Hypovirus is a genus of viruses, in the family Hypoviridae. Fungi serve as natural hosts. There are currently four species in this genus including the type species Cryphonectria hypovirus 1. Diseases associated with this genus include: host virulence reduction. The diameter is around 50-80 nm. Genomes are linear, around 9-13kb in length. The genome has 1 or 2 open reading frames. Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-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. Hypovirus CHV1 is the only hypovirus found in Europe up to 2000. It is known for reducing the virulence of the fungus that causes chestnut blight (i.e. hypovirulence). Cryphonectria parasitica, the ascomycete fungus, originated in Asia and causes the disease chestnut blight in several chestnut species (Castanea sp.). Although symptoms are mild in Asian chestnut ...

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 ...

J Jordan Steel, Brian J Geiss, (2015) A Novel System for Visualizing Alphavirus Assembly. Journal of virological methods.. N. L. Sweeney, A. M. Hanson, S. Mukherjee, J. Ndjomou, B. J. Geiss, J. J. Steel, K. J. Frankowski, F. J. Schoenen, D. N. Frick (2015) Benzothiazole and pyrrolone flavivirus inhibitors targeting the viral helicase. ACS Infectious Diseases.. K. M. Bullard, R. C. Gullberg, E. Soltani, J. J. Steel, B. J. Geiss, S. Keenan (2015) Murine Efficacy and Pharmacokinetic Evaluation of the Flaviviral NS5 Capping Enzyme 2-thioxothiazolidin-4-one Inhibitor BG-223. PLoS ONE.. J. J. Steel, R. C. Gullberg, E. Soltani, B. J. Geiss, (2014) Oxidative Stress Influences Positive Strand RNA Virus Genome Synthesis and Capping. Virology.. J. J. Steel, A.W.E. Franz, I. Sanchez-Vargas, K. E. Olson, B. J. Geiss, (2013) Subgenomic Reporter RNA System for Detection of Alphavirus Infection in Mosquitoes. PLoS ONE.. J. J. Steel, B. R. Henderson, S. B. Lama, K. E. Olson, and B. J. Geiss, (2011) Infectious ...

Hypovirulent isolates of the fruit tree fungal pathogen Diaporthe ambigua have previously been shown to harbour a double-stranded (ds)RNA genetic element of about 4 kb. In this study, we established the complete cDNA sequence of this dsRNA, which represents a replicative form of a positive-strand RNA virus that we have named D. ambigua RNA virus (DaRV). The nucleotide sequence of the genome is 4113 bp and has a GC content of 53%. Two large ORFs are present in the same reading frame. They are most probably translated by readthrough of a UAG stop codon in the central part of the genome. The longest possible translation product (p125) has a predicted molecular mass of about 125 kDa. A significant homology can be found to the non-structural proteins of carmoviruses of the positive-strand RNA virus family Tombusviridae. These proteins also include the conserved RNA-dependent RNA polymerase (RDRP) domain. In contrast to the genome organization of these plant viruses, no ORF is present at the 3′ end of the

Using [3H]glucosamine and [3H]mannose labels, two virus-specific glycosylated polypeptide species with Mr values of about 200,000 (200K) and in the 75K to 100K range, respectively, were recognized in Berne virus-infected embryonic mule skin cells. In purified virions only the latter glycoprotein occurred. Concanavalin A was bound to the virion as evidenced by reduction in infectivity. Analyses using SDS-PAGE, blotting and glycoprotein identification with concanavalin A and horseradish peroxidase showed coincidence of the virion glycoprotein signals with the maximum infectivity and haemagglutinating activity in an isokinetic sucrose gradient. Polyclonal rabbit immune serum and a neutralizing and haemagglutination-inhibiting monoclonal antibody raised against Berne virus recognized both the 75K to 100K and the 200K glycoproteins. Using tunicamycin, a concentration-dependent inhibition of infectivity was noted; however, non-infectious particles containing the two major polypeptides (20K and 22K) were

Double-stranded (ds) RNA viruses are a diverse group of viruses that vary widely in host range (humans, animals, plants, fungi, and bacteria), genome segment number (one to twelve) and virion organization (T-number, capsid layers or turrets). Members of this group include the rotaviruses, known globally as a common cause of gastroenteritis in young children, and bluetongue virus, an economically important pathogen of cattle and sheep. Of these families, the Reoviridae is the largest and most diverse in terms of host range. In recent years the increasing knowledge of virus particle assembly, virus-cell interactions, and viral pathogenesis allow approaches for the development of novel antiviral strategies or agents. Viruses with dsRNA genomes are currently grouped into a number of families, unassigned genera and species. Three families infect fungi: Totiviridae, Partitiviridae and Chrysoviridae. These families have monopartite, bipartite and quadripartite genomes respectively. They are typically ...

Rapid RNA virus evolution is a major problem due to the devastating diseases caused by human, animal and plant-pathogenic RNA viruses. A previous genome-wide screen for host factors affecting recombination in Tomato bushy stunt tombusvirus (TBSV), a small monopartite plant virus, identified Xrn1p 5′-3′ exoribonuclease of yeast, a model host, whose absence led to increased appearance of recombinants [Serviene, E., Shapka, N., Cheng, C.P., Panavas, T., Phuangrat, B., Baker, J., Nagy, P.D., (2005). Genome-wide screen identifies host genes affecting viral RNA recombination. Proc. Natl. Acad. Sci. U. S. A. 102 (30), 10545-10550]. In this paper, we tested if over-expression of Xrn1p in yeast or expression of the analogous Xrn4p cytoplasmic 5′-3′ exoribonuclease, which has similar function in RNA degradation in Arabidopsis as Xrn1p in yeast, in Nicotiana benthamiana could affect the accumulation of tombusvirus RNA. We show that over-expression of Xrn1p led to almost complete degradation of TBSV ...

