scholarly journals Structure and assembly of double-headed Sendai virus nucleocapsids

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Na Zhang ◽  
Hong Shan ◽  
Mingdong Liu ◽  
Tianhao Li ◽  
Rui Luo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Measles Virus ◽  
Sendai Virus ◽  
Nipah Virus ◽  
Mumps Virus ◽  
Genome Replication ◽  
Direct Visualization ◽  
Closed State ◽  
Cryo Electron Microscopy ◽  
Negative Sense

AbstractParamyxoviruses, including the mumps virus, measles virus, Nipah virus and Sendai virus (SeV), have non-segmented single-stranded negative-sense RNA genomes which are encapsidated by nucleoproteins into helical nucleocapsids. Here, we reported a double-headed SeV nucleocapsid assembled in a tail-to-tail manner, and resolved its helical stems and clam-shaped joint at the respective resolutions of 2.9 and 3.9 Å, via cryo-electron microscopy. Our structures offer important insights into the mechanism of the helical polymerization, in particular via an unnoticed exchange of a N-terminal hole formed by three loops of nucleoproteins, and unveil the clam-shaped joint in a hyper-closed state for nucleocapsid dimerization. Direct visualization of the loop from the disordered C-terminal tail provides structural evidence that C-terminal tail is correlated to the curvature of nucleocapsid and links nucleocapsid condensation and genome replication and transcription with different assembly forms.

scholarly journals Postembedding immunocytochemical localization of paramyxovirus antigens by light and electron microscopy.

1982 ◽  
Vol 30 (12) ◽  
pp. 1313-1319 ◽  
Author(s):  
G Schwendemann ◽  
J S Wolinsky ◽  
G Hatzidimitriou ◽  
D C Merz ◽  
M N Waxham
Keyword(s):  
Electron Microscopy ◽  
Measles Virus ◽  
Sendai Virus ◽  
Sodium Hydroxide Solution ◽  
Subacute Sclerosing Panencephalitis ◽  
Light And Electron Microscopy ◽  
Simian Virus ◽  
Mumps Virus ◽  
Immunocytochemical Staining ◽  
Adult Mice

A postembedding method is described to localize antigens specific for various paramyxoviruses in sections of cells and tissues that have been fixed and embedded in epoxy resins for conventional electron microscopy. Viral antigens were localized in CV-1 cell cultures infected with simian virus 5 (SV5), brains of suckling hamsters inoculated with either neuroadapted mumps virus or hamster-adapted measles virus, and brains of adult mice infected with Sendai (parainfluenza I) virus. Both 1-micrometer-thick and thin (gold) tissue sections were etched with alcoholic sodium hydroxide-solution and then treated following either the unlabeled antibody peroxidase-antiperoxidase or the biotinylated protein A:avidin peroxidase procedure. Primary reagents included immunoglobulin isolated from hyperimmune rabbit sera with specificity to the major viral components of SV5 or SV5 hemagglutinin-neuraminidase, to whole mumps virus or mumps virus nucleocapsids, and to whole Sendai virus. Crude rabbit anti-Sendai virus antiserum and whole human subacute sclerosing panencephalitis (SSPE) sera were used in parallel. The results indicate that tissues processed for conventional evaluation by electron microscopy may be suitable, within limits, for postembedding immunocytochemical staining of paramyxovirus antigens.

scholarly journals Insights into Paramyxovirus Nucleocapsids from Diverse Assemblies

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2479
Author(s):  
Tianhao Li ◽  
Qing-Tao Shen
Keyword(s):  
Measles Virus ◽  
Sendai Virus ◽  
Nipah Virus ◽  
Structural Diversity ◽  
Viral Proteins ◽  
Helical Structures ◽  
Intrinsically Disordered ◽  
Genome Protection ◽  
Negative Sense ◽  
Transcription And Replication

