Mechanisms of HIV Latency: an Emerging Picture of Complexity

Margolis, David M.

doi:10.1007/s11904-009-0033-9

Cited by 74 publications

(77 citation statements)

References 46 publications

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“…The power of SCIP to monitor expression /integration in individual cells might be key to investigate the still obscure mechanisms leading to HIV-1 latency (40). Taken together, these data strongly demonstrated that SCIP is a robust and clear-cut readout for understanding HIV-1 replication in details such as cellular conditions or factors affecting HIV-1 nuclear entry and the topology of integration at the individual cell level.…”

Section: Discussionmentioning

confidence: 81%

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Primio

Quercioli

Allouch

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Recent advances in fluorescence microscopy provided tools for the investigation and the analysis of the viral replication steps in the cellular context. In the HIV field, the current visualization systems successfully achieve the fluorescent labeling of the viral envelope and proteins, but not the genome. Here, we developed a system able to visualize the proviral DNA of HIV-1 through immunofluorescence detection of repair foci for DNA double-strand breaks specifically induced in the viral genome by the heterologous expression of the I-SceI endonuclease. The system for Single-Cell Imaging of HIV-1 Provirus, named SCIP, provides the possibility to individually track integrated-viral DNA within the nuclei of infected cells. In particular, SCIP allowed us to perform a topological analysis of integrated viral DNA revealing that HIV-1 preferentially integrates in the chromatin localized at the periphery of the nuclei.T echnical developments in imaging-based techniques have greatly improved our understanding of HIV-host cell interactions. HIV-1 virions labeled with fluorophores were pivotal in shedding light onto multiple aspects of the virus-host interplay during all steps of HIV-1 replication cycle (1-13). Nevertheless, few optical approaches have been so far developed to visualize viral particles within the nuclear compartment (14, 15), which limits our comprehension of the interaction between HIV-1 and the nuclear architecture. Moreover, the existing detection tools are based on the visualization of the viral protein complexes or envelope but not of the viral DNA with the only exception of the fluorescence in situ hybridization (FISH) technique. Even though FISH is a powerful technique, it is not very sensitive for HIV-1 detection and moreover disrupts the native architecture of the nuclear compartment as it requires harsh denaturation conditions. In addition, this technique does not allow the discrimination between integrated and nonintegrated viral DNA (16, 17). Here we describe a fluorescent approach to visualize HIV-1 DNA in the nuclear compartment of infected cells. We exploited a site-specific genome engineering technique that represents one of the most promising approaches to detect specific genome regions in modified organism (18) allowing for their spatial localization in the cell (19,20). This technique couples endogenous repair pathways, induced by rare cutting endonuclease, with immunofluorescence analysis. Rare cutting endonucleases, such as the yeast-homing endonuclease I-SceI, specifically cuts target sequences that cannot be found in the mammalian genome. By engineering DNA to contain the I-SceI cleavage site, it is thus possible to induce endogenous repair mechanism for double-strand breaks (DSBs) at specific genomic positions. DSB repair leads to the formation of distinct subnuclear structures that are generally referred to as "foci" (21). The first sensor of the DSB is the histone H2AX, which becomes massively phosphorylated at serine 139 (γ-H2AX). Foci of DNA repair are thus visible through immu...

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Section: Discussionmentioning

confidence: 81%

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Primio

Quercioli

Allouch

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…HIV-1 latency is characterized mainly by a reversible silencing of LTR-driven transcription of an integrated provirus (2,6,7). The inhibitory effect of Naf1 on HIV-1 LTR-driven gene expression suggests a potential role for Naf1 in HIV-1 latency.…”

Section: Naf1 Suppresses Hiv-1 Long Terminal Repeat (Ltr)-driven Genementioning

confidence: 99%

“…KEYWORDS HIV-1 latency, HIV-1 Nef-associated factor 1, NF-B, transcription P ersistence of HIV-1 infection due to viral latency is the major barrier to the eradication of AIDS (1)(2)(3)(4)(5). Although combination antiretroviral therapy effectively reduces HIV-1 replication and results in a significant viral load reduction, to a level below the limit of detection for most infected individuals, a reservoir of infected cells still persists (1,2).…”

mentioning

confidence: 99%

“…Although combination antiretroviral therapy effectively reduces HIV-1 replication and results in a significant viral load reduction, to a level below the limit of detection for most infected individuals, a reservoir of infected cells still persists (1,2). Transcriptional inefficiency of HIV-1 gene expression is an important mechanism of viral latency (2, 6, 7).…”

mentioning

confidence: 99%

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Naf1 Regulates HIV-1 Latency by Suppressing Viral Promoter-Driven Gene Expression in Primary CD4 ⁺ T Cells

