scholarly journals Sendai Virus and a Unified Model of Mononegavirus RNA Synthesis

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2466
Author(s):  
Daniel Kolakofsky ◽  
Philippe Le Mercier ◽  
Machiko Nishio ◽  
Martin Blackledge ◽  
Thibaut Crépin ◽  
...  
Keyword(s):  
Measles Virus ◽  
Rna Synthesis ◽  
Biochemical Characterization ◽  
Sendai Virus ◽  
Rna Virus ◽  
Unified Model ◽  
Vesicular Stomatitis ◽  
The 1960S ◽  
Chicken Eggs

Vesicular stomatitis virus (VSV), the founding member of the mononegavirus order (Mononegavirales), was found to be a negative strand RNA virus in the 1960s, and since then the number of such viruses has continually increased with no end in sight. Sendai virus (SeV) was noted soon afterwards due to an outbreak of newborn pneumonitis in Japan whose putative agent was passed in mice, and nowadays this mouse virus is mainly the bane of animal houses and immunologists. However, SeV was important in the study of this class of viruses because, like flu, it grows to high titers in embryonated chicken eggs, facilitating the biochemical characterization of its infection and that of its nucleocapsid, which is very close to that of measles virus (MeV). This review and opinion piece follow SeV as more is known about how various mononegaviruses express their genetic information and carry out their RNA synthesis, and proposes a unified model based on what all MNV have in common.

scholarly journals Ambisense Sendai Viruses Are Inherently Unstable but Are Useful To Study Viral RNA Synthesis

2002 ◽  
Vol 76 (11) ◽  
pp. 5492-5502 ◽  
Author(s):  
Philippe Le Mercier ◽  
Dominique Garcin ◽  
Stéphane Hausmann ◽  
Daniel Kolakofsky
Keyword(s):  
Rna Synthesis ◽  
Sendai Virus ◽  
Viral Rna ◽  
Start Site ◽  
Mrna Editing ◽  
Nascent Chain ◽  
Vesicular Stomatitis ◽  
Chicken Eggs ◽  
Modest Level ◽  
Selection Of

ABSTRACT Ambisense Sendai virus (SeV) was prepared in order to study the control of viral RNA synthesis. In these studies, we found that the relative ratios of genomes/antigenomes formed during infection are largely determined by the relative strengths of the replication promoters, independent of the presence of a functional mRNA start site. We also found that the ability of the viral polymerase (vRdRP) to respond to an mRNA editing site requires prior (re)initiation at an mRNA start site, similar to the acquisition of vRdRP processivity in the absence of nascent chain coassembly. During these studies, the inherent instability of ambisense SeV upon passage in embryonated chicken eggs was noted and was found to be associated with a point mutation in the ambisense mRNA (ambi-mRNA) start site that severely limited its expression. Since the interferon (IFN)-induced antiviral state is mediated in part via double-stranded RNA (dsRNA), the efficiency of the ambi-mRNA poly(A)/stop site was examined. This site was found to operate in a manner similar to that of other SeV mRNA poly(A)/stop sites, i.e., at ∼95% efficiency. This modest level of vRdRP read-through is apparently tolerable for natural SeV because the potential to form dsRNA during infection remains limited. However, when mRNAs are expressed from ambisense SeV antigenomes, vRdRP read-through of the ambi-mRNA poly(A)/stop site creates a capped transcript that can potentially extend the entire length of the antigenome, since there are no further poly(A)/stop sites here. In support of this hypothesis, loss of ambi-mRNA expression during passage of ambisense SeV stocks in eggs is also characterized by conversion of virus that grows poorly in IFN-sensitive cultures and is relatively IFN sensitive to virus that grows well even in IFN-pretreated cells that restrict vesicular stomatitis virus replication, i.e., the wild-type SeV phenotype. The selection of mutants unable to express ambi-mRNA on passage in chicken eggs is presumably due to increased levels of dsRNA during infection. How natural ambisense viruses may deal with this dilemma is discussed.

scholarly journals Structural and biochemical characterization of nsp12-nsp7-nsp8 core polymerase complex from COVID-19 virus

2020 ◽  
Author(s):  
Qi Peng ◽  
Ruchao Peng ◽  
Bin Yuan ◽  
Jingru Zhao ◽  
Min Wang ◽  
...  
Keyword(s):  
Rna Synthesis ◽  
Biochemical Characterization ◽  
Lower Body ◽  
Huge Number ◽  
Polymerase Complex ◽  
The Core ◽  
Global Pandemic ◽  
Reduced Activity ◽  
Resolution Structure

SummaryThe ongoing global pandemic of coronavirus disease 2019 (COVID-19) has caused huge number of human deaths. Currently, there are no specific drugs or vaccines available for this virus. The viral polymerase is a promising antiviral target. However, the structure of COVID-19 virus polymerase is yet unknown. Here, we describe the near-atomic resolution structure of its core polymerase complex, consisting of nsp12 catalytic subunit and nsp7-nsp8 cofactors. This structure highly resembles the counterpart of SARS-CoV with conserved motifs for all viral RNA-dependent RNA polymerases, and suggests the mechanism for activation by cofactors. Biochemical studies revealed reduced activity of the core polymerase complex and lower thermostability of individual subunits of COVID-19 virus as compared to that of SARS-CoV. These findings provide important insights into RNA synthesis by coronavirus polymerase and indicate a well adaptation of COVID-19 virus towards humans with relatively lower body temperatures than the natural bat hosts.

