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Flores Cortes E, Saddoris SM, Owens AK, Gibeault R, Depledge DP, Schang LM. Histone H2A variant H2A.B is enriched in transcriptionally active and replicating HSV-1 lytic chromatin. J Virol 2024; 98:e0201523. [PMID: 38451083 PMCID: PMC11019955 DOI: 10.1128/jvi.02015-23] [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: 12/22/2023] [Accepted: 02/19/2024] [Indexed: 03/08/2024] Open
Abstract
Herpes simplex virus 1 (HSV-1) transcription is restricted in latently infected neurons and the genomes are in mostly silenced chromatin, whereas all viral genes are transcribed in lytically infected cells, in which the genomes are dynamically chromatinized. Epigenetic regulation modulates HSV-1 transcription during lytic, latent, and reactivating infections but the precise mechanisms are not fully defined. Nucleosomes are dynamic: they slide, breathe, assemble, and disassemble. We and others have proposed that the most dynamic HSV-1 chromatin is transcriptionally competent, whereas the least dynamic is silenced. However, the mechanisms yielding the unusually dynamic viral chromatin remain unknown. Histone variants affect nucleosome dynamics. The dynamics of H2A, H2A.X, and macroH2A were enhanced in infected cells, whereas those of H2A.B were uniquely decreased. We constructed stably transduced cells expressing tagged histone H2A, H2A.B, macroH2A, or H2B, which assembles the H2A/H2B nucleosome dimers with all H2A variants. All H2A variants, as well as ectopic and endogenous H2B were assembled into HSV-1 chromatin evenly throughout the genome but canonical H2A was relatively depleted whereas H2A.B was enriched, particularly in the most dynamic viral chromatin. When viral transcription and DNA replication were restricted, H2A.B became as depleted from the viral chromatin through the entire genome as H2A. We propose that lytic HSV-1 nucleosomes are enriched in the dynamic variant H2A.B/H2B dimers to promote HSV-1 chromatin dynamics and transcriptional competency and conclude that the dynamics of HSV-1 chromatin are determined in part by the H2A variants. IMPORTANCE Herpes simplex virus 1 (HSV-1) transcription is epigenetically regulated during latent and lytic infections, and epigenetic inhibitors have been proposed as potential antiviral drugs to modulate latency and reactivation. However, the detailed epigenetic mechanisms of regulation of HSV-1 transcription have not been fully characterized and may differ from those regulating cellular transcription. Whereas lytic HSV-1 chromatin is unusually dynamic, latent silenced HSV-1 chromatin is not. The mechanisms resulting in the unique dynamics of the lytic chromatin remain unknown. Here we identify the enrichment of the highly dynamic histone 2A variant H2A in the most dynamic viral chromatin, which provides a mechanistic understanding of its unique dynamics. Future work to identify the mechanisms of enrichment in H2A.B on the viral chromatin may identify novel druggable epigenetic regulators that modulate HSV-1 latency and reactivation.
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Affiliation(s)
- Esteban Flores Cortes
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Sarah M. Saddoris
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Arryn K. Owens
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Rebecca Gibeault
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel P. Depledge
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Hannover, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Luis M. Schang
- Baker Institute for Animal Health and Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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Flores E, Saddoris SM, Owens AK, Gibeault R, Depledge DP, Schang LM. Histone H2A variant H2A.B is enriched in transcriptionally active HSV-1 lytic chromatin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573075. [PMID: 38187672 PMCID: PMC10769327 DOI: 10.1101/2023.12.22.573075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Herpes simplex virus 1 (HSV-1) transcription is restricted in latently infected neurons and the genomes are in mostly silenced chromatin, whereas all viral genes are transcribed in lytically infected cells, in which the genomes are dynamically chromatinized. Epigenetic regulation modulates HSV-1 transcription during lytic, latent, and reactivating infections, but the precise mechanisms are not fully defined. Nucleosomes are dynamic; they slide, breathe, assemble and disassemble. We and others have proposed that the most dynamic HSV-1 chromatin is transcriptionally competent whereas the least dynamic is silenced. However, the mechanisms yielding the unusually dynamic viral chromatin remain unknown. Histone variants affect nucleosome dynamics. The dynamics of H2A, H2A.X and macroH2A were enhanced in infected cells, whereas those of H2A.B uniquely decreased. We constructed stably transduced cells expressing tagged histone H2A, H2A.B, macroH2A, or H2B, which assembles the H2A/H2B nucleosome dimers with all H2A variants. All H2A variants, ectopic, and endogenous H2B, were assembled into HSV-1 chromatin evenly throughout the genome, but canonical H2A was relatively depleted from the viral chromatin whereas H2A.B was enriched in the most dynamic viral chromatin. When viral transcription was restricted, H2A.B became as depleted from the viral chromatin through the entire genome as H2A. We propose that lytic HSV-1 nucleosomes are enriched in the dynamic variant H2A.B/H2B dimers to promote HSV-1 chromatin dynamics and transcriptional competency, and conclude that the dynamics of HSV-1 chromatin are determined in part by the H2A variants. Importance HSV-1 transcription is epigenetically regulated during latent and lytic infections, and epigenetic inhibitors have been proposed as potential antiviral drugs to modulate latency and reactivation. However, the detailed mechanisms of regulation of HSV-1 transcription by epigenetics have not been fully characterized and may differ from those regulating cellular transcription. In particular, the lytic HSV-1 chromatin is unusually dynamic, whereas the latent silenced one is not, but the mechanisms resulting in the unique dynamics of the lytic chromatin remain unknown. Here we identify the enrichment on the highly dynamic histone 2A variant H2A in the most dynamic viral chromatin, which provides a mechanistic understanding for its unique dynamics. Future work to identify the mechanisms of enrichment in H2A.B on the viral chromatin may identify novel druggable epigenetic regulators that modulate HSV-1 latency and reactivation.
