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Pandiloski N, Horváth V, Karlsson O, Koutounidou S, Dorazehi F, Christoforidou G, Matas-Fuentes J, Gerdes P, Garza R, Jönsson ME, Adami A, Atacho DAM, Johansson JG, Englund E, Kokaia Z, Jakobsson J, Douse CH. DNA methylation governs the sensitivity of repeats to restriction by the HUSH-MORC2 corepressor. Nat Commun 2024; 15:7534. [PMID: 39214989 PMCID: PMC11364546 DOI: 10.1038/s41467-024-50765-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 07/18/2024] [Indexed: 09/04/2024] Open
Abstract
The human silencing hub (HUSH) complex binds to transcripts of LINE-1 retrotransposons (L1s) and other genomic repeats, recruiting MORC2 and other effectors to remodel chromatin. How HUSH and MORC2 operate alongside DNA methylation, a central epigenetic regulator of repeat transcription, remains largely unknown. Here we interrogate this relationship in human neural progenitor cells (hNPCs), a somatic model of brain development that tolerates removal of DNA methyltransferase DNMT1. Upon loss of MORC2 or HUSH subunit TASOR in hNPCs, L1s remain silenced by robust promoter methylation. However, genome demethylation and activation of evolutionarily-young L1s attracts MORC2 binding, and simultaneous depletion of DNMT1 and MORC2 causes massive accumulation of L1 transcripts. We identify the same mechanistic hierarchy at pericentromeric α-satellites and clustered protocadherin genes, repetitive elements important for chromosome structure and neurodevelopment respectively. Our data delineate the epigenetic control of repeats in somatic cells, with implications for understanding the vital functions of HUSH-MORC2 in hypomethylated contexts throughout human development.
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Affiliation(s)
- Ninoslav Pandiloski
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Vivien Horváth
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Ofelia Karlsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Symela Koutounidou
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Fereshteh Dorazehi
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Georgia Christoforidou
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Jon Matas-Fuentes
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden
| | - Patricia Gerdes
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Raquel Garza
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | | | - Anita Adami
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Diahann A M Atacho
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Jenny G Johansson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
| | - Elisabet Englund
- Division of Pathology, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Zaal Kokaia
- Lund Stem Cell Center, Lund University, Lund, Sweden
- Laboratory of Stem Cells and Restorative Neurology, Department of Clinical Sciences, BMC B10, Lund University, Lund, Sweden
| | - Johan Jakobsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC A11, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Christopher H Douse
- Laboratory of Epigenetics and Chromatin Dynamics, Department of Experimental Medical Science, Wallenberg Neuroscience Center, BMC B11, Lund University, Lund, Sweden.
- Lund Stem Cell Center, Lund University, Lund, Sweden.
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Zhou M, Yang T, Yuan M, Li X, Deng J, Wu S, Zhong Z, Lin Y, Zhang W, Xia B, Wu Y, Wang L, Chen T, Liu R, Pan T, Ma X, Li L, Liu B, Zhang H. ORC1 enhances repressive epigenetic modifications on HIV-1 LTR to promote HIV-1 latency. J Virol 2024; 98:e0003524. [PMID: 39082875 PMCID: PMC11334468 DOI: 10.1128/jvi.00035-24] [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: 02/21/2024] [Accepted: 06/21/2024] [Indexed: 08/21/2024] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) reservoir consists of latently infected cells which present a major obstacle to achieving a functional cure for HIV-1. The formation and maintenance of HIV-1 latency have been extensively studied, and latency-reversing agents (LRAs) that can reactivate latent HIV-1 by targeting the involved host factors are developed; however, their clinical efficacies remain unsatisfactory. Therefore, it is imperative to identify novel targets for more potential candidates or better combinations for LRAs. In this study, we utilized CRISPR affinity purification in situ of regulatory elements system to screen for host factors associated with the HIV-1 long terminal repeat region that could potentially be involved in HIV-1 latency. We successfully identified that origin recognition complex 1 (ORC1), the largest subunit of the origin recognition complex, contributes to HIV-1 latency in addition to its function in DNA replication initiation. Notably, ORC1 is enriched on the HIV-1 promoter and recruits a series of repressive epigenetic elements, including DNMT1 and HDAC1/2, and histone modifiers, such as H3K9me3 and H3K27me3, thereby facilitating the establishment and maintenance of HIV-1 latency. Moreover, the reactivation of latent HIV-1 through ORC1 depletion has been confirmed across various latency cell models and primary CD4+ T cells from people living with HIV-1. Additionally, we comprehensively validated the properties of liquid-liquid phase separation (LLPS) of ORC1 from multiple perspectives and identified the key regions that promote the formation of LLPS. This property is important for the recruitment of ORC1 to the HIV-1 promoter. Collectively, these findings highlight ORC1 as a potential novel target implicated in HIV-1 latency and position it as a promising candidate for the development of novel LRAs. IMPORTANCE Identifying host factors involved in maintaining human immunodeficiency virus type 1 (HIV-1) latency and understanding their mechanisms prepares the groundwork to discover novel targets for HIV-1 latent infection and provides further options for the selection of latency-reversing agents in the "shock" strategy. In this study, we identified a novel role of the DNA replication factor origin recognition complex 1 (ORC1) in maintaining repressive chromatin structures surrounding the HIV-1 promoter region, thereby contributing to HIV-1 latency. This discovery expands our understanding of the non-replicative functions of the ORC complex and provides a potential therapeutic strategy for HIV-1 cure.