Wang

Kuang

et al. 2017

J Virol

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HIV-1 latency is characterized by reversible silencing of viral transcription driven by the long terminal repeat (LTR) promoter of HIV-1. Cellular and viral factors regulating LTR activity contribute to HIV-1 latency, and certain repressive cellular factors modulate viral transcription silencing. Nef-associated factor 1 (Naf1) is a host nucleocytoplasmic shuttling protein that regulates multiple cellular signaling pathways and HIV-1 production. We recently reported that nuclear Naf1 promoted nuclear export of unspliced HIV-1 gag mRNA, leading to increased Gag production. Here we demonstrate new functions of Naf1 in regulating HIV-1 persistence. We found that Naf1 contributes to the maintenance of HIV-1 latency by inhibiting LTR-driven HIV-1 gene transcription in a nuclear factor kappa B-dependent manner. Interestingly, Naf1 knockdown significantly enhanced viral reactivation in both latently HIV-1-infected Jurkat T cells and primary central memory CD4+ T cells. Furthermore, Naf1 knockdown in resting CD4+ T cells from HIV-1-infected individuals treated with antiretroviral therapy significantly increased viral reactivation upon T-cell activation, suggesting an important role of Naf1 in modulating HIV-1 latency in vivo. Our findings provide new insights for a better understanding of HIV-1 latency and suggest that inhibition of Naf1 activity to activate latently HIV-1-infected cells may be a potential therapeutic strategy. IMPORTANCE HIV-1 latency is characterized mainly by a reversible silencing of LTR promoter-driven transcription of an integrated provirus. Cellular and viral proteins regulating LTR activity contribute to the modulation of HIV-1 latency. In this study, we found that the host protein Naf1 inhibited HIV-1 LTR-driven transcription of HIV genes and contributed to the maintenance of HIV-1 latency. Our findings provide new insights into the effects of host modulation on HIV-1 latency, which may lead to a potential therapeutic strategy for HIV persistence by targeting the Naf1 protein.

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“…In viral latency (Table 2), the paucity of viral protein expression appears chiefly to result from the infection of activated CD4 1 cells that later return to a resting state. This event can be associated with the suppression of HIV by transcriptional interference, chromatin restrictions [24], or detrimental mutations in APOBEC3G.…”

Section: Sequence Diversitymentioning

confidence: 99%

HIV/AIDS: 30 Years of progress and future challenges

Killian

Levy

2011

Eur J Immunol

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Acquired immune deficiency syndrome (AIDS) was first described 30 years ago in a report from the US Centers for Disease Control. Two years later the causative virus was identified and afterwards named the human immunodeficiency virus (HIV). This article reviews the progress made in the three decades since the recognition of AIDS and the discovery of HIV, with respect to the virus, the infected cell, and the host, as well as directions for future studies.

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Mechanisms of HIV Latency: an Emerging Picture of Complexity

Cited by 74 publications

References 46 publications

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Naf1 Regulates HIV-1 Latency by Suppressing Viral Promoter-Driven Gene Expression in Primary CD4 ⁺ T Cells

HIV/AIDS: 30 Years of progress and future challenges

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Mechanisms of HIV Latency: an Emerging Picture of Complexity

Cited by 74 publications

References 46 publications

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Single-Cell Imaging of HIV-1 Provirus (SCIP)

Naf1 Regulates HIV-1 Latency by Suppressing Viral Promoter-Driven Gene Expression in Primary CD4 + T Cells

HIV/AIDS: 30 Years of progress and future challenges

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Naf1 Regulates HIV-1 Latency by Suppressing Viral Promoter-Driven Gene Expression in Primary CD4 ⁺ T Cells