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Science (New York, N.Y.) Aug 2021
Topics: HIV-1; Humans; Virus Assembly; Virus Replication
PubMed: 34353938
DOI: 10.1126/science.abj9075 -
Sub-cellular Biochemistry 2023During respiratory syncytial virus (RSV) particle assembly, the mature RSV particles form as filamentous projections on the surface of RSV-infected cells. The RSV... (Review)
Review
During respiratory syncytial virus (RSV) particle assembly, the mature RSV particles form as filamentous projections on the surface of RSV-infected cells. The RSV assembly process occurs at the / on the cell surface that is modified by a virus infection, involving a combination of several different host cell factors and cellular processes. This induces changes in the lipid composition and properties of these lipid microdomains, and the virus-induced activation of associated Rho GTPase signaling networks drives the remodeling of the underlying filamentous actin (F-actin) cytoskeleton network. The modified sites that form on the surface of the infected cells form the nexus point for RSV assembly, and in this review chapter, they are referred to as the RSV assembleome. This is to distinguish these unique membrane microdomains that are formed during virus infection from the corresponding membrane microdomains that are present at the cell surface prior to infection. In this article, an overview of the current understanding of the processes that drive the formation of the assembleome during RSV particle assembly is given.
Topics: Humans; Virus Assembly; Respiratory Syncytial Virus, Human; Cell Membrane; Virus Diseases; Lipids
PubMed: 38159230
DOI: 10.1007/978-3-031-40086-5_9 -
Current Opinion in Virology Dec 2020Viral structural proteins are emerging as effective targets for new antivirals. In a viral lifecycle, the capsid must assemble, disassemble, and respond to host... (Review)
Review
Viral structural proteins are emerging as effective targets for new antivirals. In a viral lifecycle, the capsid must assemble, disassemble, and respond to host proteins, all at the right time and place. These reactions work within a narrow range of conditions, making them susceptible to small molecule interference. In at least three specific viruses, this approach has had met with preliminary success. In rhinovirus and poliovirus, compounds like pleconaril bind capsid and block RNA release. Bevirimat binds to Gag protein in HIV, inhibiting maturation. In Hepatitis B virus, core protein allosteric modulators (CpAMs) promote spontaneous assembly of capsid protein leading to empty and aberrant particles. Despite the biological diversity between viruses and the chemical diversity between antiviral molecules, we observe common features in these antivirals' mechanisms of action. These approaches work by stabilizing protein-protein interactions.
Topics: Antiviral Agents; Capsid; Drug Discovery; Hepatitis B virus; Viral Structural Proteins; Virus Assembly; Virus Replication; Viruses
PubMed: 32777753
DOI: 10.1016/j.coviro.2020.07.001 -
Molecular Microbiology Jun 2022Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus and the leading cause of congenital disabilities as well as a significant cause of disease in immunocompromised... (Review)
Review
Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus and the leading cause of congenital disabilities as well as a significant cause of disease in immunocompromised patients. The envelopment and egress of HCMV particles is an essential step of the viral life cycle as it determines viral spread and potentially tropism. Here we review the current literature on HCMV envelopment and egress with a particular focus on the role of virus-containing multivesicular body-like vesicles for virus egress and spread. We discuss the difficulties of determining the cellular provenance of these structures in light of viral redistribution of cellular marker proteins and provide potential paths to illuminate their genesis. Finally, we discuss how divergent egress pathways could result in virions of different tropisms.
Topics: Cytomegalovirus; Humans; Proteins; Virion; Virus Assembly
PubMed: 35607767
DOI: 10.1111/mmi.14946 -
ACS Nano Jan 2022Simple RNA viruses self-assemble spontaneously and encapsulate their genome into a shell called the capsid. This process is mainly driven by the attractive...
Simple RNA viruses self-assemble spontaneously and encapsulate their genome into a shell called the capsid. This process is mainly driven by the attractive electrostatics interaction between the positive charges on capsid proteins and the negative charges on the genome. Despite its importance and many decades of intense research, how the virus selects and packages its native RNA inside the crowded environment of a host cell cytoplasm in the presence of an abundance of nonviral RNA and other anionic polymers has remained a mystery. In this paper, we perform a series of simulations to monitor the growth of viral shells and find the mechanism by which cargo-coat protein interactions can impact the structure and stability of the viral shells. We show that coat protein subunits can assemble around a globular nucleic acid core by forming nonicosahedral cages, which have been recently observed in assembly experiments involving small pieces of RNA. We find that the resulting cages are strained and can easily be split into fragments along stress lines. This suggests that such metastable nonicosahedral intermediates could be easily reassembled into the stable native icosahedral shells if the larger wild-type genome becomes available, despite the presence of a myriad of nonviral RNAs.
