1
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Hays M. Genetic conflicts in budding yeast: The 2μ plasmid as a model selfish element. Semin Cell Dev Biol 2024; 161-162:31-41. [PMID: 38598944 DOI: 10.1016/j.semcdb.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/12/2024]
Abstract
Antagonistic coevolution, arising from genetic conflict, can drive rapid evolution and biological innovation. Conflict can arise both between organisms and within genomes. This review focuses on budding yeasts as a model system for exploring intra- and inter-genomic genetic conflict, highlighting in particular the 2-micron (2μ) plasmid as a model selfish element. The 2μ is found widely in laboratory strains and industrial isolates of Saccharomyces cerevisiae and has long been known to cause host fitness defects. Nevertheless, the plasmid is frequently ignored in the context of genetic, fitness, and evolution studies. Here, I make a case for further exploring the evolutionary impact of the 2μ plasmid as well as other selfish elements of budding yeasts, discuss recent advances, and, finally, future directions for the field.
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Affiliation(s)
- Michelle Hays
- Department of Genetics, Stanford University, Stanford, CA, United States.
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2
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Sinha P, Thio CL, Balagopal A. Intracellular Host Restriction of Hepatitis B Virus Replication. Viruses 2024; 16:764. [PMID: 38793645 PMCID: PMC11125714 DOI: 10.3390/v16050764] [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: 04/12/2024] [Revised: 05/06/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
The hepatitis B virus (HBV) infects hepatocytes and hijacks host cellular mechanisms for its replication. Host proteins can be frontline effectors of the cell's defense and restrict viral replication by impeding multiple steps during its intracellular lifecycle. This review summarizes many of the well-described restriction factors, their mechanisms of restriction, and counteractive measures of HBV, with a special focus on viral transcription. We discuss some of the limitations and knowledge gaps about the restriction factors, highlighting how these factors may be harnessed to facilitate therapeutic strategies against HBV.
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Affiliation(s)
| | | | - Ashwin Balagopal
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.S.); (C.L.T.)
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3
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Kilroy JM, Leal AA, Henderson AJ. Chronic HIV Transcription, Translation, and Persistent Inflammation. Viruses 2024; 16:751. [PMID: 38793632 PMCID: PMC11125830 DOI: 10.3390/v16050751] [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: 04/16/2024] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
People with HIV exhibit persistent inflammation that correlates with HIV-associated comorbidities including accelerated aging, increased risk of cardiovascular disease, and neuroinflammation. Mechanisms that perpetuate chronic inflammation in people with HIV undergoing antiretroviral treatments are poorly understood. One hypothesis is that the persistent low-level expression of HIV proviruses, including RNAs generated from defective proviral genomes, drives the immune dysfunction that is responsible for chronic HIV pathogenesis. We explore factors during HIV infection that contribute to the generation of a pool of defective proviruses as well as how HIV-1 mRNA and proteins alter immune function in people living with HIV.
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Affiliation(s)
- Jonathan M. Kilroy
- Department of Virology, Immunology, Microbiology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA; (J.M.K.); (A.A.L.)
| | - Andrew A. Leal
- Department of Virology, Immunology, Microbiology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA; (J.M.K.); (A.A.L.)
| | - Andrew J. Henderson
- Department of Virology, Immunology, Microbiology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA; (J.M.K.); (A.A.L.)
- Department of Medicine and Virology, Immunology, Microbiology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA
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4
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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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5
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Ananth S, Ambiel I, Schifferdecker S, Müller TG, Wratil PR, Mejias-Perez E, Kräusslich HG, Müller B, Keppler OT, Fackler OT. Spatial resolution of HIV-1 post-entry steps in resting CD4 T cells. Cell Rep 2024; 43:113941. [PMID: 38478523 DOI: 10.1016/j.celrep.2024.113941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/20/2023] [Accepted: 02/26/2024] [Indexed: 04/02/2024] Open
Abstract
Resting CD4 T cells resist productive HIV-1 infection. The HIV-2/simian immunodeficiency virus protein viral accessory protein X (Vpx) renders these cells permissive to infection, presumably by alleviating blocks at cytoplasmic reverse transcription and subsequent nuclear import of reverse-transcription/pre-integration complexes (RTC/PICs). Here, spatial analyses using quantitative virus imaging techniques reveal that HIV-1 capsids containing RTC/PICs are readily imported into the nucleus, recruit the host dependency factor CPSF6, and translocate to nuclear speckles in resting CD4 T cells. Reverse transcription, however, remains incomplete, impeding proviral integration and viral gene expression. Vpx or pharmacological inhibition of the deoxynucleotide triphosphohydrolase (dNTPase) activity of the restriction factor SAM domain and HD domain-containing protein 1 (SAMHD1) increases levels of nuclear reverse-transcribed cDNA and facilitates HIV-1 integration. Nuclear import and intranuclear transport of viral complexes therefore do not pose important blocks to HIV-1 in resting CD4 T cells, and the limitation to reverse transcription by SAMHD1's dNTPase activity constitutes the main pre-integration block to infection.
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Affiliation(s)
- Swetha Ananth
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Integrative Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany
| | - Ina Ambiel
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Integrative Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany
| | - Sandra Schifferdecker
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany
| | - Thorsten G Müller
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany
| | - Paul R Wratil
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Ludwig-Maximilians-Universität München, Munich, Germany; German Centre for Infection Research (DZIF), Partner Site München, Munich, Germany
| | - Ernesto Mejias-Perez
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Ludwig-Maximilians-Universität München, Munich, Germany; German Centre for Infection Research (DZIF), Partner Site München, Munich, Germany
| | - Hans-Georg Kräusslich
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany; German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Barbara Müller
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Ludwig-Maximilians-Universität München, Munich, Germany; German Centre for Infection Research (DZIF), Partner Site München, Munich, Germany
| | - Oliver T Fackler
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Integrative Virology, Center of Integrative Infectious Disease Research (CIID), Heidelberg, Germany; German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany.
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6
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Roy S, Adhikary H, D’Amours D. The SMC5/6 complex: folding chromosomes back into shape when genomes take a break. Nucleic Acids Res 2024; 52:2112-2129. [PMID: 38375830 PMCID: PMC10954462 DOI: 10.1093/nar/gkae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
High-level folding of chromatin is a key determinant of the shape and functional state of chromosomes. During cell division, structural maintenance of chromosome (SMC) complexes such as condensin and cohesin ensure large-scale folding of chromatin into visible chromosomes. In contrast, the SMC5/6 complex plays more local and context-specific roles in the structural organization of interphase chromosomes with important implications for health and disease. Recent advances in single-molecule biophysics and cryo-electron microscopy revealed key insights into the architecture of the SMC5/6 complex and how interactions connecting the complex to chromatin components give rise to its unique repertoire of interphase functions. In this review, we provide an integrative view of the features that differentiates the SMC5/6 complex from other SMC enzymes and how these enable dramatic reorganization of DNA folding in space during DNA repair reactions and other genome transactions. Finally, we explore the mechanistic basis for the dynamic targeting of the SMC5/6 complex to damaged chromatin and its crucial role in human health.
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Affiliation(s)
- Shamayita Roy
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Hemanta Adhikary
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Damien D’Amours
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
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7
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Vanegas-Torres CA, Schindler M. HIV-1 Vpr Functions in Primary CD4 + T Cells. Viruses 2024; 16:420. [PMID: 38543785 PMCID: PMC10975730 DOI: 10.3390/v16030420] [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: 01/31/2024] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 05/23/2024] Open
Abstract
HIV-1 encodes four accesory proteins in addition to its structural and regulatory genes. Uniquely amongst them, Vpr is abundantly present within virions, meaning it is poised to exert various biological effects on the host cell upon delivery. In this way, Vpr contributes towards the establishment of a successful infection, as evidenced by the extent to which HIV-1 depends on this factor to achieve full pathogenicity in vivo. Although HIV infects various cell types in the host organism, CD4+ T cells are preferentially targeted since they are highly permissive towards productive infection, concomitantly bringing about the hallmark immune dysfunction that accompanies HIV-1 spread. The last several decades have seen unprecedented progress in unraveling the activities Vpr possesses in the host cell at the molecular scale, increasingly underscoring the importance of this viral component. Nevertheless, it remains controversial whether some of these advances bear in vivo relevance, since commonly employed cellular models significantly differ from primary T lymphocytes. One prominent example is the "established" ability of Vpr to induce G2 cell cycle arrest, with enigmatic physiological relevance in infected primary T lymphocytes. The objective of this review is to present these discoveries in their biological context to illustrate the mechanisms whereby Vpr supports HIV-1 infection in CD4+ T cells, whilst identifying findings that require validation in physiologically relevant models.
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Affiliation(s)
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tuebingen, 72076 Tuebingen, Germany;
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8
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Deng Y, Lin Y, Chen S, Xiang Y, Chen H, Qi S, Oh HS, Das B, Komazin-Meredith G, Pesola JM, Knipe DM, Coen DM, Pan D. Neuronal miR-9 promotes HSV-1 epigenetic silencing and latency by repressing Oct-1 and Onecut family genes. Nat Commun 2024; 15:1991. [PMID: 38443365 PMCID: PMC10914762 DOI: 10.1038/s41467-024-46057-6] [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: 09/15/2023] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
Herpes simplex virus 1 (HSV-1) latent infection entails repression of viral lytic genes in neurons. By functional screening using luciferase-expressing HSV-1, we identify ten neuron-specific microRNAs potentially repressing HSV-1 neuronal replication. Transfection of miR-9, the most active candidate from the screen, decreases HSV-1 replication and gene expression in Neuro-2a cells. Ectopic expression of miR-9 from lentivirus or recombinant HSV-1 suppresses HSV-1 replication in male primary mouse neurons in culture and mouse trigeminal ganglia in vivo, and reactivation from latency in the primary neurons. Target prediction and validation identify transcription factors Oct-1, a known co-activator of HSV transcription, and all three Onecut family members as miR-9 targets. Knockdown of ONECUT2 decreases HSV-1 yields in Neuro-2a cells. Overexpression of each ONECUT protein increases HSV-1 replication in Neuro-2a cells, human induced pluripotent stem cell-derived neurons, and primary mouse neurons, and accelerates reactivation from latency in the mouse neurons. Mutagenesis, ChIP-seq, RNA-seq, ChIP-qPCR and ATAC-seq results suggest that ONECUT2 can nonspecifically bind to viral genes via its CUT domain, globally stimulate viral gene transcription, reduce viral heterochromatin and enhance the accessibility of viral chromatin. Thus, neuronal miR-9 promotes viral epigenetic silencing and latency by targeting multiple host transcription factors important for lytic gene activation.
