Genome replication in picornaviruses is catalyzed by a virally encoded RNA-dependent RNA polymerase, termed 3D. These viruses also use a small protein primer, named VPg, to initiate RNA replication. The recent explosion of structural information on picornaviral 3D polymerases has provided insights into the initiation of RNA synthesis and chain elongation. Comparing these data with results from previous structural analyses of viral RNA-dependent RNA polymerases that catalyze de novo RNA synthesis sheds light on the different strategies that these viruses use to initiate replication. © 2006 Elsevier Ltd. All rights reserved ...
Influenza viruses cause seasonal epidemics and pandemic outbreaks associated with significant morbidity and mortality, and a huge cost. Since resistance to the existing anti-influenza drugs is rising, innovative inhibitors with a different mode of action are urgently needed. The influenza polymerase complex is widely recognized as a key drug target, given its critical role in virus replication and high degree of conservation among influenza A (of human or zoonotic origin) and B viruses. We here review the major progress that has been made in recent years in unravelling the structure and functions of this protein complex, enabling structure-aided drug design toward the core regions of the PA endonuclease, PB1 polymerase, or cap-binding PB2 subunit. Alternatively, inhibitors may target a protein-protein interaction site, a cellular factor involved in viral RNA synthesis, the viral RNA itself, or the nucleoprotein component of the viral ribonucleoprotein. The latest advances made for these diverse
RNA silencing is an important mechanism to regulate gene expression and antiviral defense in plants. Nevertheless, RNA silencing machinery in the important oil crop Brassica napus and function in resistance to the devastating fungal pathogen Sclerotinia sclerotiorum are not well understood. In this study, gene families of RNA silencing machinery in B. napus were identified and their role in resistance to S. sclerotiorum was revealed. Genome of the allopolyploid species B. napus possessed 8 Dicer-like (DCL), 27 Argonaute (AGO) and 16 RNA-dependent RNA polymerase (RDR) genes, which included almost all copies from its progenitor species B. rapa and B. oleracea and three extra copies of RDR5 genes, indicating that the RDR5 group in B. napus appears to have undergone further expansion through duplication during evolution. Moreover, compared with Arabidopsis, some AGO and RDR genes such as AGO1, AGO4, AGO9 and RDR5 had significantly expanded in these Brassica species. Twenty-one out of 51 DCL, AGO and RDR
Hepatitis C Virus RNA-directed RNA polymerase Antibody, ALEXA FLUOR 555 datasheet and description hight quality product and Backed by our Guarantee
Hepatitis C Virus RNA-directed RNA polymerase Antibody, FITC Conjugated datasheet and description hight quality product and Backed by our Guarantee
Description: An enzyme that catalyses RNA-template-directed extension of the 3- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. (Enzyme Nomenclature, 1992, p293 ...
RNA-dependent RNA polymerase which is responsible for replication and transcription of virus RNA segments. The transcription of viral mRNAs occurs by a unique mechanism called cap-snatching. 5 methylated caps of cellular mRNAs are cleaved after 10-13 nucleotides by PA. In turn, these short capped RNAs are used as primers by PB1 for transcription of viral mRNAs. During virus replication, PB1 initiates RNA synthesis and copy vRNA into complementary RNA (cRNA) which in turn serves as a template for the production of more vRNAs.
RNA-dependent RNA polymerase which is responsible for replication and transcription of virus RNA segments. The transcription of viral mRNAs occurs by a unique mechanism called cap-snatching. 5 methylated caps of cellular mRNAs are cleaved after 10-13 nucleotides by PA. In turn, these short capped RNAs are used as primers by PB1 for transcription of viral mRNAs. During virus replication, PB1 initiates RNA synthesis and copy vRNA into complementary RNA (cRNA) which in turn serves as a template for the production of more vRNAs.
By a genetic approach, a number of mutants affected in quelling, RNAi, or PTGS have been isolated, leading to the identification of eight genes controlling these phenomena (21-23, 26, 27, 29, 33, 43, 44). QDE-1, QDE-2, and QDE-3 genes, required for quelling in the fungus N. crassa, encode proteins similar to tomato RNA-directed RNA polymerase, rabbit translation initiation factor eIF2C, and E. coli RecQ DNA helicase, respectively (21, 29, 44), whereas EGO-1, RDE-1, and MUT-7 genes required for RNAi in the nematode C. elegans encode proteins similar to tomato RNA-directed RNA polymerase, rabbit translation initiation factor eIF2C, and E. coli RNaseD, respectively (23, 26, 27). SGS2 and SGS3 genes, required for PTGS in A. thaliana, encode a protein similar to tomato RNA-directed RNA polymerase and a protein of unknown function, respectively (22). The finding of one set of related proteins shared by PTGS, quelling, and RNAi (SGS2/QDE-1/EGO-1), therefore, suggested that these three mechanisms could ...