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Jan Fada B, Guha U, Zheng Y, Reward E, Kaadi E, Dourra A, Gu H. A Novel Recognition by the E3 Ubiquitin Ligase of HSV-1 ICP0 Enhances the Degradation of PML Isoform I to Prevent ND10 Reformation in Late Infection. Viruses 2023; 15:v15051070. [PMID: 37243155 DOI: 10.3390/v15051070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/24/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
Upon viral entry, components of ND10 nuclear bodies converge with incoming DNA to repress viral expression. The infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) contains a RING-type E3 ubiquitin ligase that targets the ND10 organizer, PML, for proteasomal degradation. Consequently, ND10 components are dispersed and viral genes are activated. Previously, we reported that ICP0 E3 differentiates two similar substrates, PML isoforms I and II, and demonstrated that SUMO-interaction has profound regulatory effects on PML II degradation. In the present study, we investigated elements that regulate the PML I degradation and found that: (i) two regions of ICP0 flanking the RING redundantly facilitate the degradation of PML I; (ii) downstream of the RING, the SUMO-interaction motif located at residues 362-364 (SIM362-364) targets the SUMOylated PML I in the same manner as that of PML II; (iii) upstream of the RING, the N-terminal residues 1-83 mediate PML I degradation regardless of its SUMOylation status or subcellular localization; (iv) the reposition of residues 1-83 to downstream of the RING does not affect its function in PML I degradation; and (v) the deletion of 1-83 allows the resurgence of PML I and reformation of ND10-like structures late in HSV-1 infection. Taken together, we identified a novel substrate recognition specific for PML I, by which ICP0 E3 enforces a continuous PML I degradation throughout the infection to prevent the ND10 reformation.
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Affiliation(s)
- Behdokht Jan Fada
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Udayan Guha
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Yi Zheng
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Eleazar Reward
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Elie Kaadi
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Ayette Dourra
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Haidong Gu
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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Niu X, Zhang L, Wu Y, Zong Z, Wang B, Liu J, Zhang L, Zhou F. Biomolecular condensates: Formation mechanisms, biological functions, and therapeutic targets. MedComm (Beijing) 2023; 4:e223. [PMID: 36875159 PMCID: PMC9974629 DOI: 10.1002/mco2.223] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/20/2023] [Accepted: 02/02/2023] [Indexed: 03/06/2023] Open
Abstract
Biomolecular condensates are cellular structures composed of membraneless assemblies comprising proteins or nucleic acids. The formation of these condensates requires components to change from a state of solubility separation from the surrounding environment by undergoing phase transition and condensation. Over the past decade, it has become widely appreciated that biomolecular condensates are ubiquitous in eukaryotic cells and play a vital role in physiological and pathological processes. These condensates may provide promising targets for the clinic research. Recently, a series of pathological and physiological processes have been found associated with the dysfunction of condensates, and a range of targets and methods have been demonstrated to modulate the formation of these condensates. A more extensive description of biomolecular condensates is urgently needed for the development of novel therapies. In this review, we summarized the current understanding of biomolecular condensates and the molecular mechanisms of their formation. Moreover, we reviewed the functions of condensates and therapeutic targets for diseases. We further highlighted the available regulatory targets and methods, discussed the significance and challenges of targeting these condensates. Reviewing the latest developments in biomolecular condensate research could be essential in translating our current knowledge on the use of condensates for clinical therapeutic strategies.
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Affiliation(s)
- Xin Niu
- Department of Otolaryngology Head and Neck Surgery The First Affiliated Hospital of Soochow University Suzhou China.,MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network Life Sciences Institute Zhejiang University Hangzhou China
| | - Lei Zhang
- Department of Orthopedics The First Affiliated Hospital of Wenzhou Medical University Wenzhou China
| | - Yuchen Wu
- Department of Clinical Medicine, The First School of Medicine Wenzhou Medical University Wenzhou China
| | - Zhi Zong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network Life Sciences Institute Zhejiang University Hangzhou China
| | - Bin Wang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network Life Sciences Institute Zhejiang University Hangzhou China
| | - Jisheng Liu
- Department of Otolaryngology Head and Neck Surgery The First Affiliated Hospital of Soochow University Suzhou China
| | - Long Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network Life Sciences Institute Zhejiang University Hangzhou China
| | - Fangfang Zhou
- Institutes of Biology and Medical Science Soochow University Suzhou China
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Jiang B, Wang J, Cao M, Jin H, Liu W, Cheng J, Zhou L, Xu J, Li Y. Differential Replication and Cytokine Response between Vaccine and Very Virulent Marek's Disease Viruses in Spleens and Bursas during Latency and Reactivation. Viruses 2022; 15:6. [PMID: 36680047 PMCID: PMC9864003 DOI: 10.3390/v15010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/13/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
Marek's disease virus (MDV) infection results in Marek's disease (MD) in chickens, a lymphoproliferative and oncogenic deadly disease, leading to severe economic losses. The spleen and bursa are the most important lymphoid and major target organs for MDV replication. The immune response elicited by MDV replication in the spleen and bursa is critical for the formation of latent MDV infection and reactivation. However, the mechanism of the host immune response induced by MDV in these key lymphoid organs during the latent and reactivation infection phases is not well understood. In the study, we focused on the replication dynamics of a vaccine MDV strain MDV/CVI988 and a very virulent MDV strain MDV/RB1B in the spleen and bursa in the latent and reactivation infection phases (7-28 days post-inoculation [dpi]), as well as the expression of some previously characterized immune-related molecules. The results showed that the replication ability of MDV/RB1B was significantly stronger than that of MDV/CVI988 within 28 days post-infection, and the replication levels of both MDV strains in the spleen were significantly higher than those in the bursa. During the latent and reactivation phase of MDV infection (7-28 dpi), the transcriptional upregulation of chicken IL-1β, IL6, IL-8L1 IFN-γ and PML in the spleen and bursa induced by MDV/RB1B infection was overall stronger than that of MDV/CVI988. However, compared to MDV/RB1Binfection, MDV/CVI988 infection resulted in a more effective transcriptional activation of CCL4 in the latent infection phase (7-14 dpi), which may be a characteristic distinguishing MDV vaccine strain from the very virulent strain.