scholarly journals G3BP1 inhibits RNA virus replication by positively regulating RIG-I-mediated cellular antiviral response

2019 ◽  
Vol 10 (12) ◽  
Author(s):  
Wenping Yang ◽  
Yi Ru ◽  
Jingjing Ren ◽  
Juncui Bai ◽  
Junshu Wei ◽  
...  
Keyword(s):  
Sendai Virus ◽  
Rna Virus ◽  
Innate Immune ◽  
Positive Regulation ◽  
Antiviral Responses ◽  
Antiviral Genes ◽  
Cellular Antiviral Response ◽  
Vesicular Stomatitis ◽  
Recognition Receptor ◽  
Inducible Gene

AbstractRetinoic acid-inducible gene I (RIG-I) is a pattern recognition receptor and is involved in the innate immune response against RNA viruses infection. Here, we demonstrate that the Ras-GTPase-activating protein SH3-domain-binding protein 1 (G3BP1) serves as a positive regulator of the RIG-I-mediated signaling pathway. G3BP1-deficient cells inhibited RNA virus-triggered induction of downstream antiviral genes. Furthermore, we found that G3BP1 inhibited the replication of Sendai virus and vesicular stomatitis virus, indicating a positive regulation of G3BP1 to cellular antiviral responses. Mechanistically, G3BP1 formed a complex with RNF125 and RIG-I, leading to decreased RNF125 via its auto-ubiquitination; thus, promoting expression of RIG-I. Overall, the results suggest a novel mechanism for G3BP1 in the positive regulation of antiviral signaling mediated by RIG-I.

scholarly journals Longer and Shorter Forms of Sendai Virus C Proteins Play Different Roles in Modulating the Cellular Antiviral Response

2001 ◽  
Vol 75 (15) ◽  
pp. 6800-6807 ◽  
Author(s):  
Dominique Garcin ◽  
Joseph Curran ◽  
Masae Itoh ◽  
Daniel Kolakofsky
Keyword(s):  
Amino Acids ◽  
Vesicular Stomatitis Virus ◽  
Rna Synthesis ◽  
Sendai Virus ◽  
Antiviral Response ◽  
Parallel Pathway ◽  
Cellular Antiviral Response ◽  
Vesicular Stomatitis ◽  
C Proteins ◽  
Virus C

ABSTRACT The Sendai virus (SeV) C gene codes for a nested set of four C proteins that carry out several functions, including the modulation of viral RNA synthesis and countering of the cellular antiviral response. Using mutant C genes (and in particular a C gene with a deletion of six amino acids present only in the larger pair of C proteins) and recombinant SeV carrying these mutant C genes, we find that the nested set of C proteins carry out a nested set of functions. All of the C proteins interdict interferon (IFN) signaling to IFN-stimulated genes (ISGs) and prevent pY701-Stat1 formation. However, only the larger C proteins can induce STAT1 instability, prevent IFN from inducing an antiviral state, or prevent programmed cell death. Remarkably, interdiction of IFN signaling to ISGs and the absence of pY701-Stat1 formation did not prevent IFN-α from inducing an anti-Vesicular stomatitis virus (VSV) state. It is possible that IFN-α signaling to induce an anti-VSV state can occur independently of the well-established Jak/Stat/ISGF3 pathway and that it is this parallel pathway that is targeted by the longer C proteins.

scholarly journals Biochemical Characterization of the Equine Arteritis Virus Helicase Suggests a Close Functional Relationship between Arterivirus and Coronavirus Helicases

2000 ◽  
Vol 74 (20) ◽  
pp. 9586-9593 ◽  
Author(s):  
Anja Seybert ◽  
Leonie C. van Dinten ◽  
Eric J. Snijder ◽  
John Ziebuhr
Keyword(s):  
Functional Relationship ◽  
Biochemical Characterization ◽  
Rna Virus ◽  
Nonstructural Protein ◽  
Biochemical Properties ◽  
Equine Arteritis Virus ◽  
Helicase Domain ◽  
Rna And Dna ◽  
Combined Data

ABSTRACT The arterivirus equine arteritis virus nonstructural protein 10 (nsp10) has previously been predicted to contain a Zn finger structure linked to a superfamily 1 (SF1) helicase domain. A recombinant form of nsp10, MBP-nsp10, was produced in Escherichia coli as a fusion protein with the maltose-binding protein. The protein was partially purified by affinity chromatography and shown to have ATPase activity that was strongly stimulated by poly(dT), poly(U), and poly(dA) but not by poly(G). The protein also had both RNA and DNA duplex-unwinding activities that required the presence of 5′ single-stranded regions on the partial-duplex substrates, indicating a 5′-to-3′ polarity in the unwinding reaction. Results of this study suggest a close functional relationship between the arterivirus nsp10 and the coronavirus helicase, for which NTPase and duplex-unwinding activities were recently demonstrated. In a number of biochemical properties, both arterivirus and coronavirus SF1 helicases differ significantly from the previously characterized RNA virus SF1 and SF2 enzymes. Thus, the combined data strongly support the idea that nidovirus helicases may represent a separate group of RNA virus-encoded helicases with distinct properties.

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

Plant Pathology Diagnosed by X-Ray Microanalysis

1987 ◽  
Vol 45 ◽  
pp. 974-975
Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang
Keyword(s):  
Electron Microscopy ◽  
Plant Pathology ◽  
Biochemical Characterization ◽  
Nutrient Deficiency ◽  
Green Leaf ◽  
Parasitic Infestation ◽  
X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

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