Alphaviruses have a positive-stranded RNA genome that can serve as the mRNA for translation of the polyprotein precursor that is autocatalytically processed to the four non-structural viral proteins by the virus-encoded protease in nsP2. The non-structural proteins form the transcription/replication complex. The nsP1 protein is implicated in capping of viral RNAs. The nsP2 gene encodes a putative helicase and a protease , which presents a unique fold distantly related to that of known cysteine proteases. This protease domain is linked to the downstream domain of degenerated O-methyltransferase fold that may regulate transcription/replication through RNA binding. The nsP3 protein is required for RNA replication. Its N-terminal sequence reveals a macro domain, the crystal structures of which have recently been determined (Malet et al., 2009). The nsP4 protein carries the viral RNA dependant RNA Polymerase (RdRP), the key activity for the viral replication/transcription. Unlike the RdRP of ...
Narnaviridae is a family of positive single stranded RNA viruses. Members of this family have no capsid. Fungi serve as natural hosts. There are currently seven species in this family, divided among 2 genera. The genome of these viruses is unipartate and between 2.3 and 3.5 kilobases in length. It encodes a single gene-the RNA dependent RNA polymerase. This protein is associated with the genome in the cytoplasm of the host. The viruses do not have a capsid or envelop and do not form any infectious viral particles except lipid vesicles. They infect fungi (including yeast) and oomycetes. Mitovirues appear to be among the most common fungi viruses. Viral replication is cytoplasmic. Replication follows the positive stranded RNA virus replication model. Positive-stranded RNA-virus transcription is the method of transcription. The virus exits the host cell by cell to cell movement. Fungi serve as the natural host. Transmission routes are parental and sexual. Two genera have been recognised to date. ...
Viral RNA-dependent RNA Polymerase Assay. The Viral RNA-dependent RNA Polymerase Assay is developed using a RNA polymerase in the Flaviviridae,. a family of positive, single-stranded, enveloped RNA viruses. The assay is based on measurement of the. RNA molecules synthesized by the RNA polymerase using RNA as a template in the presence of NTPs.. The assay can be performed in a 384-well or 96-well plate format for tests of theenzyme activities of RNA. polymerases in the Flaviviridae family and high throughput screening of inhibitors. ...
4NLD: Discovery and Preclinical Characterization of the Cyclopropylindolobenzazepine BMS-791325, A Potent Allosteric Inhibitor of the Hepatitis C Virus NS5B Polymerase.
Although there have been major advances in elucidating the pathogenesis of Ebola virus infection, most of the studies were performed in non-human primate and rodent models.8 This is because of the difficulties in conducting human studies in poorly resourced settings where these infections naturally occur. The virus genome consists of a single 19 kb strand of negative sense RNA with seven viral genes that are transcribed by the viral RNA dependent RNA polymerase present in the virion. The single strand of RNA is covered by helically arranged viral nucleoproteins NP and VP30, which are linked by matrix proteins VP24 and VP4 to the lipid bilayer that coats the virion.21. Tissue invasion occurs through infected fluid coming into contact with breaks in the mucosa or skin. This can occur with animal to human or human to human transmission. Monocytes, macrophages, and dendritic cells are the preferred replication sites for filoviruses on initial infection. Infected cells migrate to the regional lymph ...
Recent studies have suggested that bats are the natural reservoir of a range of coronaviruses (CoVs), and that rhinolophid bats harbor viruses closely related to the severe acute respiratory syndrome (SARS) CoV, which caused an outbreak of respiratory illness in humans during 2002-2003. We examined the evolutionary relationships between bat CoVs and their hosts by using sequence data of the virus RNA-dependent RNA polymerase gene and the bat cytochrome b gene. Phylogenetic analyses showed multiple incongruent associations between the phylogenies of rhinolophid bats and their CoVs, which suggested that host shifts have occurred in the recent evolutionary history of this group. These shifts may be due to either virus biologic traits or host behavioral traits. This finding has implications for the emergence of SARS and for the potential future emergence of SARS-CoVs or related viruses.
