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Kizito F, Nguyen K, Mbonye U, Shukla M, Luttge B, Checkley MA, Agaponova A, Leskov K, Karn J. Structural rearrangements in the nucleus localize latent HIV proviruses to a perinucleolar compartment supportive of reactivation. Proc Natl Acad Sci U S A 2024; 121:e2202003121. [PMID: 38669184 PMCID: PMC11067448 DOI: 10.1073/pnas.2202003121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/12/2024] [Indexed: 04/28/2024] Open
Abstract
Using an immunofluorescence assay based on CRISPR-dCas9-gRNA complexes that selectively bind to the HIV LTR (HIV Cas-FISH), we traced changes in HIV DNA localization in primary effector T cells from early infection until the cells become quiescent as they transition to memory cells. Unintegrated HIV DNA colocalized with CPSF6 and HIV capsid (CA, p24) was found in the cytoplasm and nuclear periphery at days 1 and 3 post infection. From days 3 to 7, most HIV DNA was distributed primarily in the nuclear intermediate euchromatic compartment and was transcribed. By day 21, the cells had entered quiescence, and HIV DNA accumulated in the perinucleolar compartment (PNC). The localization of proviruses to the PNC was blocked by integrase inhibitor Raltegravir, suggesting it was due to chromosomal rearrangements. During the reactivation of latently infected cells through the T cell receptor (TCR), nascent viral mRNA transcripts associated with HIV DNA in the PNC were detected. The viral trans-activator Tat and its regulatory partners, P-TEFb and 7SK snRNA, assembled in large interchromatin granule clusters near the provirus within 2 h of TCR activation. As T cell activation progressed, the HIV DNA shifted away from the PNC. HIV DNA in latently infected memory T cells from patients also accumulated in the PNC and showed identical patterns of nuclear rearrangements after cellular reactivation. Thus, in contrast to transformed cells where proviruses are found primarily at the nuclear periphery, in primary memory T cells, the nuclear architecture undergoes rearrangements that shape the transcriptional silencing and reactivation of proviral HIV.
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Affiliation(s)
- Fredrick Kizito
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Kien Nguyen
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Uri Mbonye
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Meenakshi Shukla
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Benjamin Luttge
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Mary Ann Checkley
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Anna Agaponova
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Konstantin Leskov
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH44106
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Burdick RC, Morse M, Rouzina I, Williams MC, Hu WS, Pathak VK. HIV-1 uncoating requires long double-stranded reverse transcription products. SCIENCE ADVANCES 2024; 10:eadn7033. [PMID: 38657061 PMCID: PMC11042746 DOI: 10.1126/sciadv.adn7033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/21/2024] [Indexed: 04/26/2024]
Abstract
HIV-1 cores, which contain the viral genome and replication machinery, must disassemble (uncoat) during viral replication. However, the viral and host factors that trigger uncoating remain unidentified. Recent studies show that infectious cores enter the nucleus and uncoat near the site of integration. Here, we show that efficient uncoating of nuclear cores requires synthesis of a double-stranded DNA (dsDNA) genome >3.5 kb and that the efficiency of uncoating correlates with genome size. Core disruption by capsid inhibitors releases viral DNA, some of which integrates. However, most of the viral DNA is degraded, indicating that the intact core safeguards viral DNA. Atomic force microscopy and core content estimation reveal that synthesis of full-length genomic dsDNA induces substantial internal strain on the core to promote uncoating. We conclude that HIV-1 cores protect viral DNA from degradation by host factors and that synthesis of long double-stranded reverse transcription products is required to trigger efficient HIV-1 uncoating.
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Affiliation(s)
- Ryan C. Burdick
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Michael Morse
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retroviral Research and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Mark C. Williams
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
| | - Vinay K. Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702, USA
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Mbonye U, Karn J. The cell biology of HIV-1 latency and rebound. Retrovirology 2024; 21:6. [PMID: 38580979 PMCID: PMC10996279 DOI: 10.1186/s12977-024-00639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024] Open
Abstract
Transcriptionally latent forms of replication-competent proviruses, present primarily in a small subset of memory CD4+ T cells, pose the primary barrier to a cure for HIV-1 infection because they are the source of the viral rebound that almost inevitably follows the interruption of antiretroviral therapy. Over the last 30 years, many of the factors essential for initiating HIV-1 transcription have been identified in studies performed using transformed cell lines, such as the Jurkat T-cell model. However, as highlighted in this review, several poorly understood mechanisms still need to be elucidated, including the molecular basis for promoter-proximal pausing of the transcribing complex and the detailed mechanism of the delivery of P-TEFb from 7SK snRNP. Furthermore, the central paradox of HIV-1 transcription remains unsolved: how are the initial rounds of transcription achieved in the absence of Tat? A critical limitation of the transformed cell models is that they do not recapitulate the transitions between active effector cells and quiescent memory T cells. Therefore, investigation of the molecular mechanisms of HIV-1 latency reversal and LRA efficacy in a proper physiological context requires the utilization of primary cell models. Recent mechanistic studies of HIV-1 transcription using latently infected cells recovered from donors and ex vivo cellular models of viral latency have demonstrated that the primary blocks to HIV-1 transcription in memory CD4+ T cells are restrictive epigenetic features at the proviral promoter, the cytoplasmic sequestration of key transcription initiation factors such as NFAT and NF-κB, and the vanishingly low expression of the cellular transcription elongation factor P-TEFb. One of the foremost schemes to eliminate the residual reservoir is to deliberately reactivate latent HIV-1 proviruses to enable clearance of persisting latently infected cells-the "Shock and Kill" strategy. For "Shock and Kill" to become efficient, effective, non-toxic latency-reversing agents (LRAs) must be discovered. Since multiple restrictions limit viral reactivation in primary cells, understanding the T-cell signaling mechanisms that are essential for stimulating P-TEFb biogenesis, initiation factor activation, and reversing the proviral epigenetic restrictions have become a prerequisite for the development of more effective LRAs.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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Chang J, Parent LJ. HIV-1 Gag co-localizes with euchromatin histone marks at the nuclear periphery. J Virol 2023; 97:e0117923. [PMID: 37991367 PMCID: PMC10734548 DOI: 10.1128/jvi.01179-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 10/27/2023] [Indexed: 11/23/2023] Open
Abstract
IMPORTANCE The traditional view of retrovirus assembly posits that packaging of gRNA by HIV-1 Gag occurs in the cytoplasm or at the plasma membrane. However, our previous studies showing that HIV-1 Gag enters the nucleus and binds to USvRNA at transcription sites suggest that gRNA selection may occur in the nucleus. In the present study, we observed that HIV-1 Gag trafficked to the nucleus and co-localized with USvRNA within 8 hours of expression. In infected T cells (J-Lat 10.6) reactivated from latency and in a HeLa cell line stably expressing an inducible Rev-dependent HIV-1 construct, we found that Gag preferentially localized with euchromatin histone marks associated with enhancer and promoter regions near the nuclear periphery, which is the favored site HIV-1 integration. These observations support the innovative hypothesis that HIV-1 Gag associates with euchromatin-associated histones to localize to active transcription sites, promoting capture of newly synthesized gRNA for packaging.