A significant number of RNA viruses assemble their protein containers and genomic material simultaneously. Here the implications of this protein-RNA co-assembly are investigated using an extended version of a model first proposed by Adam Zlotnick in 1994 (Zlotnick, 1994). The inspirations for this extended model are the cases of bacteriophage MS2 and the STMV virus, viruses that have been well characterised experimentally. Example pathways of RNA virus assembly have been enumerated and kinetic simulations have been run on these networks. The results show the most likely pathways of virus assembly and the concentrations of the intermediates. This work will also demonstrate how kinetic traps may be avoided when proteins are able to bind RNA during assembly. Additionally modelled are DNA cages, which are three-dimensional shapes made from double-helical DNA molecules. Such cages have been seen within viruses but may also be constructed artificially. This model has been used to produce energetically ...

Polivirüsün hücresel yaşam döngüsü (1) CD155 reseptörüne bağlanmasıyla başlar. Virüs endositozla alınır, ve viral RNA serbest kalır (2). Translation of the viral RNA occurs by an IRES-mediated mechanism (3). The polyprotein is cleaved, yielding mature viral proteins (4). The positive-sense RNA serves as template for complementary negative-strand synthesis, producing double-stranded replicative form (RF) RNA(5). Many positive strand RNA copies are produced from the single negative strand (6). The newly synthesized positive-sense RNA molecules can serve as templates for translation of more viral proteins (7) or can be enclosed in a capsid (8), which ultimately generates progeny virions. Lysis of the infected cell results in release of infectious progeny virions (9).[2] ...

Registrations are now being accepted for the *VIZIER / SPINE2 Workshop on Structural Virology* taking place from 14th - 16th July 2008, in Vienna, Austria This workshop will cover recent advances in our understanding of viral entry, assembly, replication and pathogenesis principally, but not exclusively, based upon information derived from structural studies. The planned sessions are on viral assembly, double-stranded RNA viruses, the flavivirus replication machinery, the coronavirus replication machinery, virus/host interactions including aspects of viral entry, negative strand RNA viruses and viruses of prokaryotes and archea. In addition to the invited speakers, oral presentations will be selected from the submitted abstracts. The sessions are not exclusive and any topic relevant to the structural biology of viruses will be considered for a poster or oral presentation. For this reason early registration and abstract submission is strongly encouraged. The workshop is part of the training and ...

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 ...

in Gene (2004), 326. Some MX proteins are known to confer a specific resistance against a panel of single-stranded RNA viruses. Many diseases due to such viruses are known to affect cattle worldwide, raising the possibility ... [more ▼]. Some MX proteins are known to confer a specific resistance against a panel of single-stranded RNA viruses. Many diseases due to such viruses are known to affect cattle worldwide, raising the possibility that the identification of an antiviral isoform of a bovine MX protein would allow the implementation of genetic selection programs aimed at improving innate resistance of cattle. With this potential application in mind, the present study was designed to isolate the bovine Mx1 gene including its promoter region and to investigate its genomic organisation and promoter reactivity. The bovine Mx1 gene is made up of 15 exons. All exon-intron boundaries conformed to the consensus sequences. A PCR product that contained a approximately 1-kb, 5-flanking region ...

RNA enveloped viruses comprise several families belonging to plus and minus strand RNA viruses, such as retroviruses, flavoviruses and orthomyxoviruses. Viruses utilize cellular lipids during critical steps of replication like entry, assembly and egress. Growing evidence indicate important roles for lipids and lipid nanodomains in virus assembly. The proposed topic will cover key aspects of virus-membrane interactions during assembly and egress. A significant part of this special topic will address how enveloped viruses such as retroviruses, influenza, Ebola and Dengue viruses are able to recognize specific lipids in membrane during assembly and egress. Virus assembly and release involve specific and nonspecific interactions between viral proteins and membrane compartments. It is well established that assembly of retroviral Gag proteins occur predominantly on the PM. Membrane selection appears to be critical for productive virus production. Gaps in understanding of retroviral assembly still exist.

On 6 Oct 1997, Ed Rybicki wrote: , Hey, some traffic!! Wow! , , Now seriously: Paul Keese (now of National Univ of Singapore) stood , up at the last Int Soc Plant Mol Biol meeting in Singapore (21-27 , Sept) with a very interesting theory / proposition to account for , why most plant viruses have ssRNA genomes (and mammals have all , sorts). He maintains (or so my understanding goes) that organisms , tend to have the viruses that they have defence mechanisms for , (presumably because otherwise they would be dead). Thus bacteria , have mainly dsDNA viruses as they have restriction systems; mammals , have all sorts as the selection is on the basis of the virion outer , surface (immune system) - and plants have ssRNA viruses because they , have evolved mechanisms like gene silencing to shut off excessive , production of mRNA. Fungi have a prepondeance of dsRNA viruses , because they have learned to live with them (vertically transmitted, , etc.). VERY interesting... , , However, Thomas Hohn (who ...

The best Bassoon lessons in East Berne, NY as rated by students. Browse East Berne Bassoon teachers - ask questions, read reviews & compare rates!

There is no cure for this virus because RNA viruses arent diseases. They dont need a cure. They need cooperation.They are ribonucleic acid and a dynamic part of the genome. Our RNA is what allows us to evolve as a species. They are a natural part of our world and are microbes that have been…

Written by D. Manuel Mendonca, Narrated by Molly King. Download the app and start listening to Omega Virus today - Free with a 30 day Trial! Keep your audiobook forever, even if you cancel. Dont love a book? Swap it for free, anytime.

Benyviridae and Ophioviridae are both single-stranded RNA viruses that can infect plants and contain only one genus. Benyviridae, positive-sense RNA viruses with rod-shaped virions, can cause rhizomania, a disease in the roots of sugar beet. Some species of Ophioviridae are transmitted through soil and can infect many different plants including vegetables, trees and shrubs ...

Neurovirology is an interdisciplinary field representing a melding of virology, clinical neuroscience, molecular pathogenesis, diagnostic virology, molecular biology, and immunology. Neuroviral Infections: RNA Viruses and Retroviruses presents an…

genomes of accumulated deleterious changes (Muller, 1964) and to create or spread bene locial combinations of mutations in an efficient manner (Fisher, 1930;Muller, 1932), two processes which are not available to clonal organisms. Two distinct but not mutually exclusive types of genetic exchange operate in RNA viruses. The first, reassortment ...

genomes of accumulated deleterious changes (Muller, 1964) and to create or spread bene locial combinations of mutations in an efficient manner (Fisher, 1930;Muller, 1932), two processes which are not available to clonal organisms. Two distinct but not mutually exclusive types of genetic exchange operate in RNA viruses. The first, reassortment ...