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Affiliation(s)
- Bo Jiang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Jing Wang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Mengyao Cao
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, China
| | - Huan Jin
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Wenxiao Liu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Jing Cheng
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Linyi Zhou
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
| | - Jian Xu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730070, China
| | - Yongqing Li
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
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6
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St. Leger AJ, Koelle DM, Kinchington PR, Verjans GMGM. Local Immune Control of Latent Herpes Simplex Virus Type 1 in Ganglia of Mice and Man. Front Immunol 2021; 12:723809. [PMID: 34603296 PMCID: PMC8479180 DOI: 10.3389/fimmu.2021.723809] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/26/2021] [Indexed: 12/28/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a prevalent human pathogen. HSV-1 genomes persist in trigeminal ganglia neuronal nuclei as chromatinized episomes, while epithelial cells are typically killed by lytic infection. Fluctuations in anti-viral responses, broadly defined, may underlay periodic reactivations. The ganglionic immune response to HSV-1 infection includes cell-intrinsic responses in neurons, innate sensing by several cell types, and the infiltration and persistence of antigen-specific T-cells. The mechanisms specifying the contrasting fates of HSV-1 in neurons and epithelial cells may include differential genome silencing and chromatinization, dictated by variation in access of immune modulating viral tegument proteins to the cell body, and protection of neurons by autophagy. Innate responses have the capacity of recruiting additional immune cells and paracrine activity on parenchymal cells, for example via chemokines and type I interferons. In both mice and humans, HSV-1-specific CD8 and CD4 T-cells are recruited to ganglia, with mechanistic studies suggesting active roles in immune surveillance and control of reactivation. In this review we focus mainly on HSV-1 and the TG, comparing and contrasting where possible observational, interventional, and in vitro studies between humans and animal hosts.
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Affiliation(s)
- Anthony J. St. Leger
- Department of Ophthalmology and Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - David M. Koelle
- Department of Medicine, University of Washington, Seattle, WA, United States
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States
- Benaroya Research Institute, Seattle, WA, United States
| | - Paul R. Kinchington
- Department of Ophthalmology and Molecular Microbiology and Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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Xiao K, Xiong D, Chen G, Yu J, Li Y, Chen K, Zhang L, Xu Y, Xu Q, Huang X, Gao A, Cao K, Yan K, Dai J, Hu X, Ruan Y, Fu Z, Li G, Cao G. RUNX1-mediated alphaherpesvirus-host trans-species chromatin interaction promotes viral transcription. SCIENCE ADVANCES 2021; 7:7/26/eabf8962. [PMID: 34162542 PMCID: PMC8221632 DOI: 10.1126/sciadv.abf8962] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/10/2021] [Indexed: 05/04/2023]
Abstract
Like most DNA viruses, herpesviruses precisely deliver their genomes into the sophisticatedly organized nuclei of the infected host cells to initiate subsequent transcription and replication. However, it remains elusive how the viral genome specifically interacts with the host genome and hijacks host transcription machinery. Using pseudorabies virus (PRV) as model virus, we performed chromosome conformation capture assays to demonstrate a genome-wide specific trans-species chromatin interaction between the virus and host. Our data show that the PRV genome is delivered by the host DNA binding protein RUNX1 into the open chromatin and active transcription zone. This facilitates virus hijacking host RNAPII to efficiently transcribe viral genes, which is significantly inhibited by either a RUNX1 inhibitor or RNA interference. Together, these findings provide insights into the chromatin interaction between viral and host genomes and identify new areas of research to advance the understanding of herpesvirus genome transcription.