We have used vaccinia virus as a vector to clone a 22.5-kbp cDNA that represents the 5′ and 3′ ends of the human coronavirus 229E (HCoV 229E) genome, the HCoV 229E replicase gene, and a single reporter gene (coding for green fluorescent protein [GFP]) located downstream of a regulatory element for coronavirus mRNA transcription. When RNA transcribed from this cDNA was transfected into BHK-21 cells, a small percentage of cells displayed strong fluorescence. A region of the mRNA encoding GFP was amplified by PCR and shown to have the unique mRNA leader-body junction indicative of coronavirus-mediated transcription. These data show that the coronavirus replicase gene products suffice for discontinuous subgenomic mRNA transcription. ...
1. NagyPD (2008) Yeast as a model host to explore plant virus-host interactions. Annu Rev Phytopathol 46: 217-242.. 2. NagyPD, PoganyJ (2008) Multiple roles of viral replication proteins in plant RNA virus replication. Methods Mol Biol 451: 55-68.. 3. HuangYW, HuCC, LinNS, HsuYH (2012) Unusual roles of host metabolic enzymes and housekeeping proteins in plant virus replication. Curr Opin Virol 2: 676-682.. 4. ShullaA, RandallG (2012) Hepatitis C virus-host interactions, replication, and viral assembly. Curr Opin Virol 2: 725-732.. 5. MineA, OkunoT (2012) Composition of plant virus RNA replicase complexes. Curr Opin Virol 2: 669-675.. 6. BelovGA, van KuppeveldFJ (2012) (+)RNA viruses rewire cellular pathways to build replication organelles. Curr Opin Virol 2: 740-747.. 7. NagyPD, PoganyJ (2012) The dependence of viral RNA replication on co-opted host factors. Nature Reviews Microbiology 10: 137-149.. 8. AhlquistP, NoueiryAO, LeeWM, KushnerDB, DyeBT (2003) Host factors in positive-strand RNA virus ...
Reverse transcriptases (RTs) polymerize DNA on RNA templates. They fall into several structurally related but distinct classes, and form an assemblage of RT-like enzymes which, in addition to RTs, also includes certain viral RNA-dependent RNA polymerases (RdRP) polymerizing RNA on RNA templates. It is generally believed that most RT-like enzymes originate from retrotransposons or viruses and have no specific function in the host cell, with telomerases being the only notable exception. Here we report on the discovery and properties of a novel class of RT-related cellular genes collectively named rvt. We present evidence that rvt are not components of retrotransposons or viruses, but single-copy genes with a characteristic domain structure, may contain introns in evolutionarily conserved positions, occur in syntenic regions, and evolve under purifying selection. These genes can be found in all major taxonomic groups including protists, fungi, animals, plants, and even bacteria, although they ...
Polymerase basic protein 2 (PB2) complexes with polymerase basic protein 1 and polymerase acidic protein (PA) to form an RNA-dependent RNA polymerase complex. During transcription, PB2 binds the 5′,7-methylguanosine cap of the host pre-mRNA, which will be subsequently cleaved by PA. PB2 also inhibits type I interferon induction through interaction with and inhibition of the host mitochondrial antiviral signalling protein MAVS ...
Effect of depurination location on replicase activity in vitro. Regions of RNA3 were treated with PAP and then ligated to the remaining RNA to regenerate full-l
The LyteStar 2019-nCoV RT-PCR Kit is an in vitro diagnostic test system, based on real-time PCR technology, for the qualitative detection of novel coronavirus (SARS-CoV-2) specific RNA. The LyteStar 2019-nCoV RT-PCR Kit consists of 2 independent assays, one targeting the E gene (Figure 1) and the other targeting RNA-dependent RNA polymerase gene (RdRP) of the SARS-CoV-2 genome (Figure 2). The E gene assay includes a heterologous amplification system (Internal Control) to identify possible RT-PCR inhibition and to confirm the integrity of the reagents of the kit.. ...
in Clinical Chemistry (2009), 55(10), 1824-33. BACKGROUND: Most methods for estimation of rates of RNA production are not applicable in human in vivo clinical studies. We describe here an approach for measuring ribosomal RNA turnover in vivo using [6 ... [more ▼]. BACKGROUND: Most methods for estimation of rates of RNA production are not applicable in human in vivo clinical studies. We describe here an approach for measuring ribosomal RNA turnover in vivo using [6,6-(2)H(2)]-glucose as a precursor for de novo RNA synthesis. Because this method involves neither radioactivity nor toxic metabolites, it is suitable for human studies. METHODS: For method development in vitro, a lymphocyte cell line (PM1) was cultured in the presence of [6,6-(2)H(2)]-glucose. RNA was extracted, hydrolyzed enzymatically to ribonucleosides, and derivatized to either the aldonitrile tetra-acetate or the pentafluoro triacetate derivative of the pentose before GC-MS. We identified optimum derivatization and analysis ...