Topics: Virus Assembly; Capsid; Capsid Proteins; Viruses; RNA
PubMed: 35019271
DOI: 10.1021/acsnano.1c06335 -
Journal of Virology Feb 2024Antibodies are frontline defenders against influenza virus infection, providing protection through multiple complementary mechanisms. Although a subset of monoclonal...
Antibodies are frontline defenders against influenza virus infection, providing protection through multiple complementary mechanisms. Although a subset of monoclonal antibodies (mAbs) has been shown to restrict replication at the level of virus assembly and release, it remains unclear how potent and pervasive this mechanism of protection is, due in part to the challenge of separating this effect from other aspects of antibody function. To address this question, we developed imaging-based assays to determine how effectively a broad range of mAbs against the IAV surface proteins can specifically restrict viral egress. We find that classically neutralizing antibodies against hemagglutinin are broadly multifunctional, inhibiting virus assembly and release at concentrations 1-20-fold higher than the concentrations at which they inhibit viral entry. These antibodies are also capable of altering the morphological features of shed virions, reducing the proportion of filamentous particles. We find that antibodies against neuraminidase and M2 also restrict viral egress and that inhibition by anti-neuraminidase mAbs is only partly attributable to a loss in enzymatic activity. In all cases, antigen crosslinking-either on the surface of the infected cell, between the viral and cell membrane, or both-plays a critical role in inhibition, and we are able to distinguish between these modes experimentally and through a structure-based computational model. Together, these results provide a framework for dissecting antibody multifunctionality that could help guide the development of improved therapeutic antibodies or vaccines and that can be extended to other viral families and antibody isotypes.IMPORTANCEAntibodies against influenza A virus provide multifaceted protection against infection. Although sensitive and quantitative assays are widely used to measure inhibition of viral attachment and entry, the ability of diverse antibodies to inhibit viral egress is less clear. We address this challenge by developing an imaging-based approach to measure antibody inhibition of virus release across a panel of monoclonal antibodies targeting the influenza A virus surface proteins. Using this approach, we find that inhibition of viral egress is common and can have similar potency to the ability of an antibody to inhibit viral entry. Insights into this understudied aspect of antibody function may help guide the development of improved countermeasures.
Topics: Humans; Antibodies, Monoclonal; Antibodies, Neutralizing; Antibodies, Viral; Hemagglutinin Glycoproteins, Influenza Virus; Influenza A virus; Influenza Vaccines; Influenza, Human; Membrane Proteins; Neuraminidase; Virus Assembly
PubMed: 38179944
DOI: 10.1128/jvi.01398-23 -
Nature Microbiology Aug 2022Chikungunya virus (CHIKV) is a representative alphavirus causing debilitating arthritogenic disease in humans. Alphavirus particles assemble into two icosahedral layers:...
Chikungunya virus (CHIKV) is a representative alphavirus causing debilitating arthritogenic disease in humans. Alphavirus particles assemble into two icosahedral layers: the glycoprotein spike shell embedded in a lipid envelope and the inner nucleocapsid (NC) core. In contrast to matrix-driven assembly of some enveloped viruses, the assembly/budding process of two-layered icosahedral particles remains poorly understood. Here we used cryogenic electron tomography (cryo-ET) to capture snapshots of the CHIKV assembly in infected human cells. Subvolume classification of the snapshots revealed 12 intermediates representing different stages of assembly at the plasma membrane. Further subtomogram average structures ranging from subnanometre to nanometre resolutions show that immature non-icosahedral NCs function as rough scaffolds to trigger icosahedral assembly of the spike lattice, which in turn progressively transforms the underlying NCs into icosahedral cores during budding. Further, analysis of CHIKV-infected cells treated with budding-inhibiting antibodies revealed wider spaces between spikes than in icosahedral spike lattice, suggesting that spacing spikes apart to prevent their lateral interactions prevents the plasma membrane from bending around the NC, thus blocking virus budding. These findings provide the molecular mechanisms for alphavirus assembly and antibody-mediated budding inhibition that provide valuable insights for the development of broad therapeutics targeting the assembly of icosahedral enveloped viruses.
