scholarly journals Contribution of MxB Oligomerization to HIV-1 Capsid Binding and Restriction

2015 ◽  
Vol 89 (6) ◽  
pp. 3285-3294 ◽  
Author(s):  
Cindy Buffone ◽  
Bianca Schulte ◽  
Silvana Opp ◽  
Felipe Diaz-Griffero
Keyword(s):  
T Cells ◽  
Structure Function ◽  
Capsid Protein ◽  
Reverse Transcription ◽  
Tertiary Structure ◽  
Alpha Interferon ◽  
Restriction Factor ◽  
Current Structure ◽  
Modeled Structure ◽  
Hiv 1

ABSTRACTThe alpha interferon (IFN-α)-inducible restriction factor myxovirus B (MxB) blocks HIV-1 infection after reverse transcription but prior to integration. MxB binds to the HIV-1 core, which is composed of capsid protein, and this interaction leads to inhibition of the uncoating process of HIV-1. Previous studies suggested that HIV-1 restriction by MxB requires binding to capsid. This work tests the hypothesis that MxB oligomerization is important for the ability of MxB to bind to the HIV-1 core. For this purpose, we modeled the structure of MxB using the published tertiary structure of MxA. The modeled structure of MxB guided our mutagenic studies and led to the discovery of several MxB variants that lose the capacity to oligomerize. In agreement with our hypothesis, MxB variants that lost the oligomerization capacity also lost the ability to bind to the HIV-1 core. MxB variants deficient for oligomerization were not able to block HIV-1 infection. Overall, our work showed that oligomerization is required for the ability of MxB to bind to the HIV-1 core and block HIV-1 infection.IMPORTANCEMxB is a novel restriction factor that blocks infection of HIV-1. MxB is inducible by IFN-α, particularly in T cells. The current work studies the oligomerization determinants of MxB and carefully explores the contribution of oligomerization to capsid binding and restriction. This work takes advantage of the current structure of MxA and models the structure of MxB, which is used to guide structure-function studies. This work leads to the conclusion that MxB oligomerization is important for HIV-1 capsid binding and restriction.

scholarly journals HIV envelope tail truncation confers resistance to SERINC5 restriction

2021 ◽  
Vol 118 (21) ◽  
pp. e2101450118
Author(s):  
Tafhima Haider ◽  
Xenia Snetkov ◽  
Clare Jolly
Keyword(s):  
T Cells ◽  
Envelope Glycoprotein ◽  
Cytoplasmic Tail ◽  
Restriction Factor ◽  
Viral Fusion ◽  
Restriction Factors ◽  
Complete Resistance ◽  
Hiv Envelope ◽  
Hiv 1

SERINC5 is a potent lentiviral restriction factor that gets incorporated into nascent virions and inhibits viral fusion and infectivity. The envelope glycoprotein (Env) is a key determinant for SERINC restriction, but many aspects of this relationship remain incompletely understood, and the mechanism of SERINC5 restriction remains unresolved. Here, we have used mutants of HIV-1 and HIV-2 to show that truncation of the Env cytoplasmic tail (ΔCT) confers complete resistance of both viruses to SERINC5 and SERINC3 restriction. Critically, fusion of HIV-1 ΔCT virus was not inhibited by SERINC5 incorporation into virions, providing a mechanism to explain how EnvCT truncation allows escape from restriction. Neutralization and inhibitor assays showed ΔCT viruses have an altered Env conformation and fusion kinetics, suggesting that EnvCT truncation dysregulates the processivity of entry, in turn allowing Env to escape targeting by SERINC5. Furthermore, HIV-1 and HIV-2 ΔCT viruses were also resistant to IFITMs, another entry-targeting family of restriction factors. Notably, while the EnvCT is essential for Env incorporation into HIV-1 virions and spreading infection in T cells, HIV-2 does not require the EnvCT. Here, we reveal a mechanism by which human lentiviruses can evade two potent Env-targeting restriction factors but show key differences in the capacity of HIV-1 and HIV-2 to exploit this. Taken together, this study provides insights into the interplay between HIV and entry-targeting restriction factors, revealing viral plasticity toward mechanisms of escape and a key role for the long lentiviral EnvCT in regulating these processes.