in Clinical Chemistry (2009), 55(10), 1824-33. BACKGROUND: Most methods for estimation of rates of RNA production are not applicable in human in vivo clinical studies. We describe here an approach for measuring ribosomal RNA turnover in vivo using [6 ... [more ▼]. BACKGROUND: Most methods for estimation of rates of RNA production are not applicable in human in vivo clinical studies. We describe here an approach for measuring ribosomal RNA turnover in vivo using [6,6-(2)H(2)]-glucose as a precursor for de novo RNA synthesis. Because this method involves neither radioactivity nor toxic metabolites, it is suitable for human studies. METHODS: For method development in vitro, a lymphocyte cell line (PM1) was cultured in the presence of [6,6-(2)H(2)]-glucose. RNA was extracted, hydrolyzed enzymatically to ribonucleosides, and derivatized to either the aldonitrile tetra-acetate or the pentafluoro triacetate derivative of the pentose before GC-MS. We identified optimum derivatization and analysis ...
Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been identified in bats in China, Europe, and Africa, most have a genetic organization significantly distinct from human/civet SARS CoVs in the receptor-binding domain (RBD), which mediates receptor binding and determines the host spectrum, resulting in their failure to cause human infections and making them unlikely progenitors of human/civet SARS CoVs. Here, a viral metagenomic analysis of 268 bat rectal swabs collected from four counties in Yunnan Province has identified hundreds of sequences relating to alpha- and betacoronaviruses. Phylogenetic analysis based on a conserved region of the RNA-dependent RNA polymerase gene revealed that alphacoronaviruses had diversities with some obvious differences from those reported previously. Full genomic analysis of a new SARS-like CoV from Baoshan (LYRa11) showed that it was 29,805 nucleotides (nt) in length with 13 open reading frames (ORFs), sharing 91% ...
Hepatitis C virus (HCV) is a positive-strand RNA virus grouped in the genus Hepacivirus within the family Flaviviridae. HCV is classified into at least 6 genotypes (gt), and its error-prone polymerase leads to more than 50 subtypes. The long open reading frame, which encodes the HCV polyprotein, is processed by host and viral proteases and gives rise to three structural proteins (the capsid protein core and envelope glycoproteins E1 and E2) and seven nonstructural (NS) proteins (p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B). NS2 and p7 are essential for virus assembly but not RNA replication, whereas NS3 to NS5B are involved in a membrane-associated RNA replicase complex (RC). The NS3 protein is composed of a serine protease and an RNA helicase/nucleoside triphosphatase (NTPase), NS4A serves as a cofactor for NS3 serine protease, NS5B is the RNA-dependent RNA polymerase, and NS5A is considered to play key roles in multiple steps of the HCV life cycle.NS5A inhibitors exhibit a rapid inhibition of ...
Viruses are obligate parasites and can only reproduce within host cells because they lack metabolic pathways to complete their replication cycles. Host factors required in viral replication are mainly those involved in lipid metabolism, cell cycle control and apoptosis, cell-to-cell interactions, immune system regulation, etc. Several inhibitors targeting viral polymerases have been designed. However, the rapid appearance of resistant mutants, as a direct consequence of the viral population structure, diminishes the efficacy of this kind of molecules. To elude the rapid loss of treatment efficiency due to the appearance of resistance mutations, cellular factors have been proposed as a promising therapeutic target to inhibit RNA(+) virus replication. In this review, we focus on those interactions between host factors and HCV replicase, to modulate either cellular metabolism or HCV polymerase activity.. ...
The PDB archive contains information about experimentally-determined structures of proteins, nucleic acids, and complex assemblies. As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Pool of 231 peptides derived from a peptide scan through RNA-directed RNA Polymerase of SARS-CoV-2 (Severe Acute Respiratory Syndrome-related coronavirus 2) for T cell assays (e.g....
InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites. We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their individual strengths to produce a powerful integrated database and diagnostic tool.
