scholarly journals Disruption of Human TRIM5α Antiviral Activity by Nonhuman Primate Orthologues

2005 ◽  
Vol 79 (12) ◽  
pp. 7883-7888 ◽  
Author(s):  
Lionel Berthoux ◽  
Sarah Sebastian ◽  
David M. Sayah ◽  
Jeremy Luban
Keyword(s):  
Leukemia Virus ◽  
Coiled Coil ◽  
Cyclophilin A ◽  
Susceptibility To Infection ◽  
Coiled Coil Domain ◽  
Immunodeficiency Virus ◽  
Species Specific ◽  
Hiv 1 ◽  
Modest Effect

ABSTRACT TRIM5 is a determinant of species-specific differences in susceptibility to infection by retroviruses bearing particular capsids. Human immunodeficiency virus type 1 (HIV-1) infection is blocked by the alpha isoform of macaque TRIM5 (TRIM5αrh) or by the product of the owl monkey TRIM5-cyclophilin A gene fusion (TRIMCyp). Human TRIM5α potently restricts specific strains of murine leukemia virus (N-MLV) but has only a modest effect on HIV-1. The amino termini of TRIM5 orthologues are highly conserved and possess a coiled-coil domain that promotes homomultimerization. Here we show that heterologous expression of TRIM5αrh or TRIMCyp in human cells interferes with the anti-N-MLV activity of endogenous human TRIM5α (TRIM5αhu). Deletion of the cyclophilin domain from TRIMCyp has no effect on heteromultimerization or colocalization with TRIM5αhu but prevents interference with anti-N-MLV activity. These data demonstrate that TRIM5 orthologues form heteromultimers and indicate that C-terminal extensions alter virus recognition by multimers of these proteins.

scholarly journals Cyclophilin A and TRIM5α Independently Regulate Human Immunodeficiency Virus Type 1 Infectivity in Human Cells

2006 ◽  
Vol 80 (6) ◽  
pp. 2855-2862 ◽  
Author(s):  
Elena Sokolskaja ◽  
Lionel Berthoux ◽  
Jeremy Luban
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cyclophilin A ◽  
Human Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Cyclophilin A (CypA), a cytoplasmic, human immunodeficiency virus type 1 (HIV-1) CA-binding protein, acts after virion membrane fusion with human cells to increase HIV-1 infectivity. HIV-1 CA is similarly greeted by CypA soon after entry into rhesus macaque or African green monkey cells, where, paradoxically, the interaction decreases HIV-1 infectivity by facilitating TRIM5α-mediated restriction. These observations conjure a model in which CA recognition by the human TRIM5α orthologue is precluded by CypA. Consistent with the model, selection of a human cell line for decreased restriction of the TRIM5α-sensitive, N-tropic murine leukemia virus (N-MLV) rendered HIV-1 transduction of these cells independent of CypA. Additionally, HIV-1 virus-like particles (VLPs) saturate N-MLV restriction activity, particularly when the CA-CypA interaction is disrupted. Here the effects of CypA and TRIM5α on HIV-1 restriction were examined directly. RNA interference was used to show that endogenous human TRIM5α does indeed restrict HIV-1, but the magnitude of this antiviral activity was not altered by disruption of the CA-CypA interaction or by elimination of CypA protein. Conversely, the stimulatory effect of CypA on HIV-1 infectivity was completely independent of human TRIM5α. Together with previous reports, these data suggest that CypA protects HIV-1 from an unknown antiviral activity in human cells. Additionally, target cell permissivity increased after loading with heterologous VLPs, consistent with a common saturable target that is epistatic to both TRIM5α and the putative CypA-regulated restriction factor.

scholarly journals Isolation of an Active Lv1 Gene from Cattle Indicates that Tripartite Motif Protein-Mediated Innate Immunity to Retroviral Infection Is Widespread among Mammals

