scholarly journals Capsid Structure of dsRNA Fungal Viruses

Viruses ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 481 ◽  
Author(s):  
Daniel Luque ◽  
Carlos Mata ◽  
Nobuhiro Suzuki ◽  
Said Ghabrial ◽  
José Castón
Keyword(s):  
Rna Synthesis ◽  
Life Cycle Stage ◽  
Rosellinia Necatrix ◽  
Structural Variations ◽  
Low Degree ◽  
Dsrna Viruses ◽  
Fungal Viruses ◽  
Penicillium Stoloniferum ◽  
Dsrna Mycovirus ◽  
Similar Domain

Most fungal, double-stranded (ds) RNA viruses lack an extracellular life cycle stage and are transmitted by cytoplasmic interchange. dsRNA mycovirus capsids are based on a 120-subunit T = 1 capsid, with a dimer as the asymmetric unit. These capsids, which remain structurally undisturbed throughout the viral cycle, nevertheless, are dynamic particles involved in the organization of the viral genome and the viral polymerase necessary for RNA synthesis. The atomic structure of the T = 1 capsids of four mycoviruses was resolved: the L-A virus of Saccharomyces cerevisiae (ScV-L-A), Penicillium chrysogenum virus (PcV), Penicillium stoloniferum virus F (PsV-F), and Rosellinia necatrix quadrivirus 1 (RnQV1). These capsids show structural variations of the same framework, with 60 asymmetric or symmetric homodimers for ScV-L-A and PsV-F, respectively, monomers with a duplicated similar domain for PcV, and heterodimers of two different proteins for RnQV1. Mycovirus capsid proteins (CP) share a conserved α-helical domain, although the latter may carry different peptides inserted at preferential hotspots. Insertions in the CP outer surface are likely associated with enzymatic activities. Within the capsid, fungal dsRNA viruses show a low degree of genome compaction compared to reoviruses, and contain one to two copies of the RNA-polymerase complex per virion.

scholarly journals Cultivation of a lytic double-stranded RNA bacteriophage infecting Microvirgula aerodenitrificans reveals a mutualistic parasitic lifestyle

2021 ◽  
Author(s):  
Xiaoyao Cai ◽  
Fengjuan Tian ◽  
Li Teng ◽  
Hongmei Liu ◽  
Yigang Tong ◽  
...  
Keyword(s):  
Double Layer ◽  
Sequence Similarity ◽  
Double Stranded Rna ◽  
Bacteria Growth ◽  
A Genome ◽  
Domains Of Life ◽  
Parasitic Lifestyle ◽  
Dsrna Viruses ◽  
Fungal Viruses ◽  
Classical Protocol

Bacteriophages are considered the most abundant entities on earth. However, there are merely seven sequenced double-stranded (ds)RNA phages compared with thousands of dsDNA phages. Interestingly, dsRNA viruses are quite common in fungi and usually have a lifestyle of commensalism or mutualism. Thus, the classical protocol of using double-layer agar plates to characterize phage plaques might be significantly biased in the isolation of dsRNA phages beyond strictly lytic lifestyles. Thus, we applied the protocol of isolating fungal viruses to identify RNA phages in bacteria and successfully isolated a novel dsRNA phage, phiNY, from Microvirgula aerodenitrificans . phiNY has a genome of three dsRNA segments, and its genome sequence has no nucleotide sequence similarity with any other phage. Although phiNY encodes a lytic protein of glycoside hydrolase and phage particles are consistently released during bacterial growth, phiNY replication did not block bacteria growth, nor did it form any plaque on agar plates. More strikingly, the phiNY-infected strain grew faster than the phiNY-negative strain, indicating a mutualistic parasitic lifestyle. Thus, this study not only reveals a new mutualistic parasitic dsRNA phage but also implies that other virus isolation methods would be valuable to identify phages with other lifestyles. Importance Viruses with dsRNA genomes are quite diverse and infect organisms in all three domains of life. Though dsRNA viruses infecting humans, plants and fungi are quite common, dsRNA viruses infecting bacteria, known as bacteriophages, are quite understudied and only seven dsRNA phages have been sequenced so far. One possible explanation for the rare isolation of dsRNA phages might be the protocols of double-layer agar plates assay. Phages beyond strictly lytic lifestyles might not form plaques. Thus, we applied the protocol of isolating fungal viruses to identify RNA phages inside bacteria and successfully isolated a novel dsRNA phage phiNY with a mutualistic parasitic lifestyle. This study implies dsRNA phages beyond strictly lytic lifestyle might be common in nature and deserves more investigations.

scholarly journals Heterodimers as the Structural Unit of the T=1 Capsid of the Fungal Double-Stranded RNA Rosellinia necatrix Quadrivirus 1