scholarly journals Kinetics of Human Immunodeficiency Virus Type 1 Decay following Entry into Resting CD4+ T Cells

2005 ◽  
Vol 79 (4) ◽  
pp. 2199-2210 ◽  
Author(s):  
Yan Zhou ◽  
Haili Zhang ◽  
Janet D. Siliciano ◽  
Robert F. Siliciano
Keyword(s):  
Gene Expression ◽  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Reverse Transcription ◽  
Half Life ◽  
Immunodeficiency Virus ◽  
Kinetics Of ◽  
Hiv 1

ABSTRACT In untreated human immunodeficiency virus type 1 (HIV-1) infection, most viral genomes in resting CD4+ T cells are not integrated into host chromosomes. This unintegrated virus provides an inducible latent reservoir because cellular activation permits integration, virus gene expression, and virus production. It remains controversial whether HIV-1 is stable in this preintegration state. Here, we monitored the fate of HIV-1 in resting CD4+ cells by using a green fluorescent protein (GFP) reporter virus carrying an X4 envelope. After virus entry into resting CD4+ T cells, both rescuable virus gene expression, visualized with GFP, and rescuable virion production, assessed by p24 release, decayed with a half-life of 2 days. In these cells, reverse transcription goes to completion over 2 to 3 days, and 50% of the viruses that have entered undergo functional decay before reverse transcription is complete. We distinguished two distinct but closely related factors contributing to loss of rescuable virus. First, some host cells undergo virus-induced apoptosis upon viral entry, thereby reducing the amount of rescuable virus. Second, decay processes directly affecting the virus both before and after the completion of reverse transcription contribute to the loss of rescuable virus. The functional half-life of full-length, integration-competent reverse transcripts is only 1 day. We propose that rapid intracellular decay processes compete with early steps in viral replication in infected CD4+ T cells. Decay processes dominate in resting CD4+ T cells as a result of the slow kinetics of reverse transcription and blocks at subsequent steps. Therefore, the reservoir of unintegrated HIV-1 in recently infected resting CD4+ T cells is highly labile.

Investigating HIV-Human Interaction Networks to Unravel Pathogenic Mechanism for Drug Discovery: A Systems Biology Approach

2018 ◽  
Vol 16 (1) ◽  
pp. 77-95 ◽  
Author(s):  
Cheng-Wei Li ◽  
Bor-Sen Chen
Keyword(s):  
T Cells ◽  
Reverse Transcription ◽  
Late Stage ◽  
Time Course ◽  
System Modeling ◽  
Human Interaction ◽  
Flufenamic Acid ◽  
Replication Stage ◽  
Core Proteins ◽  
Hiv 1

Background: Two big issues in the study of pathogens are determining how pathogens infect hosts and how the host defends itself against infection. Therefore, investigating host-pathogen interactions is important for understanding pathogenicity and host defensive mechanisms and treating infections.Methods: In this study, we used omics data, including time-course data from high-throughput sequencing, real-time polymerase chain reaction, and human microRNA (miRNA) and protein-protein interaction to construct an interspecies protein-protein and miRNA interaction (PPMI) network of human CD4+ T cells during HIV-1 infection through system modeling and identification.Results: By applying a functional annotation tool to the identified PPMI network at each stage of HIV infection, we found that repressions of three miRNAs, miR-140-5p, miR-320a, and miR-941, are involved in the development of autoimmune disorders, tumor proliferation, and the pathogenesis of T cells at the reverse transcription stage. Repressions of miR-331-3p and miR-320a are involved in HIV-1 replication, replicative spread, anti-apoptosis, cell proliferation, and dysregulation of cell cycle control at the integration/replication stage. Repression of miR-341-5p is involved in carcinogenesis at the late stage of HIV-1 infection.Conclusion: By investigating the common core proteins and changes in specific proteins in the PPMI network between the stages of HIV-1 infection, we obtained pathogenic insights into the functional core modules and identified potential drug combinations for treating patients with HIV-1 infection, including thalidomide, oxaprozin, and metformin, at the reverse transcription stage; quercetin, nifedipine, and fenbendazole, at the integration/replication stage; and staurosporine, quercetin, prednisolone, and flufenamic acid, at the late stage.