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Affiliation(s)
- Mo Zhou
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Center for Infectious Diseases, Guangzhou Eighth People’s Hospital, Guangzhou Medical University, Guangzhou, China
| | - Tao Yang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ming Yuan
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xinyu Li
- Shenzhen Key Laboratory of Systems Medicine for Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Jieyi Deng
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shiyu Wu
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhihan Zhong
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yingtong Lin
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wanying Zhang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Baijin Xia
- Medical Research Institute, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Science), Guangzhou, China
| | - Yating Wu
- Medical Research Institute, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Science), Guangzhou, China
| | - Lilin Wang
- Shenzhen Blood Center, Shenzhen, Guangdong, China
| | - Tao Chen
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, China
| | - Ruxin Liu
- Shenzhen Key Laboratory of Systems Medicine for Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Ting Pan
- Shenzhen Key Laboratory of Systems Medicine for Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Xiancai Ma
- Guangzhou National Laboratory, Guangzhou International Bio-Island, Guangzhou, China
| | - Linghua Li
- Center for Infectious Diseases, Guangzhou Eighth People’s Hospital, Guangzhou Medical University, Guangzhou, China
| | - Bingfeng Liu
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Hui Zhang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
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Rodríguez TC, Yurkovetskiy L, Nagalekshmi K, Lam CHO, Jazbec E, Maitland SA, Wolfe SA, Sontheimer EJ, Luban J. PRC1.6 localizes on chromatin with the human silencing hub (HUSH) complex for promoter-specific silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603173. [PMID: 39026796 PMCID: PMC11257501 DOI: 10.1101/2024.07.12.603173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
An obligate step in the life cycle of HIV-1 and other retroviruses is the establishment of the provirus in target cell chromosomes. Transcriptional regulation of proviruses is complex, and understanding the mechanisms underlying this regulation has ramifications for fundamental biology, human health, and gene therapy implementation. The three core components of the Human Silencing Hub (HUSH) complex, TASOR, MPHOSPH8 (MPP8), and PPHLN1 (Periphilin 1), were identified in forward genetic screens for host genes that repress provirus expression. Subsequent loss-of-function screens revealed accessory proteins that collaborate with the HUSH complex to silence proviruses in particular contexts. To identify proteins associated with a HUSH complex-repressed provirus in human cells, we developed a technique, Provirus Proximal Proteomics, based on proximity labeling with C-BERST (dCas9-APEX2 biotinylation at genomic elements by restricted spatial tagging). Our screen exploited a lentiviral reporter that is silenced by the HUSH complex in a manner that is independent of the integration site in chromatin. Our data reveal that proviruses silenced by the HUSH complex are associated with DNA repair, mRNA processing, and transcriptional silencing proteins, including L3MBTL2, a member of the non-canonical polycomb repressive complex 1.6 (PRC1.6). A forward genetic screen confirmed that PRC1.6 components L3MBTL2 and MGA contribute to HUSH complex-mediated silencing. PRC1.6 was then shown to silence HUSH-sensitive proviruses in a promoter-specific manner. Genome wide profiling showed striking colocalization of the PRC1.6 and HUSH complexes on chromatin, primarily at sites of active promoters. Finally, PRC1.6 binding at a subset of genes that are silenced by the HUSH complex was dependent on the core HUSH complex component MPP8. These studies offer new tools with great potential for studying the transcriptional regulation of proviruses and reveal crosstalk between the HUSH complex and PRC1.6.
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Affiliation(s)
- Tomás C. Rodríguez
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Leonid Yurkovetskiy
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Karthika Nagalekshmi
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Chin Hung Oscar Lam
- Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Eva Jazbec
- Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Stacy A. Maitland
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Scot A. Wolfe
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Erik J. Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Jeremy Luban
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
- Massachusetts Consortium on Pathogen Readiness, Boston, MA 02115, USA
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4
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Khanduja JS, Joh RI, Perez MM, Paulo JA, Palmieri CM, Zhang J, Gulka AOD, Haas W, Gygi SP, Motamedi M. RNA quality control factors nucleate Clr4/SUV39H and trigger constitutive heterochromatin assembly. Cell 2024; 187:3262-3283.e23. [PMID: 38815580 PMCID: PMC11227895 DOI: 10.1016/j.cell.2024.04.042] [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: 01/19/2023] [Revised: 11/10/2023] [Accepted: 04/29/2024] [Indexed: 06/01/2024]
Abstract
In eukaryotes, the Suv39 family of proteins tri-methylate lysine 9 of histone H3 (H3K9me) to form constitutive heterochromatin. However, how Suv39 proteins are nucleated at heterochromatin is not fully described. In the fission yeast, current models posit that Argonaute1-associated small RNAs (sRNAs) nucleate the sole H3K9 methyltransferase, Clr4/SUV39H, to centromeres. Here, we show that in the absence of all sRNAs and H3K9me, the Mtl1 and Red1 core (MTREC)/PAXT complex nucleates Clr4/SUV39H at a heterochromatic long noncoding RNA (lncRNA) at which the two H3K9 deacetylases, Sir2 and Clr3, also accumulate by distinct mechanisms. Iterative cycles of H3K9 deacetylation and methylation spread Clr4/SUV39H from the nucleation center in an sRNA-independent manner, generating a basal H3K9me state. This is acted upon by the RNAi machinery to augment and amplify the Clr4/H3K9me signal at centromeres to establish heterochromatin. Overall, our data reveal that lncRNAs and RNA quality control factors can nucleate heterochromatin and function as epigenetic silencers in eukaryotes.
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Affiliation(s)
- Jasbeer S Khanduja
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Richard I Joh
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Monica M Perez
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Christina M Palmieri
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jingyu Zhang
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Alex O D Gulka
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Willhelm Haas
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mo Motamedi
- Massachusetts General Hospital Krantz Family Center for Cancer Research and Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA.
