Overexpression of an insect virus encoded silencing suppressor does not enhance plants’ susceptibility to its natural virus

VirusDisease ◽  
2021 ◽  
Author(s):  
Kumari Veena Sinha ◽  
Abdul Kader Jailani ◽  
Bikash Mandal ◽  
Sunil K. Mukherjee ◽  
Neeti Sanan-Mishra
Keyword(s):  
Silencing Suppressor ◽  
Insect Virus ◽  
Natural Virus

Periodic Structure in the Matrix Protein of an Insect Virus

1982 ◽  
Vol 40 ◽  
pp. 302-303
Author(s):  
H.M. Mazzone ◽  
W.F. Engler ◽  
R. Zerillo ◽  
G.F. Bahr
Keyword(s):  
Inclusion Body ◽  
Periodic Structure ◽  
Matrix Protein ◽  
Malacosoma Disstria ◽  
Insect Virus ◽  
Virus Particles ◽  
The Matrix ◽  
Nucleopolyhedrosis Virus

The nucleopolyhedrosis virus (NPV) of the forest tent cater - pillar (Malacosoma disstria Hubner) has been analyzed in our laboratories. As a representative of the Baculovirus class, the NPV has virus particles enclosed with in a proteinaceous structure, the inclusion body.

RNA Silencing Suppressor p19 Regulates The Expressions of Cell Cycle Related Genes*

2009 ◽  
Vol 36 (5) ◽  
pp. 541-548 ◽  
Author(s):  
Li LIU ◽  
Jian LI ◽  
Yu-Ping XU ◽  
Wen-Tao QIAO ◽  
Qi-Min CHEN ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Silencing ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor

scholarly journals Snapshots of a Non-Canonical RdRP in Action

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1260
Author(s):  
Diego S. Ferrero ◽  
Michela Falqui ◽  
Nuria Verdaguer
Keyword(s):  
Metal Ion ◽  
Rna Viruses ◽  
Ion Binding ◽  
Genome Replication ◽  
Metal Ion Binding ◽  
Insect Virus ◽  
X Ray ◽  
Template Strand ◽  
Nucleotide Incorporation ◽  
Elongation Process

RNA viruses typically encode their own RNA-dependent RNA polymerase (RdRP) to ensure genome replication and transcription. The closed “right hand” architecture of RdRPs encircles seven conserved structural motifs (A to G) that regulate the polymerization activity. The four palm motifs, arranged in the sequential order A to D, are common to all known template dependent polynucleotide polymerases, with motifs A and C containing the catalytic aspartic acid residues. Exceptions to this design have been reported in members of the Permutotetraviridae and Birnaviridae families of positive single stranded (+ss) and double-stranded (ds) RNA viruses, respectively. In these enzymes, motif C is located upstream of motif A, displaying a permuted C–A–B–D connectivity. Here we study the details of the replication elongation process in the non-canonical RdRP of the Thosea asigna virus (TaV), an insect virus from the Permutatetraviridae family. We report the X-ray structures of three replicative complexes of the TaV polymerase obtained with an RNA template-primer in the absence and in the presence of incoming rNTPs. The structures captured different replication events and allowed to define the critical interactions involved in: (i) the positioning of the acceptor base of the template strand, (ii) the positioning of the 3’-OH group of the primer nucleotide during RNA replication and (iii) the recognition and positioning of the incoming nucleotide. Structural comparisons unveiled a closure of the active site on the RNA template-primer binding, before rNTP entry. This conformational rearrangement that also includes the repositioning of the motif A aspartate for the catalytic reaction to take place is maintained on rNTP and metal ion binding and after nucleotide incorporation, before translocation.

scholarly journals Heat Stress Reduces the Susceptibility of Caenorhabditis elegans to Orsay Virus Infection

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1161
Author(s):  
Yuqing Huang ◽  
Mark G. Sterken ◽  
Koen van Zwet ◽  
Lisa van Sluijs ◽  
Gorben P. Pijlman ◽  
...  
Keyword(s):  
Heat Stress ◽  
Caenorhabditis Elegans ◽  
Virus Infection ◽  
Intracellular Pathogen ◽  
Potential Candidate ◽  
Molecular Responses ◽  
C Elegans ◽  
Pathogen Response ◽  
Orsay Virus ◽  
Natural Virus

The nematode Caenorhabditis elegans has been a versatile model for understanding the molecular responses to abiotic stress and pathogens. In particular, the response to heat stress and virus infection has been studied in detail. The Orsay virus (OrV) is a natural virus of C. elegans and infection leads to intracellular infection and proteostatic stress, which activates the intracellular pathogen response (IPR). IPR related gene expression is regulated by the genes pals-22 and pals-25, which also control thermotolerance and immunity against other natural pathogens. So far, we have a limited understanding of the molecular responses upon the combined exposure to heat stress and virus infection. We test the hypothesis that the response of C. elegans to OrV infection and heat stress are co-regulated and may affect each other. We conducted a combined heat-stress-virus infection assay and found that after applying heat stress, the susceptibility of C. elegans to OrV was decreased. This difference was found across different wild types of C. elegans. Transcriptome analysis revealed a list of potential candidate genes associated with heat stress and OrV infection. Subsequent mutant screens suggest that pals-22 provides a link between viral response and heat stress, leading to enhanced OrV tolerance of C. elegans after heat stress.