2006 ◽  
Vol 80 (15) ◽  
pp. 7332-7338 ◽  
Author(s):  
Laura M. J. Ylinen ◽  
Zuzana Keckesova ◽  
Benjamin L. J. Webb ◽  
Robert J. M. Gifford ◽  
Timothy P. L. Smith ◽  
...  
Keyword(s):  
World Monkey ◽  
Leukemia Virus ◽  
Retroviral Infection ◽  
Trim Protein ◽  
Immunodeficiency Virus ◽  
Tripartite Motif ◽  
Bovine Sequence ◽  
Species Specific ◽  
Hiv 1

ABSTRACT Lv1/TRIM5α (tripartite motif 5α) has recently emerged as an important factor influencing species-specific permissivity to retroviral infection in a range of primates, including humans. Old World monkey TRIM5α blocks human immunodeficiency virus type 1 (HIV-1) infectivity, and the human and New World monkey TRIM5α proteins are inactive against HIV-1 but active against divergent murine (N-tropic murine leukemia virus [MLV-N]) and simian (simian immunodeficiency virus from rhesus macaque [SIVmac]) retroviruses, respectively. Here we demonstrate antiviral activity of the first nonprimate TRIM protein, from cattle, active against divergent retroviruses, including HIV-1. The number of closely related human TRIM sequences makes assignment of the bovine sequence as a TRIM5α ortholog uncertain, and we therefore refer to it as bovine Lv1. Bovine Lv1 is closely related to primate TRIM5α proteins in the N-terminal RING and B-box 2 domains but significantly less homologous in the C-terminal B30.2 domain, particularly in the region shown to influence antiviral specificity. Intriguingly, some viruses restricted by bovine Lv1, including HIV-1 and MLV-N, are unable to synthesize viral DNA by reverse transcription, whereas restricted HIV-2 makes normal amounts of DNA. The data support the conclusion that TRIM protein-mediated restriction of retroviral infection is a more common attribute of mammals than previously appreciated.

scholarly journals Selection for Loss of Ref1 Activity in Human Cells Releases Human Immunodeficiency Virus Type 1 from Cyclophilin A Dependence during Infection

2004 ◽  
Vol 78 (21) ◽  
pp. 12066-12070 ◽  
Author(s):  
David M. Sayah ◽  
Jeremy Luban
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Cyclophilin A ◽  
Cellular Protein ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Capsid (CA)-specific restrictions are determinants of retroviral tropism in mammalian cells. One such restriction, human Ref1, targets strains of murine leukemia virus bearing an arginine at CA residue 110 (N-MLV), resulting in decreased accumulation of viral cDNA. The cellular factors accounting for Ref1 activity are unknown. As2O3 increases N-MLV titer in Ref1-positive cells, possibly by counteracting Ref1. Restriction factor saturation experiments suggest that Ref1 may also target human immunodeficiency virus type 1 (HIV-1), but only if its CA is not bound to the cellular protein cyclophilin A (CypA). As a step towards understanding the genetic determinants of Ref1, we subjected Ref1-positive TE671 cells to three sequential rounds of selection with N-MLV reporter viruses. We isolated a subclone, 17H1, that was permissive for N-MLV infection and therefore deficient in Ref1 activity. Stimulation of N-MLV replication by As2O3 was attenuated in 17H1, confirming that the drug acts by overcoming Ref1 activity. HIV-1 infection of 17H1 cells was resistant to disruption of the CA-CypA interaction, demonstrating that Ref1 restricts CypA-free HIV-1. Our results suggest that interaction with CypA evolved to protect HIV-1 from this human antiviral activity.

scholarly journals Fusion of Cyclophilin A to Fv1 Enables Cyclosporine-Sensitive Restriction of Human and Feline Immunodeficiency Viruses

2007 ◽  
Vol 81 (18) ◽  
pp. 10055-10063 ◽  
Author(s):  
Torsten Schaller ◽  
Laura M. J. Ylinen ◽  
Benjamin L. J. Webb ◽  
Shalene Singh ◽  
Greg J. Towers
Keyword(s):  
Reverse Transcription ◽  
Half Life ◽  
Leukemia Virus ◽  
Susceptibility Gene ◽  
Cyclophilin A ◽  
Restriction Factor ◽  
Coding Region ◽  
Immunodeficiency Virus ◽  
Species Specific ◽  
Hiv 1