In plants and several other organisms, the effects of RNA silencing can be amplified by the action of cellular RNA-DEPENDENT RNA POLYMERASES (RDRs). These enzymes were primarily studied for their role in antiviral defense in plants, but it is becoming increasingly apparent that they also have import …
Lee HC, Aalto AP, Yang Q, Chang CC, Huang G, Fisher D, Cha J, Poranen MM, Bamford DH and Liu Y. 2010 The DNA/RNA-dependent RNA polymerase QDE-1 generates aberrant RNA and dsRNA for RNAi in a process requiring Replication Protein A and a DNA helicase, PLOS Biol. Oct 5;8(10). pii: e1000496. ...
Remdesivir is an anti-viral drug administered by IV. Its known as a nucleoside analog, meaning it mimics a component of viral RNA that the virus needs to replicate itself. Remdesivir is basically faking the virus into thinking its a building block of viral genetic material. The virus uses an enzyme called RNA-dependent RNA polymerase to […]. ...
In the frame of a collaboration with Stephen Cusack (EMBL Grenoble) we showed that the direct interaction of the influenza virus polymerase (FluPol) PA
Here we describe the generation of ribavirin-resistant poliovirus by serial passage in the presence of the drug. Interestingly, no drug-resistant virus was isolated from passages in 400 μM ribavirin. Instead, data in Fig. 1C suggest that passage of virus at a lower concentration of ribavirin was necessary to allow the accumulation of mutations before the stringent selection for resistant variants provided by passage in 400 μM ribavirin. In hepatitis C virus (HCV)-infected patients treated with ribavirin, estimates of the drug concentrations in blood plasma range from 10 to 30 μM, though the concentration in hepatocytes may be higher (20, 21). Although it is uncertain whether the concentration of ribavirin required to inhibit poliovirus growth is similar to the concentration required to inhibit HCV growth, the results presented here suggest that treatment with low concentrations of the drug could facilitate later selection of resistant variants. In fact, clinical data from HCV patients have ...
Tombusviruses are single, positive strand RNA viruses of plants, often associated with parasitic defective interfering (DI) RNAs. Two viral- coded gene products, namely p33 and p92, are required for tombusvirus replication. The overlapping domains of p33 and p92 contain an arginine/proline-rich (RPR) RNA binding motif. In this study, the role of RPR motif and viral RNA in tombusvirus replication and recombination, as well as involvement of viral RNA in tombusvirus replicase assembly was examined. Using site-directed mutagenesis I generated a series of RPR mutants of Cucumber necrosis tombusvirus (CNV). Analysis of RPR mutants defined that wild type RPR motif, especially two of the four arginines, were required for efficient RNA binding in vitro, for replication of tombusviruses, their associated DI RNAs, subgenomic (sg)RNA synthesis and DI RNA recombination in vivo. Experiments using a two-component tombusvirus replication system showed that RPR motif is critical for functions of both p33 and p92 in
TY - JOUR. T1 - Full-length dengue virus RNA-dependent RNA polymerase-RNA/DNA complexes. T2 - Stoichiometries, intrinsic affinities, cooperativities, base, and conformational specificities. AU - Szymanski, Michal R.. AU - Jezewska, Maria J.. AU - Bujalowski, Paul J.. AU - Bussetta, Cecile. AU - Ye, Mengyi. AU - Choi, Kyung H.. AU - Bujalowski, Wlodzimierz. PY - 2011/9/23. Y1 - 2011/9/23. N2 - Fundamental aspects of interactions of the Dengue virus type 3 full-length polymerase with the single-stranded and double-stranded RNA and DNA have been quantitatively addressed. The polymerase exists as a monomer with an elongated shape in solution. In the absence of magnesium, the total site size of the polymerase-ssRNA complex is 26 ± 2 nucleotides. In the presence of Mg 2+, the site size increases to 29 ± 2 nucleotides, indicating that magnesium affects the enzyme global conformation. The enzyme shows a preference for the homopyrimidine ssRNAs. Positive cooperativity in the binding to homopurine ...
A carboxy-terminal peptide of the poliovirus replicase protein (p63) was chemically synthesized, coupled to bovine serum albumin carrier, and injected into rabbits. The resulting antisera reacted with six virus-specific proteins from HeLa cells infected with poliovirus: NCVP 0b, NCVP 1b, NCVP 2, a protein of about 60,000 daltons, p63, and NCVP 6b. The identity of the 60,000-dalton protein is not known, but the other results were consistent with previous experimental approaches which demonstrated that p63 and the other four polypeptides have common coding sequences. An amino-terminal peptide of p63 failed to elicit an immune response in rabbits. Antibodies raised against the p63 carboxy-terminal peptide inhibited poliovirus replicase and polyuridylic acid polymerase activities in vitro, providing strong support for earlier suggestions that these activities are a property of a single virus-specific polypeptide. ...