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Affiliation(s)
- Yue Deng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Yuqi Lin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Siyu Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Yuhang Xiang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Hongjia Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Shuyuan Qi
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China
| | - Hyung Suk Oh
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Biswajit Das
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Gloria Komazin-Meredith
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Jean M Pesola
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - David M Knipe
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Donald M Coen
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Dongli Pan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, Zhejiang, China.
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9
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Pradhan B, Deep A, König J, Baaske MD, Corbett KD, Kim E. Loop extrusion-mediated plasmid DNA cleavage by the bacterial SMC Wadjet complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.17.580791. [PMID: 38405785 PMCID: PMC10889018 DOI: 10.1101/2024.02.17.580791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Structural maintenance of chromosomes (SMC) protein complexes play pivotal roles in genome organization and maintenance across all domains of life. In prokaryotes, SMC family Wadjet complexes structurally resemble the widespread MukBEF genome-organizing complexes but serve a defensive role by inhibiting plasmid transformation. We previously showed that Wadjet specifically cleaves circular DNA; however, the molecular mechanism underlying DNA substrate recognition remains unclear. Here, we use in vitro single-molecule imaging to directly visualize DNA loop extrusion and plasmid cleavage by Wadjet. We find that Wadjet is a symmetric DNA loop extruder that simultaneously reels in DNA from both sides of a growing loop and that this activity requires a dimeric JetABC supercomplex containing two dimers of the JetC motor subunit. On surface-anchored plasmid DNAs, Wadjet extrudes the full length of a 44 kilobase pair plasmid, stalls, and then cleaves DNA. Our findings reveal the role of loop extrusion in the specific recognition and elimination of plasmids by Wadjet, and establish loop extrusion as an evolutionarily conserved mechanism among SMC complexes across kingdoms of life.
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Affiliation(s)
- Biswajit Pradhan
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Amar Deep
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla CA, USA
| | - Jessica König
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | | | - Kevin D Corbett
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla CA, USA
- Department of Molecular Biology, University of California San Diego, La Jolla CA, USA
| | - Eugene Kim
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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10
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Phan AT, Zhu Y. PTEN Mediates the Silencing of Unintegrated HIV-1 DNA. Viruses 2024; 16:291. [PMID: 38400066 PMCID: PMC10892664 DOI: 10.3390/v16020291] [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: 12/20/2023] [Revised: 01/31/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
The integration of viral DNA into a host genome is an important step in HIV-1 replication. However, due to the high failure rate of integration, the majority of viral DNA exists in an unintegrated state during HIV-1 infection. In contrast to the robust expression from integrated viral DNA, unintegrated HIV-1 DNA is very poorly transcribed in infected cells, but the molecular machinery responsible for the silencing of unintegrated HIV-1 DNA remains poorly characterized. In this study, we sought to characterize new host factors for the inhibition of expression from unintegrated HIV-1 DNA. A genome-wide CRISPR-Cas9 knockout screening revealed the essential role of phosphatase and tensin homolog (PTEN) in the silencing of unintegrated HIV-1 DNA. PTEN's phosphatase activity negatively regulates the PI3K-Akt pathway to inhibit the transcription from unintegrated HIV-1 DNA. The knockout (KO) of PTEN or inhibition of PTEN's phosphatase activity by point mutagenesis activates Akt by phosphorylation and enhances the transcription from unintegrated HIV-1 DNA. Inhibition of the PI3K-Akt pathway by Akt inhibitor in PTEN-KO cells restores the silencing of unintegrated HIV-1 DNA. Transcriptional factors (NF-κB, Sp1, and AP-1) are important for the activation of unintegrated HIV-1 DNA in PTEN-KO cells. Finally, the knockout of PTEN increases the levels of active epigenetic marks (H3ac and H3K4me3) and the recruitment of PolII on unintegrated HIV-1 DNA chromatin. Our experiments reveal that PTEN targets transcription factors (NF-κB, Sp1, and AP-1) by negatively regulating the PI3K-Akt pathway to promote the silencing of unintegrated HIV-1 DNA.
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Affiliation(s)
| | - Yiping Zhu
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA;
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11
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Xu MJ, Jordan PW. SMC5/6 Promotes Replication Fork Stability via Negative Regulation of the COP9 Signalosome. Int J Mol Sci 2024; 25:952. [PMID: 38256025 PMCID: PMC10815603 DOI: 10.3390/ijms25020952] [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: 12/04/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
It is widely accepted that DNA replication fork stalling is a common occurrence during cell proliferation, but there are robust mechanisms to alleviate this and ensure DNA replication is completed prior to chromosome segregation. The SMC5/6 complex has consistently been implicated in the maintenance of replication fork integrity. However, the essential role of the SMC5/6 complex during DNA replication in mammalian cells has not been elucidated. In this study, we investigate the molecular consequences of SMC5/6 loss at the replication fork in mouse embryonic stem cells (mESCs), employing the auxin-inducible degron (AID) system to deplete SMC5 acutely and reversibly in the defined cellular contexts of replication fork stall and restart. In SMC5-depleted cells, we identify a defect in the restart of stalled replication forks, underpinned by excess MRE11-mediated fork resection and a perturbed localization of fork protection factors to the stalled fork. Previously, we demonstrated a physical and functional interaction of SMC5/6 with the COP9 signalosome (CSN), a cullin deneddylase that enzymatically regulates cullin ring ligase (CRL) activity. Employing a combination of DNA fiber techniques, the AID system, small-molecule inhibition assays, and immunofluorescence microscopy analyses, we show that SMC5/6 promotes the localization of fork protection factors to stalled replication forks by negatively modulating the COP9 signalosome (CSN). We propose that the SMC5/6-mediated modulation of the CSN ensures that CRL activity and their roles in DNA replication fork stabilization are maintained to allow for efficient replication fork restart when a replication fork stall is alleviated.
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Affiliation(s)
- Michelle J. Xu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Philip W. Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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12
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Geis FK, Goff SP. Chromatin Immunoprecipitation of Retroviral Genomes with Antibodies Recognizing Modified Histones and Specific Viral Proteins. Methods Mol Biol 2024; 2807:163-171. [PMID: 38743228 DOI: 10.1007/978-1-0716-3862-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mammalian cells have developed and optimized defense mechanisms to prevent or hamper viral infection. The early transcriptional silencing of incoming viral DNAs is one such antiviral strategy and seems to be of fundamental importance, since most cell types silence unintegrated retroviral DNAs. In this chapter, a method for chromatin immunoprecipitation of unintegrated DNA is described. This technique allows investigators to examine histone and co-factor interactions with unintegrated viral DNAs as well as to analyze histone modifications in general or in a kinetic fashion at various time points during viral infection.
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13
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Jang S, Engelman AN. Capsid-host interactions for HIV-1 ingress. Microbiol Mol Biol Rev 2023; 87:e0004822. [PMID: 37750702 PMCID: PMC10732038 DOI: 10.1128/mmbr.00048-22] [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: 09/27/2023] Open
Abstract
The HIV-1 capsid, composed of approximately 1,200 copies of the capsid protein, encases genomic RNA alongside viral nucleocapsid, reverse transcriptase, and integrase proteins. After cell entry, the capsid interacts with a myriad of host factors to traverse the cell cytoplasm, pass through the nuclear pore complex (NPC), and then traffic to chromosomal sites for viral DNA integration. Integration may very well require the dissolution of the capsid, but where and when this uncoating event occurs remains hotly debated. Based on size constraints, a long-prevailing view was that uncoating preceded nuclear transport, but recent research has indicated that the capsid may remain largely intact during nuclear import, with perhaps some structural remodeling required for NPC traversal. Completion of reverse transcription in the nucleus may further aid capsid uncoating. One canonical type of host factor, typified by CPSF6, leverages a Phe-Gly (FG) motif to bind capsid. Recent research has shown these peptides reside amid prion-like domains (PrLDs), which are stretches of protein sequence devoid of charged residues. Intermolecular PrLD interactions along the exterior of the capsid shell impart avid host factor binding for productive HIV-1 infection. Herein we overview capsid-host interactions implicated in HIV-1 ingress and discuss important research questions moving forward. Highlighting clinical relevance, the long-acting ultrapotent inhibitor lenacapavir, which engages the same capsid binding pocket as FG host factors, was recently approved to treat people living with HIV.
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Affiliation(s)
- Sooin Jang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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14
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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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15
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Thenin-Houssier S, Machida S, Jahan C, Bonnet-Madin L, Abbou S, Chen HC, Tesfaye R, Cuvier O, Benkirane M. POLE3 is a repressor of unintegrated HIV-1 DNA required for efficient virus integration and escape from innate immune sensing. SCIENCE ADVANCES 2023; 9:eadh3642. [PMID: 37922361 PMCID: PMC10624344 DOI: 10.1126/sciadv.adh3642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 10/03/2023] [Indexed: 11/05/2023]
Abstract
Unintegrated retroviral DNA is transcriptionally silenced by host chromatin silencing factors. Here, we used the proteomics of isolated chromatin segments method to reveal viral and host factors associated with unintegrated HIV-1DNA involved in its silencing. By gene silencing using siRNAs, 46 factors were identified as potential repressors of unintegrated HIV-1DNA. Knockdown and knockout experiments revealed POLE3 as a transcriptional repressor of unintegrated HIV-1DNA. POLE3 maintains unintegrated HIV-1DNA in a repressive chromatin state, preventing RNAPII recruitment to the viral promoter. POLE3 and the recently identified host factors mediating unintegrated HIV-1 DNA silencing, CAF1 and SMC5/SMC6/SLF2, show specificity toward different forms of unintegrated HIV-1DNA. Loss of POLE3 impaired HIV-1 replication, suggesting that repression of unintegrated HIV-1DNA is important for optimal viral replication. POLE3 depletion reduces the integration efficiency of HIV-1. POLE3, by maintaining a repressive chromatin structure of unintegrated HIV-1DNA, ensures HIV-1 escape from innate immune sensing in primary CD4+ T cells.