ABSTRACT TRIM5α is a potent intracellular antiviral restriction factor governing species-specific retroviral replication. In the New World species owl monkey the coding region for the viral binding B30.2 domain of TRIM5α has been replaced by a cyclophilin A (CypA) pseudogene by retrotransposition. The resultant TRIM5-CypA fusion protein restricts human immunodeficiency virus type 1 (HIV-1), as well as feline immunodeficiency virus (FIV), by recruitment of the CypA domain to the incoming viral capsids. Infectivity is rescued by agents such as cyclosporine that disrupt CypA binding to its substrates. Mice encode an antiviral restriction factor called Fv1 (for Friend virus susceptibility gene 1), which is active against murine leukemia virus and related to endogenous gag sequences. Here we show that fusing CypA to Fv1 generates a restriction factor with the antiviral specificity of TRIMCyp but the antiviral properties of Fv1. Like TRIMCyp, Fv1-Cyp restricts HIV-1 and FIV and is sensitive to inhibition by cyclosporine. TRIM5α is known to have a short half-life and block infectivity before viral reverse transcription. We show that Fv1-Cyp has a long half-life and blocks after reverse transcription, suggesting that its longer half-life gives the restricted virus the opportunity to synthesize DNA, leading to a later block to infection. This notion is supported by the observation that infectivity of Fv1-Cyp restricted virus can be rescued by cyclosporine for several hours after infection, whereas virus restricted by TRIMCyp is terminally restricted after around 40 min. Intriguingly, the Fv1-Cyp-restricted HIV-1 generates closed circular viral DNA, suggesting that the restricted virus complex enters the nucleus.

scholarly journals Novel TRIM5 Isoforms Expressed by Macaca nemestrina

2007 ◽  
Vol 81 (22) ◽  
pp. 12210-12217 ◽  
Author(s):  
Greg Brennan ◽  
Yury Kozyrev ◽  
Toshiaki Kodama ◽  
Shiu-Lok Hu
Keyword(s):  
Coiled Coil ◽  
Macaca Nemestrina ◽  
Cdna Clones ◽  
Reading Frame ◽  
Spry Domain ◽  
Immunodeficiency Virus ◽  
Hiv Type 1 ◽  
Hiv 1

ABSTRACT The TRIM5 family of proteins contains a RING domain, one or two B boxes, and a coiled-coil domain. The TRIM5α isoform also encodes a C-terminal B30.2(SPRY) domain, differences within which define the breadth and potency of TRIM5α-mediated retroviral restriction. Because Macaca nemestrina animals are susceptible to some human immunodeficiency virus (HIV) isolates, we sought to determine if differences exist in the TRIM5 gene and transcripts of these animals. We identified a two-nucleotide deletion (Δ2) in the transcript at the 5′ terminus of exon 7 in all M. nemestrina TRIM5 cDNA clones examined. This frameshift results in a truncated protein of 300 amino acids lacking the B30.2(SPRY) domain, which we have named TRIM5θ. This deletion is likely due to a single nucleotide polymorphism that alters the 3′ splice site between intron 6 and exon 7. In some clones, a deletion of the entire 27-nucleotide exon 7 (Δexon7) resulted in the restoration of the TRIM5 open reading frame and the generation of another novel isoform, TRIM5η. There are 18 amino acid differences between M. nemestrina TRIM5η and Macaca mulatta TRIM5α, some of which are at or near locations previously shown to affect the breadth and potency of TRIM5α-mediated restriction. Infectivity assays performed on permissive CrFK cells stably transduced with TRIM5η or TRIM5θ show that these isoforms are incapable of restricting either HIV type 1 (HIV-1) or simian immunodeficiency virus infection. The expression of TRIM5 alleles incapable of restricting HIV-1 infection may contribute to the previously reported increased susceptibility of M. nemestrina to HIV-1 infection in vivo.