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Kobayashi-Ishihara M, Tsunetsugu-Yokota Y. Post-Transcriptional HIV-1 Latency: A Promising Target for Therapy? Viruses 2024; 16:666. [PMID: 38793548 PMCID: PMC11125802 DOI: 10.3390/v16050666] [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: 04/04/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/26/2024] Open
Abstract
Human Immunodeficiency Virus type 1 (HIV-1) latency represents a significant hurdle in finding a cure for HIV-1 infections, despite tireless research efforts. This challenge is partly attributed to the intricate nature of HIV-1 latency, wherein various host and viral factors participate in multiple physiological processes. While substantial progress has been made in discovering therapeutic targets for HIV-1 transcription, targets for the post-transcriptional regulation of HIV-1 infections have received less attention. However, cumulative evidence now suggests the pivotal contribution of post-transcriptional regulation to the viral latency in both in vitro models and infected individuals. In this review, we explore recent insights on post-transcriptional latency in HIV-1 and discuss the potential of its therapeutic targets, illustrating some host factors that restrict HIV-1 at the post-transcriptional level.
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Affiliation(s)
- Mie Kobayashi-Ishihara
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
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6
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Rambout X, Maquat LE. Nuclear mRNA decay: regulatory networks that control gene expression. Nat Rev Genet 2024:10.1038/s41576-024-00712-2. [PMID: 38637632 DOI: 10.1038/s41576-024-00712-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2024] [Indexed: 04/20/2024]
Abstract
Proper regulation of mRNA production in the nucleus is critical for the maintenance of cellular homoeostasis during adaptation to internal and environmental cues. Over the past 25 years, it has become clear that the nuclear machineries governing gene transcription, pre-mRNA processing, pre-mRNA and mRNA decay, and mRNA export to the cytoplasm are inextricably linked to control the quality and quantity of mRNAs available for translation. More recently, an ever-expanding diversity of new mechanisms by which nuclear RNA decay factors finely tune the expression of protein-encoding genes have been uncovered. Here, we review the current understanding of how mammalian cells shape their protein-encoding potential by regulating the decay of pre-mRNAs and mRNAs in the nucleus.
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Affiliation(s)
- Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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Izquierdo-Pujol J, Puertas MC, Martinez-Picado J, Morón-López S. Targeting Viral Transcription for HIV Cure Strategies. Microorganisms 2024; 12:752. [PMID: 38674696 PMCID: PMC11052381 DOI: 10.3390/microorganisms12040752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
Combination antiretroviral therapy (ART) suppresses viral replication to undetectable levels, reduces mortality and morbidity, and improves the quality of life of people living with HIV (PWH). However, ART cannot cure HIV infection because it is unable to eliminate latently infected cells. HIV latency may be regulated by different HIV transcription mechanisms, such as blocks to initiation, elongation, and post-transcriptional processes. Several latency-reversing (LRA) and -promoting agents (LPA) have been investigated in clinical trials aiming to eliminate or reduce the HIV reservoir. However, none of these trials has shown a conclusive impact on the HIV reservoir. Here, we review the cellular and viral factors that regulate HIV-1 transcription, the potential pharmacological targets and genetic and epigenetic editing techniques that have been or might be evaluated to disrupt HIV-1 latency, the role of miRNA in post-transcriptional regulation of HIV-1, and the differences between the mechanisms regulating HIV-1 and HIV-2 expression.
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Affiliation(s)
- Jon Izquierdo-Pujol
- IrsiCaixa, 08916 Badalona, Spain; (J.I.-P.); (M.C.P.); (J.M.-P.)
- Germans Trias i Pujol Research Institute (IGTP), 08916 Badalona, Spain
| | - Maria C. Puertas
- IrsiCaixa, 08916 Badalona, Spain; (J.I.-P.); (M.C.P.); (J.M.-P.)
- Germans Trias i Pujol Research Institute (IGTP), 08916 Badalona, Spain
- CIBERINFEC, 28029 Madrid, Spain
| | - Javier Martinez-Picado
- IrsiCaixa, 08916 Badalona, Spain; (J.I.-P.); (M.C.P.); (J.M.-P.)
- Germans Trias i Pujol Research Institute (IGTP), 08916 Badalona, Spain
- CIBERINFEC, 28029 Madrid, Spain
- Department of Infectious Diseases and Immunity, School of Medicine, University of Vic-Central University of Catalonia (UVic-UCC), 08500 Vic, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
| | - Sara Morón-López
- IrsiCaixa, 08916 Badalona, Spain; (J.I.-P.); (M.C.P.); (J.M.-P.)
- Germans Trias i Pujol Research Institute (IGTP), 08916 Badalona, Spain
- CIBERINFEC, 28029 Madrid, Spain
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Rausch JW, Parvez S, Pathak S, Capoferri AA, Kearney MF. HIV Expression in Infected T Cell Clones. Viruses 2024; 16:108. [PMID: 38257808 PMCID: PMC10820123 DOI: 10.3390/v16010108] [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: 12/13/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/24/2024] Open
Abstract
The principal barrier to an HIV-1 cure is the persistence of infected cells harboring replication-competent proviruses despite antiretroviral therapy (ART). HIV-1 transcriptional suppression, referred to as viral latency, is foremost among persistence determinants, as it allows infected cells to evade the cytopathic effects of virion production and killing by cytotoxic T lymphocytes (CTL) and other immune factors. HIV-1 persistence is also governed by cellular proliferation, an innate and essential capacity of CD4+ T cells that both sustains cell populations over time and enables a robust directed response to immunological threats. However, when HIV-1 infects CD4+ T cells, this capacity for proliferation can enable surreptitious HIV-1 propagation without the deleterious effects of viral gene expression in latently infected cells. Over time on ART, the HIV-1 reservoir is shaped by both persistence determinants, with selective forces most often favoring clonally expanded infected cell populations harboring transcriptionally quiescent proviruses. Moreover, if HIV latency is incomplete or sporadically reversed in clonal infected cell populations that are replenished faster than they are depleted, such populations could both persist indefinitely and contribute to low-level persistent viremia during ART and viremic rebound if treatment is withdrawn. In this review, select genetic, epigenetic, cellular, and immunological determinants of viral transcriptional suppression and clonal expansion of HIV-1 reservoir T cells, interdependencies among these determinants, and implications for HIV-1 persistence will be presented and discussed.
