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Zhang YN, Wang SM, Ren XR, Duan QY, Chen LH. The transmembrane and cytosolic domains of equine herpesvirus type 1 glycoprotein D determine Golgi retention by regulating vesicle formation. Biochem Biophys Res Commun 2024; 702:149654. [PMID: 38340657 DOI: 10.1016/j.bbrc.2024.149654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/28/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Accumulating evidence underscores the pivotal role of envelope proteins in viral secondary envelopment. However, the intricate molecular mechanisms governing this phenomenon remain elusive. To shed light on these mechanisms, we investigated a Golgi-retained gD of EHV-1 (gDEHV-1), distinguishing it from its counterparts in Herpes Simplex Virus-1 (HSV-1) and Pseudorabies Virus (PRV). To unravel the specific sequences responsible for the Golgi retention phenotype, we employed a gene truncation and replacement strategy. The results suggested that Golgi retention signals in gDEHV-1 exhibiting a multi-domain character. The extracellular domain of gDEHV-1 was identified as an endoplasmic reticulum (ER)-resident domain, the transmembrane domain and cytoplasmic tail (TM-CT) of gDEHV-1 were integral in facilitating the protein's residence within the Golgi complex. Deletion or replacement of either of these dual domains consistently resulted in the mutant gDEHV-1 being retained in an ER-like structure. Moreover, (TM-CT)EHV-1 demonstrated a preference for binding to endomembranes, inducing the generation of a substantial number of vesicles, potentially originate from the Golgi complex or the ER-Golgi intermediate compartment. In conclusion, our findings provide insights into the intricate molecular mechanisms governing the Golgi retention of gDEHV-1, facilitating the comprehension of the processes underlying viral secondary envelopment.
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Affiliation(s)
- Yan-Nan Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing, 10083, People's Republic of China.
| | - Shi-Min Wang
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, 830052, People's Republic of China.
| | - Xin-Rong Ren
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, 830052, People's Republic of China.
| | - Qi-Ying Duan
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, 830052, People's Republic of China.
| | - Lin-Hui Chen
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, 830052, People's Republic of China.
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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. Sci Adv 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bergeman MH, Hernandez MQ, Diefenderfer J, Drewes JA, Velarde K, Tierney WM, Enow JA, Glenn HL, Rahman MM, Hogue IB. Individual herpes simplex virus 1 (HSV-1) particles exit by exocytosis and accumulate at preferential egress sites. J Virol 2024; 98:e0178523. [PMID: 38193690 PMCID: PMC10883806 DOI: 10.1128/jvi.01785-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024] Open
Abstract
The human pathogen herpes simplex virus 1 (HSV-1) produces a lifelong infection in the majority of the world's population. While the generalities of alpha herpesvirus assembly and egress pathways are known, the precise molecular and spatiotemporal details remain unclear. In order to study this aspect of HSV-1 infection, we engineered a recombinant HSV-1 strain expressing a pH-sensitive reporter, gM-pHluorin. Using a variety of fluorescent microscopy modalities, we can detect individual virus particles undergoing intracellular transport and exocytosis at the plasma membrane. We show that particles exit from epithelial cells individually, not bulk release of many particles at once, as has been reported for other viruses. In multiple cell types, HSV-1 particles accumulate over time at the cell periphery and cell-cell contacts. We show that this accumulation effect is the result of individual particles undergoing exocytosis at preferential sites and that these egress sites can contribute to cell-cell spread. We also show that the viral membrane proteins gE, gI, and US9, which have important functions in intracellular transport in neurons, are not required for preferential egress and clustering in non-neuronal cells. Importantly, by comparing HSV-1 to a related alpha herpesvirus, pseudorabies virus, we show that this preferential exocytosis and clustering effect are cell type dependent, not virus dependent. This preferential egress and clustering appear to be the result of the arrangement of the microtubule cytoskeleton, as virus particles co-accumulate at the same cell protrusions as an exogenous plus end-directed kinesin motor.IMPORTANCEAlpha herpesviruses produce lifelong infections in their human and animal hosts. The majority of people in the world are infected with herpes simplex virus 1 (HSV-1), which typically causes recurrent oral or genital lesions. However, HSV-1 can also spread to the central nervous system, causing severe encephalitis, and might also contribute to the development of neurodegenerative diseases. Many of the steps of how these viruses infect and replicate inside host cells are known in depth, but the final step, exiting from the infected cell, is not fully understood. In this study, we engineered a novel variant of HSV-1 that allows us to visualize how individual virus particles exit from infected cells. With this imaging assay, we investigated preferential egress site formation in certain cell types and their contribution to the cell-cell spread of HSV-1.