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Affiliation(s)
- Suzie Thenin-Houssier
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
| | - Shinichi Machida
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
- Department of Structural Virology, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Cyprien Jahan
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
| | - Lucie Bonnet-Madin
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
| | - Scarlette Abbou
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
| | - Heng-Chang Chen
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
| | - Robel Tesfaye
- Laboratory of Chromatin Dynamics, Centre de Biologie Intégrative (CBI), MCD Unit (UMR5077), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Olivier Cuvier
- Laboratory of Chromatin Dynamics, Centre de Biologie Intégrative (CBI), MCD Unit (UMR5077), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Monsef Benkirane
- Institut de Génétique Humaine. Laboratoire de Virologie Moléculaire, CNRS Université de Montpellier. Montpellier. France
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16
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Seeger C. A CRISPR-based system to investigate HBV cccDNA biology. J Virol 2023; 97:e0118523. [PMID: 37819132 PMCID: PMC10617570 DOI: 10.1128/jvi.01185-23] [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: 07/31/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Hepatitis B virus cccDNA is the key target for the necessary development of antiviral therapies aimed at curing chronic hepatitis B. The CRISPR-based system to produce covalently closed circular (cccDNA)-like extrachromosomal DNAs described in this report enables large-scale screens of chemical libraries to identify drug candidates with the potential to permanently inactivate cccDNA. Moreover, this approach permits investigations on unresolved problems as described in this report concerning cccDNA biology including mechanisms of SMC5/6-dependent transcriptional silencing and the contributions of the SMC5/6 complex to cccDNA stability in resting and dividing hepatocytes.
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17
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Abstract
Many cellular processes require large-scale rearrangements of chromatin structure. Structural maintenance of chromosomes (SMC) protein complexes are molecular machines that can provide structure to chromatin. These complexes can connect DNA elements in cis, walk along DNA, build and processively enlarge DNA loops and connect DNA molecules in trans to hold together the sister chromatids. These DNA-shaping abilities place SMC complexes at the heart of many DNA-based processes, including chromosome segregation in mitosis, transcription control and DNA replication, repair and recombination. In this Review, we discuss the latest insights into how SMC complexes such as cohesin, condensin and the SMC5-SMC6 complex shape DNA to direct these fundamental chromosomal processes. We also consider how SMC complexes, by building chromatin loops, can counteract the natural tendency of alike chromatin regions to cluster. SMC complexes thus control nuclear organization by participating in a molecular tug of war that determines the architecture of our genome.
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Affiliation(s)
- Claire Hoencamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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18
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Liu HW, Roisné-Hamelin F, Gruber S. SMC-based immunity against extrachromosomal DNA elements. Biochem Soc Trans 2023; 51:1571-1583. [PMID: 37584323 PMCID: PMC10586767 DOI: 10.1042/bst20221395] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/17/2023]
Abstract
SMC and SMC-like complexes promote chromosome folding and genome maintenance in all domains of life. Recently, they were also recognized as factors in cellular immunity against foreign DNA. In bacteria and archaea, Wadjet and Lamassu are anti-plasmid/phage defence systems, while Smc5/6 and Rad50 complexes play a role in anti-viral immunity in humans. This raises an intriguing paradox - how can the same, or closely related, complexes on one hand secure the integrity and maintenance of chromosomal DNA, while on the other recognize and restrict extrachromosomal DNA? In this minireview, we will briefly describe the latest understanding of each of these complexes in immunity including speculations on how principles of SMC(-like) function may explain how the systems recognize linear or circular forms of invading DNA.
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Affiliation(s)
- Hon Wing Liu
- Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM), University of Lausanne (UNIL), 1015 Lausanne, Switzerland
| | - Florian Roisné-Hamelin
- Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM), University of Lausanne (UNIL), 1015 Lausanne, Switzerland
| | - Stephan Gruber
- Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM), University of Lausanne (UNIL), 1015 Lausanne, Switzerland
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19
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Yao Q, Peng B, Li C, Li X, Chen M, Zhou Z, Tang D, He J, Wu Y, Sun Y, Li W. SLF2 Interacts with the SMC5/6 Complex to Direct Hepatitis B Virus Episomal DNA to Promyelocytic Leukemia Bodies for Transcriptional Repression. J Virol 2023:e0032823. [PMID: 37338350 PMCID: PMC10373549 DOI: 10.1128/jvi.00328-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/23/2023] [Indexed: 06/21/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects approximately 300 million people worldwide, and permanently repressing transcription of covalently closed circular DNA (cccDNA), the episomal viral DNA reservoir, is an attractive approach toward curing HBV. However, the mechanism underlying cccDNA transcription is only partially understood. In this study, by illuminating cccDNA of wild-type HBV (HBV-WT) and transcriptionally inactive HBV that bears a deficient HBV X gene (HBV-ΔX), we found that the HBV-ΔX cccDNA more frequently colocalizes with promyelocytic leukemia (PML) bodies than that of HBV-WT cccDNA. A small interfering RNA (siRNA) screen targeting 91 PML body-related proteins identified SMC5-SMC6 localization factor 2 (SLF2) as a host restriction factor of cccDNA transcription, and subsequent studies showed that SLF2 mediates HBV cccDNA entrapment in PML bodies by interacting with the SMC5/6 complex. We further showed that the region of SLF2 comprising residues 590 to 710 interacts with and recruits the SMC5/6 complex to PML bodies, and the C-terminal domain of SLF2 containing this region is necessary for repression of cccDNA transcription. Our findings shed new light on cellular mechanisms that inhibit HBV infection and lend further support for targeting the HBx pathway to repress HBV activity. IMPORTANCE Chronic HBV infection remains a major public health problem worldwide. Current antiviral treatments rarely cure the infection, as they cannot clear the viral reservoir, cccDNA, in the nucleus. Therefore, permanently silencing HBV cccDNA transcription represents a promising approach for a cure of HBV infection. Our study provides new insights into the cellular mechanisms that restrict HBV infection, revealing the role of SLF2 in directing HBV cccDNA to PML bodies for transcriptional repression. These findings have important implications for the development of antiviral therapies against HBV.
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Affiliation(s)
- Qiyan Yao
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Bo Peng
- National Institute of Biological Sciences, Beijing, China
| | - Cong Li
- National Institute of Biological Sciences, Beijing, China
| | - Xuelei Li
- National Institute of Biological Sciences, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Mingyi Chen
- National Institute of Biological Sciences, Beijing, China
| | - Zhongmin Zhou
- National Institute of Biological Sciences, Beijing, China
| | - Dingbin Tang
- National Institute of Biological Sciences, Beijing, China
| | - Jiabei He
- National Institute of Biological Sciences, Beijing, China
| | - Yumeng Wu
- National Institute of Biological Sciences, Beijing, China
| | - Yinyan Sun
- National Institute of Biological Sciences, Beijing, China
| | - Wenhui Li
- National Institute of Biological Sciences, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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20
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Peng XP, Zhao X. The multi-functional Smc5/6 complex in genome protection and disease. Nat Struct Mol Biol 2023; 30:724-734. [PMID: 37336994 PMCID: PMC10372777 DOI: 10.1038/s41594-023-01015-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/05/2023] [Indexed: 06/21/2023]
Abstract
Structural maintenance of chromosomes (SMC) complexes are ubiquitous genome regulators with a wide range of functions. Among the three types of SMC complexes in eukaryotes, cohesin and condensin fold the genome into different domains and structures, while Smc5/6 plays direct roles in promoting chromosomal replication and repair and in restraining pathogenic viral extra-chromosomal DNA. The importance of Smc5/6 for growth, genotoxin resistance and host defense across species is highlighted by its involvement in disease prevention in plants and animals. Accelerated progress in recent years, including structural and single-molecule studies, has begun to provide greater insights into the mechanisms underlying Smc5/6 functions. Here we integrate a broad range of recent studies on Smc5/6 to identify emerging features of this unique SMC complex and to explain its diverse cellular functions and roles in disease pathogenesis. We also highlight many key areas requiring further investigation for achieving coherent views of Smc5/6-driven mechanisms.
