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 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 Determination of a phosphorylation site in Nipah virus nucleoprotein and its involvement in virus transcription

2011 ◽  
Vol 92 (9) ◽  
pp. 2133-2141 ◽  
Author(s):  
Mingshu Huang ◽  
Hiroki Sato ◽  
Kyoji Hagiwara ◽  
Akira Watanabe ◽  
Akihiro Sugai ◽  
...  
Keyword(s):  
Measles Virus ◽  
Luciferase Activity ◽  
Nipah Virus ◽  
Phosphorylation Site ◽  
Viral Proteins ◽  
Cellular Protein ◽  
Rapid Turnover ◽  
Virus Transcription ◽  
Peptide Mass ◽  
Transcription And Replication

Many viruses use their host’s cellular machinery to regulate the functions of viral proteins. The phosphorylation of viral proteins is known to play a role in genome transcription and replication in paramyxoviruses. The paramyxovirus nucleoprotein (N), the most abundant protein in infected cells, is a component of the N–RNA complex and supports the transcription and replication of virus mRNA and genomic RNA. Recently, we reported that the phosphorylation of measles virus N is involved in the regulation of viral RNA synthesis. In this study, we report a rapid turnover of phosphorylation in the Nipah virus N (NiV-N). The phosphorylated NiV-N was hardly detectable in steady-state cells, but was detected after inhibition of cellular protein phosphatases. We identified a phosphorylated serine residue at Ser451 of NiV-N by peptide mass fingerprinting by electrospray ionization–quadrupole time-of-flight mass spectrometry. In the NiV minigenome assay, using luciferase as a reporter gene, the substitution of Ser451 for alanine in NiV-N resulted in a reduction in luciferase activity of approximately 45 % compared with the wild-type protein. Furthermore, the substitution of Ser451 for glutamic acid, which mimics a phosphoserine, led to a more significant decrease in luciferase activity – approximately 81 %. Northern blot analysis showed that both virus transcription and replication were reduced by these mutations. These results suggest that a rapid turnover of the phosphorylation of NiV-N plays an important role in virus transcription and replication.

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 Structure of the RSV Polymerase Complex Reveals a Tentacular Arrangement of the Viral Phosphoprotein

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 115
Author(s):  
Jason S. McLellan
Keyword(s):  
Small Molecules ◽  
Viral Proteins ◽  
Live Attenuated Vaccine ◽  
Polymerase Complex ◽  
Intrinsically Disordered ◽  
Rsv Infection ◽  
Escape Mutants ◽  
Syncytial Virus ◽  
Transcription And Replication ◽  
Oligomerization Domain

Numerous interventions are currently in the process of clinical development for respiratory syncytial virus (RSV) infection, including the use of small molecules that target viral transcription and replication. These processes are catalyzed by a complex comprising the RNA-dependent RNA polymerase (L) and the tetrameric phosphoprotein (P). The RSV P performs many functions, including the recruitment of viral proteins to the polymerase complex. Despite their critical roles in RSV transcription and replication, the structures of L and P have remained elusive, though RSV P is thought to be intrinsically disordered in solution, with the exception of its oligomerization domain. Here, we describe the 3.2 Å cryo-EM structure of RSV L bound to the tetrameric P. The structure reveals a striking tentacular arrangement of P in which each of the four monomers adopts a distinct conformation. The structure also provides a rationale for the inhibitor-escape mutants and mutations observed in live attenuated vaccine candidates. These results provide a framework for determining the molecular underpinnings of RSV replication and transcription and should facilitate the design of effective RSV inhibitors.

scholarly journals Interaction of the C-Terminal Domains of Sendai Virus N and P Proteins: Comparison of Polymerase-Nucleocapsid Interactions within the Paramyxovirus Family

2007 ◽  
Vol 81 (13) ◽  
pp. 6807-6816 ◽  
Author(s):  
Klaartje Houben ◽  
Dominique Marion ◽  
Nicolas Tarbouriech ◽  
Rob W. H. Ruigrok ◽  
Laurence Blanchard
Keyword(s):  
Measles Virus ◽  
Intrinsically Disordered Proteins ◽  
Sendai Virus ◽  
Protein Complexes ◽  
Disordered Proteins ◽  
Resonance Spectroscopy ◽  
Intrinsically Disordered ◽  
Binding Interface ◽  
P Proteins ◽  
Terminal Domains