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Affiliation(s)
- Melissa H. Bergeman
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Michaella Q. Hernandez
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | | | - Jake A. Drewes
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Kimberly Velarde
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Wesley M. Tierney
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Junior A. Enow
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Biodesign Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Honor L. Glenn
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Masmudur M. Rahman
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Biodesign Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Ian B. Hogue
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
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Delva JL, Van Waesberghe C, Van Den Broeck W, Lamote JA, Vereecke N, Theuns S, Couck L, Favoreel HW. The Attenuated Pseudorabies Virus Vaccine Strain Bartha Hyperactivates Plasmacytoid Dendritic Cells by Generating Large Amounts of Cell-Free Virus in Infected Epithelial Cells. J Virol 2022;:e0219921. [PMID: 35604216 DOI: 10.1128/jvi.02199-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudorabies virus (PRV) is a porcine alphaherpesvirus and the causative agent of Aujeszky's disease. Successful eradication campaigns against PRV have largely relied on the use of potent PRV vaccines. The live attenuated Bartha strain, which was produced by serial passaging in cell culture, represents one of the hallmark PRV vaccines. Despite the robust protection elicited by Bartha vaccination, very little is known about the immunogenicity of the Bartha strain. Previously, we showed that Bartha-infected epithelial cells trigger plasmacytoid dendritic cells (pDC) to produce much higher levels of type I interferons than cells infected with wild-type PRV. Here, we show that this Bartha-induced pDC hyperactivation extends to other important cytokines, including interleukin-12/23 (IL-12/23) and tumor necrosis factor alpha (TNF-α) but not IL-6. Moreover, Bartha-induced pDC hyperactivation was found to be due to the strongly increased production of extracellular infectious virus (heavy particles [H-particles]) early in infection of epithelial cells, which correlated with a reduced production of noninfectious light particles (L-particles). The Bartha genome is marked by a large deletion in the US region affecting the genes encoding US7 (gI), US8 (gE), US9, and US2. The deletion of the US2 and gE/gI genes was found to be responsible for the observed increase in extracellular virus production by infected epithelial cells and the resulting increased pDC activation. The deletion of gE/gI also suppressed L-particle production. In conclusion, the deletion of US2 and gE/gI in the genome of the PRV vaccine strain Bartha results in the enhanced production of extracellular infectious virus in infected epithelial cells and concomitantly leads to the hyperactivation of pDC. IMPORTANCE The pseudorabies virus (PRV) vaccine strain Bartha has been and still is critical in the eradication of PRV in numerous countries. However, little is known about how this vaccine strain interacts with host cells and the host immune system. Here, we report the surprising observation that Bartha-infected epithelial porcine cells rapidly produce increased amounts of extracellular infectious virus compared to wild-type PRV-infected cells, which in turn potently stimulate porcine plasmacytoid dendritic cells (pDC). We found that this phenotype depends on the deletion of the genes encoding US2 and gE/gI. We also found that Bartha-infected cells secrete fewer pDC-inhibiting light particles (L-particles), which appears to be caused mainly by the deletion of the genes encoding gE/gI. These data generate novel insights into the interaction of the successful Bartha vaccine with epithelial cells and pDC and may therefore contribute to the development of vaccines against other (alphaherpes)viruses.
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Barnes J, Jordan BA, Wilson DW. An ESCRT/VPS4 envelopment trap to examine the mechanism of alphaherpesvirus assembly and transport in neurons. J Virol 2022;:jvi0217821. [PMID: 35045266 DOI: 10.1128/jvi.02178-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The assembly and egress of alphaherpesviruses, including Herpes simplex virus type 1 (HSV-1) and Pseudorabies virus (PRV), within neurons is poorly understood. A key unresolved question is the structure of the viral particle that moves by anterograde transport along the axon, and two alternative mechanisms have been described. In the "Married" model capsids acquire their envelopes in the cell body, then traffic along axons as enveloped virions within a bounding organelle. In the "Separate" model non-enveloped capsids travel from the cell body into and along the axon, eventually encountering their envelopment organelles at a distal site such as the nerve cell terminal. Here we describe an "envelopment trap" to test these models using the dominant negative terminal ESCRT component VPS4-EQ. GFP-tagged VPS4-EQ was used to arrest HSV-1 or PRV capsid envelopment, inhibit downstream trafficking and GFP-label envelopment intermediates. We found that GFP-VPS4-EQ inhibited trafficking of HSV-1 capsids into and along the neurites and axons of mouse CAD cells and rat embryonic primary cortical neurons, consistent with egress via the married pathway. In contrast, transport of HSV-1 capsids was unaffected in the neurites of human SK-N-SH neuroblastoma cells, consistent with the separate mechanism. Unexpectedly, PRV (generally thought to utilize the married pathway) also appeared to employ the separate mechanism in SK-N-SH cells. We propose that apparent differences in the methods of HSV-1 and PRV egress are more likely a reflection of the host neuron in which transport is studied, rather than true biological differences between the viruses themselves. IMPORTANCE Alphaherpesviruses, including Herpes simplex virus type 1 (HSV-1) and Pseudorabies virus (PRV), are pathogens of the nervous system. They replicate in the nerve cell body then travel great distances along axons to reach nerve termini and spread to adjacent epithelial cells, however key aspects of how these viruses travel along axons remain controversial. Here we test two alternative mechanisms for transport, the married and separate models, by blocking envelope assembly, a critical step in viral egress. When we arrest formation of the viral envelope using a mutated component of the cellular ESCRT apparatus we find that entry of viral particles into axons is blocked in some types of neuron, but not others. This approach allows us to determine whether envelope assembly occurs prior to entry of viruses into axons, or afterwards, and thus to distinguish between the alternative models for viral transport.
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