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Cui Y, Wang M, Cheng A, Zhang W, Yang Q, Tian B, Ou X, Huang J, Wu Y, Zhang S, Sun D, He Y, Zhao X, Wu Z, Zhu D, Jia R, Chen S, Liu M. The precise function of alphaherpesvirus tegument proteins and their interactions during the viral life cycle. Front Microbiol 2024; 15:1431672. [PMID: 39015737 PMCID: PMC11250606 DOI: 10.3389/fmicb.2024.1431672] [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: 05/12/2024] [Accepted: 06/20/2024] [Indexed: 07/18/2024] Open
Abstract
Alphaherpesvirus is a widespread pathogen that causes diverse diseases in humans and animals and can severely damage host health. Alphaherpesvirus particles comprise a DNA core, capsid, tegument and envelope; the tegument is located between the nuclear capsid and envelope. According to biochemical and proteomic analyses of alphaherpesvirus particles, the tegument contains at least 24 viral proteins and plays an important role in the alphaherpesvirus life cycle. This article reviews the important role of tegument proteins and their interactions during the viral life cycle to provide a reference and inspiration for understanding alphaherpesvirus infection pathogenesis and identifying new antiviral strategies.
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Affiliation(s)
- Yuxi Cui
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mingshu Wang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Anchun Cheng
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Wei Zhang
- Sinopharm Yangzhou VAC Biological Engineering Co., Ltd., Yangzhou, China
| | - Qiao Yang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Bin Tian
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xumin Ou
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Juan Huang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ying Wu
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shaqiu Zhang
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Di Sun
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yu He
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xinxin Zhao
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Zhen Wu
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Dekang Zhu
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Renyong Jia
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shun Chen
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mafeng Liu
- Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, China
- International Joint Research Center for Animal Disease Prevention and Control of Sichuan Province, Chengdu, China
- Institute of Veterinary Medicine and Immunology, Sichuan Agricultural University, Chengdu, China
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
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Kim D, Cianfrocco MA, Verhey KJ, Smith GA. The HSV-1 pUL37 protein promotes cell invasion by regulating the kinesin-1 motor. Proc Natl Acad Sci U S A 2024; 121:e2401341121. [PMID: 38696466 PMCID: PMC11087751 DOI: 10.1073/pnas.2401341121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/17/2024] [Indexed: 05/04/2024] Open
Abstract
Neurotropic alphaherpesviruses, including herpes simplex virus type 1 (HSV-1), recruit microtubule motor proteins to invade cells. The incoming viral particle traffics to nuclei in a two-step process. First, the particle uses the dynein-dynactin motor to sustain transport to the centrosome. In neurons, this step is responsible for long-distance retrograde axonal transport and is an important component of the neuroinvasive property shared by these viruses. Second, a kinesin-dependent mechanism redirects the particle from the centrosome to the nucleus. We have reported that the kinesin motor used during the second step of invasion is assimilated into nascent virions during the previous round of infection. Here, we report that the HSV-1 pUL37 tegument protein suppresses the assimilated kinesin-1 motor during retrograde axonal transport. Region 2 (R2) of pUL37 was required for suppression and functioned independently of the autoinhibitory mechanism native to kinesin-1. Furthermore, the motor domain and proximal coiled coil of kinesin-1 were sufficient for HSV-1 assimilation, pUL37 suppression, and nuclear trafficking. pUL37 localized to the centrosome, the site of assimilated kinesin-1 activation during infection, when expressed in cells in the absence of other viral proteins; however, pUL37 did not suppress kinesin-1 in this context. These results indicate that the pUL37 tegument protein spatially and temporally regulates kinesin-1 via the amino-terminal motor region in the context of the incoming viral particle.
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Affiliation(s)
- DongHo Kim
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Michael A. Cianfrocco
- Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI48109
| | - Kristen J. Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI48109
| | - Gregory A. Smith
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
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Jih J, Liu YT, Liu W, Zhou ZH. The incredible bulk: Human cytomegalovirus tegument architectures uncovered by AI-empowered cryo-EM. SCIENCE ADVANCES 2024; 10:eadj1640. [PMID: 38394211 PMCID: PMC10889378 DOI: 10.1126/sciadv.adj1640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
The compartmentalization of eukaryotic cells presents considerable challenges to the herpesvirus life cycle. The herpesvirus tegument, a bulky proteinaceous aggregate sandwiched between herpesviruses' capsid and envelope, is uniquely evolved to address these challenges, yet tegument structure and organization remain poorly characterized. We use deep-learning-enhanced cryogenic electron microscopy to investigate the tegument of human cytomegalovirus virions and noninfectious enveloped particles (NIEPs; a genome packaging-aborted state), revealing a portal-biased tegumentation scheme. We resolve atomic structures of portal vertex-associated tegument (PVAT) and identify multiple configurations of PVAT arising from layered reorganization of pUL77, pUL48 (large tegument protein), and pUL47 (inner tegument protein) assemblies. Analyses show that pUL77 seals the last-packaged viral genome end through electrostatic interactions, pUL77 and pUL48 harbor a head-linker-capsid-binding motif conducive to PVAT reconfiguration, and pUL47/48 dimers form 45-nm-long filaments extending from the portal vertex. These results provide a structural framework for understanding how herpesvirus tegument facilitates and evolves during processes spanning viral genome packaging to delivery.