ABSTRACT Interaction of the C-terminal domains of Sendai virus (SeV) P and N proteins is crucial for RNA synthesis by correctly positioning the polymerase complex (L+P) onto the nucleocapsid (N/RNA). To better understand this mechanism within the paramyxovirus family, we have studied the complex formed by the SeV C-terminal domains of P (PX) and N (NTAIL) proteins by solution nuclear magnetic resonance spectroscopy. We have characterized SeV NTAIL, which belongs to the class of intrinsically disordered proteins, and precisely defined the binding regions within this latter domain and within PX. SeV NTAIL binds with residues 472 to 493, which have a helical propensity (residues 477 to 491) to the surface created by helices α2 and α3 of PX with a 1:1 stoichiometry, as was also found for measles virus (MV). The binding interface is dominated by charged residues, and the dissociation constant was determined to be 57 ± 18 μM under conditions of the experiment (i.e., in 0.5 M NaCl). We have also shown that the extreme C terminus of SeV NTAIL does not interact with PX, which is in contrast to MV, where a second binding site was identified. In addition, the interaction surfaces of the MV proteins are hydrophobic and a stronger binding constant was found. This gives a good illustration of how selection pressure allowed the C-terminal domains of N and P proteins to evolve concomitantly within this family of viruses in order to lead to protein complexes having the same three-dimensional fold, and thus the same function, but with completely different binding interfaces.

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.

Studies of a Defective Measles Virus

1968 ◽  
Vol 26 ◽  
pp. 208-209
Author(s):  
R. M. McCombs ◽  
M. Benyesh-Melnick ◽  
J. P. Brunschwig
Keyword(s):  
Inclusion Bodies ◽  
Measles Virus ◽  
Giant Cells ◽  
Helical Structures ◽  
Thin Sections ◽  
Virus Particles ◽  
Extracellular Virus ◽  
Culture Cells ◽  
Infected Cells ◽  
Eosinophilic Inclusions

Measles virus is an agent that is capable of replicating in a number of different culture cells and generally causes the formation of multinucleated giant cells. As a result of infection, virus is released from the cells into the culture fluids and reinfection can be initiated by this cell-free virus. The extracellular virus has been examined by negative staining with phosphotungstic acid and has been shown to be a rather pleomorphic particle with a diameter of about 140 mμ. However, no such virus particles have been detected in thin sections of the infected cells. Rather, the only virus-induced structures present in the giant cells are eosinophilic inclusions (intracytoplasmic or intranuclear). These inclusion bodies have been shown to contain helical structures, resembling the nucleocapsid observed in negatively stained preparations.

scholarly journals Sendai Virus V Protein Inhibits the Secretion of Interleukin-1β by Preventing NLRP3 Inflammasome Assembly

2018 ◽  
Vol 92 (19) ◽  
Author(s):  
Takayuki Komatsu ◽  
Yukie Tanaka ◽  
Yoshinori Kitagawa ◽  
Naoki Koide ◽  
Yoshikazu Naiki ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Sendai Virus ◽  
Nipah Virus ◽  
Innate Immune ◽  
Parainfluenza Virus ◽  
Inflammasome Activation ◽  
V Protein ◽  
Nlrp3 Inflammasome Activation ◽  
Human Parainfluenza Virus

ABSTRACT Inflammasomes play a key role in host innate immune responses to viral infection by caspase-1 (Casp-1) activation to facilitate interleukin-1β (IL-1β) secretion, which contributes to the host antiviral defense. The NLRP3 inflammasome consists of the cytoplasmic sensor molecule NLRP3, adaptor protein ASC, and effector protein pro-caspase-1 (pro-Casp-1). NLRP3 and ASC promote pro-Casp-1 cleavage, leading to IL-1β maturation and secretion. However, as a countermeasure, viral pathogens have evolved virulence factors to antagonize inflammasome pathways. Here we report that V gene knockout Sendai virus [SeV V(−)] induced markedly greater amounts of IL-1β than wild-type SeV in infected THP1 macrophages. Deficiency of NLRP3 in cells inhibited SeV V(−)-induced IL-1β secretion, indicating an essential role for NLRP3 in SeV V(−)-induced IL-1β activation. Moreover, SeV V protein inhibited the assembly of NLRP3 inflammasomes, including NLRP3-dependent ASC oligomerization, NLRP3-ASC association, NLRP3 self-oligomerization, and intermolecular interactions between NLRP3 molecules. Furthermore, a high correlation between the NLRP3-binding capacity of V protein and the ability to block inflammasome complex assembly was observed. Therefore, SeV V protein likely inhibits NLRP3 self-oligomerization by interacting with NLRP3 and inhibiting subsequent recruitment of ASC to block NLRP3-dependent ASC oligomerization, in turn blocking full activation of the NLRP3 inflammasome and thus blocking IL-1β secretion. Notably, the inhibitory action of SeV V protein on NLRP3 inflammasome activation is shared by other paramyxovirus V proteins, such as Nipah virus and human parainfluenza virus type 2. We thus reveal a mechanism by which paramyxovirus inhibits inflammatory responses by inhibiting NLRP3 inflammasome complex assembly and IL-1β activation. IMPORTANCE The present study demonstrates that the V protein of SeV, Nipah virus, and human parainfluenza virus type 2 interacts with NLRP3 to inhibit NLRP3 inflammasome activation, potentially suggesting a novel strategy by which viruses evade the host innate immune response. As all members of the Paramyxovirinae subfamily carry similar V genes, this new finding may also lead to identification of novel therapeutic targets for paramyxovirus infection and related diseases.