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Affiliation(s)
- Ke Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Dan Xiong
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Gong Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinsong Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Yue Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Kening Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lu Zhang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Yangyang Xu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Qian Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Xi Huang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Anran Gao
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai Cao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Keji Yan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinxia Dai
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Xueying Hu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Yijun Ruan
- Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Zhenfang Fu
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
| | - Guoliang Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
- College of Biomedicine and Health, Huazhong Agricultural University, Wuhan 430070, China
| | - Gang Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
- College of Biomedicine and Health, Huazhong Agricultural University, Wuhan 430070, China
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8
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Clinical Manifestations and Epigenetic Regulation of Oral Herpesvirus Infections. Viruses 2021; 13:v13040681. [PMID: 33920978 PMCID: PMC8071331 DOI: 10.3390/v13040681] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 12/20/2022] Open
Abstract
The oral cavity is often the first site where viruses interact with the human body. The oral epithelium is a major site of viral entry, replication and spread to other cell types, where chronic infection can be established. In addition, saliva has been shown as a primary route of person-to-person transmission for many viruses. From a clinical perspective, viral infection can lead to several oral manifestations, ranging from common intraoral lesions to tumors. Despite the clinical and biological relevance of initial oral infection, little is known about the mechanism of regulation of the viral life cycle in the oral cavity. Several viruses utilize host epigenetic machinery to promote their own life cycle. Importantly, viral hijacking of host chromatin-modifying enzymes can also lead to the dysregulation of host factors and in the case of oncogenic viruses may ultimately play a role in promoting tumorigenesis. Given the known roles of epigenetic regulation of viral infection, epigenetic-targeted antiviral therapy has been recently explored as a therapeutic option for chronic viral infection. In this review, we highlight three herpesviruses with known roles in oral infection, including herpes simplex virus type 1, Epstein–Barr virus and Kaposi’s sarcoma-associated herpesvirus. We focus on the respective oral clinical manifestations of these viruses and their epigenetic regulation, with a specific emphasis on the viral life cycle in the oral epithelium.
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The Role of ND10 Nuclear Bodies in Herpesvirus Infection: A Frenemy for the Virus? Viruses 2021; 13:v13020239. [PMID: 33546431 PMCID: PMC7913651 DOI: 10.3390/v13020239] [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: 01/05/2021] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022] Open
Abstract
Nuclear domains 10 (ND10), a.k.a. promyelocytic leukemia nuclear bodies (PML-NBs), are membraneless subnuclear domains that are highly dynamic in their protein composition in response to cellular cues. They are known to be involved in many key cellular processes including DNA damage response, transcription regulation, apoptosis, oncogenesis, and antiviral defenses. The diversity and dynamics of ND10 residents enable them to play seemingly opposite roles under different physiological conditions. Although the molecular mechanisms are not completely clear, the pro- and anti-cancer effects of ND10 have been well established in tumorigenesis. However, in herpesvirus research, until the recently emerged evidence of pro-viral contributions, ND10 nuclear bodies have been generally recognized as part of the intrinsic antiviral defenses that converge to the incoming viral DNA to inhibit the viral gene expression. In this review, we evaluate the newly discovered pro-infection influences of ND10 in various human herpesviruses and analyze their molecular foundation along with the traditional antiviral functions of ND10. We hope to shed light on the explicit role of ND10 in both the lytic and latent cycles of herpesvirus infection, which is imperative to the delineation of herpes pathogenesis and the development of prophylactic/therapeutic treatments for herpetic diseases.
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10
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Kim ET, Dybas JM, Kulej K, Reyes ED, Price AM, Akhtar LN, Orr A, Garcia BA, Boutell C, Weitzman MD. Comparative proteomics identifies Schlafen 5 (SLFN5) as a herpes simplex virus restriction factor that suppresses viral transcription. Nat Microbiol 2021; 6:234-245. [PMID: 33432153 PMCID: PMC7856100 DOI: 10.1038/s41564-020-00826-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023]
Abstract
Intrinsic antiviral host factors confer cellular defence by limiting virus replication and are often counteracted by viral countermeasures. We reasoned that host factors that inhibit viral gene expression could be identified by determining proteins bound to viral DNA (vDNA) in the absence of key viral antagonists. Herpes simplex virus 1 (HSV-1) expresses E3 ubiquitin-protein ligase ICP0 (ICP0), which functions as an E3 ubiquitin ligase required to promote infection. Cellular substrates of ICP0 have been discovered as host barriers to infection but the mechanisms for inhibition of viral gene expression are not fully understood. To identify restriction factors antagonized by ICP0, we compared proteomes associated with vDNA during HSV-1 infection with wild-type virus and a mutant lacking functional ICP0 (ΔICP0). We identified the cellular protein Schlafen family member 5 (SLFN5) as an ICP0 target that binds vDNA during HSV-1 ΔICP0 infection. We demonstrated that ICP0 mediates ubiquitination of SLFN5, which leads to its proteasomal degradation. In the absence of ICP0, SLFN5 binds vDNA to repress HSV-1 transcription by limiting accessibility of RNA polymerase II to viral promoters. These results highlight how comparative proteomics of proteins associated with viral genomes can identify host restriction factors and reveal that viral countermeasures can overcome SLFN antiviral activity.
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Affiliation(s)
- Eui Tae Kim
- 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 Microbiology and Immunology, Jeju National University School of Medicine, Jeju, Republic of Korea
| | - 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
| | - Katarzyna Kulej
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA,Department of Biochemistry and Biophysics, 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
| | - 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
| | - Lisa N. Akhtar
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA,Division of Infectious Diseases, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Pennsylvania, USA
| | - Ann Orr
- MRC-University of Glasgow Center for Virus Research, Glasgow, Scotland, United Kingdom
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA,Epigenetics Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Chris Boutell
- MRC-University of Glasgow Center for Virus Research, Glasgow, Scotland, United Kingdom
| | - 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,Epigenetics Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA,Correspondence: All correspondence and request for materials should be addressed to Matthew D. Weitzman (, )
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Emerging Role of PYHIN Proteins as Antiviral Restriction Factors. Viruses 2020; 12:v12121464. [PMID: 33353088 PMCID: PMC7767131 DOI: 10.3390/v12121464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/11/2022] Open
Abstract
Innate immune sensors and restriction factors are cellular proteins that synergize to build an effective first line of defense against viral infections. Innate sensors are usually constitutively expressed and capable of detecting pathogen-associated molecular patterns (PAMPs) via specific pattern recognition receptors (PRRs) to stimulate the immune response. Restriction factors are frequently upregulated by interferons (IFNs) and may inhibit viral pathogens at essentially any stage of their replication cycle. Members of the Pyrin and hematopoietic interferon-inducible nuclear (HIN) domain (PYHIN) family have initially been recognized as important sensors of foreign nucleic acids and activators of the inflammasome and the IFN response. Accumulating evidence shows, however, that at least three of the four members of the human PYHIN family restrict viral pathogens independently of viral sensing and innate immune activation. In this review, we provide an overview on the role of human PYHIN proteins in the innate antiviral immune defense and on viral countermeasures.