This institute contributes to the education of students in Graduate School for Environmental and Life Science (Masters and Doctors Degree Course of Okayama University).

One fossil gene, called VP35, appeared in the same spot in the genomes of four different rodent species: two hamsters and two voles. This meant the material was likely acquired in or before the Miocene Epoch, prior to when these rodents evolved into distinct species some 16-23 million years ago.. In other words: It appears that the known filovirus family is at least as old as the common ancestor of hamsters and voles.. These rodents have billions of base pairs in their genomes, so the odds of a viral gene inserting itself at the same position in different species at different times are very small, Taylor says. Its likely that the insertion was present in the common ancestor of these rodents.. The genetic material in the VP35 fossil was more closely related to Ebola than to Marburg, indicating that the lines leading to these viruses had already begun diverging from each other in the Miocene.. The new study builds on Taylors previous work with Bruenn and other biologists, which used viral ...

Viruses are very small biological constructs which contain either DNA or RNA. As they lack cellular machinery and rely on an infected cell to actually replicate their viral genomes, there is debate as to whether viruses should be considered living. A virus consists of three main parts. 1) Genetic Material - This can be either DNA or RNA. Upon a viral infection, the virus inserts its genome into the host cell, where it is processed by various polymerases. 2) Protein capsid - this is a simple protein shell which envelops the genetic material and gives the virus structure. 3) Coat - there may exist certain proteins or lipids on the surface of the virus that identify the virus and aid in receptor binding to the cell surface. These surface modifications to the virus can induce an immune response in the host organism. The figure to the right is a schematic of a bacteriophage (virus that infects bacteria) inserting its DNA . Viral replication is essentially a positive feedback loop in which the ...

professor of biology at the University of Sydney, and his Australian colleagues decided to confront this mystery head on. Using viral genome data, they reconstructed the evolutionary history of 19 major virus families, each of which contained between 23 and 142 viruses found in diverse hosts ranging from mammals to fish to plants. They created phylogenetic, or evolutionary, trees for both the virus families and their host species and then compared them. They reasoned that if a virus had largely co-diverged with its host, evolving right alongside it, then the viruss phylogenetic tree should resemble its hosts: ancestral versions of the virus ought to have infected the hosts ancestors. But if the virus is jumping between species, the trees of the hosts and viruses will look different. How different depends on how many cross-species jumps are made ...

Viruses. Viruses and bacteria are too small to be seen without the aid of microscopes. As disease agents, their effects on mankind are well known. Both are ubiquitous and adaptable.. The Bridge Between Living and Non-Living. Someone once suggested that if people were the size of viruses, the entire population of the U.S. would fit on the end of two pencil erasers. There would be room left over for future generations. Extremely small, simple in structure, and widely distributed, viruses exist in a realm all their own. Viruses do not qualify as cells yet affect cells and so exist as if on a bridge between the living and nonliving.. Structure and Classification of Viruses. Viruses differ from cellular organisms in many ways. A virus contains only a single type of nucleic acid. This DNA or RNA may be single or double-stranded. The core of nucleic acid is covered by a protein coat called a capsid. Some of the proteins in the capsid are enzymes. A complete virus particle is called a virion. Some ...

So if viruses are not alive, what do they do and how do they do it? A virus, as long as it is not subjected to harsh conditions, is fairly stable. As it moves through the world, in saliva, on a counter top, or in a sneeze-induced projectile, it is waiting for its protein spikes to find the right cell. Once the virus finds a cell to which protein spikes can attach, it then migrates into the interior and takes over operations. Since a protein spike-cell wall match is necessary for the virus to enter, certain viruses can only infect certain cells. Once inside, the nucleic acid in the virus starts giving instructions to the cell, instructions which override those coming from the DNA in the nucleus of the cell. The virus then forces the cell to make copies of the virus, lots and lots of copies. After enough copies have been made, the virus moves on to other cells either by killing the host cell or diffusing back out through the cell wall ...

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A mathematical model that combines stochasticity and spatial structure describes the dynamics of the viral population during an infection cycle, and fitting the model to RNA and virus abundances over time shows that poliovirus follows a geometric replication mode.

Geoff Kuenning, a professor of computer science at Harvey Mudd College, provides this explanation. Malicious software comes in several flavors, distinguished primarily by their method of propagation. The two most pervasive forms are viruses and worms. A virus attaches itself to an existing program such that, when that program is executed, bad things happen. Like a biological virus, it cannot live without a host. In contrast, a worm is an independent program that reproduces itself without requiring a host program. Depending on the form, a worm may be able to propagate without any action on the victims part. Most malicious software today consists of worms rather than viruses. Worms and viruses require slightly different protection mechanisms because of their different propagation methods. A virus scanner operates by searching for the signatures of known viruses. A signature is a characteristic pattern that occurs in every copy of a virus. It might be a string of characters, such as a message that ...

See on Scoop.it - Virology News Viruses have generally been studied either as disease-causing infectious agents that have a negative impact on the host (most eukaryote-infecting viruses), or as tools for molecular biology (especially bacteria-infecting viruses, or phage). Virus ecology looks at the more complex issues of virus-host-environment interactions. For plant viruses this includes studies…

Lets face it: the last thing your computer needs is a virus. Viruses are nasty programs designed to damage computers and networks. A virus may cause odd messages to appear on screens, spread itself by sending unintended emails to your email contacts, damage your data, or worse. Whatever the case, a virus is never a welcome surprise. The Internet is a particularly dangerous tool for those who create viruses, as it provides them with access to so many computers, opening a whole new world of trouble. Most viruses spread when users share infected floppy discs, unknowingly run infected programs or open email attachments. If you download software (or just open attachments from friends, relatives, or business associates), theres a chance youll bring home one of these digital bugs. Still, its fairly easy to protect your computer and valuable info from viruses. Youll just need to consistently do a couple of things:. 1) Never open, view or run an unexpected email attachment, even if its from someone ...

