scholarly journals The Role of the Chloroplast in the Replication of Positive-Sense Single-Stranded Plant RNA Viruses

2018 ◽  
Vol 9 ◽  
Author(s):  
Marta Budziszewska ◽  
Aleksandra Obrępalska-Stęplowska
Keyword(s):  
Rna Viruses ◽  
Positive Sense

scholarly journals Investigation of the role of GBF1 in the replication of positive-sense single-stranded RNA viruses

2018 ◽  
Vol 99 (8) ◽  
pp. 1086-1096 ◽  
Author(s):  
Juliette Ferlin ◽  
Rayan Farhat ◽  
Sandrine Belouzard ◽  
Laurence Cocquerel ◽  
Antoine Bertin ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Positive Sense

scholarly journals Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Rana Abdelnabi ◽  
Ana Theresa Silveira de Morais ◽  
Pieter Leyssen ◽  
Isabelle Imbert ◽  
Stéphanie Beaucourt ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Broad Spectrum ◽  
Rna Viruses ◽  
Negative Impact ◽  
Antiviral Agent ◽  
Wild Type Virus ◽  
Viral Polymerase ◽  
Ssrna Virus ◽  
Positive Sense

ABSTRACT Favipiravir (T-705) is a broad-spectrum antiviral agent that has been approved in Japan for the treatment of influenza virus infections. T-705 also inhibits the replication of various RNA viruses, including chikungunya virus (CHIKV). We demonstrated earlier that the K291R mutation in the F1 motif of the RNA-dependent RNA polymerase (RdRp) of CHIKV is responsible for low-level resistance to T-705. Interestingly, this lysine is highly conserved in the RdRp of positive-sense single-stranded RNA (+ssRNA) viruses. To obtain insights into the unique broad-spectrum antiviral activity of T-705, we explored the role of this lysine using another +ssRNA virus, namely, coxsackievirus B3 (CVB3). Introduction of the corresponding K-to-R substitution in the CVB3 RdRp (K159R) resulted in a nonviable virus. Replication competence of the K159R variant was restored by spontaneous acquisition of an A239G substitution in the RdRp. A mutagenesis analysis at position K159 identified the K159M variant as the only other viable variant which had also acquired the A239G substitution. The K159 substitutions markedly decreased the processivity of the purified viral RdRp, which was restored by the introduction of the A239G mutation. The K159R A239G and K159M A239G variants proved, surprisingly, more susceptible than the wild-type virus to T-705 and exhibited lower fidelity in polymerase assays. Furthermore, the K159R A239G variant was found to be highly attenuated in mice. We thus demonstrate that the conserved lysine in the F1 motif of the RdRp of +ssRNA viruses is involved in the broad-spectrum antiviral activity of T-705 and that it is a key amino acid for the proper functioning of the enzyme. IMPORTANCE In this study, we report the key role of a highly conserved lysine residue of the viral polymerase in the broad-spectrum antiviral activity of favipiravir (T-705) against positive-sense single-stranded RNA viruses. Substitutions of this conserved lysine have a major negative impact on the functionality of the RdRp. Furthermore, we show that this lysine is involved in the fidelity of the RdRp and that the RdRp fidelity influences the sensitivity of the virus for the antiviral efficacy of T-705. Consequently, these results provide insights into the mechanism of the antiviral activity of T-705 and may lay the basis for the design of novel chemical scaffolds that may be endowed with a more potent broad-spectrum antiviral activity than that of T-705.

The role of 3'UTR of RNA viruses on mRNA stability and translation enhancement

2021 ◽  
Vol 21 ◽  
Author(s):  
Mahsa Rasekhian ◽  
Farzin Roohvand ◽  
Solomon Habtemariam ◽  
Marzieh Marzbany ◽  
Monireh Kazemimanesh
Keyword(s):  
Mrna Stability ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Viruses ◽  
Nucleotide Composition ◽  
Rna Molecules ◽  
A Genome ◽  
Functional Product ◽  
Positive Sense