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12
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Gu H, Jan Fada B. Specificity in Ubiquitination Triggered by Virus Infection. Int J Mol Sci 2020; 21:E4088. [PMID: 32521668 PMCID: PMC7313089 DOI: 10.3390/ijms21114088] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023] Open
Abstract
Ubiquitination is a prominent posttranslational modification, in which the ubiquitin moiety is covalently attached to a target protein to influence protein stability, interaction partner and biological function. All seven lysine residues of ubiquitin, along with the N-terminal methionine, can each serve as a substrate for further ubiquitination, which effectuates a diverse combination of mono- or poly-ubiquitinated proteins with linear or branched ubiquitin chains. The intricately composed ubiquitin codes are then recognized by a large variety of ubiquitin binding domain (UBD)-containing proteins to participate in the regulation of various pathways to modulate the cell behavior. Viruses, as obligate parasites, involve many aspects of the cell pathways to overcome host defenses and subjugate cellular machineries. In the virus-host interactions, both the virus and the host tap into the rich source of versatile ubiquitination code in order to compete, combat, and co-evolve. Here, we review the recent literature to discuss the role of ubiquitin system as the infection progresses in virus life cycle and the importance of ubiquitin specificity in the regulation of virus-host relation.
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Affiliation(s)
- Haidong Gu
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA;
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13
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Reversal of Epigenetic Silencing Allows Robust HIV-1 Replication in the Absence of Integrase Function. mBio 2020; 11:mBio.01038-20. [PMID: 32487757 PMCID: PMC7267885 DOI: 10.1128/mbio.01038-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While retroviral DNA is synthesized normally after infection by integrase-deficient viruses, the resultant episomal DNA is then epigenetically silenced. Here, we show that expression of the Tax transcription factor encoded by a second human retrovirus, HTLV-1, prevents or reverses the epigenetic silencing of unintegrated HIV-1 DNA and instead induces the addition of activating epigenetic marks and the recruitment of NF-κB/Rel proteins to the HIV-1 LTR promoter. Moreover, in the presence of Tax, the HIV-1 DNA circles that form in the absence of integrase function are not only efficiently transcribed but also support a spreading, pathogenic integrase-deficient (IN−) HIV-1 infection. Thus, retroviruses have the potential to replicate without integration, as is indeed seen with HBV. Moreover, these data suggest that integrase inhibitors may be less effective in the treatment of HIV-1 infections in individuals who are also coinfected with HTLV-1. Integration of the proviral DNA intermediate into the host cell genome normally represents an essential step in the retroviral life cycle. While the reason(s) for this requirement remains unclear, it is known that unintegrated proviral DNA is epigenetically silenced. Here, we demonstrate that human immunodeficiency virus 1 (HIV-1) mutants lacking a functional integrase (IN) can mount a robust, spreading infection in cells expressing the Tax transcription factor encoded by human T-cell leukemia virus 1 (HTLV-1). In these cells, HIV-1 forms episomal DNA circles, analogous to hepatitis B virus (HBV) covalently closed circular DNAs (cccDNAs), that are transcriptionally active and fully capable of supporting viral replication. In the presence of Tax, induced NF-κB proteins are recruited to the long terminal repeat (LTR) promoters present on unintegrated HIV-1 DNA, and this recruitment in turn correlates with the loss of inhibitory epigenetic marks and the acquisition of activating marks on histones bound to viral DNA. Therefore, HIV-1 is capable of replication in the absence of integrase function if the epigenetic silencing of unintegrated viral DNA can be prevented or reversed.