It is January 21st, 2021. Its always sad and frustrating when I read an article that includes misinformation about the Wuhan virus. A trip to the CDCs website will give you the actual numbers, but its probable that the CDC hadnt changed their numbers to reflect reality at the time of this article. As of today, in the United States, 18,700 persons have died from the virus, the vast majority of whom were elderly. The leftist media currently exclaims that over 300,000 have died of the virus, but that is misleading. Just testing positive for the virus at the time of death will earn the deceased the medical code of a Covid-19 death, but there is a difference between dying FROM the virus and dying having tested positive for the virus. Only 6% of the deaths that the leftist media state have been solely from the virus. 6% is 18,700. The rest, most of whom were elderly, had an average of 2.9 co-morbidities and primarily died of an heart attack, suicide, diabetes complications, etc. and averaged ...

It is January 21st, 2021. Its always sad and frustrating when I read an article that includes misinformation about the Wuhan virus. A trip to the CDCs website will give you the actual numbers, but its probable that the CDC hadnt changed their numbers to reflect reality at the time of this article. As of today, in the United States, 18,700 persons have died from the virus, the vast majority of whom were elderly. The leftist media currently exclaims that over 300,000 have died of the virus, but that is misleading. Just testing positive for the virus at the time of death will earn the deceased the medical code of a Covid-19 death, but there is a difference between dying FROM the virus and dying having tested positive for the virus. Only 6% of the deaths that the leftist media state have been solely from the virus. 6% is 18,700. The rest, most of whom were elderly, had an average of 2.9 co-morbidities and primarily died of an heart attack, suicide, diabetes complications, etc. and averaged ...

The W32.Shodi.C program is a virus that pretends to be executable or .exe files. It can also drop a fixed access tool. When a file contaminated w/ a W32.Shodi.C virus is opened, it extracts the original file to a file with a .sho extension, and then it opens it. For instance, if notepad.exe is contaminated, the W32.Shodi.C program will extract the notepad program to notepad.sho and then opens it. The virus searches for the files with .exe extensions on all the hard drives, beginning w/ drive C. The virus looks for the folders on the hard drive, except names such as windows, system, and system32. The virus doesnt contaminate the files with names such as iexplorer.exe, ccApp.exe, and ccRegVfy.exe. The virus conceals itself to some of the files that it locates. The W32.Shodi.Cprogram changes its icon to resemble that of the host file. The virus creates a temporary duplicate of itself as %System%Shohdi.hdi ...

Mouse K virus was first discovered by Lawrence Kilham - thus K virus. It belongs to the family Pavovaviridae. The virus is usually spread by the oronasal route. When a young mouse is orally inoculated with the virus, the virus first replicates in the intestine and then spreads to other organs such as liver, lung, spleen and brain. Older mice may mount an immune response to the virus and thus may limit the spread of the virus through the body. However, athymic or nude mice suffer significantly if infected ...

Instead, the researchers focused on glycoproteins, which sit on the outside of all viruses and attach to cells in the body, allowing the viruses to do their dirty work by infecting cells and making us sick. Using that knowledge, the researchers created a macromolecule, which is basically one giant molecule made of smaller subunits. This macromolecule has key factors that are crucial in fighting viruses. First, its able to attract viruses towards itself using electrostatic charges. Once the virus is close, the macromolecule attaches to the virus and makes the virus unable to attach to healthy cells. Then it neutralizes the virus acidity levels, which makes it less able to replicate. ...

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Survey of Microorganisms. Virus Bacteria Cyanobacteria Algae Fungi protozoa. VIRUS. Obligated intracellular parasite. host specific: bacteriophage animal virus plant virus according to its genetic material DNA virus RNA virus Shape: Slideshow 202506 by Faraday

Emerging human and zoonotic RNA viruses including SARS-CoV cause significant global morbidity, mortality, and social disruption. The current model for RNA virus...

Principal Investigator：ENAMI Masayoshi, Project Period (FY)：1997 - 1999, Research Category：Grant-in-Aid for Scientific Research (A), Section：展開研究, Research Field：Virology

Watch video lessons, and learn about the different aspects of various viral infections, like the stomach flu, HIV and rabies. Take the quizzes that...

Medical Xpress is a web-based medical and health news service that features the most comprehensive coverage in the fields of neuroscience, cardiology, cancer, HIV/AIDS, psychology, psychiatry, dentistry, genetics, diseases and conditions, medications and more.

Medical Xpress is a web-based medical and health news service that features the most comprehensive coverage in the fields of neuroscience, cardiology, cancer, HIV/AIDS, psychology, psychiatry, dentistry, genetics, diseases and conditions, medications and more.

Vivaldi Biosciences was developing small molecule antiviral drugs for the treatment of respiratory diseases caused by negative-strand RNA viruses, including

See the latest information on computer virus attacks and their removal. McAfee is the leader in internet security and virus detection. Keep up to date on the most recent virus threats, recently discovered viruses and recently updated viruses.

Rice (Oryza spp.) has long been an important food staple for many traditional rice growing communities. Key developments in efforts to improve rice production such as the development of NERICA varieties have been widely recognised. Nonetheless, emerging diseases such as the Rice Yellow Mottle Virus sobemovirus (RYMV) undermine dissemination of new technologies and sustained productivity of the crop. The RYMV is highly variable and several resistance-breaking strains have been identified. Appropriate sources of resistance to RYMV should be identified and characterised in order to pyramid genes for both complete and partial resistance. In this study, reaction of nine (9) rice cultivars to RYMV virulent strain in Uganda was determined. Four upland and three lowland NERICA varieties, an O. Sativa lowland variety, Gigante and IR64 were observed. Isolates of RYMV were collected from three hot-spots in Uganda (Lira, Luweero and Iganga). The isolate from Iganga was most virulent on RYMV susceptible ...