All paramyxoviruses, which include the mumps virus, measles virus, Nipah virus, Newcastle disease virus, and Sendai virus, have non-segmented single-stranded negative-sense RNA genomes. These RNA genomes are enwrapped throughout the viral life cycle by nucleoproteins, forming helical nucleocapsids. In addition to these helical structures, recombinant paramyxovirus nucleocapsids may occur in other assembly forms such as rings, clam-shaped structures, and double-headed nucleocapsids; the latter two are composed of two single-stranded helices packed in a back-to-back pattern. In all of these assemblies, the neighboring nucleoprotein protomers adopt the same domain-swapping mode via the N-terminal arm, C-terminal arm, and recently disclosed N-hole. An intrinsically disordered region in the C-terminal domain of the nucleoproteins, called the N-tail, plays an unexpected role in regulating the transition among the different assembly forms that occurs with other viral proteins, especially phosphoprotein. These structures, together with the helical nucleocapsids, significantly enrich the structural diversity of the paramyxovirus nucleocapsids and help explain the functions of these diverse assemblies, including RNA genome protection, transcription, and replication, as well as encapsulation.

scholarly journals Capturing Enveloped Viruses on Affinity Grids for Downstream Cryo-Electron Microscopy Applications

2013 ◽  
Vol 20 (1) ◽  
pp. 164-174 ◽  
Author(s):  
Gabriella Kiss ◽  
Xuemin Chen ◽  
Melinda A. Brindley ◽  
Patricia Campbell ◽  
Claudio L. Afonso ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Measles Virus ◽  
Influenza A ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Nitrilotriacetic Acid ◽  
Dimensional Structure ◽  
Enveloped Viruses ◽  
Cryo Electron Microscopy ◽  
Human Immunodeficiency Virus Virus

AbstractElectron microscopy (EM), cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) are essential techniques used for characterizing basic virus morphology and determining the three-dimensional structure of viruses. Enveloped viruses, which contain an outer lipoprotein coat, constitute the largest group of pathogenic viruses to humans. The purification of enveloped viruses from cell culture presents certain challenges. Specifically, the inclusion of host-membrane-derived vesicles, the complete destruction of the viruses, and the disruption of the internal architecture of individual virus particles. Here, we present a strategy for capturing enveloped viruses on affinity grids (AG) for use in both conventional EM and cryo-EM/ET applications. We examined the utility of AG for the selective capture of human immunodeficiency virus virus-like particles, influenza A, and measles virus. We applied nickel-nitrilotriacetic acid lipid layers in combination with molecular adaptors to selectively adhere the viruses to the AG surface. This further development of the AG method may prove essential for the gentle and selective purification of enveloped viruses directly onto EM grids for ultrastructural analyses.

scholarly journals Direct visualization of Escherichia coli chemotaxis receptor arrays using cryo-electron microscopy

2007 ◽  
Vol 104 (10) ◽  
pp. 3777-3781 ◽  
Author(s):  
P. Zhang ◽  
C. M. Khursigara ◽  
L. M. Hartnell ◽  
S. Subramaniam
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Direct Visualization ◽  
Cryo Electron Microscopy

scholarly journals Paramyxovirus V Proteins Interact with the RIG-I/TRIM25 Regulatory Complex and Inhibit RIG-I Signaling

2018 ◽  
Vol 92 (6) ◽  
Author(s):  
Maria T. Sánchez-Aparicio ◽  
Leighland J. Feinman ◽  
Adolfo García-Sastre ◽  
Megan L. Shaw
Keyword(s):  
Signaling Pathway ◽  
Measles Virus ◽  
Sendai Virus ◽  
Regulatory Protein ◽  
Nipah Virus ◽  
Antiviral Signaling ◽  
V Protein ◽  
Protein Functions ◽  
Regulatory Complex ◽  
Mitochondrial Antiviral Signaling