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14
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Effect of SUMO-SIM Interaction on the ICP0-Mediated Degradation of PML Isoform II and Its Associated Proteins in Herpes Simplex Virus 1 Infection. J Virol 2020; 94:JVI.00470-20. [PMID: 32295906 DOI: 10.1128/jvi.00470-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/01/2020] [Indexed: 12/22/2022] Open
Abstract
ND10 nuclear bodies, as part of the intrinsic defenses, impose repression on incoming DNA. Infected cell protein 0 (ICP0), an E3 ubiquitin ligase of herpes simplex virus 1 (HSV-1), can derepress viral genes by degrading ND10 organizers to disrupt ND10. These events are part of the initial tug of war between HSV-1 and host, which determines the ultimate outcome of infection. Previously, we reported that ICP0 differentially recognizes promyelocytic leukemia (PML) isoforms. ICP0 depends on a SUMO-interaction motif located at residues 362 to 364 (SIM362-364) to trigger the degradation of PML isoforms II, IV, and VI, while using a bipartite sequence flanking the RING domain to degrade PML I. In this study, we investigated how the SUMO-SIM interaction regulates the degradation of PML II and PML II-associated proteins in ND10. We found that (i) the same regulatory mechanism for PML II degradation was detected in cells permissive or nonpermissive to the ICP0-null virus; (ii) the loss of a single SIM362-364 motif was restored by the presence of four consecutive SIMs from RNF4, but was not rescued by only two of the RNF4 SIMs; (iii) the loss of three C-terminal SIMs of ICP0 was fully restored by four RNF4 SIMs and also partially rescued by two RNF4 SIMs; and (iv) a PML II mutant lacking both lysine SUMOylation and SIM was not recognized by ICP0 for degradation, but was localized to ND10 and mitigated the degradation of other ND10 components, leading to delayed viral production. Taken together, SUMO regulates ICP0 substrate recognition via multiple fine-tuned mechanisms in HSV-1 infection.IMPORTANCE HSV-1 ICP0 is a multifunctional immediate early protein key to effective replication in the HSV-1 lytic cycle and reactivation in the latent cycle. ICP0 transactivates gene expression by orchestrating an overall mitigation in host intrinsic/innate restrictions. How ICP0 coordinates its multiple active domains and its diverse protein-protein interactions is a key question in understanding the HSV-1 life cycle and pathogenesis. The present study focuses on delineating the regulatory effects of the SUMO-SIM interaction on ICP0 E3 ubiquitin ligase activity regarding PML II degradation. For the first time, we discovered the importance of multivalency in the PML II-ICP0 interaction network and report the involvement of different regulatory mechanisms in PML II recognition by ICP0 in HSV-1 infection.
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15
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RNA Polymerase II Promoter-Proximal Pausing and Release to Elongation Are Key Steps Regulating Herpes Simplex Virus 1 Transcription. J Virol 2020; 94:JVI.02035-19. [PMID: 31826988 DOI: 10.1128/jvi.02035-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/03/2019] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) genes are transcribed by cellular RNA polymerase II (Pol II). Expression of viral immediate early (α) genes is followed sequentially by early (β), late (γ1), and true late (γ2) genes. We used precision nuclear run-on with deep sequencing to map and to quantify Pol II on the HSV-1(F) genome with single-nucleotide resolution. Approximately 30% of total Pol II relocated to viral genomes within 3 h postinfection (hpi), when it occupied genes of all temporal classes. At that time, Pol II on α genes accumulated most heavily at promoter-proximal pause (PPP) sites located ∼60 nucleotides downstream of the transcriptional start site, while β genes bore Pol II more evenly across gene bodies. At 6 hpi, Pol II increased on γ1 and γ2 genes while Pol II pausing remained prominent on α genes. At that time, average cytoplasmic mRNA expression from α and β genes decreased, relative to levels at 3 hpi, while γ1 relative expression increased slightly and γ2 expression increased more substantially. Cycloheximide treatment during the first 3 h reduced the amount of Pol II associated with the viral genome and confined most of the remaining Pol II to α gene PPP sites. Inhibition of both cyclin-dependent kinase 9 activity and viral DNA replication reduced Pol II on the viral genome and restricted much of the remaining Pol II to PPP sites.IMPORTANCE These data suggest that viral transcription is regulated not only by Pol II recruitment to viral genes but also by control of elongation into viral gene bodies. We provide a detailed map of Pol II occupancy on the HSV-1 genome that clarifies features of the viral transcriptome, including the first identification of Pol II PPP sites. The data indicate that Pol II is recruited to late genes early in infection. Comparing α and β gene occupancy at PPP sites and gene bodies suggests that Pol II is released more efficiently into the bodies of β genes than α genes at 3 hpi and that repression of α gene expression late in infection is mediated by prolonged promoter-proximal pausing. In addition, DNA replication is required to maintain full Pol II occupancy on viral DNA and to promote elongation on late genes later in infection.
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16
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Schneider SM, Pritchard SM, Wudiri GA, Trammell CE, Nicola AV. Early Steps in Herpes Simplex Virus Infection Blocked by a Proteasome Inhibitor. mBio 2019; 10:e00732-19. [PMID: 31088925 PMCID: PMC6520451 DOI: 10.1128/mbio.00732-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 04/08/2019] [Indexed: 12/17/2022] Open
Abstract
Viruses commandeer host cell 26S proteasome activity to promote viral entry, gene expression, replication, assembly, and egress. Proteasomal degradation activity is critical for herpes simplex virus (HSV) infection. The proteasome inhibitor bortezomib (also known as Velcade and PS-341) is a clinically effective antineoplastic drug that is FDA approved for treatment of hematologic malignancies such as multiple myeloma and mantle cell lymphoma. Low nanomolar concentrations of bortezomib inhibited infection by HSV-1, HSV-2, and acyclovir-resistant strains. Inhibition coincided with minimal cytotoxicity. Bortezomib did not affect attachment of HSV to cells or inactivate the virus directly. Bortezomib acted early in HSV infection by perturbing two distinct proteasome-dependent steps that occur within the initial hours of infection: the transport of incoming viral nucleocapsids to the nucleus and the virus-induced disruption of host nuclear domain 10 (ND10) structures. The combination of bortezomib with acyclovir demonstrated synergistic inhibitory effects on HSV infection. Thus, bortezomib is a novel potential therapeutic for HSV with a defined mechanism of action.IMPORTANCE Viruses usurp host cell functions to advance their replicative agenda. HSV relies on cellular proteasome activity for successful infection. Proteasome inhibitors, such as MG132, block HSV infection at multiple stages of the infectious cycle. Targeting host cell processes for antiviral intervention is an unconventional approach that might limit antiviral resistance. Here we demonstrated that the proteasome inhibitor bortezomib, which is a clinically effective cancer drug, has the in vitro features of a promising anti-HSV therapeutic. Bortezomib inhibited HSV infection during the first hours of infection at nanomolar concentrations that were minimally cytotoxic. The mechanism of bortezomib's inhibition of early HSV infection was to halt nucleocapsid transport to the nucleus and to stabilize the ND10 cellular defense complex. Bortezomib and acyclovir acted synergistically to inhibit HSV infection. Overall, we present evidence for the repurposing of bortezomib as a novel antiherpesviral agent and describe specific mechanisms of action.