The Cryphonectria parasitica gene cpmk2, which encodes a mitogen-activated protein kinase belonging to the yeast extracellular signalling-regulated kinase (YERK1) subfamily, was isolated and its biological function was examined. Disruption of cpmk2 resulted in impaired pigmentation and abolished conidiation. Growth defects were observed in the cpmk2 mutant grown on solid plates, but growth of the mutant appeared normal in liquid media, including EP complete and PD broth, suggesting that the cpmk2 gene is involved in sensing and responding to growth conditions. The mutant's production of laccase, as measured by the size of the coloured area produced on tannic-acid-supplemented plates, was significantly reduced compared with the wild-type, but the intensity of the coloured area was unchanged, suggesting that the reduced laccase activity was owing to reduced growth on solid media rather than transcriptional downregulation. A dramatic reduction observed in the canker area produced by the cpmk2 mutant

Beet necrotic yellow vein virus (BNYVV), vectored by Polymyxa betae, causes rhizomania in sugar beet. For disease control, the cultivation of hybrids carrying Rz1 resistance is crucial, but is compromised by resistance-breaking (RB) strains with specific mutations in the P25 protein at amino acids 67-70 (tetrad). To obtain evidence for P25 variability from soil-borne populations, where the virus persists for decades, populations with wild-type (WT) and RB properties were analysed by P25 deep sequencing. The level of P25 variation in the populations analysed did not correlate with RB properties. Remarkably, one WT population contained P25 with RB mutations at a frequency of 11%. To demonstrate selection by Rz1 and the influence of RB mutations on relative fitness, competition experiments between strains were performed. Following a mixture of strains with four RNAs, a shift in tetrad variants was observed, suggesting that strains did not mix or transreplicate. The plant genotype exerted a clear ...

The temperature-inducible expression vector containing the beet necrotic yellow vein virus(BNYVV)isolate NM coat protein gene was constructed and transferred into E. coli DH5 α. High-level expression of the specific protein was achieved by temperature induction. The results of SDSPAGE and Western blotting show that the expression product which accumulates 19.5％ of the total cellular proteins estimated by Shimadzu CS-910 scanning is 21kd BNYVV coat protein.

Read Distribution of various types and P25 subtypes of Beet necrotic yellow vein virus in Germany and other European countries, Archives of Virology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

A panel of four monoclonal antibodies (MAbs) was used to study the immunological profile of Rice yellow mottle virus (RYMV) genus Sobemovirus. Serological profiles of 35 representative isolates of RYMV from Borno, Gombe, Kaduna, Kano, Niger, Sokoto and Zamfara states in Northern Nigeria. All the RYMV isolates were classified into three major serogroups (SG1, SG2 and SG3) and further separated into six subgroups (Sg1a, Sg1b, Sg2a, Sg2b, Sg3a and Sg3b). The results demonstrate a significant serological variability among RYMV isolates in Northern Nigeria. The hierarchical analysis of the serological profiles data revealed high viral load in Kano, Kaduna and Gombe states, these show they are suitable locations for strategic RYMV diagnostic and field epidemiological studies

Cryphonectria hypovirus 1 (CHV1) is a double-stranded (ds)RNA virus without a capsid that infects phytopathogenic fungus Cryphonectria parasitica, the causal agent of chestnut blight. This virus reduces virulence and reproductive capacities of the fungus and thus is very important in biological control of the chestnut blight. If a hypovirulent fungus carrying CHV1 is introduced into an active canker caused by virulent C. parasitica strain, canker expansion ceases and callus is formed. The aim of this research was to evaluate the prevalence of CHV1 in chestnut calli. A total of 24 calli from Ozalj and Markuševac were included in the research. Observed presence of virulent fungal strains in chestnut calli was high. As many as 29.16% of calli had only virulent fungal strains in their tissue, 45.84% of calli had the combination of virulent and hypovirulent fungal strains, and only 25% of calli had solely hypovirulent fungal strains in their tissue. It is assumed that this could have happened ...

Phytopathogenic fungus Cryphonectria parasitica is the causal agent of chestnut blight in the European chestnut Castanea sativa Miller. This fungus is also the natural host of the virus Cryphonectria hypovirus 1 (CHV-1), which reduces fungal virulence and sporulation ability. Hypovirus can spread only between fungal strains that belong to the same vegetative compatibility (VC) type, i.e. that contain identical alleles at all vic loci, and less frequently from the strains in which theres a a difference in only one of six loci which determine the diversity of VC types in Europe. In this research C. parasitica populations from Ozalj and Kašt area were analyzed. The aim was to determine the diversity of VC types and the percentage of hypovirulent isolates with white morphology. In Ozalj population the dominant VC type was EU2 which represented 34% of the total number of isolates, followed by EU1 which represented 19% of the total number of isolates. The prevalence of VC types EU14, EU39 and EU40 ...

ID AY501442; SV 1; linear; genomic RNA; STD; VRL; 618 BP. XX AC AY501442; XX DT 11-JAN-2004 (Rel. 78, Created) DT 28-MAY-2005 (Rel. 84, Last updated, Version 2) XX DE Cryphonectria hypovirus 4 strain NJ129-2 polyprotein R1 region gene, DE partial cds. XX KW . XX OS Cryphonectria hypovirus 4 OC Viruses; Riboviria; Hypoviridae; Hypovirus. XX RN [1] RP 1-618 RX DOI; 10.1016/j.virol.2005.03.038. RX PUBMED; 15914232. RA Linder-Basso D., Dynek J.N., Hillman B.I.; RT Genome analysis of Cryphonectria hypovirus 4, the most common hypovirus RT species in North America; RL Virology 337(1):192-203(2005). XX RN [2] RP 1-618 RA Linder-Basso D., Dynek J., Hillman B.I.; RT ; RL Submitted (04-DEC-2003) to the INSDC. RL Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New RL Brunswick, NJ 08901-8520, USA XX DR MD5; 1f171f27c2560a9a98982e74c0114fcf. XX FH Key Location/Qualifiers FH FT source 1..618 FT /organism=Cryphonectria hypovirus 4 FT /strain=NJ129-2 FT /mol_type=genomic RNA FT ...

