Search results for " REPLICATION"
showing 10 items of 406 documents
Hop stunt viroid: A polyphagous pathogenic RNA that has shed light on viroid–host interactions
2021
[Taxonomy]: Hop stunt viroid (HSVd) is the type species of the genus Hostuviroid (family Pospiviroidae). The other species of this genus is Dahlia latent viroid, which presents an identical central conserved region (CCR) but lacks other structural hallmarks present in Hop stunt viroid. HSVd replication occurs in the nucleus through an asymmetric rolling-circle model as in the other members of the family Pospiviroidae, which also includes the genera Pospiviroid, Cocadviroid, Apscaviroid, and Coleoviroid.
Broad bean wilt virus 1 encoded VP47 and SCP are suppressors of plant post-transcriptional gene silencing
2020
Broad bean wilt virus 1 (BBWV-1, genus Fabavirus, family Secoviridae) is a bipartite positive single-stranded RNA (+ssRNA) virus infecting important horticultural and ornamental crops worldwide. RNA1 encodes proteins involved in virus replication, whereas RNA2 encodes the large and small coat proteins (LCP, and SCP, respectively) and two putative movement proteins with overlapping C-terminal but different sizes: 47.2 kDa (VP47) and 37 kDa (VP37). Post-transcriptional gene silencing (PTGS) is a mechanism of gene regulation and defense against pathogens such as viruses. However, most plant viruses encode proteins called viral suppressors of RNA silencing (VSRs) which able to inhibit PTGS. Pre…
Selection for Robustness in Mutagenized RNA Viruses
2007
Mutational robustness is defined as the constancy of a phenotype in the face of deleterious mutations. Whether robustness can be directly favored by natural selection remains controversial. Theory and in silico experiments predict that, at high mutation rates, slow-replicating genotypes can potentially outcompete faster counterparts if they benefit from a higher robustness. Here, we experimentally validate this hypothesis, dubbed the ‘‘survival of the flattest,’’ using two populations of the vesicular stomatitis RNA virus. Characterization of fitness distributions and genetic variability indicated that one population showed a higher replication rate, whereas the other was more robust to mut…
Localization microscopy of DNA in situ using Vybrant(®) DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single m…
2016
Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant(®) DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of …
Lack of a peroxiredoxin suppresses the lethality of cells devoid of electron donors by channelling electrons to oxidized ribonucleotide reductase
2017
The thioredoxin and glutaredoxin pathways are responsible of recycling several enzymes which undergo intramolecular disulfide bond formation as part of their catalytic cycles such as the peroxide scavengers peroxiredoxins or the enzyme ribonucleotide reductase (RNR). RNR, the rate-limiting enzyme of deoxyribonucleotide synthesis, is an essential enzyme relying on these electron flow cascades for recycling. RNR is tightly regulated in a cell cycle-dependent manner at different levels, but little is known about the participation of electron donors in such regulation. Here, we show that cytosolic thioredoxins Trx1 and Trx3 are the primary electron donors for RNR in fission yeast. Unexpectedly,…
Collective Infection of Cells by Viral Aggregates Promotes Early Viral Proliferation and Reveals a Cellular-Level Allee Effect
2018
In addition to the conventional release of free, individual virions, virus dispersal can involve multi-virion assemblies that collectively infect cells. However, the implications of collective infection for viral fitness remain largely unexplored. Using vesicular stomatitis virus, here, we compare the fitness of free versus saliva-aggregated viral particles. We find that aggregation has a positive effect on early progeny production, conferring a fitness advantage relative to equal numbers of free particles in most cell types. The advantage of aggregation resides, at least partially, in increasing the cellular multiplicity of infection. In mouse embryonic fibroblasts, the per capita, short-t…
ICTV Virus Taxonomy Profile: Dicistroviridae
2017
Dicistroviridae is a family of small non-enveloped viruses with monopartite, linear, positive-sense RNA genomes of approximately 8–10 kb. Viruses of all classified species infect arthropod hosts, with some having devastating economic consequences, such as acute bee paralysis virus in domesticated honeybees and taura syndrome virus in shrimp farming. Conversely, the host specificity and other desirable traits exhibited by several members of this group make them potential natural enemies for intentional use against arthropod pests, such as triatoma virus against triatomine bugs that vector Chagas disease. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on…
High genetic stability of potato yellow mosaic Panama virus infecting tomato in Panama
2018
The relevant regions in Panama involved in commercial tomato production, including the Chiriqui, Veraguas, Herrera, Los Santos and Panama Oeste provinces, were surveyed for the distribution and genetic diversity of potato yellow mosaic Panama virus (PYMPV) in the growing seasons of 2011 and 2012. A total of 28 tomato plots were surveyed and 314 individual tomato plants were sampled. DNA was extracted from each plant for a subsequent rolling circle amplification (RCA) analysis, to confirm the presence of begomovirus infections. The samples displaying a positive RCA reaction were subsequently analysed by PCR with a specific primer pair to identify PYMPV. This virus was detected in samples col…
Cyclins B1, T1, and H differ in their molecular mode of interaction with cytomegalovirus protein kinase pUL97
2019
Human cytomegalovirus (HCMV) is a common β-herpesvirus causing life-long latent infections. HCMV replication interferes with cell cycle regulation in host cells because the HCMV-encoded cyclin-dependent kinase (CDK) ortholog pUL97 extensively phosphorylates the checkpoint regulator retinoblastoma protein. pUL97 also interacts with cyclins B1, T1, and H, and recent findings have strongly suggested that these interactions influence pUL97 substrate recognition. Interestingly, here we detected profound mechanistic differences among these pUL97-cyclin interactions. Our study revealed the following. (i) pUL97 interacts with cyclins B1 and H in a manner dependent on pUL97 activity and HCMV-specifi…
DNA Injury and Repair Systems
2018
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