, mitomycin C, nocodazole, or aphidicolin, confirming that nuclear import and integration of ASV DNA can occur in the absence of mitosis. By monitoring GFP expression in individual cells, we also obtained evidence for nuclear import of viral DNA during interphase in cycling cells. Lastly, we observed that ASV can transduce postmitotic mouse neurons. These results support an active nuclear import mechanism for the oncoretrovirus ASV and suggest that this mechanism can operate in both nondividing and dividing cells.
Collapse
Affiliation(s)
- Richard A Katz
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
| | | | | | | | | | | |
Collapse
|
17
|
Reed M, Mariani R, Sheppard L, Pekrun K, Landau NR, Soong NW. Chimeric human immunodeficiency virus type 1 containing murine leukemia virus matrix assembles in murine cells. J Virol 2002; 76:436-43. [PMID: 11739711 PMCID: PMC135687 DOI: 10.1128/jvi.76.1.436-443.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Murine cells do not support efficient assembly and release of human immunodeficiency virus type 1 (HIV-1) virions. HIV-1-infected mouse cells that express transfected human cyclin T1 synthesize abundant Gag precursor polyprotein, but inefficiently assemble and release virions. This assembly defect may result from a failure of the Gag polyprotein precursor to target to the cell membrane. Plasma membrane targeting of the precursor is mediated by the amino-terminal region of polyprotein. To compensate for the assembly block, we substituted the murine leukemia virus matrix coding sequences into an infectious HIV-1 clone. Transfection of murine fibroblasts expressing cyclin T1 with the chimeric proviruses resulted in viruses that were efficiently assembled and released. Chimeric viruses, in which the cytoplasmic tail of the transmembrane subunit, gp41, was truncated to prevent potential interference between the envelope glycoprotein and the heterologous matrix, could infect human and murine cells. They failed to further replicate in the murine cells, but replicated with delayed kinetics in human MT-4 cells. These findings may be useful for establishing a murine model for HIV-1 replication.
Collapse
|
18
|
Goff SP. Intracellular trafficking of retroviral genomes during the early phase of infection: viral exploitation of cellular pathways. J Gene Med 2001; 3:517-28. [PMID: 11778899 DOI: 10.1002/1521-2254(200111)3:6<517::aid-jgm234>3.0.co;2-e] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Retroviruses enter cells through specific cell-surface receptors and then embark on a journey that ultimately leads to the establishment of the integrated proviral DNA. The steps of the journey include the reverse transcription of the viral RNA into DNA, the trafficking of the viral protein-DNA complex through the cytoplasm, the entry of the complex into the nucleus, and the insertion of the linear viral DNA into the host genome. All these steps are likely to involve specific interactions of viral proteins with host machinery. Our knowledge of the details of these interactions is very limited but is rapidly expanding, and should provide a deeper understanding of the pathways and components used by the different classes of retroviruses. This knowledge in turn should enable the development of better and more efficient retroviral vectors for use in gene therapy protocols in vivo.
Collapse
Affiliation(s)
- S P Goff
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
19
|
Van Tendeloo VF, Van Broeckhoven C, Berneman ZN. Gene therapy: principles and applications to hematopoietic cells. Leukemia 2001; 15:523-44. [PMID: 11368355 DOI: 10.1038/sj.leu.2402085] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ever since the development of technology allowing the transfer of new genes into eukaryotic cells, the hematopoietic system has been an obvious and desirable target for gene therapy. The last 10 years have witnessed an explosion of interest in this approach to treat human disease, both inherited and acquired, with the initiation of multiple clinical protocols. All gene therapy strategies have two essential technical requirements. These are: (1) the efficient introduction of the relevant genetic material into the target cell and (2) the expression of the transgene at therapeutic levels. Conceptual and technical hurdles involved with these requirements are still the objects of active research. To date, the most widely used and best understood vectors for gene transfer in hematopoietic cells are derived from retroviruses, although they suffer from several limitations. However, as gene transfer mechanisms become more efficient and long-term gene expression is enhanced, the variety of diseases that can be tackled by gene therapy will continue to expand. However, until the problem of delivery and subsequent expression is adequately resolved, gene therapy will not realize its full potential. The first part of this review gives an overview of the gene delivery technology available at present to transfer genetic sequences in human somatic cells. The relevance of the hematopoietic system to the development of gene therapy strategies as well as hematopoietic cell-based gene therapy is discussed in the second part.
Collapse
Affiliation(s)
- V F Van Tendeloo
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp University Hospital, Belgium
| | | | | |
Collapse
|
20
|
Nègre D, Mangeot PE, Duisit G, Blanchard S, Vidalain PO, Leissner P, Winter AJ, Rabourdin-Combe C, Mehtali M, Moullier P, Darlix JL, Cosset FL. Characterization of novel safe lentiviral vectors derived from simian immunodeficiency virus (SIVmac251) that efficiently transduce mature human dendritic cells. Gene Ther 2000; 7:1613-23. [PMID: 11083469 DOI: 10.1038/sj.gt.3301292] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe the generation and the characterization of new lentiviral vectors derived from SIVmac251, a simian immunodeficiency virus (SIV). A methodical approach was used to engineer both efficient and safe packaging constructs allowing the production of SIV viral core proteins. SIV-vectors encoding GFP (green fluorescent protein) were generated as VSV-G-pseudotyped particles upon transient expression of the vector construct and helper functions in 293 cells. The SIV vectors were able to transduce efficiently various target cell types at low multiplicity of infection, including monocyte-differentiated human dendritic cells (DCs) which retained their capacity to differentiate into mature DCs after gene transfer. Transduction of the DCs by the SIV vectors was prevented when infections were performed in the presence of AZT, a reverse-transcriptase inhibitor. After gene transfer, expression of the GFP in the target cells remained constant after several weeks, indicating that the vectors had been stably integrated into the genome of the host cells. Preparations of SIV vectors were systematically checked for the absence of replication-competent and recombinant retroviruses but remained negative, suggesting the innocuousness of these novel gene delivery vectors. Side-to-side comparisons with vectors derived from HIV-1 (human immunodeficiency virus) indicated that the SIV vectors were equally potent in transducing proliferating target cells. Finally, we have determined the infectivity of SIV vectors pseudotyped with surface glycoproteins of several membrane-enveloped viruses.