ID AY501466; SV 1; linear; genomic RNA; STD; VRL; 795 BP. XX AC AY501466; XX DT 11-JAN-2004 (Rel. 78, Created) DT 28-MAY-2005 (Rel. 84, Last updated, Version 2) XX DE Cryphonectria hypovirus 4 strain NJ129-2 polyprotein R4 region gene, DE partial cds. XX KW . XX OS Cryphonectria hypovirus 4 OC Viruses; dsRNA viruses; Hypoviridae; Hypovirus. XX RN [1] RP 1-795 RX DOI; 10.1016/j.virol.2005.03.038. RX PUBMED; 15914232. RA Linder-Basso D., Dynek J.N., Hillman B.I.; RT Genome analysis of Cryphonectria hypovirus 4, the most common hypovirus RT species in North America; RL Virology 337(1):192-203(2005). XX RN [2] RP 1-795 RA Linder-Basso D., Dynek J., Hillman B.I.; RT ; RL Submitted (04-DEC-2003) to the INSDC. RL Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New RL Brunswick, NJ 08901-8520, USA XX DR MD5; b56dd84b9e876d2d2b22e17df48e49f0. XX FH Key Location/Qualifiers FH FT source 1..795 FT /organism=Cryphonectria hypovirus 4 FT /strain=NJ129-2 FT /mol_type=genomic RNA FT ...

Deformed wing virus (DWV) is a positive-strand RNA virus that infects European honeybees (Apis mellifera L.) and has been isolated from the brains of aggressive bees in Japan. DWV is known to be transmitted both vertically and horizontally between bees in a colony and can lead to both symptomatic and asymptomatic infections in bees. In environmentally stressful conditions, DWV can contribute to the demise of a honeybee colony. The purpose of the current study is to identify regions within the brains of honeybees where DWV replicates using in-situ hybridization. In-situ hybridizations were conducted with both sense and antisense probes on the brains of honeybees that were positive for DWV as measured by real-time RT-PCR. The visual neuropils demonstrated detectable levels of the DWV positive-strand genome. The mushroom bodies and antenna lobe neuropils also showed the presence of the viral genome. Weaker staining with the sense probe in the same regions demonstrates that the antigenome is also present

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

Ragonnet-Cronin, M., S. Aris-Brosou, I. Joanisse, H. Merks, D. Vallée, K. Caminiti, et al. 2012. Genetic diversity as a marker for timing Infection in HIV-infected patients: evaluation of a 6-month window and comparison with BED. J. Infect. Dis. 206:756-764 ...

Read The readthrough region of Potato mop-top virus (PMTV) coat protein encoding RNA, the second largest RNA of PMTV genome, undergoes structural changes in naturally infected and experimentally inoculated plants, Archives of Virology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

For a growing number of positive-strand RNA viruses, it has been demonstrated that transformation of host plants with the viral coat protein gene confers resistance to the corresponding virus. Thus far, successful transformation strategies to obtain resistance to negative-strand RNA viruses have not been reported. Here we show that genetically engineered resistance can be obtained to tomato spotted wilt virus, an enveloped virus with a negative-strand RNA genome, by transforming tobacco with the gene encoding the viral nucleocapsid protein, an internal RNA-binding protein. This approach may be useful for producing plants resistant to infection by other negative-strand viruses.

CRISPR-Cas systems endow bacterial and archaeal species with adaptive immunity mechanisms to fend off invading phages and foreign genetic elements. CRISPR-Cas9 has been harnessed to confer virus interference against DNA viruses in eukaryotes, including plants. In addition, CRISPR-Cas13 systems have been used to target RNA viruses and the transcriptome in mammalian and plant cells. Recently, CRISPR-Cas13a has been shown to confer modest interference against RNA viruses. Here, we characterized a set of different Cas13 variants to identify those with the most efficient, robust, and specific interference activities against RNA viruses in planta using Nicotiana benthamiana. Our data show that LwaCas13a, PspCas13b, and CasRx variants mediate high interference activities against RNA viruses in transient assays. Moreover, CasRx mediated robust interference in both transient and stable overexpression assays when compared to the other variants tested. CasRx targets either one virus alone or two RNA viruses

The cosmopolitan fungus Rhizoctonia solani has a wide host range and is the causal agent of numerous crop diseases, leading to significant economic losses. To date, no cultivars showing complete resistance to R. solani have been identified and it is imperative to develop a strategy to control the spread of the disease. Fungal viruses, or mycoviruses, are widespread in all major groups of fungi and next-generation sequencing (NGS) is currently the most efficient approach for their identification. An increasing number of novel mycoviruses are being reported, including double-stranded (ds) RNA, circular single-stranded (ss) DNA, negative sense (−)ssRNA, and positive sense (+)ssRNA viruses. The majority of mycovirus infections are cryptic with no obvious symptoms on the hosts; however, some mycoviruses may alter fungal host pathogenicity resulting in hypervirulence or hypovirulence and are therefore potential biological control agents that could be used to combat fungal diseases. R. solani harbors a

Creative BioMart, a global leader in the supply of protein related products and services, recently added RNA Viruses Triggered Signal Pathway to its signal pathway resources, enlarging more comprehensive assess to the knowledge on signal pathway. Up to now, Creative BioMart has introductions about RNA Viruses Triggered Signal Pathway, Apoptosis Signal Pathway Overview and Mitochondrial Control of Apoptosis.. Many human diseases are caused by RNA viruses include influenza, the common cold, hepatitis C, SARS, Ebola hemorrhoragic fever, West Nile fever and polio etc. It is very important for organism to virus killing and disease prevention by antiviral response. Innate immunity is the most critical process in antiviral response.. This newly added resource gives a detailed introduction about the background, the recognition of RNA viruses signal pathway, and RNA viruses triggered IPS-1 downstream signal pathway.. By continually enlarge our knowledge base on our site, we are dedicated to providing ...

Creative BioMart, a global leader in the supply of protein related products and services, recently added RNA Viruses Triggered Signal Pathway to its signal pathway resources, enlarging more comprehensive assess to the knowledge on signal pathway. Up to now, Creative BioMart has introductions about RNA Viruses Triggered Signal Pathway, Apoptosis Signal Pathway Overview and Mitochondrial Control of Apoptosis.. Many human diseases are caused by RNA viruses include influenza, the common cold, hepatitis C, SARS, Ebola hemorrhoragic fever, West Nile fever and polio etc. It is very important for organism to virus killing and disease prevention by antiviral response. Innate immunity is the most critical process in antiviral response.. This newly added resource gives a detailed introduction about the background, the recognition of RNA viruses signal pathway, and RNA viruses triggered IPS-1 downstream signal pathway.. By continually enlarge our knowledge base on our site, we are dedicated to providing ...