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Affiliation(s)
- Jason W. Rausch
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; (S.P.); (S.P.); (A.A.C.); (M.F.K.)
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Müller I, Helin K. Keep quiet: the HUSH complex in transcriptional silencing and disease. Nat Struct Mol Biol 2024; 31:11-22. [PMID: 38216658 DOI: 10.1038/s41594-023-01173-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/23/2023] [Indexed: 01/14/2024]
Abstract
The human silencing hub (HUSH) complex is an epigenetic repressor complex whose role has emerged as an important guardian of genome integrity. It protects the genome from exogenous DNA invasion and regulates endogenous retroelements by recruiting histone methyltransferases catalyzing histone 3 lysine 9 trimethylation (H3K9me3) and additional proteins involved in chromatin compaction. In particular, its regulation of transcriptionally active LINE1 retroelements, by binding to and neutralizing LINE1 transcripts, has been well characterized. HUSH is required for mouse embryogenesis and is associated with disease, in particular cancer. Here we provide insights into the structural and biochemical features of the HUSH complex. Furthermore, we discuss the molecular mechanisms by which the HUSH complex is recruited to specific genomic regions and how it silences transcription. Finally, we discuss the role of HUSH complex members in mammalian development, antiretroviral immunity, and diseases such as cancer.
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Affiliation(s)
- Iris Müller
- Cell Biology Program and Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kristian Helin
- Cell Biology Program and Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- The Institute of Cancer Research, London, UK.
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10
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Jackson-Jones KA, McKnight Á, Sloan RD. The innate immune factor RPRD2/REAF and its role in the Lv2 restriction of HIV. mBio 2023; 14:e0257221. [PMID: 37882563 PMCID: PMC10746242 DOI: 10.1128/mbio.02572-21] [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: 10/27/2023] Open
Abstract
Intracellular innate immunity involves co-evolved antiviral restriction factors that specifically inhibit infecting viruses. Studying these restrictions has increased our understanding of viral replication, host-pathogen interactions, and pathogenesis, and represent potential targets for novel antiviral therapies. Lentiviral restriction 2 (Lv2) was identified as an unmapped early-phase restriction of HIV-2 and later shown to also restrict HIV-1 and simian immunodeficiency virus. The viral determinants of Lv2 susceptibility have been mapped to the envelope and capsid proteins in both HIV-1 and HIV-2, and also viral protein R (Vpr) in HIV-1, and appears dependent on cellular entry mechanism. A genome-wide screen identified several likely contributing host factors including members of the polymerase-associated factor 1 (PAF1) and human silencing hub (HUSH) complexes, and the newly characterized regulation of nuclear pre-mRNA domain containing 2 (RPRD2). Subsequently, RPRD2 (or RNA-associated early-stage antiviral factor) has been shown to be upregulated upon T cell activation, is highly expressed in myeloid cells, binds viral reverse transcripts, and potently restricts HIV-1 infection. RPRD2 is also bound by HIV-1 Vpr and targeted for degradation by the proteasome upon reverse transcription, suggesting RPRD2 impedes reverse transcription and Vpr targeting overcomes this block. RPRD2 is mainly localized to the nucleus and binds RNA, DNA, and DNA:RNA hybrids. More recently, RPRD2 has been shown to negatively regulate genome-wide transcription and interact with the HUSH and PAF1 complexes which repress HIV transcription and are implicated in maintenance of HIV latency. In this review, we examine Lv2 restriction and the antiviral role of RPRD2 and consider potential mechanism(s) of action.
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Affiliation(s)
- Kathryn A. Jackson-Jones
- Centre for Inflammation Research, Institute of Regeneration and Repair, The University of Edinburgh, Edinburgh, United Kingdom
- Division of Infectious Diseases & Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Áine McKnight
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Richard D. Sloan
- Centre for Inflammation Research, Institute of Regeneration and Repair, The University of Edinburgh, Edinburgh, United Kingdom
- ZJU-UoE Institute, Zhejiang University, Haining, China
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11
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Martin B, Suter DM. Gene expression flux analysis reveals specific regulatory modalities of gene expression. iScience 2023; 26:107758. [PMID: 37701574 PMCID: PMC10493597 DOI: 10.1016/j.isci.2023.107758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 06/02/2023] [Accepted: 08/24/2023] [Indexed: 09/14/2023] Open
Abstract
The level of a given protein is determined by the synthesis and degradation rates of its mRNA and protein. While several studies have quantified the contribution of different gene expression steps in regulating protein levels, these are limited by using equilibrium approximations in out-of-equilibrium biological systems. Here, we introduce gene expression flux analysis to quantitatively dissect the dynamics of the expression level for specific proteins and use it to analyze published transcriptomics and proteomics datasets. Our analysis reveals distinct regulatory modalities shared by sets of genes with clear functional signatures. We also find that protein degradation plays a stronger role than expected in the adaptation of protein levels. These findings suggest that shared regulatory strategies can lead to versatile responses at the protein level and highlight the importance of going beyond equilibrium approximations to dissect the quantitative contribution of different steps of gene expression to protein dynamics.