scholarly journals Cytokine Signals Are Sufficient for HIV-1 Infection of Resting Human T Lymphocytes

1999 ◽  
Vol 189 (11) ◽  
pp. 1735-1746 ◽  
Author(s):  
Derya Unutmaz ◽  
Vineet N. KewalRamani ◽  
Shana Marmon ◽  
Dan R. Littman
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Structure Function ◽  
Human Lymphocytes ◽  
Stable Gene ◽  
Mutant Form ◽  
Primary Cells ◽  
Human T Cells ◽  
Transformed Cell Lines ◽  
Hiv 1

Lentiviral vectors have been advocated to be effective vehicles for the delivery and stable expression of genes in nondividing primary cells. However, certain cell types, such as resting T lymphocytes, are resistant to infection with HIV-1. Establishing parameters for stable gene delivery into primary human lymphocytes and approaches to overcome the resistance of resting T cells to HIV infection may permit potential gene therapy applications, genetic studies of primary cells in vitro, and a better understanding of the stages of the lentiviral life cycle. Here we demonstrate that an HIV-1–derived vector can be used for stable delivery of genes into activated human T cells as well as natural killer and dendritic cells. Remarkably, a sizeable fraction of resting T cells was stably transduced with the HIV-1 vector when cultured with the cytokine interleukin (IL)-2, IL-4, IL-7, or IL-15, or, at a lower level, with IL-6, in the absence of any other stimuli. Resting T cells stimulated with these cytokines could also be infected with replication-competent HIV-1. To test the utility of this system for performing structure–function analysis in primary T cells, we introduced wild-type as well as a mutant form of murine CD28 into human T cells and showed a requirement for the CD28 cytoplasmic domain in costimulatory signaling. The ability to stably express genes of interest in primary T cells will be a valuable tool for genetic and structure–function studies that previously have been limited to transformed cell lines. In addition, the finding that cytokine signals are sufficient to permit transduction of resting T cells with HIV may be relevant for understanding mechanism of HIV-1 transmission and pathogenesis.

scholarly journals Immature Dendritic Cells Selectively Replicate Macrophagetropic (M-Tropic) Human Immunodeficiency Virus Type 1, while Mature Cells Efficiently Transmit both M- and T-Tropic Virus to T Cells

1998 ◽  
Vol 72 (4) ◽  
pp. 2733-2737 ◽  
Author(s):  
Angela Granelli-Piperno ◽  
Elena Delgado ◽  
Victoria Finkel ◽  
William Paxton ◽  
Ralph M. Steinman
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Dendritic Cells ◽  
Human Immunodeficiency Virus Type ◽  
Reverse Transcription ◽  
Blood Monocytes ◽  
Gm Csf ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Dendritic cells (DCs) can develop from CD14+ peripheral blood monocytes cultured in granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4). By 6 days in culture, the cells have the characteristics of immature DCs and can be further induced to mature by inflammatory stimuli or by monocyte-conditioned medium. After infection with macrophagetropic (M-tropic) human immunodeficiency virus type 1 (HIV-1), monocytes and mature DCs show a block in reverse transcription and only form early transcripts that can be amplified with primers for the R/U5 region. In contrast, immature DCs cultured for 6 or 11 days in GM-CSF and IL-4 complete reverse transcription and show a strong signal when LTR/gag primers are used. Blood monocytes and mature DCs do not replicate HIV-1, whereas immature DCs can be productively infected, but only with M-tropic HIV-1. The virus produced by immature DCs readily infects activated T cells. Although mature DCs do not produce virus, these cells transmit both M- and T-tropic virus to T cells. In the cocultures, both DCs and T cells must express functional chemokine coreceptors for viral replication to occur. Therefore, the developmental stage of DCs can influence the interaction of these cells with HIV-1 and influence the extent to which M-tropic and T-tropic virus can replicate.

