scholarly journals Functions of Conserved Motifs in the RNA-Dependent RNA Polymerase of a Yeast Double-Stranded RNA Virus

1998 ◽  
Vol 72 (5) ◽  
pp. 4427-4429 ◽  
Author(s):  
Eric Routhier ◽  
Jeremy A. Bruenn
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Rna Virus ◽  
Rna Dependent Rna Polymerase ◽  
Conserved Motifs ◽  
Double Stranded Rna ◽  
Conserved Regions

ABSTRACT At least eight conserved motifs are visible in the totivirus RNA-dependent RNA polymerase (RDRP). We have systematically altered each of these in the Saccharomyces cerevisiaedouble-stranded RNA virus ScVL1 by substituting the conserved motifs from a giardiavirus. The results help define the conserved regions of the RDRP involved in polymerase function and those essential for other reasons.

scholarly journals Late Male-Killing Viruses in Homona magnanima Identified as Osugoroshi Viruses, Novel Members of Partitiviridae

2021 ◽  
Vol 11 ◽  
Author(s):  
Ryosuke Fujita ◽  
Maki N. Inoue ◽  
Takumi Takamatsu ◽  
Hiroshi Arai ◽  
Mayu Nishino ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Rna Polymerase ◽  
Rna Viruses ◽  
Rna Virus ◽  
Horizontal Transmission ◽  
Rna Dependent Rna Polymerase ◽  
Double Stranded Rna ◽  
First Report ◽  
Male Killing ◽  
Male Specific

Late male-killing, a male-specific death after hatching, is a unique phenotype found in Homona magnanima, oriental tea tortrix. The male-killing agent was suspected to be an RNA virus, but details were unknown. We herein successfully isolated and identified the putative male-killing virus as Osugoroshi viruses (OGVs). The three RNA-dependent RNA polymerase genes detected were phylogenetically related to Partitiviridae, a group of segmented double-stranded RNA viruses. Purified dsRNA from a late male-killing strain of H. magnanima revealed 24 segments, in addition to the RdRps, with consensus terminal sequences. These segments included the previously found male-killing agents MK1068 (herein OGV-related RNA16) and MK1241 (OGV-related RNA7) RNAs. Ultramicroscopic observation of purified virions, which induced late male-killing in the progeny of injected moths, showed sizes typical of Partitiviridae. Mathematical modeling showed the importance of late male-killing in facilitating horizontal transmission of OGVs in an H. magnanima population. This study is the first report on the isolation of partiti-like virus from insects, and one thought to be associated with late male-killing, although the viral genomic contents and combinations in each virus are still unknown.

scholarly journals Noncatalytic Ions Direct the RNA-Dependent RNA Polymerase of Bacterial Double-Stranded RNA Virus  6 from De Novo Initiation to Elongation

2011 ◽  
Vol 86 (5) ◽  
pp. 2837-2849 ◽  
Author(s):  
S. Wright ◽  
M. M. Poranen ◽  
D. H. Bamford ◽  
D. I. Stuart ◽  
J. M. Grimes
Keyword(s):  
Rna Polymerase ◽  
De Novo ◽  
Rna Virus ◽  
Rna Dependent Rna Polymerase ◽  
Double Stranded Rna

The coat protein of the yeast double-stranded RNA virus L-A attaches covalently to the cap structure of eukaryotic mRNA

1992 ◽  
Vol 12 (8) ◽  
pp. 3390-3398
Author(s):  
A Blanc ◽  
C Goyer ◽  
N Sonenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Coat Protein ◽  
Translation Initiation ◽  
Rna Virus ◽  
Binding Protein ◽  
Covalent Bond ◽  
Cellular Proteins ◽  
Double Stranded Rna ◽  
Virus Coat ◽  
Drosophila Cells

The eukaryotic mRNA 5' cap structure m7GpppX (where X is any nucleotide) interacts with a number of cellular proteins. Several of these proteins were studied in mammalian, yeast, and drosophila cells and found to be involved in translation initiation. Here we describe a novel cap-binding protein, the coat protein of L-A, a double-stranded RNA virus that is persistently maintained in many Saccharomyces cerevisiae strains. The results also suggest that the coat protein of a related double-stranded RNA virus (L-BC) is likewise a cap-binding protein. Strikingly, in contrast to the cellular cap-binding proteins, the interaction between the L-A virus coat protein and the cap structure is through a covalent bond.

scholarly journals RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1738
Author(s):  
Alesia A. Levanova ◽  
Eeva J. Vainio ◽  
Jarkko Hantula ◽  
Minna M. Poranen
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Rna Virus ◽  
Polymerization Reaction ◽  
Rna Dependent Rna Polymerase ◽  
Independent Manner ◽  
Nucleotidyl Transferase ◽  
Rna Polymerization ◽  
The Family

Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus Orthocurvulavirus within the family Orthocurvulaviridae. The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in Escherichia coli and isolated to near homogeneity using liquid chromatography. The enzyme activities were studied in vitro using radiolabeled UTP. The HetRV6 RdRp was able to initiate RNA synthesis in a primer-independent manner using both virus-related and heterologous single-stranded (ss)RNA templates, with a polymerization rate of about 46 nt/min under optimal NTP concentration and temperature. NTPs with 2′-fluoro modifications were also accepted as substrates in the HetRV6 RdRp-catalyzed RNA polymerization reaction. HetRV6 RdRp transcribed viral RNA genome via semi-conservative mechanism. Furthermore, the enzyme demonstrated terminal nucleotidyl transferase (TNTase) activity. Presence of Mn2+ was required for the HetRV6 RdRp catalyzed enzymatic activities. In summary, our study shows that HetRV6 RdRp is an active replicase in vitro that can be potentially used in biotechnological applications, molecular biology, and biomedicine.

scholarly journals Identifying SARS-CoV-2 Antiviral Compounds by Screening for Small Molecule Inhibitors of Nsp12/7/8 RNA-dependent RNA Polymerase

2021 ◽  
Author(s):  
Agustina P. Bertolin ◽  
Florian Weissmann ◽  
Jingkun Zeng ◽  
Viktor Posse ◽  
Jennifer C. Milligan ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Virus ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Etiologic Agent ◽  
Host Cells ◽  
Rdrp Activity ◽  
Chemical Library ◽  
Rna Dependent Rna Polymerase

SummaryThe coronavirus disease 2019 (COVID-19) global pandemic has turned into the largest public health and economic crisis in recent history impacting virtually all sectors of society. There is a need for effective therapeutics to battle the ongoing pandemic. Repurposing existing drugs with known pharmacological safety profiles is a fast and cost-effective approach to identify novel treatments. The COVID-19 etiologic agent is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a single-stranded positive-sense RNA virus. Coronaviruses rely on the enzymatic activity of the replication-transcription complex (RTC) to multiply inside host cells. The RTC core catalytic component is the RNA-dependent RNA polymerase (RdRp) holoenzyme. The RdRp is one of the key druggable targets for CoVs due to its essential role in viral replication, high degree of sequence and structural conservation and the lack of homologs in human cells. Here, we have expressed, purified and biochemically characterised active SARS-CoV-2 RdRp complexes. We developed a novel fluorescence resonance energy transfer (FRET)-based strand displacement assay for monitoring SARS-CoV-2 RdRp activity suitable for a high-throughput format. As part of a larger research project to identify inhibitors for all the enzymatic activities encoded by SARS-CoV-2, we used this assay to screen a custom chemical library of over 5000 approved and investigational compounds for novel SARS-CoV-2 RdRp inhibitors. We identified 3 novel compounds (GSK-650394, C646 and BH3I-1) and confirmed suramin and suramin-like compounds as in vitro SARS-CoV-2 RdRp activity inhibitors. We also characterised the antiviral efficacy of these drugs in cell-based assays that we developed to monitor SARS-CoV-2 growth.

scholarly journals Thermolabile L-A virus-like particles from pet18 mutants of Saccharomyces cerevisiae.

1986 ◽  
Vol 6 (2) ◽  
pp. 404-410 ◽  
Author(s):  
T Fujimura ◽  
R B Wickner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Polymerase Activity ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Rna Dependent Rna Polymerase ◽  
Virus Like Particles ◽  
Rna Polymerase Activity ◽  
Lines Of Evidence

pet18 mutations in Saccharomyces cerevisiae confer on the cell the inability to maintain either L-A or M double-stranded RNAs (dsRNAs) at the nonpermissive temperature. In in vitro experiments, we examined the effects of pet18 mutations on the RNA-dependent RNA polymerase activity associated with virus-like particles (VLPs). pet18 mutations caused thermolabile RNA polymerase activity of L-A VLPs, and this thermolability was found to be due to the instability of the L-A VLP structure. The pet18 mutations did not affect RNA polymerase activity of M VLPs. Furthermore, the temperature sensitivity of wild-type L-A RNA polymerase differed substantially from that of M RNA polymerase. From these results, and from other genetic and biochemical lines of evidence which suggest that replication of M dsRNA requires the presence of L-A dsRNA, we propose that the primary effect of the pet18 mutation is on the L-A VLP structure and that the inability of pet18 mutants to maintain M dsRNA comes from the loss of L-A dsRNA.

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