scholarly journals The Susceptibility of Primate Lentiviruses to Nucleosides and Vpx during Infection of Dendritic Cells Is Regulated by CA

2015 ◽  
Vol 89 (7) ◽  
pp. 4030-4034 ◽  
Author(s):  
Véronique Barateau ◽  
Xuan-Nhi Nguyen ◽  
Fanny Bourguillault ◽  
Grégory Berger ◽  
Stéphanie Cordeil ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Dendritic Cells ◽  
Simian Immunodeficiency Virus ◽  
Viral Protein ◽  
Immunodeficiency Virus ◽  
Protein X ◽  
Primate Lentiviruses ◽  
Species Specific ◽  
Hiv 1

The block toward human immunodeficiency virus type 1 (HIV-1) infection of dendritic cells (DCs) can be relieved by Vpx (viral protein X), which degrades sterile alpha motif-hydroxylase domain 1 (SAMHD1) or by exogenously added deoxynucleosides (dNs), lending support to the hypothesis that SAMHD1 acts by limiting deoxynucleoside triphosphates (dNTPs). This notion has, however, been questioned. We show that while dNs and Vpx increase the infectivity of HIV-1, only the latter restores the infectivity of a simian immunodeficiency virus of macaques variant, SIVMACΔVpx virus. This distinct behavior seems to map to CA, suggesting that species-specific CA interactors modulate infection of DCs.

scholarly journals Binding and Susceptibility to Postentry Restriction Factors in Monkey Cells Are Specified by Distinct Regions of the Human Immunodeficiency Virus Type 1 Capsid

2004 ◽  
Vol 78 (10) ◽  
pp. 5423-5437 ◽  
Author(s):  
Christopher M. Owens ◽  
Byeongwoon Song ◽  
Michel J. Perron ◽  
Peter C. Yang ◽  
Matthew Stremlau ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cyclophilin A ◽  
New World Monkeys ◽  
Restriction Factors ◽  
Factor Binding ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT In cells of Old World and some New World monkeys, dominant factors restrict human immunodeficiency virus type 1 (HIV-1) infections after virus entry. The simian immunodeficiency virus SIVmac is less susceptible to these restrictions, a property that is determined largely by the viral capsid protein. For this study, we altered exposed amino acid residues on the surface of the HIV-1 capsid, changing them to the corresponding residues found on the SIVmac capsid. We identified two distinct pathways of escape from early, postentry restriction in monkey cells. One set of mutants that were altered near the base of the cyclophilin A-binding loop of the N-terminal capsid domain or in the interdomain linker exhibited a decreased ability to bind the restricting factor(s). Consistent with the location of this putative factor-binding site, cyclophilin A and the restricting factor(s) cooperated to achieve the postentry block. A second set of mutants that were altered in the ridge formed by helices 3 and 6 of the N-terminal capsid domain efficiently bound the restricting factor(s) but were resistant to the consequences of factor binding. These results imply that binding of the simian restricting factor(s) is not sufficient to mediate the postentry block to HIV-1 and that SIVmac capsids escape the block by decreases in both factor binding and susceptibility to the effects of the factor(s).

scholarly journals Evidence that Ecotropic Murine Leukemia Virus Contamination in TZM-bl Cells Does Not Affect the Outcome of Neutralizing Antibody Assays with Human Immunodeficiency Virus Type 1

2009 ◽  
Vol 83 (16) ◽  
pp. 8289-8292 ◽  
Author(s):  
Emily J. Platt ◽  
Miroslawa Bilska ◽  
Susan L. Kozak ◽  
David Kabat ◽  
David C. Montefiori
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT The TZM-bl cell line that is commonly used to assess neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) was recently reported to be contaminated with an ecotropic murine leukemia virus (MLV) (Y. Takeuchi, M. O. McClure, and M. Pizzato, J. Virol. 82:12585-12588, 2008), raising questions about the validity of results obtained with this cell line. Here we confirm this observation and show that HIV-1 neutralization assays performed with a variety of serologic reagents in a similar cell line that does not harbor MLV yield results that are equivalent to those obtained in TZM-bl cells. We conclude that MLV contamination has no measurable effect on HIV-1 neutralization when TZM-bl cells are used as targets for infection.