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Affiliation(s)
- Xiao P Peng
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Sloan Kettering Cancer Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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21
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Dekker JG, Klaver B, Berkhout B, Das AT. HIV-1 3'-Polypurine Tract Mutations Confer Dolutegravir Resistance by Switching to an Integration-Independent Replication Mechanism via 1-LTR Circles. J Virol 2023; 97:e0036123. [PMID: 37125907 PMCID: PMC10231180 DOI: 10.1128/jvi.00361-23] [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: 03/07/2023] [Accepted: 04/07/2023] [Indexed: 05/02/2023] Open
Abstract
Several recent studies indicate that mutations in the human immunodeficiency virus type 1 (HIV-1) 3'polypurine tract (3'PPT) motif can reduce sensitivity to the integrase inhibitor dolutegravir (DTG). Using an in vivo systematic evolution of ligands by exponential enrichment (SELEX) approach, we discovered that multiple different mutations in this viral RNA element can confer DTG resistance, suggesting that the inactivation of this critical reverse transcription element causes resistance. An analysis of the viral DNA products formed upon infection by these 3'PPT mutants revealed that they replicate without integration into the host cell genome, concomitant with an increased production of 1-LTR circles. As the replication of these virus variants is activated by the human T-lymphotropic virus 1 (HTLV-1) Tax protein, a factor that reverses epigenetic silencing of episomal HIV DNA, these data indicate that the 3'PPT-mutated viruses escape from the integrase inhibitor DTG by switching to an integration-independent replication mechanism. IMPORTANCE The integrase inhibitor DTG is a potent inhibitor of HIV replication and is currently recommended in drug regimens for people living with HIV. Whereas HIV normally escapes from antiviral drugs by the acquisition of specific mutations in the gene that encodes the targeted enzyme, mutational inactivation of the viral 3'PPT sequence, an RNA element that has a crucial role in the viral reverse transcription process, was found to allow HIV replication in the presence of DTG in cell culture experiments. While the integration of the viral DNA into the cellular genome is considered one of the hallmarks of retroviruses, including HIV, 3'PPT inactivation caused integration-independent replication, which can explain the reduced DTG sensitivity. Whether this exotic escape route can also contribute to viral escape in HIV-infected persons remains to be determined, but our results indicate that screening for 3'PPT mutations in patients that fail on DTG therapy should be considered.
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Affiliation(s)
- José G. Dekker
- Amsterdam UMC location University of Amsterdam, Medical Microbiology and Infection Prevention, Amsterdam, The Netherlands
- Amsterdam institute for Infection and Immunity, Infectious diseases, Amsterdam, The Netherlands
| | - Bep Klaver
- Amsterdam UMC location University of Amsterdam, Medical Microbiology and Infection Prevention, Amsterdam, The Netherlands
- Amsterdam institute for Infection and Immunity, Infectious diseases, Amsterdam, The Netherlands
| | - Ben Berkhout
- Amsterdam UMC location University of Amsterdam, Medical Microbiology and Infection Prevention, Amsterdam, The Netherlands
- Amsterdam institute for Infection and Immunity, Infectious diseases, Amsterdam, The Netherlands
| | - Atze T. Das
- Amsterdam UMC location University of Amsterdam, Medical Microbiology and Infection Prevention, Amsterdam, The Netherlands
- Amsterdam institute for Infection and Immunity, Infectious diseases, Amsterdam, The Netherlands
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22
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Ngo AM, Puschnik AS. Genome-Scale Analysis of Cellular Restriction Factors That Inhibit Transgene Expression from Adeno-Associated Virus Vectors. J Virol 2023; 97:e0194822. [PMID: 36971544 PMCID: PMC10134838 DOI: 10.1128/jvi.01948-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
Adeno-associated virus (AAV) vectors are one of the leading platforms for gene delivery for the treatment of human genetic diseases, but the antiviral cellular mechanisms that interfere with optimal transgene expression are incompletely understood. Here, we performed two genome-scale CRISPR screens to identify cellular factors that restrict transgene expression from recombinant AAV vectors. Our screens revealed several components linked to DNA damage response, chromatin remodeling, and transcriptional regulation. Inactivation of the Fanconi anemia gene FANCA; the human silencing hub (HUSH)-associated methyltransferase SETDB1; and the gyrase, Hsp90, histidine kinase, and MutL (GHKL)-type ATPase MORC3 led to increased transgene expression. Moreover, SETDB1 and MORC3 knockout improved transgene levels of several AAV serotypes as well as other viral vectors, such as lentivirus and adenovirus. Finally, we demonstrated that the inhibition of FANCA, SETDB1, or MORC3 also enhanced transgene expression in human primary cells, suggesting that they could be physiologically relevant pathways that restrict AAV transgene levels in therapeutic settings. IMPORTANCE Recombinant AAV (rAAV) vectors have been successfully developed for the treatment of genetic diseases. The therapeutic strategy often involves the replacement of a defective gene by the expression of a functional copy from the rAAV vector genome. However, cells possess antiviral mechanisms that recognize and silence foreign DNA elements thereby limiting transgene expression and its therapeutic effect. Here, we utilize a functional genomics approach to uncover a comprehensive set of cellular restriction factors that inhibit rAAV-based transgene expression. Genetic inactivation of selected restriction factors increased rAAV transgene expression. Hence, modulation of identified restriction factors has the potential to enhance AAV gene replacement therapies.
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Affiliation(s)
- Ashley M. Ngo
- Chan Zuckerberg Biohub, San Francisco, California, USA
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23
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Li J, Ren J, Liao H, Guo W, Feng K, Huang T, Cai YD. Identification of dynamic gene expression profiles during sequential vaccination with ChAdOx1/BNT162b2 using machine learning methods. Front Microbiol 2023; 14:1138674. [PMID: 37007526 PMCID: PMC10063797 DOI: 10.3389/fmicb.2023.1138674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/01/2023] [Indexed: 03/19/2023] Open
Abstract
To date, COVID-19 remains a serious global public health problem. Vaccination against SARS-CoV-2 has been adopted by many countries as an effective coping strategy. The strength of the body’s immune response in the face of viral infection correlates with the number of vaccinations and the duration of vaccination. In this study, we aimed to identify specific genes that may trigger and control the immune response to COVID-19 under different vaccination scenarios. A machine learning-based approach was designed to analyze the blood transcriptomes of 161 individuals who were classified into six groups according to the dose and timing of inoculations, including I-D0, I-D2-4, I-D7 (day 0, days 2–4, and day 7 after the first dose of ChAdOx1, respectively) and II-D0, II-D1-4, II-D7-10 (day 0, days 1–4, and days 7–10 after the second dose of BNT162b2, respectively). Each sample was represented by the expression levels of 26,364 genes. The first dose was ChAdOx1, whereas the second dose was mainly BNT162b2 (Only four individuals received a second dose of ChAdOx1). The groups were deemed as labels and genes were considered as features. Several machine learning algorithms were employed to analyze such classification problem. In detail, five feature ranking algorithms (Lasso, LightGBM, MCFS, mRMR, and PFI) were first applied to evaluate the importance of each gene feature, resulting in five feature lists. Then, the lists were put into incremental feature selection method with four classification algorithms to extract essential genes, classification rules and build optimal classifiers. The essential genes, namely, NRF2, RPRD1B, NEU3, SMC5, and TPX2, have been previously associated with immune response. This study also summarized expression rules that describe different vaccination scenarios to help determine the molecular mechanism of vaccine-induced antiviral immunity.
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Affiliation(s)
- Jing Li
- School of Computer Science, Baicheng Normal University, Baicheng, Jilin, China
| | - JingXin Ren
- School of Life Sciences, Shanghai University, Shanghai, China
| | | | - Wei Guo
- Key Laboratory of Stem Cell Biology, Shanghai Jiao Tong University School of Medicine (SJTUSM) and Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai, China
| | - KaiYan Feng
- Department of Computer Science, Guangdong AIB Polytechnic College, Guangzhou, China
| | - Tao Huang
- CAS Key Laboratory of Computational Biology, Bio-Med Big Data Center, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Science, Shanghai, China
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Tao Huang, ; Yu-Dong Cai,
| | - Yu-Dong Cai
- School of Life Sciences, Shanghai University, Shanghai, China
- *Correspondence: Tao Huang, ; Yu-Dong Cai,
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24
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Irwan ID, Cullen BR. The SMC5/6 complex: An emerging antiviral restriction factor that can silence episomal DNA. PLoS Pathog 2023; 19:e1011180. [PMID: 36862666 PMCID: PMC9980727 DOI: 10.1371/journal.ppat.1011180] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Affiliation(s)
- Ishak D. Irwan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Bryan R. Cullen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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25
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Albarnaz JD, Weekes MP. Proteomic analysis of antiviral innate immunity. Curr Opin Virol 2023; 58:101291. [PMID: 36529073 DOI: 10.1016/j.coviro.2022.101291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/03/2022] [Accepted: 11/17/2022] [Indexed: 12/23/2022]
Abstract
The capacity of host cells to detect and restrict an infecting virus rests on an array of cell-autonomous antiviral effectors and innate immune receptors that can trigger inflammatory processes at tissue and organismal levels. Dynamic changes in protein abundance, subcellular localisation, post-translational modifications and interactions with other biomolecules govern these processes. Proteomics is therefore an ideal experimental tool to discover novel mechanisms of host antiviral immunity. Additional information can be gleaned both about host and virus by systematic analysis of viral immune evasion strategies. In this review, we summarise recent advances in proteomic technologies and their application to antiviral innate immunity.
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Affiliation(s)
- Jonas D Albarnaz
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Michael P Weekes
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK.
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26
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Wu Y. HIV Preintegration Transcription and Host Antagonism. Curr HIV Res 2023; 21:160-171. [PMID: 37345240 PMCID: PMC10661980 DOI: 10.2174/1570162x21666230621122637] [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: 04/21/2023] [Revised: 05/25/2023] [Accepted: 06/08/2023] [Indexed: 06/23/2023]
Abstract
Retrovirus integration is an obligatory step for the viral life cycle, but large amounts of unintegrated DNA (uDNA) accumulate during retroviral infection. For simple retroviruses, in the absence of integration, viral genomes are epigenetically silenced in host cells. For complex retroviruses such as HIV, preintegration transcription has been found to occur at low levels from a large population of uDNA even in the presence of host epigenetic silencing mechanisms. HIV preintegration transcription has been suggested to be a normal early process of HIV infection that leads to the syntheses of all three classes of viral transcripts: multiply-spliced, singly-spliced, and unspliced genomic RNA; only viral early proteins such as Nef are selectively translated at low levels in blood CD4 T cells and macrophages, the primary targets of HIV. The initiation and persistence of HIV preintegration transcription have been suggested to rely on viral accessory proteins, particularly virion Vpr and de novo Tat generated from uDNA; both proteins have been shown to antagonize host epigenetic silencing of uDNA. In addition, stimulation of latently infected resting T cells and macrophages with cytokines, PKC activator, or histone deacetylase inhibitors has been found to greatly upregulate preintegration transcription, leading to low-level viral production or even replication from uDNA. Functionally, Nef synthesized from preintegration transcription is biologically active in modulating host immune functions, lowering the threshold of T cell activation, and downregulating surface CD4, CXCR4/CCR5, and HMC receptors. The early Tat activity from preintegration transcription antagonizes repressive minichromatin assembled onto uDNA. The study of HIV preintegration transcription is important to understanding virus-host interaction and antagonism, viral persistence, and the mechanism of integrase drug resistance. The application of unintegrated lentiviral vectors for gene therapy also offers a safety advantage for minimizing retroviral vector-mediated insertional mutagenesis.