Creative BioMart, a global leader in the supply of protein related products and services, recently added RNA Viruses Triggered Signal Pathway to its signal pathway resources, enlarging more comprehensive assess to the knowledge on signal pathway. Up to now, Creative BioMart has introductions about RNA Viruses Triggered Signal Pathway, Apoptosis Signal Pathway Overview and Mitochondrial Control of Apoptosis.. Many human diseases are caused by RNA viruses include influenza, the common cold, hepatitis C, SARS, Ebola hemorrhoragic fever, West Nile fever and polio etc. It is very important for organism to virus killing and disease prevention by antiviral response. Innate immunity is the most critical process in antiviral response.. This newly added resource gives a detailed introduction about the background, the recognition of RNA viruses signal pathway, and RNA viruses triggered IPS-1 downstream signal pathway.. By continually enlarge our knowledge base on our site, we are dedicated to providing ...

Potato mop-top virus (PMTV) causes an economically important disease of potato. Serious yield and quality reductions can occur in some cultivars.

Genetic diversity and abundance of RNA viruses are due to three major forces: mutation, recombination and reassortment. The evolution of these viruses has been studied both experimentally and through sequence analysis. Massive numbers of virus genome sequences and bioinformatics tools give us a chance to explore evolutionary mechanisms through whole genome analysis.;Potato virus Y (PVY) is a positive-strand RNA virus in the Potyvirus genus. It is one of the most damaging plant pathogens, causing significant yield and quality losses in four main crops: potato, tomato, tobacco and pepper. Because of multiple documented mutations and frequent recombination, it is a particularly attractive model to study mechanisms of general RNA virus evolution. Various PVY strains can be distinguished by symptoms in different host plants, serology and with reverse transcript polymerase chain reaction (RT-PCR) tools, and newly emerged strains can also be identified. In this study, we characterized two new PVY ...

Abstract: Beet necrotic yellow vein virus (BNYVV), which causes a viral disease of sugar beet known as rhizomania, is widely spread throughout the sugar beet growing areas of Poland. The analysis of the molecular variability of two separate regions, namely the part of coat protein (CP) and triple gene block (TGB) genes of the BNYVV genome, revealed very low level of nucleotide sequence diversity among the isolates (98-100% sequence identity). Sequence alignments of BNYVV isolates from Poland and other isolates available to data showed also high level of nucleotide sequence identity among these isolates. Based on multiplex RT-PCR and phylogenetic analysis we distinguished types A and B of BNYVV. The sequence identity matrix between type A and B revealed 92-93% similarity. Mainly, BNYVV type A is widespread in Poland whereas type B has rarely been found. These results suggest that Polish isolates probably originated from Southern Europe rather then from Germany or France where BNYVV type B is a ...

Learn Single-stranded Negative-sense RNA Viruses in USMLE Step 1 - Virology for Medicine faster and easier with Picmonics unforgettable videos, stories, and quizzes! Picmonic is research proven to increase your memory retention and test scores. Start learning today for free!

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 ...

Photo 2. Canker with hypovirus. The tree has enclosed the canker with wound tissue that stops canker expansion. The canker in this picture has died (bare wood at the center of the stem, and the wound tissue is slowly covering the old infection site.. Our work on hypoviruses began in 2010 when we introduced hypovirus onto ten trees in an orchard of Japanese-European hybrids on the MSU campus that is infected with blight. One or two cankers per tree were inoculated with hypovirus. Our first goal is to determine if hypovirus treatments result in healing cankers. This will be accomplished by monitoring the treated cankers for three to five years to document that treatments halt canker expansion and lead to tree recovery. A second goal is to determine how well hypovirus spreads to untreated cankers on a tree. The extent of spread to new cankers on a treated tree will influence how hypoviruses are used. If the hypovirus spread quickly in orchard situations, then only a few cankers need to be treated ...

Figure 2 shows the genome organization of GRV; those of other umbraviruses are very similar. For each RNA, there is at the 5′ end a very short non-coding region preceding ORF1, which encodes a putative product of 31-37 kDa. ORF2, which slightly overlaps the end of ORF1, could encode a product of 63-65 kDa but lacks an AUG initiation codon near its 5′ end. However, immediately before the stop codon of ORF1 there is a 7 nt sequence that is associated with frameshifting in several plant and animal viruses, and it seems probable that ORF1 and ORF2 are translated as a single polypeptide of 94-98 kDa by a mechanism involving a −1 frameshift. The predicted product contains, in the ORF2 region, sequence motifs characteristic of viral RdRp. A short untranslated region separates ORF2 from ORF3 and ORF4, which overlap each other almost completely in different reading frames and each yield a putative product of 26-29 kDa. The ORF4 product contains sequences characteristic of plant virus MPs. The ORF3 ...

Dea, S.; Roy, R.S.; Begin, M.E., 1979: Counterimmunoelectroosmophoresis for detection of neonatal calf diarrhea coronavirus: methodology and comparison with electron microscopy

6.2. Viral Carcinogenesis. Carcinogenesis is the mechanisms whereby viruses cause cancer that virus carried out a gene altered the cell regulation. Example of viruses that contribute to carcinogenesis.. There are two classes of tumour viruses: RNA viruses and DNA viruses.. 6.2.1. RNA viruses. RNA virus infect competent cells. Their RNA is converted into DNA that incorporated into the host genome. Hence, that is classification as retroviruses. Example of retrovirus: human T-lymphotropic virus(HTLV-1) and Rous sarcoma virus(RSV). RNA viruses show two general ways: provision of an oncogene or insertional mutagenesis in which regulatory sequences alter host gene activity.. Provision of an oncogene: Many oncogenic RNA viruses contain an oncogene additional to the sequences for viral replication. The Rous sarcoma virus, in which the oncogene v-src codes for a 60 kDa phoshoprotein(pp60src) that has tyrosine kinase activity.. Insertional mutagenesis: Mouse mammary tumour virue(MMTV) has regulatory ...