scholarly journals Coding Sequences Upstream of the Human Immunodeficiency Virus Type 1 Reverse Transcriptase Domain in Gag-Pol Are Not Essential for Incorporation of the Pr160gag-pol into Virus Particles

2002 ◽  
Vol 76 (7) ◽  
pp. 3221-3231 ◽  
Author(s):  
Hsu-Chen Chiu ◽  
Szu-Yung Yao ◽  
Chin-Tien Wang
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Leukemia Virus ◽  
Deletion Mutants ◽  
Coding Region ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Incorporation of the human immunodeficiency virus type 1 (HIV-1) Gag-Pol into virions is thought to be mediated by the N-terminal Gag domain via interaction with the Gag precursor. However, one recent study has demonstrated that the murine leukemia virus Pol can be incorporated into virions independently of Gag-Pol expression, implying a possible interaction between the Pol and Gag precursor. To test whether the HIV-1 Pol can be incorporated into virions on removal of the N-terminal Gag domain and to define sequences required for the incorporation of Gag-Pol into virions in more detail, a series of HIV Gag-Pol expression plasmids with various extensive deletions in the region upstream of the reverse transcriptase (RT) domain was constructed, and viral incorporation of the Gag-Pol deletion mutants was examined by cotransfecting 293T cells with a plasmid expressing Pr55 gag . Analysis indicated that deletion of the N-terminal two-thirds of the gag coding region did not significantly affect the incorporation of Gag-Pol into virions. In contrast, Gag-Pol proteins with deletions covering the capsid (CA) major homology regions and the adjacent C-terminal CA regions were impaired with respect to assembly into virions. However, Gag-Pol with sequences deleted upstream of the protease, or of the RT domain but retaining 15 N-terminal gag codons, could still be rescued into virions at a level about 20% of the wild-type level. When assayed in a nonmyristylated Gag-Pol context, all of the Gag-Pol deletion mutants were incorporated into virions at a level comparable to their myristylated counterparts, suggesting that the incorporation of the Gag-Pol deletion mutants into virions is independent of the N-terminal myristylation signal.

scholarly journals Characterization of Stable, Soluble Trimers Containing Complete Ectodomains of Human Immunodeficiency Virus Type 1 Envelope Glycoproteins

2000 ◽  
Vol 74 (12) ◽  
pp. 5716-5725 ◽  
Author(s):  
Xinzhen Yang ◽  
Michael Farzan ◽  
Richard Wyatt ◽  
Joseph Sodroski
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cleavage Site ◽  
Neutralizing Antibodies ◽  
Coiled Coil ◽  
Envelope Glycoproteins ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins function as a membrane-anchored trimer of three gp120 exterior glycoproteins and three gp41 transmembrane glycoproteins. Previously, we reported three approaches to stabilize soluble trimers containing parts of the gp41 ectodomains: addition of GCN4 trimeric helices, disruption of the cleavage site between gp120 and gp41, and introduction of cysteines in the gp41 coiled coil to form intersubunit disulfide bonds. Here, we applied similar approaches to stabilize soluble gp140 trimers including the complete gp120 and gp41 ectodomains. A combination of fusion with the GCN4 trimeric sequences and disruption of the gp120-gp41 cleavage site resulted in relatively homogeneous gp140 trimers with exceptional stability. The gp120 epitopes recognized by neutralizing antibodies are intact and exposed on these gp140 trimers. By contrast, the nonneutralizing antibody epitopes on the gp120 subunits of the soluble trimers are relatively occluded compared with those on monomeric gp120 preparations. This antigenic similarity to the functional HIV-1 envelope glycoproteins and the presence of the complete gp41 ectodomain should make the soluble gp140 trimers useful tools for structural and immunologic studies.

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