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Affiliation(s)
- Yuntao Wu
- Center for Infectious Disease Research, George Mason University, Manassas, Virginia, United States
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27
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DNA-measuring Wadjet SMC ATPases restrict smaller circular plasmids by DNA cleavage. Mol Cell 2022; 82:4727-4740.e6. [PMID: 36525956 DOI: 10.1016/j.molcel.2022.11.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/31/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
Structural maintenance of chromosome (SMC) complexes fold DNA by loop extrusion to support chromosome segregation and genome maintenance. Wadjet systems (JetABCD/MksBEFG/EptABCD) are derivative SMC complexes with roles in bacterial immunity against selfish DNA. Here, we show that JetABCD restricts circular plasmids with an upper size limit of about 100 kb, whereas a linear plasmid evades restriction. Purified JetABCD complexes cleave circular DNA molecules, regardless of the DNA helical topology; cleavage is DNA sequence nonspecific and depends on the SMC ATPase. A cryo-EM structure reveals a distinct JetABC dimer-of-dimers geometry, with the two SMC dimers facing in opposite direction-rather than the same as observed with MukBEF. We hypothesize that JetABCD is a DNA-shape-specific endonuclease and propose the "total extrusion model" for DNA cleavage exclusively when extrusion of an entire plasmid has been completed by a JetABCD complex. Total extrusion cannot be achieved on the larger chromosome, explaining how self-DNA may evade processing.
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28
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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29
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Oravcová M, Nie M, Zilio N, Maeda S, Jami-Alahmadi Y, Lazzerini-Denchi E, Wohlschlegel JA, Ulrich HD, Otomo T, Boddy MN. The Nse5/6-like SIMC1-SLF2 complex localizes SMC5/6 to viral replication centers. eLife 2022; 11:e79676. [PMID: 36373674 PMCID: PMC9708086 DOI: 10.7554/elife.79676] [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: 04/22/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
The human SMC5/6 complex is a conserved guardian of genome stability and an emerging component of antiviral responses. These disparate functions likely require distinct mechanisms of SMC5/6 regulation. In yeast, Smc5/6 is regulated by its Nse5/6 subunits, but such regulatory subunits for human SMC5/6 are poorly defined. Here, we identify a novel SMC5/6 subunit called SIMC1 that contains SUMO interacting motifs (SIMs) and an Nse5-like domain. We isolated SIMC1 from the proteomic environment of SMC5/6 within polyomavirus large T antigen (LT)-induced subnuclear compartments. SIMC1 uses its SIMs and Nse5-like domain to localize SMC5/6 to polyomavirus replication centers (PyVRCs) at SUMO-rich PML nuclear bodies. SIMC1's Nse5-like domain binds to the putative Nse6 orthologue SLF2 to form an anti-parallel helical dimer resembling the yeast Nse5/6 structure. SIMC1-SLF2 structure-based mutagenesis defines a conserved surface region containing the N-terminus of SIMC1's helical domain that regulates SMC5/6 localization to PyVRCs. Furthermore, SLF1, which recruits SMC5/6 to DNA lesions via its BRCT and ARD motifs, binds SLF2 analogously to SIMC1 and forms a separate Nse5/6-like complex. Thus, two Nse5/6-like complexes with distinct recruitment domains control human SMC5/6 localization.
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Affiliation(s)
- Martina Oravcová
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
| | - Minghua Nie
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
| | | | - Shintaro Maeda
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States
| | | | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States
| | | | - Takanori Otomo
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
- San Diego Biomedical Research InstituteSan DiegoUnited States
| | - Michael N Boddy
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
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30
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Smc5/6 silences episomal transcription by a three-step function. Nat Struct Mol Biol 2022; 29:922-931. [PMID: 36097294 DOI: 10.1038/s41594-022-00829-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 07/29/2022] [Indexed: 11/08/2022]
Abstract
In addition to its role in chromosome maintenance, the six-membered Smc5/6 complex functions as a restriction factor that binds to and transcriptionally silences viral and other episomal DNA. However, the underlying mechanism is unknown. Here, we show that transcriptional silencing by the human Smc5/6 complex is a three-step process. The first step is entrapment of the episomal DNA by a mechanism dependent on Smc5/6 ATPase activity and a function of its Nse4a subunit for which the Nse4b paralog cannot substitute. The second step results in Smc5/6 recruitment to promyelocytic leukemia nuclear bodies by SLF2 (the human ortholog of Nse6). The third step promotes silencing through a mechanism requiring Nse2 but not its SUMO ligase activity. By contrast, the related cohesin and condensin complexes fail to bind to or silence episomal DNA, indicating a property unique to Smc5/6.
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31
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KSHV RTA antagonizes SMC5/6 complex-induced viral chromatin compaction by hijacking the ubiquitin-proteasome system. PLoS Pathog 2022; 18:e1010744. [PMID: 35914008 PMCID: PMC9371351 DOI: 10.1371/journal.ppat.1010744] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 08/11/2022] [Accepted: 07/15/2022] [Indexed: 02/07/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is a double-stranded DNA virus with the capacity to establish life-long latent infection. During latent infection, the viral genome persists as a circular episome that associates with cellular histones and exists as a nonintegrated minichromosome in the nucleus of infected cells. Chromatin structure and epigenetic programming are required for the proper control of viral gene expression and stable maintenance of viral DNA. However, there is still limited knowledge regarding how the host regulates the chromatin structure and maintenance of episomal DNA. Here, we found that the cellular protein structural maintenance of chromosome (SMC) complex SMC5/6 recognizes and associates with the KSHV genome to inhibit its replication. The SMC5/6 complex can bind to the KSHV genome and suppress KSHV gene transcription by condensing the viral chromatin and creating a repressive chromatin structure. Correspondingly, KSHV employs an antagonistic strategy by utilizing the viral protein RTA to degrade the SMC5/6 complex and antagonize the inhibitory effect of this complex on viral gene transcription. Interestingly, this antagonistic mechanism of RTA is evolutionarily conserved among γ-herpesviruses. Our work suggests that the SMC5/6 complex is a new host factor that restricts KSHV replication. KSHV can establish life-long latent infection. During latency, the viral genome is maintained as an extrachromosomal episome in the infected cells. We demonstrated that the host protein SMC5/6 complex associates with the KSHV genome and results in direct transcriptional inhibition by creating a transcriptionally repressive chromatin structure of the viral genome. RTA, the master switch protein of KSHV, can hijack the ubiquitin-proteasome system to degrade the SMC5/6 complex to antagonize its inhibitory effect on viral gene transcription. Interestingly, this function of RTA is evolutionarily conserved among γ-herpesviruses.
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32
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Geis FK, Kelenis DP, Goff SP. Two lymphoid cell lines potently silence unintegrated HIV-1 DNAs. Retrovirology 2022; 19:16. [PMID: 35810297 PMCID: PMC9271240 DOI: 10.1186/s12977-022-00602-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/04/2022] [Indexed: 11/23/2022] Open
Abstract
Mammalian cells mount a variety of defense mechanisms against invading viruses to prevent or reduce infection. One such defense is the transcriptional silencing of incoming viral DNA, including the silencing of unintegrated retroviral DNA in most cells. Here, we report that the lymphoid cell lines K562 and Jurkat cells reveal a dramatically higher efficiency of silencing of viral expression from unintegrated HIV-1 DNAs as compared to HeLa cells. We found K562 cells in particular to exhibit an extreme silencing phenotype. Infection of K562 cells with a non-integrating viral vector encoding a green fluorescent protein reporter resulted in a striking decrease in the number of fluorescence-positive cells and in their mean fluorescence intensity as compared to integration-competent controls, even though the levels of viral DNA in the nucleus were equal or in the case of 2-LTR circles even higher. The silencing in K562 cells was functionally distinctive. Histones loaded on unintegrated HIV-1 DNA in K562 cells revealed high levels of the silencing mark H3K9 trimethylation and low levels of the active mark H3 acetylation, as detected in HeLa cells. But infection of K562 cells resulted in low H3K27 trimethylation levels on unintegrated viral DNA as compared to higher levels in HeLa cells, corresponding to low H3K27 trimethylation levels of silent host globin genes in K562 cells as compared to HeLa cells. Most surprisingly, treatment with the HDAC inhibitor trichostatin A, which led to a highly efficient relief of silencing in HeLa cells, only weakly relieved silencing in K562 cells. In summary, we found that the capacity for silencing viral DNAs differs between cell lines in its extent, and likely in its mechanism.
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Affiliation(s)
- Franziska K Geis
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY, USA.,Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA.,Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY, USA
| | - Demetra P Kelenis
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY, USA.,Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Stephen P Goff
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY, USA. .,Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA. .,Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY, USA.