: The central dogma of molecular biology explains the flow of genetic information from DNA to functional products such as proteins. In most cases, a linear relationship with high correlation coefficient exists between the concentration of mRNA, the middle man, and the functional product. Untranslated regions (UTRs) of RNA form considerable base pairing that contributes to the secondary and tertiary structures of mRNA. The interaction between the mRNA secondary structures (cis-elements), RNA-binding proteins (RBP) and miRs (trans-element) are critical determinants of mRNAs' fate and stability. Among different viral families, the positive sense (+) RNA viruses use the simplest possible strategy of replication and expression; as the same molecule functions both as a genome and mRNA. Additionally, nucleotide composition and codon usage of +RNA viruses are the closest to human codon adaptation index (CAI). Since the origin of replication of viral intermediate RNA molecules is at the 3'-end of the genome, the 3'UTR plays a role in viral RNA replication. Moreover, the messenger role of RNA likely places functional demands on the 3'UTR to serve a role typical of cellular mRNA. This article reviews the effect of 3'UTR of RNA viruses with positive sense and genomes on mRNA stability and translation improvement. A range of animal (e.g., Dengue, Sindbis, Corona and Polio) and plant (Barley yellow dwarf, Brome mosaic, Turnip crinkle, Tobacco mosaic, Cowpea mosaic and Alfalfa mosaic) viruses are examined to highlight the role of 3'UTR in viral survival and as a potential target for pharmaceutical applications.

THE ROLE OF METAPHOR IN HISTORICAL KNOWLEDGE

Cultural code ◽  
2020 ◽  
pp. 30-37
Author(s):  
MARIYA PETROVNA LAPTEVA ◽  
Keyword(s):  
Semantic Content ◽  
Cognitive Significance ◽  
Historical Knowledge ◽  
Positive Sense

The article continues the author's series of publications on the terminological apparatus of the historian. The problems of humanitarian science cannot have "final solutions". F.R.Ankersmith paid attention to the fact that the attitude to the role of metaphors knows not onli "ups" but also "downs". Exploring aspects of the conceptual arsenal associated with the explicit use of the metaphor. "Implicit use" refers to those semantic situations when a historian or another humanist enters into a kind of dialogue with other sciences, carrying out terminological borrowing. Since the semantic content of the term changes in this case, then, in essence, a metaphorical action takes place that does not require a special name. The article contains, the author's reflection on the circumstances and features of the use of metaphors. The author finds out how and why historiography becomes metaphorical. Referring to specialists who developed the cognitive basis of the theory of metaphor, the author analyzes different traditions of understanding what metaphor is. There is a search for a positive sense of metaphor usage with some ambiguity. Since the metaphor creates a new meaning of the word, its cognitive significance becomes unquestionable. By citing examples of various uses of metaphors in the texts of historians, the author shows how a metaphor helps clarify the uniqueness of historical situations.

The Role of microRNAs in the Viral Infections

2019 ◽  
Vol 24 (39) ◽  
pp. 4659-4667 ◽  
Author(s):  
Mona Fani ◽  
Milad Zandi ◽  
Majid Rezayi ◽  
Nastaran Khodadad ◽  
Hadis Langari ◽  
...  
Keyword(s):  
Viral Infections ◽  
Rna Viruses ◽  
Regulation Of Gene Expression ◽  
Molecular Structures ◽  
Main Function ◽  
Cellular Functions ◽  
Viral Genes ◽  
Non Coding Rnas ◽  
Post Transcriptional Regulation

MicroRNAs (miRNAs) are non-coding RNAs with 19 to 24 nucleotides which are evolutionally conserved. MicroRNAs play a regulatory role in many cellular functions such as immune mechanisms, apoptosis, and tumorigenesis. The main function of miRNAs is the post-transcriptional regulation of gene expression via mRNA degradation or inhibition of translation. In fact, many of them act as an oncogene or tumor suppressor. These molecular structures participate in many physiological and pathological processes of the cell. The virus can also produce them for developing its pathogenic processes. It was initially thought that viruses without nuclear replication cycle such as Poxviridae and RNA viruses can not code miRNA, but recently, it has been proven that RNA viruses can also produce miRNA. The aim of this articles is to describe viral miRNAs biogenesis and their effects on cellular and viral genes.

COVID 19, All a Radiologist Needs to Know: A Narrative Review

2020 ◽  
Vol 16 ◽  
Author(s):  
Farzaneh Shobeirian
Keyword(s):  
Computed Tomography ◽  
Rna Viruses ◽  
Imaging Findings ◽  
Protective Measures ◽  
Infection Transmission ◽  
The World ◽  
Positive Sense ◽  
Global Concern ◽  
Interlobular Septal Thickening ◽  
Radiologic Characteristics

Background: Coronaviruses are non-segmented enveloped positive-sense single-strand RNA viruses, and COVID-19 is the seventh known coronavirus, infecting humans. Objective: As the COVID-19 continued to spread the world wildly, every radiologist or clinician needs to be familiar with its imaging findings. Methods: In this study, we reviewed available studies to provide a comprehensive statement on COVID-19 imaging findings. Results: Ground-glass opacities, linear opacities, interlobular septal thickening, consolidation, and Crazy-paving patterns are the most frequent findings in computed tomography (CT) of lungs in patients with COVID-19 pneumonia, which are mostly bilateral, multifocal, and peripheral. Staff needs to follow some rules to reduce infection transmission. Conclusion: COVID-19 pneumonia is a new global concern which has many unknown features. In this article, the radiologic characteristics of COVID-19 pneumonia are discussed. We also discussed appropriate protective measures that the radiology team should be aware of.