During meiosis in C. elegans, unpaired chromosomes and chromosomal regions accumulate high levels of histone H3 lysine 9 dimethylation (H3K9me2), a modification associated with facultative heterochromatin assembly and the resulting transcriptional silencing. Meiotic silencing of unpaired DNA may be …
A picornavirus is a virus belonging to the family Picornaviridae, a family of viruses in the order Picornavirales. Vertebrates, including humans, serve as natural hosts. Picornaviruses are nonenveloped viruses that represent a large family of small, cytoplasmic, plus-strand RNA(~7.5kb) viruses with a 30 nm icosahedral capsid. Its genome does not have a lipid membrane. Picornaviruses are found in mammals and birds. There are currently 80 species in this family, divided among 35 genera. These include the Enterovirus, Aphthovirus, Cardiovirus, Rhinovirus and Hepatovirus genera. The viruses in this family can cause a range of diseases including paralysis, meningitis, hepatitis and poliomyelitis. Picornaviruses are in Baltimore IV class. Their genome single-stranded (+) sense RNA is that functions as mRNA after entry into the cell and all viral mRNA synthesized is of genome polarity. The mRNA encodes RNA dependent RNA polymerase. This polymerase makes complementary minus strands of RNA, then uses ...
Virus replication is an essential step for viral infection and symptom development in crops. Both virus-encoded proteins, such as RNA-dependent RNA polymerase (RdRP), and RNA secondary structures formed through intra-molecular interactions of viral genomic RNA play crucial roles in RNA virus replication. However, it has been difficult to study some RNA structures because they are part of sequences that encode replication proteins. To study the predicted RNA secondary structures located within the RdRP coding sequence of Turnip crinkle virus (TCV), we developed a system that supplies TCV RdRP in trans, so that the impact of the RdRP coding capacity and the secondary structures become decoupled. The coding sequence of TCV RdRP was then subjected to systematic mutagenesis to identify and characterize cis-acting RNA elements therein. Using this system, a secondary structure designated Fa was found to be essential to the replication of TCV viral genome. Additionally, a tertiary pseudoknot structure ...
The exploration of the evolution of RNA viruses has been aided recently by the discovery of copies of fragments or complete genomes of non-retroviral RNA viruses (Non-retroviral Endogenous RNA Viral Elements, or NERVEs) in many eukaryotic nuclear genomes. Among the most prominent NERVEs are partial copies of the RNA dependent RNA polymerase (RdRP) of the mitoviruses in plant mitochondrial genomes. Mitoviruses are in the family Narnaviridae, which are the simplest viruses, encoding only a single protein (the RdRP) in their unencapsidated viral plus strand. Narnaviruses are known only in fungi, and the origin of plant mitochondrial mitovirus NERVEs appears to be horizontal transfer from plant pathogenic fungi. At least one mitochondrial mitovirus NERVE, but not its nuclear copy, is expressed.
1 Abstract Arabidopsis thaliana is a weed by standard definitions, growing geographically in temperate climates, and having a relatively short life span of about six weeks. Despite being only a weed, it is used as the model organism for plant genetics. With a fully mapped genome, we can not only practice Forward Genetics, but Reverse Genetics as well. Reverse Genetics is used by scientists to knockout a gene or mutate it intentionally, then using the newly created mutation they grow a crop which will be observed for any phenotypic differences. Using mutated genes RDR 6 (RNA dependent RNA polymerase) and DCL 4 (Dicer Like 4), we grew 48 plants, 16 plants of each: Wild Type, RDR 6 and DCL 4. Half of thesewere subjected to the treatment of an upped amount of calcium in the water that already had fertilizer present. We choose calcium as our stress because the known benefits of calcium for humans and other animals are huge; we were curious to see how it would affect Arabidopsis and if it would ...
During the replication cycle of double-stranded (ds) RNA viruses, the viral RNA-dependent RNA polymerase (RdRP) replicates and transcribes the viral genome from within the viral capsid. How the RdRP molecules are packaged within the virion and how they function within the confines of an intact capsid are intriguing questions with answers that most likely vary across the different dsRNA virus families. In this study, we have determined a 2.4 Å resolution structure of an RdRP from the human picobirnavirus (hPBV). In addition to the conserved polymerase fold, the hPBV RdRP possesses a highly flexible 24 amino acid loop structure located near the C-terminus of the protein that is inserted into its active site. In vitro RNA polymerization assays and site-directed mutagenesis showed that: (1) the hPBV RdRP is fully active using both ssRNA and dsRNA templates; (2) the insertion loop likely functions as an assembly platform for the priming nucleotide to allow de novo initiation; (3) RNA transcription ...