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33
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Wu L, Pan T, Zhou M, Chen T, Wu S, Lv X, Liu J, Yu F, Guan Y, Liu B, Zhang W, Deng X, Chen Q, Liang A, Lin Y, Wang L, Tang X, Cai W, Li L, He X, Zhang H, Ma X. CBX4 contributes to HIV-1 latency by forming phase-separated nuclear bodies and SUMOylating EZH2. EMBO Rep 2022; 23:e53855. [PMID: 35642598 PMCID: PMC9253744 DOI: 10.15252/embr.202153855] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 04/17/2022] [Accepted: 05/18/2022] [Indexed: 09/13/2023] Open
Abstract
The retrovirus HIV-1 integrates into the host genome and establishes a latent viral reservoir that escapes immune surveillance. Molecular mechanisms of HIV-1 latency have been studied extensively to achieve a cure for the acquired immunodeficiency syndrome (AIDS). Latency-reversing agents (LRAs) have been developed to reactivate and eliminate the latent reservoir by the immune system. To develop more promising LRAs, it is essential to evaluate new therapeutic targets. Here, we find that CBX4, a component of the Polycomb Repressive Complex 1 (PRC1), contributes to HIV-1 latency in seven latency models and primary CD4+ T cells. CBX4 forms nuclear bodies with liquid-liquid phase separation (LLPS) properties on the HIV-1 long terminal repeat (LTR) and recruits EZH2, the catalytic subunit of PRC2. CBX4 SUMOylates EZH2 utilizing its SUMO E3 ligase activity, thereby enhancing the H3K27 methyltransferase activity of EZH2. Our results indicate that CBX4 acts as a bridge between the repressor complexes PRC1 and PRC2 that act synergistically to maintain HIV-1 latency. Dissolution of phase-separated CBX4 bodies could be a potential intervention to reactivate latent HIV-1.
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Affiliation(s)
- Liyang Wu
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Ting Pan
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Center for Infection and Immunity StudySchool of MedicineSun Yat‐sen UniversityShenzhenChina
| | - Mo Zhou
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Tao Chen
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Shiyu Wu
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Xi Lv
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Jun Liu
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Fei Yu
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Yuanjun Guan
- Core Laboratory Platform for Medical ScienceZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Bingfeng Liu
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Wanying Zhang
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Xiaohui Deng
- Center for Infection and Immunity StudySchool of MedicineSun Yat‐sen UniversityShenzhenChina
| | - Qianyu Chen
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Anqi Liang
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Yingtong Lin
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | | | - Xiaoping Tang
- Department of Infectious DiseasesGuangzhou 8 People's HospitalGuangzhouChina
| | - Weiping Cai
- Department of Infectious DiseasesGuangzhou 8 People's HospitalGuangzhouChina
| | - Linghua Li
- Department of Infectious DiseasesGuangzhou 8 People's HospitalGuangzhouChina
| | - Xin He
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Hui Zhang
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Guangzhou LaboratoryGuangzhou International Bio‐IslandGuangzhouChina
| | - Xiancai Ma
- Institute of Human VirologyKey Laboratory of Tropical Disease Control of Ministry EducationGuangdong Engineering Research Center for Antimicrobial Agent and ImmunotechnologyZhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
- Guangzhou LaboratoryGuangzhou International Bio‐IslandGuangzhouChina
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34
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Engelman AN, Kvaratskhelia M. Multimodal Functionalities of HIV-1 Integrase. Viruses 2022; 14:926. [PMID: 35632668 PMCID: PMC9144474 DOI: 10.3390/v14050926] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 01/11/2023] Open
Abstract
Integrase is the retroviral protein responsible for integrating reverse transcripts into cellular genomes. Co-packaged with viral RNA and reverse transcriptase into capsid-encased viral cores, human immunodeficiency virus 1 (HIV-1) integrase has long been implicated in reverse transcription and virion maturation. However, the underlying mechanisms of integrase in these non-catalytic-related viral replication steps have remained elusive. Recent results have shown that integrase binds genomic RNA in virions, and that mutational or pharmacological disruption of integrase-RNA binding yields eccentric virion particles with ribonucleoprotein complexes situated outside of the capsid shell. Such viruses are defective for reverse transcription due to preferential loss of integrase and viral RNA from infected target cells. Parallel research has revealed defective integrase-RNA binding and eccentric particle formation as common features of class II integrase mutant viruses, a phenotypic grouping of viruses that display defects at steps beyond integration. In light of these new findings, we propose three new subclasses of class II mutant viruses (a, b, and c), all of which are defective for integrase-RNA binding and particle morphogenesis, but differ based on distinct underlying mechanisms exhibited by the associated integrase mutant proteins. We also assess how these findings inform the role of integrase in HIV-1 particle maturation.
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Affiliation(s)
- Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
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35
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Reuschl AK, Mesner D, Shivkumar M, Whelan MVX, Pallett LJ, Guerra-Assunção JA, Madansein R, Dullabh KJ, Sigal A, Thornhill JP, Herrera C, Fidler S, Noursadeghi M, Maini MK, Jolly C. HIV-1 Vpr drives a tissue residency-like phenotype during selective infection of resting memory T cells. Cell Rep 2022; 39:110650. [PMID: 35417711 PMCID: PMC9350556 DOI: 10.1016/j.celrep.2022.110650] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/23/2022] [Accepted: 03/17/2022] [Indexed: 12/03/2022] Open
Abstract
HIV-1 replicates in CD4+ T cells, leading to AIDS. Determining how HIV-1 shapes its niche to create a permissive environment is central to informing efforts to limit pathogenesis, disturb reservoirs, and achieve a cure. A key roadblock in understanding HIV-T cell interactions is the requirement to activate T cells in vitro to make them permissive to infection. This dramatically alters T cell biology and virus-host interactions. Here we show that HIV-1 cell-to-cell spread permits efficient, productive infection of resting memory T cells without prior activation. Strikingly, we find that HIV-1 infection primes resting T cells to gain characteristics of tissue-resident memory T cells (TRM), including upregulating key surface markers and the transcription factor Blimp-1 and inducing a transcriptional program overlapping the core TRM transcriptional signature. This reprogramming is driven by Vpr and requires Vpr packaging into virions and manipulation of STAT5. Thus, HIV-1 reprograms resting T cells, with implications for viral replication and persistence.
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Affiliation(s)
- Ann-Kathrin Reuschl
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK.
| | - Dejan Mesner
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Maitreyi Shivkumar
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Matthew V X Whelan
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Laura J Pallett
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | | | - Rajhmun Madansein
- Department of Cardiothoracic Surgery, University of KwaZulu-Natal, Durban 4091, South Africa; Centre for the AIDS Programme of Research in South Africa, Durban 4091, South Africa
| | - Kaylesh J Dullabh
- Department of Cardiothoracic Surgery, University of KwaZulu-Natal, Durban 4091, South Africa
| | - Alex Sigal
- Africa Health Research Institute, Durban 4001, South Africa; School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban 4091, South Africa; Max Planck Institute for Infection Biology, 10117 Berlin, Germany
| | - John P Thornhill
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford OX1 3XY, UK; Department of Infectious Disease, Faculty of Medicine, Imperial College, London W2 1NY, UK
| | - Carolina Herrera
- Department of Infectious Disease, Faculty of Medicine, Imperial College, London W2 1NY, UK
| | - Sarah Fidler
- Department of Infectious Disease, Faculty of Medicine, Imperial College, London W2 1NY, UK; Imperial College NIHR Biomedical Research Centre, London W2 1NY, UK
| | - Mahdad Noursadeghi
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Mala K Maini
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Clare Jolly
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK.
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36
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Yiu SPT, Guo R, Zerbe C, Weekes MP, Gewurz BE. Epstein-Barr virus BNRF1 destabilizes SMC5/6 cohesin complexes to evade its restriction of replication compartments. Cell Rep 2022; 38:110411. [PMID: 35263599 PMCID: PMC8981113 DOI: 10.1016/j.celrep.2022.110411] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/29/2021] [Accepted: 01/28/2022] [Indexed: 11/11/2022] Open
Abstract
Epstein-Barr virus (EBV) persistently infects people worldwide. Delivery of ∼170-kb EBV genomes to nuclei and use of nuclear membrane-less replication compartments (RCs) for their lytic cycle amplification necessitate evasion of intrinsic antiviral responses. Proteomics analysis indicates that, upon B cell infection or lytic reactivation, EBV depletes the cohesin SMC5/6, which has major roles in chromosome maintenance and DNA damage repair. The major tegument protein BNRF1 targets SMC5/6 complexes by a ubiquitin proteasome pathway dependent on calpain proteolysis and Cullin-7. In the absence of BNRF1, SMC5/6 associates with R-loop structures, including at the viral lytic origin of replication, and interferes with RC formation and encapsidation. CRISPR analysis identifies RC restriction roles of SMC5/6 components involved in DNA entrapment and SUMOylation. Our study highlights SMC5/6 as an intrinsic immune sensor and restriction factor for a human herpesvirus RC and has implications for the pathogenesis of EBV-associated cancers.
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Affiliation(s)
- Stephanie Pei Tung Yiu
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Harvard Graduate Program in Virology, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Rui Guo
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Cassie Zerbe
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Michael P Weekes
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Benjamin E Gewurz
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Harvard Graduate Program in Virology, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
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37
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Crosstalk between Hepatitis B Virus and the 3D Genome Structure. Viruses 2022; 14:v14020445. [PMID: 35216038 PMCID: PMC8877387 DOI: 10.3390/v14020445] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/04/2022] [Accepted: 02/14/2022] [Indexed: 12/17/2022] Open
Abstract
Viruses that transcribe their DNA within the nucleus have to adapt to the existing cellular mechanisms that govern transcriptional regulation. Recent technological breakthroughs have highlighted the highly hierarchical organization of the cellular genome and its role in the regulation of gene expression. This review provides an updated overview on the current knowledge on how the hepatitis B virus interacts with the cellular 3D genome and its consequences on viral and cellular gene expression. We also briefly discuss the strategies developed by other DNA viruses to co-opt and sometimes subvert cellular genome spatial organization.