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Affiliation(s)
- Jonathan Jih
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Wei Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Z. Hong Zhou
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
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Collantes TMA, Clark CM, Musarrat F, Jambunathan N, Jois S, Kousoulas KG. Predicted Structure and Functions of the Prototypic Alphaherpesvirus Herpes Simplex Virus Type-1 UL37 Tegument Protein. Viruses 2022; 14:2189. [PMID: 36298744 PMCID: PMC9608200 DOI: 10.3390/v14102189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
The alphaherpesvirus UL37 tegument protein is a highly conserved, multi-functional protein. Mutagenesis analysis delineated the UL37 domains necessary for retrograde transport and viral replication. Specifically, the amino-terminal 480 amino acids are dispensable for virus replication in epithelial cell culture, but it is unknown whether this amino-terminal deletion affects UL37 structure and intracellular transport in epithelial cells and neurons. To investigate the structure and function of UL37, we utilized multiple computational approaches to predict and characterize the secondary and tertiary structure and other functional features. The structure of HSV-1 UL37 and Δ481N were deduced using publicly available predictive algorithms. The predicted model of HSV-1 UL37 is a stable, multi-functional, globular monomer, rich in alpha helices, with unfolded regions within the linker and the C-tail domains. The highly flexible C-tail contains predicted binding sites to the dynein intermediate chain, as well as DNA and RNA. Predicted interactions with the cytoplasmic surface of the lipid membrane suggest UL37 is a peripheral membrane protein. The Δ481N truncation did not alter the predicted structure of the UL37 C-terminus protein and its predicted interaction with dynein. We validated these models by examining the replication kinetics and transport of the Δ481N virus toward the nuclei of infected epithelial and neuronal cells. The Δ481N virus had substantial defects in virus spread; however, it exhibited no apparent defects in virus entry and intracellular transport. Using computational analyses, we identified several key features of UL37, particularly the flexible unstructured tail; we then demonstrated that the UL37 C-terminus alone is sufficient to effectively transport the virus towards the nucleus of infected epithelial and neuronal cells.
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Affiliation(s)
- Therese Marie A. Collantes
- Division of Biotechnology and Molecular Medicine and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
- College of Veterinary Medicine, University of the Philippines Los Baños, Los Baños, Laguna 4031, Philippines
| | - Carolyn M. Clark
- Division of Biotechnology and Molecular Medicine and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Farhana Musarrat
- Division of Biotechnology and Molecular Medicine and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | | | - Seetharama Jois
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA
| | - Konstantin G. Kousoulas
- Division of Biotechnology and Molecular Medicine and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
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Wilson DW. Motor Skills: Recruitment of Kinesins, Myosins and Dynein during Assembly and Egress of Alphaherpesviruses. Viruses 2021; 13:v13081622. [PMID: 34452486 PMCID: PMC8402756 DOI: 10.3390/v13081622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
The alphaherpesviruses are pathogens of the mammalian nervous system. Initial infection is commonly at mucosal epithelia, followed by spread to, and establishment of latency in, the peripheral nervous system. During productive infection, viral gene expression, replication of the dsDNA genome, capsid assembly and genome packaging take place in the infected cell nucleus, after which mature nucleocapsids emerge into the cytoplasm. Capsids must then travel to their site of envelopment at cytoplasmic organelles, and enveloped virions need to reach the cell surface for release and spread. Transport at each of these steps requires movement of alphaherpesvirus particles through a crowded and viscous cytoplasm, and for distances ranging from several microns in epithelial cells, to millimeters or even meters during egress from neurons. To solve this challenging problem alphaherpesviruses, and their assembly intermediates, exploit microtubule- and actin-dependent cellular motors. This review focuses upon the mechanisms used by alphaherpesviruses to recruit kinesin, myosin and dynein motors during assembly and egress.