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Affiliation(s)
- Seth M Schneider
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Suzanne M Pritchard
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - George A Wudiri
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Chasity E Trammell
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Anthony V Nicola
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
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17
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Calil IP, Quadros IPS, Araújo TC, Duarte CEM, Gouveia-Mageste BC, Silva JCF, Brustolini OJB, Teixeira RM, Oliveira CN, Milagres RWMM, Martins GS, Chory J, Reis PAB, Machado JPB, Fontes EPB. A WW Domain-Containing Protein Forms Immune Nuclear Bodies against Begomoviruses. MOLECULAR PLANT 2018; 11:1449-1465. [PMID: 30296599 DOI: 10.1016/j.molp.2018.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 08/27/2018] [Accepted: 09/28/2018] [Indexed: 05/23/2023]
Abstract
The bipartite begomoviruses (Geminiviridae family), which are DNA viruses that replicate in the nucleus of infected cells, encode the nuclear shuttle protein (NSP) to facilitate the translocation of viral DNA from the nucleus to the cytoplasm via nuclear pores. This intracellular trafficking of NSP-DNA complexes is accessorized by the NSP-interacting guanosine triphosphatase (NIG) at the cytosolic side. Here, we report the nuclear redistribution of NIG by AtWWP1, a WW domain-containing protein that forms immune nuclear bodies (NBs) against begomoviruses. We demonstrated that AtWWP1 relocates NIG from the cytoplasm to the nucleus where it is confined to AtWWP1-NBs, suggesting that the NIG-AtWWP1 interaction may interfere with the NIG pro-viral function associated with its cytosolic localization. Consistent with this assumption, loss of AtWWP1 function cuased plants more susceptible to begomovirus infection, whereas overexpression of AtWWP1 enhanced plant resistance to begomovirus. Furthermore, we found that a mutant version of AtWWP1 defective for NB formation was no longer capable of interacting with and relocating NIG to the nucleus and lost its immune function against begomovirus. The antiviral function of AtWWP1-NBs, however, could be antagonized by viral infection that induced either the disruption or a decrease in the number of AtWWP1-NBs. Collectively, these results led us to propose that AtWWP1 organizes nuclear structures into nuclear foci, which provide intrinsic immunity against begomovirus infection.
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Affiliation(s)
- Iara P Calil
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Iana P S Quadros
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Thais C Araújo
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Christiane E M Duarte
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Bianca C Gouveia-Mageste
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - José Cleydson F Silva
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Otávio J B Brustolini
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Ruan M Teixeira
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Cauê N Oliveira
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Rafael W M M Milagres
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Gilberto S Martins
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; Departament of Genetics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute of Biological Studies, La Jolla, CA 92037, USA
| | - Pedro A B Reis
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil
| | - Joao Paulo B Machado
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; Agronomy Institute, Universidade Federal de Viçosa, Campus Florestal, Florestal, Minas Gerais 35690-000, Brazil.
| | - Elizabeth P B Fontes
- Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil; National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000, Brazil.
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Sawyer IA, Bartek J, Dundr M. Phase separated microenvironments inside the cell nucleus are linked to disease and regulate epigenetic state, transcription and RNA processing. Semin Cell Dev Biol 2018; 90:94-103. [PMID: 30017905 DOI: 10.1016/j.semcdb.2018.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/03/2018] [Indexed: 01/01/2023]
Abstract
Proteins and RNAs inside the cell nucleus are organized into distinct phases, also known as liquid-liquid phase separated (LLPS) droplet organelles or nuclear bodies. These regions exist within the spaces between chromatin-rich regions but their function is tightly linked to gene activity. They include major microscopically-observable structures such as the nucleolus, paraspeckle and Cajal body. The biochemical and assembly factors enriched inside these microenvironments regulate chromatin structure, transcription, and RNA processing, and other important cellular functions. Here, we describe published evidence that suggests nuclear bodies are bona fide LLPS droplet organelles and major regulators of the processes listed above. We also outline an updated "Supply or Sequester" model to describe nuclear body function, in which proteins or RNAs are supplied to surrounding genomic regions or sequestered away from their sites of activity. Finally, we describe recent evidence that suggests these microenvironments are both reflective and drivers of diverse pathophysiological states.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jiri Bartek
- Danish Cancer, Society Research Center, Genome Integrity Unit, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States.