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Affiliation(s)
- Benjamin Martin
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - David M. Suter
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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12
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Challal D, Menant A, Goksal C, Leroy E, Al-Sady B, Rougemaille M. A dual, catalytic role for the fission yeast Ccr4-Not complex in gene silencing and heterochromatin spreading. Genetics 2023; 224:iyad108. [PMID: 37279920 PMCID: PMC10411572 DOI: 10.1093/genetics/iyad108] [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: 04/11/2023] [Revised: 04/11/2023] [Accepted: 05/31/2023] [Indexed: 06/08/2023] Open
Abstract
Heterochromatic gene silencing relies on combinatorial control by specific histone modifications, the occurrence of transcription, and/or RNA degradation. Once nucleated, heterochromatin propagates within defined chromosomal regions and is maintained throughout cell divisions to warrant proper genome expression and integrity. In the fission yeast Schizosaccharomyces pombe, the Ccr4-Not complex partakes in gene silencing, but its relative contribution to distinct heterochromatin domains and its role in nucleation versus spreading have remained elusive. Here, we unveil major functions for Ccr4-Not in silencing and heterochromatin spreading at the mating type locus and subtelomeres. Mutations of the catalytic subunits Caf1 or Mot2, involved in RNA deadenylation and protein ubiquitinylation, respectively, result in impaired propagation of H3K9me3 and massive accumulation of nucleation-distal heterochromatic transcripts. Both silencing and spreading defects are suppressed upon disruption of the heterochromatin antagonizing factor Epe1. Overall, our results position the Ccr4-Not complex as a critical, dual regulator of heterochromatic gene silencing and spreading.
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Affiliation(s)
- Drice Challal
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Alexandra Menant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Can Goksal
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, CA 94143, USA
| | - Estelle Leroy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Bassem Al-Sady
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, CA 94143, USA
| | - Mathieu Rougemaille
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
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13
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Visvabharathy L, Hanson BA, Orban ZS, Lim PH, Palacio NM, Jimenez M, Clark JR, Graham EL, Liotta EM, Tachas G, Penaloza-MacMaster P, Koralnik IJ. Neuro-PASC is characterized by enhanced CD4+ and diminished CD8+ T cell responses to SARS-CoV-2 Nucleocapsid protein. Front Immunol 2023; 14:1155770. [PMID: 37313412 PMCID: PMC10258318 DOI: 10.3389/fimmu.2023.1155770] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/11/2023] [Indexed: 06/15/2023] Open
Abstract
Introduction Many people with long COVID symptoms suffer from debilitating neurologic post-acute sequelae of SARS-CoV-2 infection (Neuro-PASC). Although symptoms of Neuro-PASC are widely documented, it is still unclear whether PASC symptoms impact virus-specific immune responses. Therefore, we examined T cell and antibody responses to SARS-CoV-2 Nucleocapsid protein to identify activation signatures distinguishing Neuro-PASC patients from healthy COVID convalescents. Results We report that Neuro-PASC patients exhibit distinct immunological signatures composed of elevated CD4+ T cell responses and diminished CD8+ memory T cell activation toward the C-terminal region of SARS-CoV-2 Nucleocapsid protein when examined both functionally and using TCR sequencing. CD8+ T cell production of IL-6 correlated with increased plasma IL-6 levels as well as heightened severity of neurologic symptoms, including pain. Elevated plasma immunoregulatory and reduced pro-inflammatory and antiviral response signatures were evident in Neuro-PASC patients compared with COVID convalescent controls without lasting symptoms, correlating with worse neurocognitive dysfunction. Discussion We conclude that these data provide new insight into the impact of virus-specific cellular immunity on the pathogenesis of long COVID and pave the way for the rational design of predictive biomarkers and therapeutic interventions.
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Affiliation(s)
- Lavanya Visvabharathy
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Barbara A. Hanson
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Zachary S. Orban
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Patrick H. Lim
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Nicole M. Palacio
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Millenia Jimenez
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jeffrey R. Clark
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Edith L. Graham
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Eric M. Liotta
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - George Tachas
- Drug Discovery & Patents, Antisense Therapeutics Ltd., Melbourne, VIC, Australia
| | - Pablo Penaloza-MacMaster
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Igor J. Koralnik
- Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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14
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Spencley AL, Bar S, Swigut T, Flynn RA, Lee CH, Chen LF, Bassik MC, Wysocka J. Co-transcriptional genome surveillance by HUSH is coupled to termination machinery. Mol Cell 2023; 83:1623-1639.e8. [PMID: 37164018 PMCID: PMC10915761 DOI: 10.1016/j.molcel.2023.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 01/12/2023] [Accepted: 04/12/2023] [Indexed: 05/12/2023]
Abstract
The HUSH complex recognizes and silences foreign DNA such as viruses, transposons, and transgenes without prior exposure to its targets. Here, we show that endogenous targets of the HUSH complex fall into two distinct classes based on the presence or absence of H3K9me3. These classes are further distinguished by their transposon content and differential response to the loss of HUSH. A de novo genomic rearrangement at the Sox2 locus induces a switch from H3K9me3-independent to H3K9me3-associated HUSH targeting, resulting in silencing. We further demonstrate that HUSH interacts with the termination factor WDR82 and-via its component MPP8-with nascent RNA. HUSH accumulates at sites of high RNAPII occupancy including long exons and transcription termination sites in a manner dependent on WDR82 and CPSF. Together, our results uncover the functional diversity of HUSH targets and show that this vertebrate-specific complex exploits evolutionarily ancient transcription termination machinery for co-transcriptional chromatin targeting and genome surveillance.