scholarly journals Mimicry between respiratory virus proteins and some human immune proteins

2020 ◽  
Vol 10 (2) ◽  
pp. 305-314
Author(s):  
I. N. Zhilinskaya
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Amino Acid ◽  
Measles Virus ◽  
Respiratory Infections ◽  
Viral Proteins ◽  
Cellular Protein ◽  
Amino Acid Sequences ◽  
Host Immune System ◽  
Human Immune

A comparative analysis on search for amino acid sequences in viral proteins causing respiratory infections (or respiratory infections syndrome) homologous to amino acid sequences from some human immune proteins was performed. The following viruses were used for comparative computer analysis: coronavirus (SARS-CoV), serotype C subgroup adenovirus C (adenoid 71 strain), measles virus (ICHINOSE-BA strain), rubella (Therien strain) and respiratory syncytial (B1 strain) virus. The search for homologous sequences in viral and human immune proteins was carried out by computer comparison of 12 amino acid fragments, which were assigned as homologous at identity in ≥ 8 positions. The data obtained showed that viral proteins contained homologous motifs in several host immune proteins involved in regulating both the inflammatory response and immune response. Mechanistically, all viruses studied were characterized by sequences homologous to host immune proteins such as complement system proteins, integrins, apoptosis inhibitory proteins, interleukins, and toll-like receptors. Such cellular proteins are actively involved in regulating host inflammatory process and immune response formation. Upon that, a set of host immune proteins, to which homologous fragments were found in viral proteins, was individual for each virus. Interestingly, the largest amount of homologous fragments (up to 20) was mainly concentrated in viral proteins with polymerase and protease activity suggesting that these proteins apart to their major role were involved in production of viral nucleic acids and might participate in regulating host immune system. Envelope, internal and non-structural viral proteins, homologous fragments were detected in much smaller quantities (from 1 to 4). In addition, two fragments homologous to various motifs of the same cellular protein were detected in some viral proteins. Thus, the data obtained further support our understanding that signs of immune system disorders in viral infections can result from multi-layered processes associated with modulation of host innate and adaptive immune system, and open up new approaches to study interaction of viruses with host immune system and identify new functions of viral proteins.

scholarly journals In vitro trackable assembly of RNA-specific nucleocapsids of the respiratory syncytial virus

2019 ◽  
Vol 295 (3) ◽  
pp. 883-895 ◽  
Author(s):  
Yunrong Gao ◽  
Dongdong Cao ◽  
Hyunjun Max Ahn ◽  
Anshuman Swain ◽  
Shaylan Hill ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rna Synthesis ◽  
Genomic Rnas ◽  
Viral Rnas ◽  
N Protein ◽  
Syncytial Virus ◽  
Nucleoprotein N ◽  
Negative Sense ◽  
Transcription And Replication

The templates for transcription and replication by respiratory syncytial virus (RSV) polymerase are helical nucleocapsids (NCs), formed by viral RNAs that are encapsidated by the nucleoprotein (N). Proper NC assembly is vital for RSV polymerase to engage the RNA template for RNA synthesis. Previous studies of NCs or nucleocapsid-like particles (NCLPs) from RSV and other nonsegmented negative-sense RNA viruses have provided insights into the overall NC architecture. However, in these studies, the RNAs were either random cellular RNAs or average viral genomic RNAs. An in-depth mechanistic understanding of NCs has been hampered by lack of an in vitro assay that can track NC or NCLP assembly. Here we established a protocol to obtain RNA-free N protein (N0) and successfully demonstrated the utility of a new assay for tracking assembly of N with RNA oligonucleotides into NCLPs. We discovered that the efficiency of the NCLP (N–RNA) assembly depends on the length and sequence of the RNA incorporated into NCLPs. This work provides a framework to generate purified N0 and incorporate it with RNA into NCLPs in a controllable manner. We anticipate that our assay for in vitro trackable assembly of RSV-specific nucleocapsids may enable in-depth mechanistic analyses of this process.

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