Proteomic profiling of HIV-1 infection of human CD4+ T cells identifies PSGL-1 as an HIV restriction factor

2019 ◽  
Vol 4 (5) ◽  
pp. 813-825 ◽  
Author(s):  
Ying Liu ◽  
Yajing Fu ◽  
Qian Wang ◽  
Mushan Li ◽  
Zheng Zhou ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Restriction Factor ◽  
Proteomic Profiling ◽  
Hiv 1

scholarly journals A Cell-Intrinsic Inhibitor of HIV-1 Reverse Transcription in CD4+ T Cells from Elite Controllers

2014 ◽  
Vol 15 (6) ◽  
pp. 717-728 ◽  
Author(s):  
Jin Leng ◽  
Hsin-Pin Ho ◽  
Maria J. Buzon ◽  
Florencia Pereyra ◽  
Bruce D. Walker ◽  
...  
Keyword(s):  
T Cells ◽  
Reverse Transcription ◽  
Cd4 T Cells ◽  
Elite Controllers ◽  
A Cell ◽  
Hiv 1

scholarly journals A Cell Internalizing Antibody Targeting Capsid Protein (p24) Inhibits the Replication of HIV-1 in T Cells Lines and PBMCs: A Proof of Concept Study

PLoS ONE ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. e0145986 ◽  
Author(s):  
Syed A. Ali ◽  
Sin-Yeang Teow ◽  
Tasyriq Che Omar ◽  
Alan Soo-Beng Khoo ◽  
Tan Soo Choon ◽  
...  
Keyword(s):  
T Cells ◽  
Capsid Protein ◽  
Proof Of Concept ◽  
Concept Study ◽  
A Cell ◽  
Antibody Targeting ◽  
Hiv 1

scholarly journals Suppression of HIV-1 Infection by APOBEC3 Proteins in Primary Human CD4+T Cells Is Associated with Inhibition of Processive Reverse Transcription as Well as Excessive Cytidine Deamination

2012 ◽  
Vol 87 (3) ◽  
pp. 1508-1517 ◽  
Author(s):  
Kieran Gillick ◽  
Darja Pollpeter ◽  
Prabhjeet Phalora ◽  
Eun-Young Kim ◽  
Steven M. Wolinsky ◽  
...  
Keyword(s):  
T Cells ◽  
Reverse Transcription ◽  
Protein Function ◽  
Viral Inhibition ◽  
Apobec3 Protein ◽  
Viral Cdna ◽  
Apobec3 Proteins ◽  
Multiple Donors ◽  
Cytidine Deamination ◽  
Hiv 1

ABSTRACTThe Vif protein of human immunodeficiency virus type 1 (HIV-1) promotes viral replication by downregulation of the cell-encoded, antiviral APOBEC3 proteins. These proteins exert their suppressive effects through the inhibition of viral reverse transcription as well as the induction of cytidine deamination within nascent viral cDNA. Importantly, these two effects have not been characterized in detail in human CD4+T cells, leading to controversies over their possible contributions to viral inhibition in the natural cell targets of HIV-1 replication. Here we use wild-type and Vif-deficient viruses derived from the CD4+T cells of multiple donors to examine the consequences of APOBEC3 protein function at natural levels of expression. We demonstrate that APOBEC3 proteins impart a profound deficiency to reverse transcription from the initial stages of cDNA synthesis, as well as excessive cytidine deamination (hypermutation) of the DNAs that are synthesized. Experiments using viruses from transfected cells and a novel method for mapping the 3′ termini of cDNAs indicate that the inhibition of reverse transcription is not limited to a few specific sites, arguing that APOBEC3 proteins impede enzymatic processivity. Detailed analyses of mutation spectra in viral cDNA strongly imply that one particular APOBEC3 protein, APOBEC3G, provides the bulk of the antiviral phenotype in CD4+T cells, with the effects of APOBEC3F and APOBEC3D being less significant. Taken together, we conclude that the dual mechanisms of action of APOBEC3 proteins combine to deliver more effective restriction of HIV-1 than either function would by itself.

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