Collapse
Affiliation(s)
- D Nègre
- Vectorologie Rétrovirale and Thérapie Génique, U412 INSERM, IFR 74 and ENS de Lyon, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Parveen Z, Krupetsky A, Engelstädter M, Cichutek K, Pomerantz RJ, Dornburg R. Spleen necrosis virus-derived C-type retroviral vectors for gene transfer to quiescent cells. Nat Biotechnol 2000; 18:623-9. [PMID: 10835599 DOI: 10.1038/76458] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gene therapy applications of retroviral vectors derived from C-type retroviruses have been limited to introducing genes into dividing target cells. Here, we report genetically engineered C-type retroviral vectors derived from spleen necrosis virus (SNV), which are capable of infecting nondividing cells. This has been achieved by introducing a nuclear localization signal (NLS) sequence into the matrix protein (MA) of SNV by site-directed mutagenesis. This increased the efficiency of infecting nondividing cells and was sufficient to endow the virus with the capability to efficiently infect growth-arrested human T lymphocytes and quiescent primary monocyte-derived macrophages. We demonstrate that this vector actively penetrates the nucleus of a target cell, and has potential use as a gene therapy vector to transfer genes into nondividing cells.
Collapse
Affiliation(s)
- Z Parveen
- The Dorrance H. Hamilton Laboratories, Thomas Jefferson University, Division of Infectious Diseases, Center for Human Virology, 1020 Locust Street, Suite 329, Philadelphia, PA 19107, USA
| | | | | | | | | | | |
Collapse
|
22
|
Weldon RA, Parker WB, Sakalian M, Hunter E. Type D retrovirus capsid assembly and release are active events requiring ATP. J Virol 1998; 72:3098-106. [PMID: 9525635 PMCID: PMC109760 DOI: 10.1128/jvi.72.4.3098-3106.1998] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mason-Pfizer monkey virus (M-PMV), the prototype type D retrovirus, differs from most other retroviruses by assembling its Gag polyproteins into procapsids in the cytoplasm of infected cells. Once assembled, the procapsids migrate to the plasma membrane, where they acquire their envelope during budding. Because the processes of M-PMV protein transport, procapsid assembly, and budding are temporally and spatially unlinked, we have been able to determine whether cellular proteins play an active role during the different stages of procapsid morphogenesis. We report here that at least two stages of morphogenesis require ATP. Both procapsid assembly and procapsid transport to the plasma membrane were reversibly blocked by treating infected cells with sodium azide and 2-deoxy-D-glucose, which we show rapidly and reversibly depletes cellular ATP pools. Assembly of procapsids in vitro in a cell-free translation/assembly system was inhibited by the addition of nonhydrolyzable ATP analogs, suggesting that ATP hydrolysis and not just ATP binding is required. Since retrovirus Gag polyproteins do not bind or hydrolyze ATP, these results demonstrate that cellular components must play an active role during retrovirus morphogenesis.
Collapse
Affiliation(s)
- R A Weldon
- Department of Microbiology, University of Alabama at Birmingham, 35294, USA
| | | | | | | |
Collapse
|
23
|
Abstract
Many viral and non-viral vector systems have now been developed for gene therapy applications. In this article, the pros and cons of these vector systems are discussed in relation to the different cancer gene therapy strategies. The protocols used in cancer gene therapy can be broadly divided into six categories including gene transfer to explanted cells for use as cell-based cancer vaccines; gene transfer to a small number of tumour cells in situ to achieve a vaccine effect; gene transfer to vascular endothelial cells (VECs) lining the blood vessels of the tumour to interfere with tumour angiogenesis; gene transfer to T lymphocytes to enhance their antitumour effector capability; gene transfer to haemopoietic stem cells (HSCs) to enhance their resistance to cytotoxic drugs and gene transfer to a large number of tumour cells in situ to achieve nonimmune tumour reduction with or without bystander effect. Each of the six strategies makes unique demands on the vector system and these are discussed with reference to currently available vectors. Aspects of vector biology that are in need of further development are discussed in some detail. The final section points to the potential use of replicating viruses as delivery vehicles for efficient in vivo gene transfer to disseminated cancers.
Collapse
Affiliation(s)
- J Zhang
- Cambridge Centre for Protein Engineering, MRC Centre, UK
| | | |
Collapse
|
24
|
Mehtali M. Complementation cell lines for viral vectors to be used in gene therapy. Cytotechnology 1996; 19:43-54. [DOI: 10.1007/bf00749754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/1995] [Accepted: 09/05/1995] [Indexed: 11/24/2022] Open
|
25
|
Kräusslich HG, Welker R. Intracellular transport of retroviral capsid components. Curr Top Microbiol Immunol 1996; 214:25-63. [PMID: 8791724 DOI: 10.1007/978-3-642-80145-7_2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H G Kräusslich
- Department of Cell Biology and Virology, Heinrich Pette Institute of Experimental Virology and Immunology, Hamburg, Germany
| | | |
Collapse
|