Capsid protein VP1: Forms an icosahedral capsid of pseudo T=3 symmetry with capsid proteins VP2 and VP3. The capsid is 300 Angstroms in diameter, composed of 60 copies of each capsid protein and enclosing the viral positive strand RNA genome. Capsid protein VP1 mainly forms the vertices of the capsid. Capsid protein VP1 interacts with host cell receptor to provide virion attachment to target host cells. This attachment induces virion internalization. Tyrosine kinases are probably involved in the entry process. After binding to its receptor, the capsid undergoes conformational changes. Capsid protein VP1 N-terminus (that contains an amphipathic alpha-helix) and capsid protein VP4 are externalized. Together, they shape a pore in the host membrane through which viral genome is translocated to host cell cytoplasm. After genome has been released, the channel shrinks (By similarity).

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Aphids and related insects are important plant pests for two reasons: they directly damage many crops and they transmit most plant viruses. For many farmers in sub-Saharan Africa, insecticides are either too expensive or unavailable, and aphid populations are very high, especially in warmer regions. For these reasons, new, inexpensive and sustainable control methods are vitally important. Can good viruses such as insect-infecting dicistroviruses help? Dicistroviruses are remarkable in that they use plants as infection reservoirs - these viruses do not reproduce or cause disease in plants but insects that feed on these reservoir plants will become infected and can become diseased and die. We believe that dicistroviruses have important potential as biological control agents that would limit direct insect damage and inhibit transmission of crop-infecting viruses. We propose to use next-generation sequencing, a state-of-the-art genetic fingerprinting technique, to discover the variety of ...

Coronaviruses are positive-strand RNA viruses that are important infectious agents of both animals and humans. A common feature among positive-strand RNA viruses is their assembly of replication-transcription complexes in association with cytoplasmic membranes. Upon infection, coronaviruses extensively rearrange cellular membranes into organelle-like replicative structures that consist of double-membrane vesicles and convoluted membranes to which the nonstructural proteins involved in RNA synthesis localize. Double-stranded RNA, presumably functioning as replicative intermediate during viral RNA synthesis, has been detected at the double-membrane vesicle interior. Recent studies have provided new insights into the assembly and functioning of the coronavirus replicative structures. This review will summarize the current knowledge on the biogenesis of the replicative structures, the membrane anchoring of the replication-transcription complexes, and the location of viral RNA synthesis, with particular

The group of Negative-Stranded RNA Viruses (NSVs) includes many human pathogens, like the influenza, measles, mumps, respiratory syncytial or Ebola viruses, which produce frequent epidemics of disease and occasional, high mortality outbreaks by transmission from animal reservoirs. The genome of NSVs consists of one to several single-stranded, negative-polarity RNA molecules that are always assembled into mega Dalton-sized complexes by association to many nucleoprotein monomers. These RNA-protein complexes or ribonucleoproteins function as templates for transcription and replication by action of the viral RNA polymerase and accessory proteins. Here we review our knowledge on these large RNA-synthesis machines, including the structure of their components, the interactions among them and their enzymatic activities, and we discuss models showing how they perform the virus transcription and replication programmes. - Highlights: • Overall organisation of NSV RNA synthesis machines. • Structure and ...

The construction of cDNA clones encoding large-size RNA molecules of biological interest, like coronavirus genomes, which are among the largest mature RNA molecules known to biology, has been hampered by the instability of those cDNAs in bacteria. Herein, we show that the application of two strategi …

Abstract: Characterizing the genome of mature virions is pivotal to understanding the highly dynamic processes of virus assembly and infection. Owing to the different cellular fates of DNA and RNA, the life cycles of double-stranded (ds)DNA and dsRNA viruses are dissimilar. In terms of nucleic acid packing, dsDNA viruses, which lack genome segmentation and intra-capsid transcriptional machinery, predominantly display single-spooled genome organizations1,2,3,4,5,6,7,8. Because the release of dsRNA into the cytoplasm triggers host defence mechanisms9, dsRNA viruses retain their genomes within a core particle that contains the enzymes required for RNA replication and transcription10,11,12. The genomes of dsRNA viruses vary greatly in the degree of segmentation. In members of the Reoviridae family, genomes consist of 10-12 segments and exhibit a non-spooled arrangement mediated by RNA-dependent RNA polymerases11,12,13,14. However, whether this arrangement is a general feature of dsRNA viruses ...

Abstract: Characterizing the genome of mature virions is pivotal to understanding the highly dynamic processes of virus assembly and infection. Owing to the different cellular fates of DNA and RNA, the life cycles of double-stranded (ds)DNA and dsRNA viruses are dissimilar. In terms of nucleic acid packing, dsDNA viruses, which lack genome segmentation and intra-capsid transcriptional machinery, predominantly display single-spooled genome organizations1,2,3,4,5,6,7,8. Because the release of dsRNA into the cytoplasm triggers host defence mechanisms9, dsRNA viruses retain their genomes within a core particle that contains the enzymes required for RNA replication and transcription10,11,12. The genomes of dsRNA viruses vary greatly in the degree of segmentation. In members of the Reoviridae family, genomes consist of 10-12 segments and exhibit a non-spooled arrangement mediated by RNA-dependent RNA polymerases11,12,13,14. However, whether this arrangement is a general feature of dsRNA viruses ...

Reverse genetics has been an indispensable tool revolutionising insights into viral pathogenesis and vaccine development. Large RNA virus genomes, such as from Coronaviruses, are cumbersome to clone and manipulate in E. coli due to size and occasional instability1-3. Therefore, an alternative rapid and robust reverse genetics platform for RNA viruses would benefit the research community. Here we show the full functionality of a yeast-based synthetic genomics platform to genetically reconstruct diverse RNA viruses, including members of the Coronaviridae, Flaviviridae and Paramyxoviridae families. Viral subgenomic fragments were generated using viral isolates, cloned viral DNA, clinical samples, or synthetic DNA, and reassembled in one step in Saccharomyces cerevisiae using transformation associated recombination (TAR) cloning to maintain the genome as a yeast artificial chromosome (YAC). T7-RNA polymerase has been used to generate infectious RNA to rescue viable virus. Based on this platform we have been

Current Research and Scholarly Interests The biochemistry of RNA-dependent RNA polymerase function, the cell biology of the membrane rearrangements induced by positive-strand RNA virus infection of human cells, and the genetics of RNA viruses, which, with their high error rates, live at the brink of error catastrophe, are investigated in the Kirkegaard laboratory. ...