Shop Replicase polyprotein ELISA Kit, Recombinant Protein and Replicase polyprotein Antibody at MyBioSource. Custom ELISA Kit, Recombinant Protein and Antibody are available.
The negative sense RNA genome of influenza A virus is transcribed and replicated in the nuclei of infected cells by the viral RNA polymerase. Only four viral polypeptides are required but multiple cellular components are potentially involved. We used fluorescence recovery after photobleaching (FRAP) to characterise the dynamics of GFP-tagged viral ribonucleoprotein (RNP) components in living cells. The nucleoprotein (NP) displayed very slow mobility that significantly increased on formation of transcriptionally active RNPs. Conversely, single or dimeric polymerase subunits showed fast nuclear dynamics that decreased upon formation of heterotrimers, suggesting increased interaction of the full polymerase complex with a relatively immobile cellular component(s). Treatment with inhibitors of cellular transcription indicated that in part, this reflected an interaction with cellular RNA polymerase II. Analysis of mutated influenza virus polymerase complexes further suggested that this was through an
Influenza virus polymerase uses a capped primer, derived by cap-snatching from host pre-messenger RNA, to transcribe its RNA genome into mRNA and a stuttering mechanism to generate the poly(A) tail. By contrast, genome replication is unprimed and generates exact full-length copies of the template. Here we use crystal structures of bat influenza A and human influenza B polymerases (FluA and FluB), bound to the viral RNA promoter, to give mechanistic insight into these distinct processes. In the FluA structure, a loop analogous to the priming loop of flavivirus polymerases suggests that influenza could initiate unprimed template replication by a similar mechanism. Comparing the FluA and FluB structures suggests that cap-snatching involves in situ rotation of the PB2 cap-binding domain to direct the capped primer first towards the endonuclease and then into the polymerase active site. The polymerase probably undergoes considerable conformational changes to convert the observed pre-initiation state into
CpG dinucleotides are known to play a crucial role in regulatory domains, affecting gene expression in their natural context. Here, we demonstrate that intragenic CpG frequency and distribution impacts transgene and genomic gene expression levels in mammalian cells. As shown for the Macrophage Inflammatory Protein 1α, de novo RNA synthesis correlates with the number of CpG dinucleotides, whereas RNA splicing, stability, nuclear export and translation are not affected by the sequence modification. Differences in chromatin accessibility in vivo and altered nucleosome positioning in vitro suggest that increased CpG levels destabilize the chromatin structure. Moreover, enriched CpG levels correlate with increased RNA polymerase II elongation rates in vivo. Interestingly, elevated CpG levels particularly at the 5 end of the gene promote efficient transcription. We show that this is a genome-wide feature of highly expressed genes, by identifying a domain of ∼700 bp with high CpG content downstream of the
RNA viruses have been isolated that infect marine organisms ranging from bacteria to whales, but little is known about the composition and population structure of the in situ marine RNA virus community. In a recent study, the majority of three genomes of previously unknown positive-sense single-stranded (ss) RNA viruses were assembled from reverse-transcribed whole-genome shotgun libraries. The present contribution comparatively analyzes these genomes with respect to representative viruses from established viral taxa. Two of the genomes (JP-A and JP-B), appear to be polycistronic viruses in the proposed order Picornavirales that fall into a well-supported clade of marine picorna-like viruses, the characterized members of which all infect marine protists. A temporal and geographic survey indicates that the JP genomes are persistent and widespread in British Columbia waters. The third genome, SOG, encodes a putative RNA-dependent RNA polymerase (RdRp) that is related to the RdRp of viruses in the family
All viruses utilize host cell machinery to synthesize their own genetic materials. Upon entry into cells, the virus has to initiate replication and gene expression. Paramyxoviruses use a unique strategy for replication and gene expression. The active template for paramyxovirus replication is not the naked RNA genome but the protein and RNA complex. Viral genomic RNA is completely encapsidated by the nucleocapsid (N) protein to form an N-RNA complex. During RNA synthesis, the N-RNA template is recognized by viral RNA-dependent RNA polymerase (RdRp) that carries out two distinct processes: (i) transcription to yield 6-10 capped, methylated and polyadenylated messenger RNAs and (ii) replication to yield full-length antigenomic and subsequently genomic RNA.. Our lab uses hMPV and aMPV as models to understand the mechanisms by which the RdRp controls these two processes: replication and transcription. We will focus on the two major components of RdRp, the large protein catalytic subunit (L) and the ...