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Affiliation(s)
- Duncan W. Wilson
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; ; Tel.: +1-718-430-2305
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Ahmad I, Wilson DW. HSV-1 Cytoplasmic Envelopment and Egress. Int J Mol Sci 2020; 21:ijms21175969. [PMID: 32825127 PMCID: PMC7503644 DOI: 10.3390/ijms21175969] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 12/25/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a structurally complex enveloped dsDNA virus that has evolved to replicate in human neurons and epithelia. Viral gene expression, DNA replication, capsid assembly, and genome packaging take place in the infected cell nucleus, which mature nucleocapsids exit by envelopment at the inner nuclear membrane then de-envelopment into the cytoplasm. Once in the cytoplasm, capsids travel along microtubules to reach, dock, and envelope at cytoplasmic organelles. This generates mature infectious HSV-1 particles that must then be sorted to the termini of sensory neurons, or to epithelial cell junctions, for spread to uninfected cells. The focus of this review is upon our current understanding of the viral and cellular molecular machinery that enables HSV-1 to travel within infected cells during egress and to manipulate cellular organelles to construct its envelope.
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Affiliation(s)
- Imran Ahmad
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
| | - Duncan W. Wilson
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- Correspondence:
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The pseudorabies virus R2 non-neuroinvasive vaccine: A proof-of-concept study in pigs. Vaccine 2020; 38:4524-4528. [PMID: 32448623 DOI: 10.1016/j.vaccine.2020.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 11/24/2022]
Abstract
Neurotropic alpha-herpesviruses that infect mammals establish life-long latent infections in the peripheral nervous system after initial infection of exposed mucosal tissues. The neuroinvasive properties can lead to severe complications both with clinical and veterinary alpha-herpesviruses, and vaccines are often unavailable or provide limited protection. Here we assess the properties and efficacy of an R2 vaccine derived from the alpha-herpesvirus, pseudorabies virus (PRV), in pigs. We demonstrate that the PRV R2 vaccine does not invade the porcine peripheral nervous system within the limits of detection. Furthermore, after a single intranasal vaccination, R2 conferred protection to pigs subsequently challenged with a virulent PRV field strain (NIA-3). These findings support that the R2 vaccine design is non-neuroinvasive and is an effective vaccine in the context of a natural host.
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Metrick CM, Koenigsberg AL, Heldwein EE. Conserved Outer Tegument Component UL11 from Herpes Simplex Virus 1 Is an Intrinsically Disordered, RNA-Binding Protein. mBio 2020; 11:e00810-20. [PMID: 32371601 PMCID: PMC7403781 DOI: 10.1128/mbio.00810-20] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/07/2020] [Indexed: 12/23/2022] Open
Abstract
A distinguishing morphological feature of all herpesviruses is the multiprotein tegument layer located between the nucleocapsid and lipid envelope of the virion. Tegument proteins play multiple roles in viral replication, including viral assembly, but we do not yet understand their individual functions or how the tegument is assembled and organized. UL11, the smallest tegument protein, is important for several distinct processes in replication, including efficient virion morphogenesis and cell-cell spread. However, the mechanistic understanding of its role in these and other processes is limited in part by the scant knowledge of its biochemical and structural properties. Here, we report that UL11 from herpes simplex virus 1 (HSV-1) is an intrinsically disordered, conformationally dynamic protein that undergoes liquid-liquid phase separation (LLPS) in vitro Intrinsic disorder may underlie the ability of UL11 to exert multiple functions and bind multiple partners. Sequence analysis suggests that not only all UL11 homologs but also all HSV-1 tegument proteins contain intrinsically disordered regions of different lengths. The presence of intrinsic disorder, and potentially, the ability to form LLPS, may thus be a common feature of the tegument proteins. We hypothesize that tegument assembly may involve the formation of a biomolecular condensate, driven by the heterogeneous mixture of intrinsically disordered tegument proteins.IMPORTANCE Herpesvirus virions contain a unique tegument layer sandwiched between the capsid and lipid envelope and composed of multiple copies of about two dozen viral proteins. However, little is known about the structure of the tegument or how it is assembled. Here, we show that a conserved tegument protein UL11 from herpes simplex virus 1, a prototypical alphaherpesvirus, is an intrinsically disordered protein that undergoes liquid-liquid phase separation in vitro Through sequence analysis, we find intrinsically disordered regions of different lengths in all HSV-1 tegument proteins. We hypothesize that intrinsic disorder is a common characteristic of tegument proteins and propose a new model of tegument as a biomolecular condensate.