ABSTRACT Paramyxovirus V proteins are known antagonists of the RIG-I-like receptor (RLR)-mediated interferon induction pathway, interacting with and inhibiting the RLR MDA5. We report interactions between the Nipah virus V protein and both RIG-I regulatory protein TRIM25 and RIG-I. We also observed interactions between these host proteins and the V proteins of measles virus, Sendai virus, and parainfluenza virus. These interactions are mediated by the conserved C-terminal domain of the V protein, which binds to the tandem caspase activation and recruitment domains (CARDs) of RIG-I (the region of TRIM25 ubiquitination) and to the SPRY domain of TRIM25, which mediates TRIM25 interaction with the RIG-I CARDs. Furthermore, we show that V interaction with TRIM25 and RIG-I prevents TRIM25-mediated ubiquitination of RIG-I and disrupts downstream RIG-I signaling to the mitochondrial antiviral signaling protein. This is a novel mechanism for innate immune inhibition by paramyxovirus V proteins, distinct from other known V protein functions such as MDA5 and STAT1 antagonism. IMPORTANCE The host RIG-I signaling pathway is a key early obstacle to paramyxovirus infection, as it results in rapid induction of an antiviral response. This study shows that paramyxovirus V proteins interact with and inhibit the activation of RIG-I, thereby interrupting the antiviral signaling pathway and facilitating virus replication.

scholarly journals Reduced Nucleoprotein availability impairs negative-sense RNA virus replication and promotes host recognition

2021 ◽  
Author(s):  
Benjamin E. Nilsson-Payant ◽  
Daniel Blanco-Melo ◽  
Skyler Uhl ◽  
Beatriz Escudero-Pérez ◽  
Silke Olschewski ◽  
...  
Keyword(s):  
Host Response ◽  
Measles Virus ◽  
Influenza A ◽  
Ebola Virus ◽  
Rna Viruses ◽  
Viral Rna ◽  
Genome Replication ◽  
Replication Machinery ◽  
Molecular Patterns ◽  
Negative Sense

Negative-sense RNA viruses (NSVs) rely on prepackaged viral RNA-dependent RNA polymerases (RdRp) to replicate and transcribe their viral genomes. Their replication machinery consists of an RdRp bound to viral RNA which is wound around a nucleoprotein (NP) scaffold, forming a viral ribonucleoprotein complex. NSV NP is known to regulate transcription and replication of genomic RNA, however its role in maintaining and protecting the viral genetic material is unknown. Here, we exploited host microRNA expression to target NP of influenza A virus and Sendai virus to ascertain how this would impact genomic levels and the host response to infection. We find that in addition to inducing a drastic decrease in genome replication, the antiviral host response in the absence of NP is dramatically enhanced. Additionally, our data shows that insufficient levels of NP prevent the replication machinery of these NSVs to process full-length genomes, resulting in aberrant replication products which form pathogen-associated molecular patterns in the process. These dynamics facilitate immune recognition by cellular pattern recognition receptors leading to a strong host antiviral response. Moreover, we observe that the consequences of limiting NP levels are universal amongst NSVs including Ebola virus, Lassa virus and Measles virus. Overall, these results provide new insights into viral genome replication of negative-sense RNA viruses and highlight novel avenues towards developing effective antiviral strategies, adjuvants, and/or live-attenuated vaccines. IMPORTANCE Negative-sense RNA viruses comprise some of the most important known human pathogens, including influenza A virus, measles virus and Ebola virus. These viruses possess RNA genomes that are unreadable to the host as they require specific viral RNA dependent RNA polymerases in conjunction with other viral proteins such as nucleoprotein to be replicated and transcribed. As this process generates a significant amount of pathogen-associated molecular patterns, this phylum of viruses can result in a robust induction of the intrinsic host cellular response. To circumvent these defenses, these viruses form tightly regulated ribonucleoprotein replication complexes in order to protect their genomes from detection and to prevent excessive aberrant replication. Here we demonstrate the balance that negative-sense RNA viruses must achieve to both replicate efficiently and to avoid induction of the host defenses.

scholarly journals An ensemble of cryo-EM structures of TRiC reveal its conformational landscape and subunit specificity

