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 ...
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
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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.
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
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 ...
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 ...
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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. ...
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 ...
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 ...
Poliovirus 3A protein is known to have numerous functions in the viral replicative cycle, but the relationship between these functions is not known. Mutations in the 3A coding region, including the 3A-2 mutation at the restrictive growth temperature, are known to cause defects in viral RNA synthesis (3, 23). The larger polypeptide 3AB, which contains the 22-amino-acid protein primer for viral RNA synthesis fused to its carboxyl terminus, binds to 3D, the poliovirus RNA-dependent RNA polymerase (27, 66) and, when purified in the presence of detergent, stimulates polymerase activity (33, 45, 48, 51, 66). Recently, we have shown that viral proteins 2BC and 3A, expressed together, can mimic the ultrastructure and membrane rearrangements of poliovirus-infected cells (60), suggesting a role for 3A in vesicle formation during infection.. When expressed in isolation, viral 3A protein localizes to the ER, where it causes a three- to fivefold reduction in the rate of ER-to-Golgi traffic. In the presence ...
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 ...
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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 ...
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. ...
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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.
Protein target information for Chain A, Hepatitis C Virus Polymerase Ns5b (Bk) With Amide Bioisostere Thumb Site Inhibitor (Hepatitis C virus (isolate BK)). Find diseases associated with this biological target and compounds tested against it in bioassay experiments.
ID HE586972; SV 1; linear; mRNA; STD; VRL; 533 BP. XX AC HE586972; XX DT 20-SEP-2011 (Rel. 110, Created) DT 13-AUG-2012 (Rel. 113, Last updated, Version 2) XX DE Gremmeniella mitovirus partial viral mRNA for RNA dependent RNA polymerase DE (RdRp gene), strain GaMRV-S35, isolate Gremmeniella abietina-OOP-5 XX KW . XX OS Gremmeniella mitovirus OC Viruses; ssRNA viruses; ssRNA positive-strand viruses, no DNA stage; OC Narnaviridae; Mitovirus; unclassified Mitovirus. XX RN [1] RP 1-533 RA Botella L.; RT ; RL Submitted (06-SEP-2011) to the INSDC. RL Resources, AV. Madrid 44 Edif E. Campus, Dept. Plant Production and Forest, RL Universty of Valladolid, SPAIN. XX RN [2] RX PUBMED; 22862915. RA Botella L., Tuomivirta T.T., Vervuurt S., Diez J.J., Hantula J.; RT "Occurrence of two different species of mitoviruses in the European race of RT Gremmeniella abietina var. abietina, both hosted by the genetically unique RT Spanish population"; RL Fungal Biol 116(8):872-882(2012). XX DR MD5; ...
The hepatitis C virus (HCV) is a pandemic human pathogen posing a substantial health and economic burden in both developing and developed countries. Controlling the spread of HCV through behavioural prevention strategies has met with limited success and vaccine development remains slow. The development of antiviral therapeutic agents has also been challenging, primarily due to the lack of efficient cell culture and animal models for all HCV genotypes, as well as the large genetic diversity between HCV strains. On the other hand, the use of interferon-α-based treatments in combination with the guanosine analogue, ribavirin, achieved limited success, and widespread use of these therapies has been hampered by prevalent side effects. For more than a decade, the HCV RNA-dependent RNA polymerase (RdRp) has been targeted for antiviral development, and direct-acting antivirals (DAA) have been identified which bind to one of at least six RdRp inhibitor-binding sites, and are now becoming a mainstay of highly
RNA viruses use various strategies to condense their genetic information into small genomes. Potyviruses not only use the polyprotein strategy, but also embed an open reading frame, pipo, in the P3 cistron in the -1 reading frame. PIPO is expressed as a fusion protein with the N-terminal half of P3 (P3N-PIPO) via transcriptional slippage of viral RNA-dependent RNA polymerase (RdRp). We herein show that clover yellow vein virus (ClYVV) produces a previously unidentified factor, P3N-ALT, in the +1 reading frame via transcriptional slippage at a conserved G1-2A6-7 motif, as is the case for P3N-PIPO. The translation of P3N-ALT terminates soon, and it is considered to be a C-terminal truncated form of P3. In planta experiments indicate that P3N-ALT functions in cell-to-cell movement along with P3N-PIPO. Hence, all three reading frames are used to produce functional proteins. Deep sequencing of ClYVV RNA from infected plants endorses the slippage by viral RdRp. Our findings unveil a virus strategy that
Chronic hepatitis C virus (HCV) infection is the leading cause of chronic liver disease. Current therapy using pegylated interferon-α with ribavirin is poorly tolerated and confers an overall sustained virological response around 56%. Compounds exhibiting an improved safety profile with similar or enhanced antiviral properties may represent future treatment options. Several drug discovery programmes are ongoing to directly target the viral enzymes involved in HCV replication. Recent clinical success using a peptidomimetic inhibitor of the viral serine protease has demonstrated proof-of-concept for the use of direct antiviral agents in reducing viral load. The RNA-dependent RNA polymerase (RdRp) of HCV is also required for viral RNA replication and thus represents an attractive drug discovery target. Preclinical characterization of several non-nucleoside inhibitors (NNIs) of the HCV RdRp have been described, including a promising series of benzothiadiazine derivatives which have been shown to ...
Until recently, the standard therapy for hepatitis C treatment has been interferon and ribavirin. Such treatment has only 50% efficacy and is not well tolerated. The emergence of new drugs has increased the treatment efficacy to 90%. Despite such an achievement, the success is limited since the virus mutates rapidly, causing the emergence of drug resistant forms. In addition, most new drugs were developed to treat genotype 1 infections. Thus, development of new potent antivirals is needed and drug discovery against hepatitis C is continued.. In this thesis, a FRET-based protease assay was used to evaluate new pyrazinone based NS3 protease inhibitors that are structurally different to the newly approved and currently developing drugs. Several compounds in this series showed good potencies in the nanomolar range against NS3 proteases from genotype 1, 3, and the drug resistance variant R155K. We assume that these compounds can be further developed into drug candidates that possess activity against ...
Maize Chlorotic Mottle Virus (MCMV) is a deleterious pathogen which causes Maize Lethal Necrosis Disease that result in substantial yield loss of Maize crop worldwide. The positive-sense RNA genome of MCMV (4.4 kb) encodes six proteins: P32 (32kDa protein), RNA dependent RNA polymerases (P50 and P111), P31 (31kDa protein), P7 (7kDa protein), coat protein (25 kDa). P31, P7 and coat protein are encoded from sgRNA1, located at the 3′end of the genome and sgRNA2, located at the extremity of the 3′genome end. The objective of this study is to locate the possible attachment sites of Zea mays derived miRNAs in the genome of MCMV, using four diverse efficient miRNA target prediction algorithms. In total, 321 mature miRNAs were retrieved from miRBase (miRNA database) and were tested for hybridization of MCMV. These algorithms considered the parameters of seed pairing, minimum free energy, target site accessibility, multiple target sites, pattern recognition and folding energy for attachment. Out of 321 only
Nucleic acid sandwich hybridization assays are provided that incorporate one or a combination of background reduction steps. Those steps include use of a separate capture probe and separation from immobilized capture probes by cleavage and isolation. A very sensitive assay for RNA targets includes both of those steps, plus RNA binary probes, an RNA-directed RNA ligase and amplification by an RNA-directed RNA polymerase. Kits of reagents for performing assays according to this invention are also provided.