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Affiliation(s)
- Claire M Metrick
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Biochemistry, Tufts School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Andrea L Koenigsberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate Program in Molecular Microbiology, Tufts School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ekaterina E Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
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The ESCRT-II Subunit EAP20/VPS25 and the Bro1 Domain Proteins HD-PTP and BROX Are Individually Dispensable for Herpes Simplex Virus 1 Replication. J Virol 2020; 94:JVI.01641-19. [PMID: 31748394 DOI: 10.1128/jvi.01641-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/14/2019] [Indexed: 12/14/2022] Open
Abstract
Capsid envelopment during assembly of the neurotropic herpesviruses herpes simplex virus 1 (HSV-1) and pseudorabies virus (PRV) in the infected cell cytoplasm is thought to involve the late-acting cellular ESCRT (endosomal sorting complex required for transport) components ESCRT-III and VPS4 (vacuolar protein sorting 4). However, HSV-1, unlike members of many other families of enveloped viruses, does not appear to require the ESCRT-I subunit TSG101 or the Bro1 domain-containing protein ALIX (Alg-2-interacting protein X) to recruit and activate ESCRT-III. Alternative cellular factors that are known to be capable of regulating ESCRT-III function include the ESCRT-II complex and other members of the Bro1 family. We therefore used small interfering RNA (siRNA) to knock down the essential ESCRT-II subunit EAP20/VPS25 (ELL-associated protein 20/vacuolar protein sorting 25) and the Bro1 proteins HD-PTP (His domain-containing protein tyrosine phosphatase) and BROX (Bro1 domain and CAAX motif containing). We demonstrated reductions in levels of the targeted proteins by Western blotting and used quantitative microscopic assays to confirm loss of ESCRT-II and HD-PTP function. We found that in single-step replication experiments, the final yields of HSV-1 were unchanged following loss of EAP20, HD-PTP, or BROX.IMPORTANCE HSV-1 is a pathogen of the human nervous system that uses its own virus-encoded proteins and the normal cellular ESCRT machinery to drive the construction of its envelope. How HSV-1 structural proteins interact with ESCRT components and which subsets of cellular ESCRT proteins are utilized by the virus remain largely unknown. Here, we demonstrate that an essential component of the ESCRT-II complex and two ESCRT-associated Bro1 proteins are dispensable for HSV-1 replication.
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Diwaker D, Wilson DW. Microtubule-Dependent Trafficking of Alphaherpesviruses in the Nervous System: The Ins and Outs. Viruses 2019; 11:v11121165. [PMID: 31861082 PMCID: PMC6950448 DOI: 10.3390/v11121165] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/13/2019] [Accepted: 12/15/2019] [Indexed: 12/12/2022] Open
Abstract
The Alphaherpesvirinae include the neurotropic pathogens herpes simplex virus and varicella zoster virus of humans and pseudorabies virus of swine. These viruses establish lifelong latency in the nuclei of peripheral ganglia, but utilize the peripheral tissues those neurons innervate for productive replication, spread, and transmission. Delivery of virions from replicative pools to the sites of latency requires microtubule-directed retrograde axonal transport from the nerve terminus to the cell body of the sensory neuron. As a corollary, during reactivation newly assembled virions must travel along axonal microtubules in the anterograde direction to return to the nerve terminus and infect peripheral tissues, completing the cycle. Neurotropic alphaherpesviruses can therefore exploit neuronal microtubules and motors for long distance axonal transport, and alternate between periods of sustained plus end- and minus end-directed motion at different stages of their infectious cycle. This review summarizes our current understanding of the molecular details by which this is achieved.