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Abstract
REC8 meiotic recombination protein (REC8) is a member of structural maintenance of chromosome (SMC) protein partners, which play an important role in meiosis, anti-tumor, and sperm formation. As the adapter proteins of RLR signaling and cGAS-DNA signaling, the activity and stability of MAVS (also known as VISA, Cardif and IPS-1) and STING (also known as MITA) are critical for innate immunity. Here, we report that REC8 interacts with MAVS and STING, and inhibits their ubiquitination and subsequent degradation, thereby promoting innate antiviral signaling. REC8 is upregulated through the JAK-STAT signaling pathway under viral infection. Knockdown of REC8 impair the innate immune responses against VSV (Vesicular Stomatitis Virus), NDV (Newcastle disease virus) and HSV (herpes simplex virus). Mechanistically, under the infection of viruses, the SUMOylated REC8 is transferred from the nucleus to the cytoplasm and then interacts with MAVS and STING to inhibit their K48-linked ubiquitination triggered by RNF5. Moreover, REC8 promotes the recruitment of TBK1 to MAVS and STING. Thus, REC8 functions as a positive modulator of innate immunity. Our work highlights a previously undocumented role of meiosis-associated protein REC8 in regulating innate immunity. IMPORTANCE The innate immune response is crucial for the host to resist the invasion of viruses and other pathogens. STING and MAVS play a critical role in the innate immune response to DNA and RNA viral infection, respectively. In this study, REC8 promotes the innate immune response by targeting STING and MAVS. Notably, REC8 interacts with MAVS and STING in the cytoplasm and inhibits K48-linked ubiquitination of MAVS and STING triggered by RNF5, stabilizing MAVS and STING protein to promote innate immunity and gradually inhibiting viral infection. Our study provides a new insight for the study of antiviral innate immune.
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Geis FK, Sabo Y, Chen X, Li Y, Lu C, Goff SP. CHAF1A/B mediate silencing of unintegrated HIV-1 DNAs early in infection. Proc Natl Acad Sci U S A 2022; 119:e2116735119. [PMID: 35074917 PMCID: PMC8795523 DOI: 10.1073/pnas.2116735119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/20/2021] [Indexed: 12/27/2022] Open
Abstract
Early events of the retroviral life cycle are the targets of many host restriction factors that have evolved to prevent establishment of infection. Incoming retroviral DNAs are transcriptionally silenced before integration in most cell types, and efficient viral gene expression occurs only after formation of the provirus. The molecular machinery for silencing unintegrated retroviral DNAs of HIV-1 remains poorly characterized. Here, we identified the histone chaperones CHAF1A and CHAF1B as essential factors for silencing of unintegrated HIV-1 DNAs. Using RNAi-mediated knockdown (KD) of multiple histone chaperones, we found that KD of CHAF1A or CHAF1B resulted in a pronounced increase in expression of incoming viral DNAs. The function of these two proteins in silencing was independent of their interaction partner RBBP4. Viral DNA levels accumulated to significantly higher levels in CHAF1A KD cells over controls, suggesting enhanced stabilization of actively transcribed DNAs. Chromatin immunoprecipitation assays revealed no major changes in histone loading onto viral DNAs in the absence of CHAF1A, but levels of the H3K9 trimethylation silencing mark were reduced. KD of the H3K9me3-binding protein HP1γ accelerated the expression of unintegrated HIV-1 DNAs. While CHAF1A was critical for silencing HIV-1 DNAs, it showed no role in silencing of unintegrated retroviral DNAs of mouse leukemia virus. Our study identifies CHAF1A and CHAF1B as factors involved specifically in silencing of HIV-1 DNAs early in infection. The results suggest that these factors act by noncanonical pathways, distinct from their histone loading activities, to mediate silencing of newly synthesized HIV-1 DNAs.
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Affiliation(s)
- Franziska K Geis
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032
- HHMI, Columbia University Medical Center, New York, NY 10032
- Aaron Diamond AIDS Research Center, Columbia University Medical Center, New York, NY 10032
| | - Yosef Sabo
- Aaron Diamond AIDS Research Center, Columbia University Medical Center, New York, NY 10032
- Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY 10032
| | - Xiao Chen
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032
| | - Yinglu Li
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032
| | - Chao Lu
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032
| | - Stephen P Goff
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032;
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032
- HHMI, Columbia University Medical Center, New York, NY 10032
- Aaron Diamond AIDS Research Center, Columbia University Medical Center, New York, NY 10032
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032
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Fink DL, Cai J, Whelan MVX, Monit C, Maluquer de Motes C, Towers GJ, Sumner RP. HIV-2/SIV Vpx antagonises NF-κB activation by targeting p65. Retrovirology 2022; 19:2. [PMID: 35073912 PMCID: PMC8785589 DOI: 10.1186/s12977-021-00586-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/24/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The NF-κB family of transcription factors and associated signalling pathways are abundant and ubiquitous in human immune responses. Activation of NF-κB transcription factors by viral pathogen-associated molecular patterns, such as viral RNA and DNA, is fundamental to anti-viral innate immune defences and pro-inflammatory cytokine production that steers adaptive immune responses. Diverse non-viral stimuli, such as lipopolysaccharide and cytokines, also activate NF-κB and the same anti-pathogen gene networks. Viruses adapted to human cells often encode multiple proteins targeting the NF-κB pathway to mitigate the anti-viral effects of NF-κB-dependent host immunity. RESULTS In this study we have demonstrated using a variety of assays, in a number of different cell types including primary cells, that plasmid-encoded or virus-delivered simian immunodeficiency virus (SIV) accessory protein Vpx is a broad antagonist of NF-κB signalling active against diverse innate NF-κB agonists. Using targeted Vpx mutagenesis, we showed that this novel Vpx phenotype is independent of known Vpx cofactor DCAF1 and other cellular binding partners, including SAMHD1, STING and the HUSH complex. We found that Vpx co-immunoprecipitated with canonical NF-κB transcription factor p65, but not NF-κB family members p50 or p100, preventing nuclear translocation of p65. We found that broad antagonism of NF-κB activation by Vpx was conserved across distantly related lentiviruses as well as for Vpr from SIV Mona monkey (SIVmon), which has Vpx-like SAMHD1-degradation activity. CONCLUSIONS We have discovered a novel mechanism by which lentiviruses antagonise NF-κB activation by targeting p65. These findings extend our knowledge of how lentiviruses manipulate universal regulators of immunity to avoid the anti-viral sequelae of pro-inflammatory gene expression stimulated by both viral and extra-viral agonists. Importantly our findings are also relevant to the gene therapy field where virus-like particle associated Vpx is routinely used to enhance vector transduction through antagonism of SAMHD1, and perhaps also through manipulation of NF-κB.
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Affiliation(s)
- Douglas L Fink
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK
| | - James Cai
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK
| | - Matthew V X Whelan
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK
| | - Christopher Monit
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK
| | - Carlos Maluquer de Motes
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Greg J Towers
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK
| | - Rebecca P Sumner
- Division of Infection and Immunity, University College London, 90 Gower Street, London, WC1E 6BT, UK.
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK.
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Irwan ID, Bogerd HP, Cullen BR. Epigenetic silencing by the SMC5/6 complex mediates HIV-1 latency. Nat Microbiol 2022; 7:2101-2113. [PMID: 36376394 PMCID: PMC9712108 DOI: 10.1038/s41564-022-01264-z] [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: 05/23/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022]
Abstract
After viral entry and reverse transcription, HIV-1 proviruses that fail to integrate are epigenetically silenced, but the underlying mechanism has remained unclear. Using a genome-wide CRISPR/Cas9 knockout screen, we identified the host SMC5/6 complex as essential for this epigenetic silencing. We show that SMC5/6 binds to and then SUMOylates unintegrated chromatinized HIV-1 DNA. Inhibition of SUMOylation, either by point mutagenesis of the SMC5/6 component NSMCE2-a SUMO E3 ligase-or using the SUMOylation inhibitor TAK-981, prevents epigenetic silencing, enables transcription from unintegrated HIV-1 DNA and rescues the replication of integrase-deficient HIV-1. Finally, we show that blocking SMC5/6 complex expression, or inhibiting its SUMOylation activity, suppresses the establishment of latent HIV-1 infections in both CD4+ T cell lines and primary human T cells. Collectively, our data show that the SMC5/6 complex plays a direct role in mediating the establishment of HIV-1 latency by epigenetically silencing integration-competent HIV-1 proviruses before integration.
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Affiliation(s)
- Ishak D. Irwan
- grid.189509.c0000000100241216Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC USA
| | - Hal P. Bogerd
- grid.189509.c0000000100241216Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC USA
| | - Bryan R. Cullen
- grid.189509.c0000000100241216Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC USA
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Epigenetic Regulation of Human T-Cell Leukemia Virus Gene Expression. Microorganisms 2021; 10:microorganisms10010084. [PMID: 35056532 PMCID: PMC8781281 DOI: 10.3390/microorganisms10010084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/17/2022] Open
Abstract
Viral and cellular gene expression are regulated by epigenetic alterations, including DNA methylation, histone modifications, nucleosome positioning, and chromatin looping. Human T-cell leukemia virus type 1 (HTLV-1) is a pathogenic retrovirus associated with inflammatory disorders and T-cell lymphoproliferative malignancy. The transforming activity of HTLV-1 is driven by the viral oncoprotein Tax, which acts as a transcriptional activator of the cAMP response element-binding protein (CREB) and nuclear factor kappa B (NFκB) pathways. The epigenetic effects of Tax and the induction of lymphoproliferative malignancy include alterations in DNA methylation and histone modifications. In addition, alterations in nucleosome positioning and DNA looping also occur in HTLV-1-induced malignant cells. A mechanistic definition of these effects will pave the way to new therapies for HTLV-1-associated disorders.