Inhibitions of Positive-Sense (ss) RNA Viruses RNA-Dependent RNA Polymerases

2009 ◽  
Vol 5 (4) ◽  
pp. 234-244 ◽  
Author(s):  
Kajohn Boonrod ◽  
Gabriele Krczal
Keyword(s):  
Rna Viruses ◽  
Rna Polymerases ◽  
Positive Sense

scholarly journals RNA Helicase A Regulates the Replication of RNA Viruses

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 361
Author(s):  
Rui-Zhu Shi ◽  
Yuan-Qing Pan ◽  
Li Xing
Keyword(s):  
Virus Replication ◽  
Rna Binding ◽  
Rna Viruses ◽  
Rna Helicase ◽  
Rna Helicase A ◽  
Double Stranded Rna ◽  
Binding Domains ◽  
N Terminus

The RNA helicase A (RHA) is a member of DExH-box helicases and characterized by two double-stranded RNA binding domains at the N-terminus. RHA unwinds double-stranded RNA in vitro and is involved in RNA metabolisms in the cell. RHA is also hijacked by a variety of RNA viruses to facilitate virus replication. Herein, this review will provide an overview of the role of RHA in the replication of RNA viruses.

scholarly journals Essential role of IPS-1 in innate immune responses against RNA viruses

2006 ◽  
Vol 203 (7) ◽  
pp. 1795-1803 ◽  
Author(s):  
Himanshu Kumar ◽  
Taro Kawai ◽  
Hiroki Kato ◽  
Shintaro Sato ◽  
Ken Takahashi ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Rna Virus ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Type I ◽  
Innate Immune Responses ◽  
Antiviral Responses ◽  
Deficient Mice

IFN-β promoter stimulator (IPS)-1 was recently identified as an adapter for retinoic acid–inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (Mda5), which recognize distinct RNA viruses. Here we show the critical role of IPS-1 in antiviral responses in vivo. IPS-1–deficient mice showed severe defects in both RIG-I– and Mda5-mediated induction of type I interferon and inflammatory cytokines and were susceptible to RNA virus infection. RNA virus–induced interferon regulatory factor-3 and nuclear factor κB activation was also impaired in IPS-1–deficient cells. IPS-1, however, was not essential for the responses to either DNA virus or double-stranded B-DNA. Thus, IPS-1 is the sole adapter in both RIG-I and Mda5 signaling that mediates effective responses against a variety of RNA viruses.

scholarly journals From Capsids to Complexes: Expanding the Role of TRIM5α in the Restriction of Divergent RNA Viruses and Elements

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 446
Author(s):  
Kevin M. Rose ◽  
Stephanie J. Spada ◽  
Rebecca Broeckel ◽  
Kristin L. McNally ◽  
Vanessa M. Hirsch ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Molecular Basis ◽  
Human Population ◽  
Rna Viruses ◽  
Arms Race ◽  
Innate Immune ◽  
Immunodeficiency Virus ◽  
Underlying Mechanisms ◽  
Hiv 1

An evolutionary arms race has been ongoing between retroviruses and their primate hosts for millions of years. Within the last century, a zoonotic transmission introduced the Human Immunodeficiency Virus (HIV-1), a retrovirus, to the human population that has claimed the lives of millions of individuals and is still infecting over a million people every year. To counteract retroviruses such as this, primates including humans have evolved an innate immune sensor for the retroviral capsid lattice known as TRIM5α. Although the molecular basis for its ability to restrict retroviruses is debated, it is currently accepted that TRIM5α forms higher-order assemblies around the incoming retroviral capsid that are not only disruptive for the virus lifecycle, but also trigger the activation of an antiviral state. More recently, it was discovered that TRIM5α restriction is broader than previously thought because it restricts not only the human retroelement LINE-1, but also the tick-borne flaviviruses, an emergent group of RNA viruses that have vastly different strategies for replication compared to retroviruses. This review focuses on the underlying mechanisms of TRIM5α-mediated restriction of retroelements and flaviviruses and how they differ from the more widely known ability of TRIM5α to restrict retroviruses.

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