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Affiliation(s)
- Andrew L Spencley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Cancer Biology Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Shiran Bar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ryan A Flynn
- Stem Cell Program, Boston Children's Hospital, Boston, MA, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Cameron H Lee
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Liang-Fu Chen
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael C Bassik
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.
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15
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Seczynska M, Lehner PJ. The sound of silence: mechanisms and implications of HUSH complex function. Trends Genet 2023; 39:251-267. [PMID: 36754727 DOI: 10.1016/j.tig.2022.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/14/2022] [Accepted: 12/30/2022] [Indexed: 02/08/2023]
Abstract
The vertebrate genome is under constant threat of invasion by genetic parasites. Whether the host can immediately recognize and respond to invading elements has been unclear. The discovery of the human silencing hub (HUSH) complex, and the finding that it provides immediate protection from genome invasion by silencing products of reverse transcription, have important implications for mammalian genome evolution. In this review, we summarize recent insights into HUSH function and describe how cellular introns provide a novel means of self-nonself discrimination, allowing HUSH to recognize and transcriptionally repress a broad range of intronless genetic elements. We discuss how HUSH contributes to genome evolution, and highlight studies reporting the critical role of HUSH in development and implicating HUSH in the control of immune signaling and cancer progression.
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Affiliation(s)
- Marta Seczynska
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK.
| | - Paul J Lehner
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK.
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16
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Appel LM, Benedum J, Engl M, Platzer S, Schleiffer A, Strobl X, Slade D. SPOC domain proteins in health and disease. Genes Dev 2023; 37:140-170. [PMID: 36927757 PMCID: PMC10111866 DOI: 10.1101/gad.350314.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Since it was first described >20 yr ago, the SPOC domain (Spen paralog and ortholog C-terminal domain) has been identified in many proteins all across eukaryotic species. SPOC-containing proteins regulate gene expression on various levels ranging from transcription to RNA processing, modification, export, and stability, as well as X-chromosome inactivation. Their manifold roles in controlling transcriptional output implicate them in a plethora of developmental processes, and their misregulation is often associated with cancer. Here, we provide an overview of the biophysical properties of the SPOC domain and its interaction with phosphorylated binding partners, the phylogenetic origin of SPOC domain proteins, the diverse functions of mammalian SPOC proteins and their homologs, the mechanisms by which they regulate differentiation and development, and their roles in cancer.
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Affiliation(s)
- Lisa-Marie Appel
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
| | - Johannes Benedum
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Magdalena Engl
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Sebastian Platzer
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), 1030 Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Xué Strobl
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Dea Slade
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria;
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
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17
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Stamidis N, Żylicz JJ. RNA-mediated heterochromatin formation at repetitive elements in mammals. EMBO J 2023; 42:e111717. [PMID: 36847618 PMCID: PMC10106986 DOI: 10.15252/embj.2022111717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/12/2022] [Accepted: 02/07/2023] [Indexed: 03/01/2023] Open
Abstract
The failure to repress transcription of repetitive genomic elements can lead to catastrophic genome instability and is associated with various human diseases. As such, multiple parallel mechanisms cooperate to ensure repression and heterochromatinization of these elements, especially during germline development and early embryogenesis. A vital question in the field is how specificity in establishing heterochromatin at repetitive elements is achieved. Apart from trans-acting protein factors, recent evidence points to a role of different RNA species in targeting repressive histone marks and DNA methylation to these sites in mammals. Here, we review recent discoveries on this topic and predominantly focus on the role of RNA methylation, piRNAs, and other localized satellite RNAs.
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Affiliation(s)
- Nikolaos Stamidis
- Novo Nordisk Foundation Center for Stem Cell Medicine, reNEW, University of Copenhagen, Copenhagen, Denmark
| | - Jan Jakub Żylicz
- Novo Nordisk Foundation Center for Stem Cell Medicine, reNEW, University of Copenhagen, Copenhagen, Denmark
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18
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Warkocki Z. An update on post-transcriptional regulation of retrotransposons. FEBS Lett 2023; 597:380-406. [PMID: 36460901 DOI: 10.1002/1873-3468.14551] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Abstract
Retrotransposons, including LINE-1, Alu, SVA, and endogenous retroviruses, are one of the major constituents of human genomic repetitive sequences. Through the process of retrotransposition, some of them occasionally insert into new genomic locations by a copy-paste mechanism involving RNA intermediates. Irrespective of de novo genomic insertions, retrotransposon expression can lead to DNA double-strand breaks and stimulate cellular innate immunity through endogenous patterns. As a result, retrotransposons are tightly regulated by multi-layered regulatory processes to prevent the dangerous effects of their expression. In recent years, significant progress was made in revealing how retrotransposon biology intertwines with general post-transcriptional RNA metabolism. Here, I summarize current knowledge on the involvement of post-transcriptional factors in the biology of retrotransposons, focusing on LINE-1. I emphasize general RNA metabolisms such as methylation of adenine (m6 A), RNA 3'-end polyadenylation and uridylation, RNA decay and translation regulation. I discuss the effects of retrotransposon RNP sequestration in cytoplasmic bodies and autophagy. Finally, I summarize how innate immunity restricts retrotransposons and how retrotransposons make use of cellular enzymes, including the DNA repair machinery, to complete their replication cycles.