Identification of RNA silencing suppressor encoded by wheat blue dwarf (WBD) phytoplasma

Plant Biology ◽  
2021 ◽  
Author(s):  
Licheng Wang ◽  
Wenbao Chen ◽  
Huan Ma ◽  
Jingyuan Li ◽  
Xingan Hao ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor

A sensitive and rapid RNA silencing suppressor activity assay based on alfalfa mosaic virus expression vector

2019 ◽  
Vol 272 ◽  
pp. 197733 ◽  
Author(s):  
Mireya Martínez-Pérez ◽  
José A. Navarro ◽  
Vicente Pallás ◽  
Jesús A. Sánchez-Navarro
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Expression Vector ◽  
Alfalfa Mosaic Virus ◽  
Silencing Suppressor ◽  
Activity Assay ◽  
Suppressor Activity ◽  
Rna Silencing Suppressor ◽  
Virus Expression

scholarly journals Requirement for Host RNA-Silencing Components and the Virus-Silencing Suppressor when Second-Site Mutations Compensate for Structural Defects in the 3′ Untranslated Region

2015 ◽  
Vol 89 (22) ◽  
pp. 11603-11618 ◽  
Author(s):  
Maitreyi Chattopadhyay ◽  
Vera A. Stupina ◽  
Feng Gao ◽  
Christine R. Szarko ◽  
Micki M. Kuhlmann ◽  
...  
Keyword(s):  
Small Rnas ◽  
Rna Silencing ◽  
Untranslated Region ◽  
Higher Order ◽  
Order Structure ◽  
Silencing Suppressor ◽  
Turnip Crinkle Virus ◽  
Site Mutation ◽  
Primary Mutation ◽  
Positive Strand Rna

ABSTRACTTurnip crinkle virus (TCV) contains a structured 3′ region with hairpins and pseudoknots that form a complex network of noncanonical RNA:RNA interactions supporting higher-order structure critical for translation and replication. We investigated several second-site mutations in the p38 coat protein open reading frame (ORF) that arose in response to a mutation in the asymmetric loop of a critical 3′ untranslated region (UTR) hairpin that disrupts local higher-order structure. All tested second-site mutations improved accumulation of TCV in conjunction with a partial reversion of the primary mutation (TCV-rev1) but had neutral or a negative effect on wild-type (wt) TCV or TCV with the primary mutation. SHAPE (selective 2′-hydroxylacylation analyzed byprimerextension) structure probing indicated that these second-site mutations reside in an RNA domain that includes most of p38 (domain 2), and evidence for RNA:RNA interactions between domain 2 and 3′UTR-containing domain 1 was found. However, second-site mutations were not compensatory in the absence of p38, which is also the TCV silencing suppressor, or indcl-2/dcl4orago1/ago2backgrounds. One second-site mutation reduced silencing suppressor activity of p38 by altering one of two GW motifs that are required for p38 binding to double-stranded RNAs (dsRNAs) and interaction with RNA-induced silencing complex (RISC)-associated AGO1/AGO2. Another second-site mutation substantially reduced accumulation of TCV-rev1 in the absence of p38 or DCL2/DCL4. We suggest that the second-site mutations in the p38 ORF exert positive effects through a similar downstream mechanism, either by enhancing accumulation of beneficial DCL-produced viral small RNAs that positively regulate the accumulation of TCV-rev1 or by affecting the susceptibility of TCV-rev1 to RISC loaded with viral small RNAs.IMPORTANCEGenomes of positive-strand RNA viruses fold into high-order RNA structures. Viruses with mutations in regions critical for translation and replication often acquire second-site mutations that exert a positive compensatory effect through reestablishment of canonical base pairing with the altered region. In this study, two distal second-site mutations that individually arose in response to a primary mutation in a critical 3′ UTR hairpin in the genomic RNA of turnip crinkle virus did not directly interact with the primary mutation. Although different second-site changes had different attributes, compensation was dependent on the production of the viral p38 silencing suppressor and on the presence of silencing-required DCL and AGO proteins. Our results provide an unexpected connection between a 3′ UTR primary-site mutation proposed to disrupt higher-order structure and the RNA-silencing machinery.

On the multiplication of an insect virus

1952 ◽  
Vol 8 ◽  
pp. 360-368 ◽  
Author(s):  
F.T. Bird
Keyword(s):  
Insect Virus
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