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Characterization of Elements Regulating the Nuclear-to-Cytoplasmic Translocation of ICP0 in Late Herpes Simplex Virus 1 Infection. J Virol 2018; 92:JVI.01673-17. [PMID: 29093084 DOI: 10.1128/jvi.01673-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 10/24/2017] [Indexed: 01/16/2023] Open
Abstract
Infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) is an immediate early protein containing a RING-type E3 ubiquitin ligase. It targets several host factors for proteasomal degradation and subsequently activates viral expression. ICP0 has a nuclear localization sequence and functions in the nucleus early during infection. However, later in infection, ICP0 is found solely in the cytoplasm. The molecular mechanism and biological function of the ICP0 nuclear-to-cytoplasmic translocation are not well understood. In this study, we sought to characterize elements important for this translocation. We found that (i) in human embryonic lung fibroblast (HEL) cells, ICP0 C-terminal residues 741 to 775 were necessary but not sufficient for the nuclear-to-cytoplasmic translocation; (ii) the loss of ICP0 E3 ubiquitin ligase activity, which led to defective viral replication in nonpermissive cells, also caused mutant ICP0 to be retained in the nucleus of HEL cells; (iii) in permissive U2OS cells, however, ICP0 lacking E3 ligase activity was translocated to the cytoplasm at a pace faster than that of wild-type ICP0, suggesting that nuclear retention of ICP0 occurs in an ICP0 E3 ligase-dependent manner; and (iv) the ICP0 C terminus and late viral proteins cooperate in order to overcome nuclear retention and stimulate ICP0 cytoplasmic translocation. Taken together, less ICP0 nuclear retention may contribute to the permissiveness of U2OS cells to HSV-1 in the absence of functional ICP0.IMPORTANCE A distinct characteristic for eukaryotes is the compartmentalization of cell metabolic pathways, which allows greater efficiency and specificity of cellular functions. ICP0 of HSV-1 is a multifunctional viral protein that travels through different compartments as infection progresses. Its main regulatory functions are carried out in the nucleus, but it is translocated to the cytoplasm late during HSV-1 infection. To understand the biological significance of cytoplasmic ICP0 in HSV-1 infection, we investigated the potential players involved in this nuclear-to-cytoplasmic translocation. We found that there is a nuclear retention force in an ICP0 E3 ubiquitin ligase-dependent manner. In addition, we identified the C terminus of ICP0 as a cis element cooperating with late viral proteins to overcome the nuclear retention and stimulate the nuclear-to-cytoplasmic translocation of ICP0.
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A Tale of Two PMLs: Elements Regulating a Differential Substrate Recognition by the ICP0 E3 Ubiquitin Ligase of Herpes Simplex Virus 1. J Virol 2016; 90:10875-10885. [PMID: 27681131 DOI: 10.1128/jvi.01636-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/20/2016] [Indexed: 01/08/2023] Open
Abstract
Infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) is an α gene product required for viral replication at low multiplicities of infection. Upon entry, nuclear domain 10 (ND10) converges at the incoming DNA and represses viral gene expression. ICP0 contains a RING-type E3 ubiquitin ligase that degrades the ND10 organizer PML and disperses ND10 to alleviate the repression. In the present study, we focused on understanding the regulation of ICP0 E3 ligase activity in the degradation of different ICP0 substrates. We report the following. (i) A SUMO interaction motif located at ICP0 residues 362 to 364 is required for the degradation of PML isoforms II, IV, and VI but not isoform I. This differentiation mechanism exists in both HEp-2 and U2OS cells, regardless of the cell's permissiveness to the ICP0-null virus. (ii) Physical interaction between SIM362-364 and PML II is necessary but not sufficient for PML II degradation. Both proximal sequences surrounding SIM362-364 and distal sequences located at the ICP0 C terminus enhance the degradation of PML II. (iii) The ICP0 C terminus is dispensable for PML I degradation. Instead, bipartite PML I binding domains located in the N-terminal half of ICP0 coordinate to promote the degradation of PML I. (iv) The stability of ICP0, but not its ND10 fusion ability, affects the rate of PML I degradation. Taken together, our results show that ICP0 uses at least two regulatory mechanisms to differentiate its substrates. The disparate recognition of the ICP0 E3 substrates may be related to the different roles these substrates may play in HSV-1 infection. IMPORTANCE Viruses have a limited genetic coding capacity but must encounter a multilayered comprehensive host defense. To establish a successful infection, viruses usually produce multifunctional proteins to coordinate the counteractions. Here we report that an HSV-1 protein, ICP0, can recognize individual host factors and target them differently for destruction. We identified elements that are important for the ICP0 E3 ubiquitin ligase to differentially recognize two of its substrates, PML I and PML II. This is the first study that has systematically investigated how ICP0 discriminates two similar molecules by very different mechanisms. This work lays the foundation for understanding the role of host defensive factors and the mechanisms viruses use to take advantage of some host proteins while destroying others.
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Hare D, Collins S, Cuddington B, Mossman K. The Importance of Physiologically Relevant Cell Lines for Studying Virus-Host Interactions. Viruses 2016; 8:v8110297. [PMID: 27809273 PMCID: PMC5127011 DOI: 10.3390/v8110297] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/13/2016] [Accepted: 10/26/2016] [Indexed: 12/11/2022] Open
Abstract
Viruses interact intimately with the host cell at nearly every stage of replication, and the cell model that is chosen to study virus infection is critically important. Although primary cells reflect the phenotype of healthy cells in vivo better than cell lines, their limited lifespan makes experimental manipulation challenging. However, many tumor-derived and artificially immortalized cell lines have defects in induction of interferon-stimulated genes and other antiviral defenses. These defects can affect virus replication, especially when cells are infected at lower, more physiologically relevant, multiplicities of infection. Understanding the selective pressures and mechanisms underlying the loss of innate signaling pathways is helpful to choose immortalized cell lines without impaired antiviral defense. We describe the trials and tribulations we encountered while searching for an immortalized cell line with intact innate signaling, and how directed immortalization of primary cells avoids many of the pitfalls of spontaneous immortalization.
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Affiliation(s)
- David Hare
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Susan Collins
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Breanne Cuddington
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Karen Mossman
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
- Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
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