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Affiliation(s)
- Zbigniew Warkocki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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19
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Lian X, Seiger KW, Parsons EM, Gao C, Sun W, Gladkov GT, Roseto IC, Einkauf KB, Osborn MR, Chevalier JM, Jiang C, Blackmer J, Carrington M, Rosenberg ES, Lederman MM, McMahon DK, Bosch RJ, Jacobson JM, Gandhi RT, Peluso MJ, Chun TW, Deeks SG, Yu XG, Lichterfeld M. Progressive transformation of the HIV-1 reservoir cell profile over two decades of antiviral therapy. Cell Host Microbe 2023; 31:83-96.e5. [PMID: 36596305 PMCID: PMC9839361 DOI: 10.1016/j.chom.2022.12.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/08/2022] [Accepted: 11/30/2022] [Indexed: 01/03/2023]
Abstract
HIV-1 establishes a life-long reservoir of virally infected cells which cannot be eliminated by antiretroviral therapy (ART). Here, we demonstrate a markedly altered viral reservoir profile of long-term ART-treated individuals, characterized by large clones of intact proviruses preferentially integrated in heterochromatin locations, most prominently in centromeric satellite/micro-satellite DNA. Longitudinal evaluations suggested that this specific reservoir configuration results from selection processes that promote the persistence of intact proviruses in repressive chromatin positions, while proviruses in permissive chromosomal locations are more likely to be eliminated. A bias toward chromosomal integration sites in heterochromatin locations was also observed for intact proviruses in study participants who maintained viral control after discontinuation of antiretroviral therapy. Together, these results raise the possibility that antiviral selection mechanisms during long-term ART may induce an HIV-1 reservoir structure with features of deep latency and, possibly, more limited abilities to drive rebound viremia upon treatment interruptions.
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Affiliation(s)
- Xiaodong Lian
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Kyra W Seiger
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Elizabeth M Parsons
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Ce Gao
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Weiwei Sun
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Gregory T Gladkov
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | | | - Kevin B Einkauf
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Matthew R Osborn
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Joshua M Chevalier
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Chenyang Jiang
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Jane Blackmer
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Mary Carrington
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA; Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA; Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Eric S Rosenberg
- Infectious Disease Division, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | | | - Ronald J Bosch
- Center for Biostatistics in AIDS Research, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | | | - Rajesh T Gandhi
- Infectious Disease Division, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Michael J Peluso
- Division of HIV, Infectious Diseases and Global Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Tae-Wook Chun
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Steven G Deeks
- Division of HIV, Infectious Diseases and Global Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Xu G Yu
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Mathias Lichterfeld
- Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA.
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20
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Roles of RNA-binding proteins in neurological disorders, COVID-19, and cancer. Hum Cell 2023; 36:493-514. [PMID: 36528839 PMCID: PMC9760055 DOI: 10.1007/s13577-022-00843-w] [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: 08/30/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022]
Abstract
RNA-binding proteins (RBPs) have emerged as important players in multiple biological processes including transcription regulation, splicing, R-loop homeostasis, DNA rearrangement, miRNA function, biogenesis, and ribosome biogenesis. A large number of RBPs had already been identified by different approaches in various organisms and exhibited regulatory functions on RNAs' fate. RBPs can either directly or indirectly interact with their target RNAs or mRNAs to assume a key biological function whose outcome may trigger disease or normal biological events. They also exert distinct functions related to their canonical and non-canonical forms. This review summarizes the current understanding of a wide range of RBPs' functions and highlights their emerging roles in the regulation of diverse pathways, different physiological processes, and their molecular links with diseases. Various types of diseases, encompassing colorectal carcinoma, non-small cell lung carcinoma, amyotrophic lateral sclerosis, and Severe acute respiratory syndrome coronavirus 2, aberrantly express RBPs. We also highlight some recent advances in the field that could prompt the development of RBPs-based therapeutic interventions.
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21
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Furtado Milão J, Love L, Gourgi G, Derhaschnig L, Svensson JP, Sönnerborg A, van Domselaar R. Natural killer cells induce HIV-1 latency reversal after treatment with pan-caspase inhibitors. Front Immunol 2022; 13:1067767. [PMID: 36561752 PMCID: PMC9763267 DOI: 10.3389/fimmu.2022.1067767] [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: 10/12/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022] Open
Abstract
The establishment of a latency reservoir is the major obstacle for a cure of HIV-1. The shock-and-kill strategy aims to reactivate HIV-1 replication in HIV -1 latently infected cells, exposing the HIV-1-infected cells to cytotoxic lymphocytes. However, none of the latency reversal agents (LRAs) tested so far have shown the desired effect in people living with HIV-1. We observed that NK cells stimulated with a pan-caspase inhibitor induced latency reversal in co-cultures with HIV-1 latently infected cells. Synergy in HIV-1 reactivation was observed with LRAs prostratin and JQ1. The supernatants of the pan-caspase inhibitor-treated NK cells activated the HIV-1 LTR promoter, indicating that a secreted factor by NK cells was responsible for the HIV-1 reactivation. Assessing changes in the secreted cytokine profile of pan-caspase inhibitor-treated NK cells revealed increased levels of the HIV-1 suppressor chemokines MIP1α (CCL3), MIP1β (CCL4) and RANTES (CCL5). However, these cytokines individually or together did not induce LTR promoter activation, suggesting that CCL3-5 were not responsible for the observed HIV-1 reactivation. The cytokine profile did indicate that pan-caspase inhibitors induce NK cell activation. Altogether, our approach might be-in combination with other shock-and-kill strategies or LRAs-a strategy for reducing viral latency reservoirs and a step forward towards eradication of functionally active HIV-1 in infected individuals.