Aartjan te Velthuis Sir William Dunn School of Pathology, University of Oxford.Department of Pathology, University of Cambridge.Biomedical Sciences Research Complex, University of St Andrews.The Influenza A virus is an infectious agent that usually causes a mild respiratory disease and induces innate immune responses through the activation of RNA sensor RIG-I. However, infections with highly pathogenic influenza viruses such as the H5N1 subtypes or the 1918 H1N1 virus, can lead to an innate immune dysregulation and severe disease. The genome of the virus is replicated and transcribed by the viral RNA-dependent RNA polymerase in the context of viral RNA-nucleoprotein (vRNP) complexes. The RNA polymerase is a complex enzyme that consists of a central core composed of the viral proteins PB1, PB2 and PA, and at least three auxiliary domains involved in viral transcription. Various mutations in the RNA polymerase have been linked to host adaptation and viral virulence, but it is presently unclear what
Aartjan te Velthuis Sir William Dunn School of Pathology, University of Oxford.Department of Pathology, University of Cambridge.Biomedical Sciences Research Complex, University of St Andrews.The Influenza A virus is an infectious agent that usually causes a mild respiratory disease and induces innate immune responses through the activation of RNA sensor RIG-I. However, infections with highly pathogenic influenza viruses such as the H5N1 subtypes or the 1918 H1N1 virus, can lead to an innate immune dysregulation and severe disease. The genome of the virus is replicated and transcribed by the viral RNA-dependent RNA polymerase in the context of viral RNA-nucleoprotein (vRNP) complexes. The RNA polymerase is a complex enzyme that consists of a central core composed of the viral proteins PB1, PB2 and PA, and at least three auxiliary domains involved in viral transcription. Various mutations in the RNA polymerase have been linked to host adaptation and viral virulence, but it is presently unclear what
Role of Influenza Virus Polymerase in Host Adaptation: We participate in the virology research team of the New York Influenza Center of Excellence (NYICE), which is part of the NIH Centers of Excellence for Influenza Research and Surveillance (CEIRS) network. Our focus is on the influenza virus RNA polymerase, and understanding how it contributes to host adaptation. We characterize the polymerase activities of avian and human strains, and identify residues and subunits of the polymerase complex important for the enhanced activity in mammalian hosts in vitro and in vivo. URSMD Collaborators = David Topham, John Treanor, Steve Dewhurst, Baek Kim. ...
Thank you for your interest in spreading the word about Biochemical Society Transactions.. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.. ...
RNA viruses replicate with low fidelity due to the error-prone nature of the RNA-dependent RNA polymerase, which generates approximately one mutation per round of genome replication. Due to the large population sizes produced by RNA viruses during replication, this results in a cloud of closely related virus variants during host infection, of which small increases or decreases in replication fidelity have been shown to result in virus attenuation in vivo, but not typically in vitro. Since the discovery of the first RNA virus fidelity mutants during the mid-aughts, the field has exploded with the identification of over 50 virus fidelity mutants distributed amongst 7 RNA virus families. This review summarizes the current RNA virus fidelity mutant literature, with a focus upon the definition of a fidelity mutant as well as methods to confirm any mutational changes associated with the fidelity mutant. Due to the complexity of such a definition, in addition to reports of unstable virus fidelity ...
VCH-916 is a novel allosteric inhibitor of HCV NS5B polymerase. The RNA-dependent RNA polymerase (NS5B) of HCV is one of the attractive validated targets for development of new drugs to block HCV infection. VCH-916 is currently being evaluated for safety/tolerability, pharmacokinetics and anti-viral efficacy in chronically infected HCV patient ...
The Tap-tagged PA and its interacting proteins ended up co-purified with immunoglobinlin G-Sepharose (GE Health care) and washed with binding buffer . The
Tusq X Plus-ன் பயன்பாடுகள், மருந்தளவு, பக்க விளைவுகள், நன்மைகள், தொடர்புகள் மற்றும் எச்சரிக்கைகள் ஆகியவற்றை கண்டுபிடியுங்கள்.
Tusq X Plus-ன் பயன்பாடுகள், மருந்தளவு, பக்க விளைவுகள், நன்மைகள், தொடர்புகள் மற்றும் எச்சரிக்கைகள் ஆகியவற்றை கண்டுபிடியுங்கள்.