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Affiliation(s)
- Drishya Diwaker
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
| | - Duncan W. Wilson
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA;
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- Correspondence: ; Tel.: +1-(718)-430-2305
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11
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Grzesik P, Pryce EN, Bhalala A, Vij M, Ahmed R, Etienne L, Perez P, McCaffery JM, Desai APJ. Functional Domains of the Herpes Simplex Virus Type 1 Tegument Protein pUL37: The Amino Terminus is Dispensable for Virus Replication in Tissue Culture. Viruses 2019; 11:E853. [PMID: 31540043 PMCID: PMC6783895 DOI: 10.3390/v11090853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 01/01/2023] Open
Abstract
The herpes simplex virus type 1 (HSV-1) UL37 gene encodes for a multifunctional component of the virion tegument, which is necessary for secondary envelopment in the cytoplasm of infected cells, for motility of the viral particle, and for the first steps in the initiation of virus infection. This 120 kDa protein has several known viral interacting partners, including pUL36, gK/pUL20, pUS10, and VP26, and cellular interacting proteins which include TRAF6, RIG-I, and dystonin. These interactions are likely important for the functions of pUL37 at both early and late stages of infection. We employed a genetic approach to determine essential domains and amino acid residues of pUL37 and their associated functions in cellular localization and virion morphogenesis. Using marker-rescue/marker-transfer methods, we generated a library of GFP-tagged pUL37 mutations in the HSV-1 strain KOS genome. Through viral growth and ultra-structural analysis, we discovered that the C-terminus is essential for replication. The N-terminal 480 amino acids are dispensable for replication in cell culture, although serve some non-essential function as viral titers are reduced in the presence of this truncation. Furthermore, the C-terminal 133 amino acids are important in so much that their absence leads to a lethal phenotype. We further probed the carboxy terminal half of pUL37 by alanine scanning mutagenesis of conserved residues among alphaherpesviruses. Mutant viruses were screened for the inability to form plaques-or greatly reduced plaque size-on Vero cells, of which 22 mutations were chosen for additional analysis. Viruses discovered to have the greatest reduction in viral titers on Vero cells were examined by electron microscopy (EM) and by confocal light microscopy for pUL37-EGFP cellular localization. This genetic approach identified both essential and non-essential domains and residues of the HSV-1 UL37 gene product. The mutations identified in this study are recognized as significant candidates for further analysis of the pUL37 function and may unveil previously undiscovered roles and interactions of this essential tegument gene.
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Affiliation(s)
- Peter Grzesik
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
| | - Erin N Pryce
- Integrated Imaging Center, Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Akshay Bhalala
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
| | - Mannika Vij
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
| | - Ray Ahmed
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
| | - Lyns Etienne
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
| | - Patric Perez
- Integrated Imaging Center, Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - J Michael McCaffery
- Integrated Imaging Center, Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - And Prashant J Desai
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, MD 21231, USA.
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Abstract
The Herpesviridae are structurally complex DNA viruses whose capsids undergo primary envelopment at the inner nuclear membrane and secondary envelopment at organelles in the cytoplasm. In both locations, there is evidence that envelope formation and scission involve the participation of multiple viral proteins and also the cellular ESCRT apparatus. It nevertheless appears that the best-understood viral strategies for ESCRT recruitment, those adopted by the retroviruses and many other families of enveloped RNA viruses, are not utilized by the Herpesviridae, at least during envelopment in the cytoplasm. Thus, although a large number of herpesvirus proteins have been assigned roles in envelopment, there is a dearth of candidates for the acquisition of the ESCRT complex and the control of envelope scission. This review summarizes our current understanding of ESCRT association by enveloped viruses, examines what is known of herpesvirus ESCRT utilization in the nucleus and cytoplasm, and identifies candidate cellular and viral proteins that could link enveloping herpesviruses to cellular ESCRT components.
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13
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Koenigsberg AL, Heldwein EE. The dynamic nature of the conserved tegument protein UL37 of herpesviruses. J Biol Chem 2018; 293:15827-15839. [PMID: 30166339 PMCID: PMC6187633 DOI: 10.1074/jbc.ra118.004481] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/26/2018] [Indexed: 12/26/2022] Open
Abstract
In all herpesviruses, the space between the capsid shell and the lipid envelope is occupied by the unique tegument layer composed of proteins that, in addition to structural roles, play many other roles in the viral replication. UL37 is a highly conserved tegument protein that has activities ranging from virion morphogenesis to directional capsid trafficking to manipulation of the host innate immune response and binds multiple partners. The N-terminal half of UL37 (UL37N) has a compact bean-shaped α-helical structure that contains a surface region essential for neuroinvasion. However, no biochemical or structural information is currently available for the C-terminal half of UL37 (UL37C) that mediates most of its interactions with multiple binding partners. Here, we show that the C-terminal half of UL37 from pseudorabies virus UL37C is a conformationally flexible monomer composed of an elongated folded core and an unstructured C-terminal tail. This elongated structure, along with that of its binding partner UL36, explains the nature of filamentous tegument structures bridging the capsid and the envelope. We propose that the dynamic nature of UL37 underlies its ability to perform diverse roles during viral replication.
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Affiliation(s)
- Andrea L Koenigsberg
- From the Department of Molecular Biology and Microbiology and Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Ekaterina E Heldwein
- From the Department of Molecular Biology and Microbiology and Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts 02111
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