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Affiliation(s)
- Joana Furtado Milão
- Division of Infectious Diseases, ANA Futura Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Luca Love
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - George Gourgi
- Division of Infectious Diseases, ANA Futura Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Lukas Derhaschnig
- Division of Infectious Diseases, ANA Futura Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - J. Peter Svensson
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Anders Sönnerborg
- Division of Infectious Diseases, ANA Futura Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden,Division of Clinical Microbiology, ANA Futura Laboratory, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Robert van Domselaar
- Division of Infectious Diseases, ANA Futura Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden,*Correspondence: Robert van Domselaar,
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Vauthier V, Lasserre A, Morel M, Versapuech M, Berlioz-Torrent C, Zamborlini A, Margottin-Goguet F, Matkovic R. HUSH-mediated HIV silencing is independent of TASOR phosphorylation on threonine 819. Retrovirology 2022; 19:23. [PMID: 36309692 PMCID: PMC9618200 DOI: 10.1186/s12977-022-00610-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 10/16/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND TASOR, a component of the HUSH repressor epigenetic complex, and SAMHD1, a cellular triphosphohydrolase (dNTPase), are both anti-HIV proteins antagonized by HIV-2/SIVsmm Viral protein X. As a result, the same viral protein is able to relieve two different blocks along the viral life cell cycle, one at the level of reverse transcription, by degrading SAMHD1, the other one at the level of proviral expression, by degrading TASOR. Phosphorylation of SAMHD1 at T592 has been shown to downregulate its antiviral activity. The discovery that T819 in TASOR was lying within a SAMHD1 T592-like motif led us to ask whether TASOR is phosphorylated on this residue and whether this post-translational modification could regulate its repressive activity. RESULTS Using a specific anti-phospho-antibody, we found that TASOR is phosphorylated at T819, especially in cells arrested in early mitosis by nocodazole. We provide evidence that the phosphorylation is conducted by a Cyclin/CDK1 complex, like that of SAMHD1 at T592. While we could not detect TASOR in quiescent CD4 + T cells, TASOR and its phosphorylated form are present in activated primary CD4 + T lymphocytes. In addition, TASOR phosphorylation appears to be independent from TASOR repressive activity. Indeed, on the one hand, nocodazole barely reactivates HIV-1 in the J-Lat A1 HIV-1 latency model despite TASOR T819 phosphorylation. On the other hand, etoposide, a second cell cycle arresting drug, reactivates latent HIV-1, without concomitant TASOR phosphorylation. Furthermore, overexpression of wt TASOR or T819A or T819E similarly represses gene expression driven by an HIV-1-derived LTR promoter. Finally, while TASOR is degraded by HIV-2 Vpx, TASOR phosphorylation is prevented by HIV-1 Vpr, likely as a consequence of HIV-1 Vpr-mediated-G2 arrest. CONCLUSIONS Altogether, we show that TASOR phosphorylation occurs in vivo on T819. This event does not appear to correlate with TASOR-mediated HIV-1 silencing. We speculate that TASOR phosphorylation is related to a role of TASOR during cell cycle progression.
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Affiliation(s)
- Virginie Vauthier
- Université Paris Cité, CNRS, INSERM, Institut Cochin, 22 Rue Méchain, 75014, Paris, France
| | - Angélique Lasserre
- Université Paris Cité, CNRS, INSERM, Institut Cochin, 22 Rue Méchain, 75014, Paris, France
| | - Marina Morel
- Université Paris Cité, CNRS, INSERM, Institut Cochin, 22 Rue Méchain, 75014, Paris, France
| | - Margaux Versapuech
- Université Paris Cité, CNRS, INSERM, Institut Cochin, 22 Rue Méchain, 75014, Paris, France
| | | | - Alessia Zamborlini
- Center for Immunology of Viral, Auto-Immune, Hematological and Bacterial Diseases, Université Paris-Saclay, Inserm, CEA, IMVA-HB/IDMIT), Fontenay-Aux-Roses, France
| | | | - Roy Matkovic
- Université Paris Cité, CNRS, INSERM, Institut Cochin, 22 Rue Méchain, 75014, Paris, France.
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The KT Jeang Retrovirology prize 2022: Florence Margottin-Goguet. Retrovirology 2022; 19:20. [PMID: 36068604 PMCID: PMC9446835 DOI: 10.1186/s12977-022-00606-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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24
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Lichterfeld M, Gao C, Yu XG. An ordeal that does not heal: understanding barriers to a cure for HIV-1 infection. Trends Immunol 2022; 43:608-616. [PMID: 35905706 PMCID: PMC9346997 DOI: 10.1016/j.it.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 12/23/2022]
Abstract
With more than 38 million people living with HIV-1 (PLWH) worldwide, developing a cure for HIV-1 remains a major global health priority. Lifelong persistence of HIV-1 is frequently attributed to a pool of stable, transcriptionally silent HIV-1 proviruses, which are unaffected by currently available antiretroviral therapy (ART) or host immune activity. In this opinion article, we propose a more dynamic interpretation of HIV-1 reservoir cell biology and argue that HIV-1 proviruses frequently display residual viral transcriptional activity, making them vulnerable to longitudinal immune-mediated selection processes. Such mechanisms may, over extended periods of ART, induce an attenuated viral reservoir profile characterized by intact proviruses preferentially integrated into heterochromatin locations. We suggest that intensifying and accelerating naturally occurring selection mechanisms might represent a promising strategy for finding a potential cure for HIV-1 infection.
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Affiliation(s)
- Mathias Lichterfeld
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA; Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA.
| | - Ce Gao
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA; Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Xu G Yu
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA; Infectious Disease Division, Brigham and Women's Hospital, Boston, MA 02115, USA.
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