Topics: Chikungunya Fever; Chikungunya virus; Electron Microscope Tomography; Humans; Nucleocapsid; Virus Assembly; Virus Release
PubMed: 35773421
DOI: 10.1038/s41564-022-01164-2 -
Wiley Interdisciplinary Reviews.... Jul 2020Viruses are highly ordered supramolecular complexes that have evolved to propagate by hijacking the host cell's machinery. Although viruses are very diverse, spreading... (Review)
Review
Viruses are highly ordered supramolecular complexes that have evolved to propagate by hijacking the host cell's machinery. Although viruses are very diverse, spreading through cells of all kingdoms of life, they share common functions and properties. Next to the general interest in virology, fundamental viral mechanisms are of growing importance in other disciplines such as biomedicine and (bio)nanotechnology. However, in order to optimally make use of viruses and virus-like particles, for instance as vehicle for targeted drug delivery or as building blocks in electronics, it is essential to understand their basic chemical and physical properties and characteristics. In this context, the number of studies addressing the mechanisms governing viral properties and processes has recently grown drastically. This review summarizes a specific part of these scientific achievements, particularly addressing physical virology approaches aimed to understand the self-assembly of viruses and the mechanical properties of viral particles. Using a physicochemical perspective, we have focused on fundamental studies providing an overview of the molecular basis governing these key aspects of viral systems. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.
Topics: Biomechanical Phenomena; Genome, Viral; Humans; Virion; Virus Assembly; Viruses
PubMed: 31960585
DOI: 10.1002/wnan.1613 -
Cell Host & Microbe Nov 2019Dengue virus assembly requires cleavage of viral C-prM-E polyprotein into three structural proteins (capsid, premembrane, and envelope), packaging of viral RNA with C...
Dengue virus assembly requires cleavage of viral C-prM-E polyprotein into three structural proteins (capsid, premembrane, and envelope), packaging of viral RNA with C protein into nucleocapsid, and budding of prM and E proteins into virions. The molecular mechanisms underlying these assembly events are unclear. Here, we show that dengue nonstructural protein 2A (NS2A protein) recruits viral RNA, structural proteins, and protease to the site of virion assembly and coordinates nucleocapsid and virus formation. The last 285 nucleotides of viral 3' UTR serve as a "recruiting signal for packaging" that binds to a cytosolic loop of NS2A. This interaction allows NS2A to recruit nascent RNA from the replication complex to the virion assembly site. NS2A also recruits the C-prM-E polyprotein and NS2B-NS3 protease to the virion assembly site by interacting with prM, E, and NS3, leading to coordinated C-prM-E cleavage. Mature C protein assembles onto genomic RNA to form nucleocapsid, followed by prM and E envelopment and virion formation.
Topics: Aedes; Animals; Cell Line; Chlorocebus aethiops; Cricetinae; Dengue Virus; HEK293 Cells; Humans; Nucleocapsid; RNA Helicases; RNA, Viral; Serine Endopeptidases; Vero Cells; Viral Envelope Proteins; Viral Nonstructural Proteins; Viral Proteins; Virus Assembly
PubMed: 31631053
DOI: 10.1016/j.chom.2019.09.015 -
ACS Synthetic Biology Nov 2022Virus-like particles (VLPs) have been used for numerous pharmaceutical applications, particularly vaccination and drug delivery. Recombinant adeno-associated virus...
Virus-like particles (VLPs) have been used for numerous pharmaceutical applications, particularly vaccination and drug delivery. Recombinant adeno-associated virus (rAAV), a leading candidate in gene therapy, has been proposed as a vaccine scaffold, but high production costs limit its use. Here we establish intracellular production of AAV VLPs in . VP3 capsid proteins of AAV serotype 5 (AAV5) were expressed, and VLPs were readily purified. The correct assembly was confirmed by ELISA with an intact-capsid AAV5 antibody and an AAVR domain as well as by atomic force microscopy. Biological functionality was demonstrated with a HeLa cell internalization assay. Coexpression of the assembly-activating protein (AAP) of AAV5 in improved capsid yield. This work provides the first evidence that AAV VLPs form in , opening new opportunities for production and exploration of AAV VLPs for biomedical applications.
Topics: Humans; Dependovirus; Escherichia coli; Virus Assembly; HeLa Cells; Capsid; Capsid Proteins
PubMed: 36279242
DOI: 10.1021/acssynbio.2c00451