2019 ◽  
Vol 116 (39) ◽  
pp. 19513-19522 ◽  
Author(s):  
Mingliang Jin ◽  
Wenyu Han ◽  
Caixuan Liu ◽  
Yunxiang Zang ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ring Closure ◽  
Atomic Resolution ◽  
Protein Homeostasis ◽  
Structural Detail ◽  
Experimental Conditions ◽  
Closed State ◽  
Cryo Electron Microscopy ◽  
Conformational Landscape ◽  
Substrate Processing

TRiC/CCT assists the folding of ∼10% of cytosolic proteins through an ATP-driven conformational cycle and is essential in maintaining protein homeostasis. Here, we determined an ensemble of cryo-electron microscopy (cryo-EM) structures of yeast TRiC at various nucleotide concentrations, with 4 open-state maps resolved at near-atomic resolutions, and a closed-state map at atomic resolution, revealing an extra layer of an unforeseen N-terminal allosteric network. We found that, during TRiC ring closure, the CCT7 subunit moves first, responding to nucleotide binding; CCT4 is the last to bind ATP, serving as an ATP sensor; and CCT8 remains ADP-bound and is hardly involved in the ATPase-cycle in our experimental conditions; overall, yeast TRiC consumes nucleotide in a 2-ring positively coordinated manner. Our results depict a thorough picture of the TRiC conformational landscape and its allosteric transitions from the open to closed states in more structural detail and offer insights into TRiC subunit specificity in ATP consumption and ring closure, and potentially in substrate processing.

scholarly journals A new approach for the direct visualization of the membrane cytoskeleton in cryo-electron microscopy: a comparative study with freeze-etching electron microscopy

Microscopy ◽  
2016 ◽  
Vol 65 (6) ◽  
pp. 488-498 ◽  
Author(s):  
Masaki Makihara ◽  
Takashi Watanabe ◽  
Eiji Usukura ◽  
Kozo Kaibuchi ◽  
Akihiro Narita ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Comparative Study ◽  
Direct Visualization ◽  
New Approach ◽  
Membrane Cytoskeleton ◽  
Cryo Electron Microscopy ◽  
Freeze Etching

scholarly journals V protein, the virulence factor across the family Paramyxoviridae: a review

2019 ◽  
pp. 73-85
Author(s):  
May Ling Tham ◽  
Khatijah Yusoff ◽  
Sarah Othman ◽  
Suet Lin Chia
Keyword(s):  
Measles Virus ◽  
Sendai Virus ◽  
Nipah Virus ◽  
Host Cells ◽  
V Protein ◽  
Signal Transducers ◽  
Stat Proteins ◽  
Animal Pathogens ◽  
The Family ◽  
Interferon Antagonists

Paramyxoviridae is a family of viruses within the order Mononegavirales and comprises 14 genera; Metaavulavirus, Orthoavulavirus, Paraavulavirus, Synodonvirus, Ferlavirus, Aquaparamyxovirus, Henipavirus, Morbillivirus, Respirovirus, Jeilongvirus, Narmovirus, Salemvirus, Pararubulavirus and Orthorubulavirus. The members within this family are negative and single-stranded RNA viruses including human and animal pathogens such as measles virus (MeV), Nipah virus (NiV), mumps virus (MuV), Sendai virus (SeV) and Newcastle disease virus (NDV). The V protein is conserved within the family and plays an essential role in viral pathogenicity. Although V proteins of many paramyxoviruses are interferon-antagonists which counteract with the host’s innate immunity, there are still differences in the mode of action of the V protein between different genera or species within the same genera. The strategies to circumvent the host interferon (IFN) pathway can be divided into three general mechanisms; degradation of signal transducers and activators of transcription (STAT) protein, inhibition of phosphorylation of the transcription factor and, inhibition of translocation of STAT proteins into the nucleus. As a result, inhibition of IFN signalling and production promotes viral replication in the host cells. This review highlights the mechanism of the paramyxoviral V protein in evading the host IFN system.

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