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Affiliation(s)
- Jordan Chang
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Leslie J. Parent
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
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Tough Way In, Tough Way Out: The Complex Interplay of Host and Viral Factors in Nucleocytoplasmic Trafficking during HIV-1 Infection. Viruses 2022; 14:v14112503. [PMID: 36423112 PMCID: PMC9696704 DOI: 10.3390/v14112503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Human immunodeficiency virus-1 (HIV-1) is a retrovirus that integrates its reverse-transcribed genome as proviral DNA into the host genome to establish a successful infection. The viral genome integration requires safeguarding the subviral complexes, reverse transcription complex (RTC) and preintegration complex (PIC), in the cytosol from degradation, presumably effectively secured by the capsid surrounding these complexes. An intact capsid, however, is a large structure, which raises concerns about its translocation from cytoplasm to nucleus crossing the nuclear membrane, guarded by complex nuclear pore structures, which do not allow non-specific transport of large molecules. In addition, the generation of new virions requires the export of incompletely processed viral RNA from the nucleus to the cytoplasm, an event conventionally not permitted through mammalian nuclear membranes. HIV-1 has evolved multiple mechanisms involving redundant host pathways by liaison with the cell's nucleocytoplasmic trafficking system, failure of which would lead to the collapse of the infection cycle. This review aims to assemble the current developments in temporal and spatial events governing nucleocytoplasmic transport of HIV-1 factors. Discoveries are anticipated to serve as the foundation for devising host-directed therapies involving selective abolishment of the critical interactomes between viral proteins and their host equivalents.
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Lindqvist B, Jütte BB, Love L, Assi W, Roux J, Sönnerborg A, Tezil T, Verdin E, Svensson JP. T cell stimulation remodels the latently HIV-1 infected cell population by differential activation of proviral chromatin. PLoS Pathog 2022; 18:e1010555. [PMID: 35666761 PMCID: PMC9203004 DOI: 10.1371/journal.ppat.1010555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/16/2022] [Accepted: 04/26/2022] [Indexed: 01/22/2023] Open
Abstract
The reservoir of latently HIV-1 infected cells is heterogeneous. To achieve an HIV-1 cure, the reservoir of activatable proviruses must be eliminated while permanently silenced proviruses may be tolerated. We have developed a method to assess the proviral nuclear microenvironment in single cells. In latently HIV-1 infected cells, a zinc finger protein tethered to the HIV-1 promoter produced a fluorescent signal as a protein of interest came in its proximity, such as the viral transactivator Tat when recruited to the nascent RNA. Tat is essential for viral replication. In these cells we assessed the proviral activation and chromatin composition. By linking Tat recruitment to proviral activity, we dissected the mechanisms of HIV-1 latency reversal and the consequences of HIV-1 production. A pulse of promoter-associated Tat was identified that contrasted to the continuous production of viral proteins. As expected, promoter H3K4me3 led to substantial expression of the provirus following T cell stimulation. However, the activation-induced cell cycle arrest and death led to a surviving cell fraction with proviruses encapsulated in repressive chromatin. Further, this cellular model was used to reveal mechanisms of action of small molecules. In a proof-of-concept study we determined the effect of modifying enhancer chromatin on HIV-1 latency reversal. Only proviruses resembling active enhancers, associated with H3K4me1 and H3K27ac and subsequentially recognized by BRD4, efficiently recruited Tat upon cell stimulation. Tat-independent HIV-1 latency reversal of unknown significance still occurred. We present a method for single cell assessment of the microenvironment of the latent HIV-1 proviruses, used here to reveal how T cell stimulation modulates the proviral activity and how the subsequent fate of the infected cell depends on the chromatin context.
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Affiliation(s)
- Birgitta Lindqvist
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Bianca B. Jütte
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Luca Love
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Wlaa Assi
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- Laboratory of Viral Infectious Diseases, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Julie Roux
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Anders Sönnerborg
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden, Division of Infectious Diseases, Department of Medicine Huddinge, I73, Karolinska University Hospital, Stockholm, Sweden
| | - Tugsan Tezil
- Buck Institute for Research on Aging, Novato, California, United States of America
| | - Eric Verdin
- Buck Institute for Research on Aging, Novato, California, United States of America
| | - J. Peter Svensson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- * E-mail:
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