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Goff SP. Silencing of Unintegrated Retroviral DNAs. Viruses 2021; 13:v13112248. [PMID: 34835055 PMCID: PMC8621569 DOI: 10.3390/v13112248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 12/23/2022] Open
Abstract
Retroviral infection delivers an RNA genome into the cytoplasm that serves as the template for the synthesis of a linear double-stranded DNA copy by the viral reverse transcriptase. Within the nucleus this linear DNA gives rise to extrachromosomal circular forms, and in a key step of the life cycle is inserted into the host genome to form the integrated provirus. The unintegrated DNA forms, like those of DNAs entering cells by other means, are rapidly loaded with nucleosomes and heavily silenced by epigenetic histone modifications. This review summarizes our present understanding of the silencing machinery for the DNAs of the mouse leukemia viruses and human immunodeficiency virus type 1. We consider the potential impact of the silencing on virus replication, on the sensing of the virus by the innate immune system, and on the formation of latent proviruses. We also speculate on the changeover to high expression from the integrated proviruses in permissive cell types, and briefly consider the silencing of proviruses even after integration in embryonic stem cells and other developmentally primitive cell types.
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Affiliation(s)
- Stephen P Goff
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
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Martin MM, Matkovic R, Larrous P, Morel M, Lasserre A, Vauthier V, Margottin-Goguet F. Binding to DCAF1 distinguishes TASOR and SAMHD1 degradation by HIV-2 Vpx. PLoS Pathog 2021; 17:e1009609. [PMID: 34699574 PMCID: PMC8570500 DOI: 10.1371/journal.ppat.1009609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 11/05/2021] [Accepted: 10/15/2021] [Indexed: 01/18/2023] Open
Abstract
Human Immunodeficiency viruses type 1 and 2 (HIV-1 and HIV-2) succeed to evade host immune defenses by using their viral auxiliary proteins to antagonize host restriction factors. HIV-2/SIVsmm Vpx is known for degrading SAMHD1, a factor impeding the reverse transcription. More recently, Vpx was also shown to counteract HUSH, a complex constituted of TASOR, MPP8 and periphilin, which blocks viral expression from the integrated viral DNA. In a classical ubiquitin ligase hijacking model, Vpx bridges the DCAF1 ubiquitin ligase substrate adaptor to SAMHD1, for subsequent ubiquitination and degradation. Here, we investigated whether the same mechanism is at stake for Vpx-mediated HUSH degradation. While we confirm that Vpx bridges SAMHD1 to DCAF1, we show that TASOR can interact with DCAF1 in the absence of Vpx. Nonetheless, this association was stabilized in the presence of Vpx, suggesting the existence of a ternary complex. The N-terminal PARP-like domain of TASOR is involved in DCAF1 binding, but not in Vpx binding. We also characterized a series of HIV-2 Vpx point mutants impaired in TASOR degradation, while still degrading SAMHD1. Vpx mutants ability to degrade TASOR correlated with their capacity to enhance HIV-1 minigenome expression as expected. Strikingly, several Vpx mutants impaired for TASOR degradation, but not for SAMHD1 degradation, had a reduced binding affinity for DCAF1, but not for TASOR. In macrophages, Vpx R34A-R42A and Vpx R42A-Q47A-V48A, strongly impaired in DCAF1, but not in TASOR binding, could not degrade TASOR, while being efficient in degrading SAMHD1. Altogether, our results highlight the central role of a robust Vpx-DCAF1 association to trigger TASOR degradation. We then propose a model in which Vpx interacts with both TASOR and DCAF1 to stabilize a TASOR-DCAF1 complex. Furthermore, our work identifies Vpx mutants enabling the study of HUSH restriction independently from SAMHD1 restriction in primary myeloid cells. Human Immunodeficiency Virus (HIV) is still a major public health issue. The understanding of the molecular battle occurring during viral infection, between HIV components and cellular antiviral factors, the so-called restriction factors, is a key determinant for new treatment development. Namely, HIV auxiliary proteins are powerful to induce the downregulation of cellular restriction factors by hijacking the Ubiquitin/proteasome pathway, in order to facilitate the completion of a well-processed HIV replication cycle. For instance, HIV-2 Vpx eases reverse transcription in myeloid cells by counteracting the SAMDH1 restriction factor. More recently, we discovered the ability of Vpx to induce the degradation of the HUSH epigenetic repressor complex to favor in turn, the expression of the provirus. In this study, we uncovered the mechanisms by which Vpx antagonizes TASOR, the core subunit of the HUSH complex. We highlighted key differences between Vpx-induced TASOR and SAMHD1 degradation. These findings will help to propose strategies to study or to target either HUSH or SAMHD1, especially in myeloid cells where SAMHD1 restriction operates.
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Affiliation(s)
| | - Roy Matkovic
- Institut Cochin, Université de Paris, INSERM U1016, Paris, France
| | - Pauline Larrous
- Institut Cochin, Université de Paris, INSERM U1016, Paris, France
| | - Marina Morel
- Institut Cochin, Université de Paris, INSERM U1016, Paris, France
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Dybas JM, Lum KK, Kulej K, Reyes ED, Lauman R, Charman M, Purman CE, Steinbock RT, Grams N, Price AM, Mendoza L, Garcia BA, Weitzman MD. Adenovirus Remodeling of the Host Proteome and Host Factors Associated with Viral Genomes. mSystems 2021; 6:e0046821. [PMID: 34463575 DOI: 10.1128/msystems.00468-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/09/2021] [Indexed: 12/22/2022] Open
Abstract
Viral infections are associated with extensive remodeling of the cellular proteome. Viruses encode gene products that manipulate host proteins to redirect cellular processes or subvert antiviral immune responses. Adenovirus (AdV) encodes proteins from the early E4 region which are necessary for productive infection. Some cellular antiviral proteins are known to be targeted by AdV E4 gene products, resulting in their degradation or mislocalization. However, the full repertoire of host proteome changes induced by viral E4 proteins has not been defined. To identify cellular proteins and processes manipulated by viral products, we developed a global, unbiased proteomics approach to analyze changes to the host proteome during infection with adenovirus serotype 5 (Ad5) virus. We used whole-cell proteomics to measure total protein abundances in the proteome during Ad5 infection. Since host antiviral proteins can antagonize viral infection by associating with viral genomes and inhibiting essential viral processes, we used Isolation of Proteins on Nascent DNA (iPOND) proteomics to identify proteins associated with viral genomes during infection with wild-type Ad5 or an E4 mutant virus. By integrating these proteomics data sets, we identified cellular factors that are degraded in an E4-dependent manner or are associated with the viral genome in the absence of E4 proteins. We further show that some identified proteins exert inhibitory effects on Ad5 infection. Our systems-level analysis reveals cellular processes that are manipulated during Ad5 infection and points to host factors counteracted by early viral proteins as they remodel the host proteome to promote efficient infection. IMPORTANCE Viral infections induce myriad changes to the host cell proteome. As viruses harness cellular processes and counteract host defenses, they impact abundance, post-translational modifications, interactions, or localization of cellular proteins. Elucidating the dynamic changes to the cellular proteome during viral replication is integral to understanding how virus-host interactions influence the outcome of infection. Adenovirus encodes early gene products from the E4 genomic region that are known to alter host response pathways and promote replication, but the full extent of proteome modifications they mediate is not known. We used an integrated proteomics approach to quantitate protein abundance and protein associations with viral DNA during virus infection. Systems-level analysis identifies cellular proteins and processes impacted in an E4-dependent manner, suggesting ways that adenovirus counteracts potentially inhibitory host defenses. This study provides a global view of adenovirus-mediated proteome remodeling, which can serve as a model to investigate virus-host interactions of DNA viruses.
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Affiliation(s)
- Joseph M Dybas
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Krystal K Lum
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Katarzyna Kulej
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Emigdio D Reyes
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Richard Lauman
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Penn Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Matthew Charman
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Caitlin E Purman
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert T Steinbock
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Nicholas Grams
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Alexander M Price
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lydia Mendoza
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Penn Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Matthew D Weitzman
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Penn Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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Bauby H, Ward CC, Hugh-White R, Swanson CM, Schulz R, Goujon C, Malim MH. HIV-1 Vpr Induces Widespread Transcriptomic Changes in CD4 + T Cells Early Postinfection. mBio 2021; 12:e0136921. [PMID: 34154423 PMCID: PMC8263007 DOI: 10.1128/mbio.01369-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 05/19/2021] [Indexed: 12/12/2022] Open
Abstract
The interactions between a virus and its host are complex but can be broadly categorized as either viral manipulation of cellular functions or cellular responses to infection. These processes begin at the earliest point of contact between virus and cell and frequently result in changes to cellular gene expression, making genome-wide transcriptomics a useful tool to study them. Several previous studies have used transcriptomics to evaluate the cellular responses to human immunodeficiency virus type 1 (HIV-1) infection; however, none have examined events in primary CD4+ T cells during the first 24 h of infection. Here, we analyzed CD4+ T cells at 4.5, 8, 12, 24, and 48 h following infection. We describe global changes to host gene expression commencing at 4.5 h postinfection and evolving over the ensuing time points. We identify upregulation of genes related to innate immunity, cytokine production, and apoptosis and downregulation of those involved in transcription and translation. We further demonstrate that the viral accessory protein Vpr is necessary for almost all gene expression changes seen at 12 h postinfection and the majority of those seen at 48 h. Identifying this new role for Vpr not only provides fresh perspective on its possible function but also adds further insight into the interplay between HIV-1 and its host at the cellular level. IMPORTANCE HIV-1, while now treatable, remains an important human pathogen causing significant morbidity and mortality globally. The virus predominantly infects CD4+ T cells and, if not treated with medication, ultimately causes their depletion, resulting in AIDS and death. Further refining our understanding of the interaction between HIV-1 and these cells has the potential to inform further therapeutic development. Previous studies have used transcriptomics to assess gene expression changes in CD4+ T cells following HIV-1 infection; here, we provide a detailed examination of changes occurring in the first 24 h of infection. Importantly, we define the viral protein Vpr as essential for the changes observed at this early stage. This finding has significance for understanding the role of Vpr in infection and pathogenesis and also for interpreting previous transcriptomic analyses of HIV-1 infection.
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Affiliation(s)
- Hélène Bauby
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Christopher C. Ward
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Rupert Hugh-White
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Chad M. Swanson
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Reiner Schulz
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Caroline Goujon
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Michael H. Malim
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
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