2016 ◽  
Vol 90 (24) ◽  
pp. 11220-11230 ◽  
Author(s):  
Daniel Luque ◽  
Carlos P. Mata ◽  
Fernando González-Camacho ◽  
José M. González ◽  
Josué Gómez-Blanco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Sieves ◽  
Three Dimensional ◽  
Rosellinia Necatrix ◽  
Double Stranded Rna ◽  
Content Type ◽  
Cryo Electron Microscopy ◽  
Wide Range ◽  
The Family ◽  
Dsrna Viruses

ABSTRACTMost double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts. Rosellinia necatrix quadrivirus 1 (RnQV1), the type species of the familyQuadriviridae, is a dsRNA fungal virus with a multipartite genome consisting of four monocistronic segments (segments 1 to 4). dsRNA-2 and dsRNA-4 encode two CPs (P2 and P4, respectively), which coassemble into ∼450-Å-diameter capsids. We used three-dimensional cryo-electron microscopy combined with complementary biophysical techniques to determine the structures of RnQV1 virion strains W1075 and W1118. RnQV1 has a quadripartite genome, and the capsid is based on a single-shelled T=1 lattice built of P2-P4 dimers. Whereas the RnQV1-W1118 capsid is built of full-length CP, P2 and P4 of RnQV1-W1075 are cleaved into several polypeptides, maintaining the capsid structural organization. RnQV1 heterodimers have a quaternary organization similar to that of homodimers of reoviruses and other dsRNA mycoviruses. The RnQV1 capsid is the first T=1 capsid with a heterodimer as an asymmetric unit reported to date and follows the architectural principle for dsRNA viruses that a 120-subunit capsid is a conserved assembly that supports dsRNA replication and organization.IMPORTANCEGiven their importance to health, members of the familyReoviridaeare the basis of most structural and functional studies and provide much of our knowledge of dsRNA viruses. Analysis of bacterial, protozoal, and fungal dsRNA viruses has improved our understanding of their structure, function, and evolution, as well. Here, we studied a dsRNA virus that infects the fungusRosellinia necatrix, an ascomycete that is pathogenic to a wide range of plants. Using three-dimensional cryo-electron microscopy and analytical ultracentrifugation analysis, we determined the structure and stoichiometry of Rosellinia necatrix quadrivirus 1 (RnQV1). The RnQV1 capsid is a T=1 capsid with 60 heterodimers as the asymmetric units. The large amount of genetic information used by RnQV1 to construct a simple T=1 capsid is probably related to the numerous virus-host and virus-virus interactions that it must face in its life cycle, which lacks an extracellular phase.

Novel, diverse RNA viruses from Mediterranean isolates of the phytopathogenic fungus,Rosellinia necatrix: insights into evolutionary biology of fungal viruses

2018 ◽  
Vol 20 (4) ◽  
pp. 1464-1483 ◽  
Author(s):  
Juan Manuel Arjona-Lopez ◽  
Paul Telengech ◽  
Atif Jamal ◽  
Sakae Hisano ◽  
Hideki Kondo ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Rna Viruses ◽  
Phytopathogenic Fungus ◽  
Rosellinia Necatrix ◽  
Fungal Viruses

scholarly journals Differential Inductions of RNA Silencing among Encapsidated Double-Stranded RNA Mycoviruses in the White Root Rot Fungus Rosellinia necatrix

2016 ◽  
Vol 90 (12) ◽  
pp. 5677-5692 ◽  
Author(s):  
Hajime Yaegashi ◽  
Takeo Shimizu ◽  
Tsutae Ito ◽  
Satoko Kanematsu
Keyword(s):  
Rna Silencing ◽  
Defense Mechanism ◽  
Fluorescent Protein ◽  
Constitutive Expression ◽  
Phytopathogenic Fungus ◽  
Rosellinia Necatrix ◽  
Double Stranded Rna ◽  
Content Type ◽  
Molecular Features ◽  
Fungal Viruses

ABSTRACTRNA silencing acts as a defense mechanism against virus infection in a wide variety of organisms. Here, we investigated inductions of RNA silencing against encapsidated double-stranded RNA (dsRNA) fungal viruses (mycoviruses), including a partitivirus (RnPV1), a quadrivirus (RnQV1), a victorivirus (RnVV1), a mycoreovirus (RnMyRV3), and a megabirnavirus (RnMBV1) in the phytopathogenic fungusRosellinia necatrix. Expression profiling of RNA silencing-related genes revealed that a dicer-like gene, an Argonaute-like gene, and two RNA-dependent RNA polymerase genes were upregulated by RnMyRV3 or RnMBV1 infection but not by other virus infections or by constitutive expression of dsRNA inR. necatrix. Massive analysis of viral small RNAs (vsRNAs) from the five mycoviruses showed that 19- to 22-nucleotide (nt) vsRNAs were predominant; however, their ability to form duplexes with 3′ overhangs and the 5′ nucleotide preferences of vsRNAs differed among the five mycoviruses. The abundances of 19- to 22-nt vsRNAs from RnPV1, RnQV1, RnVV1, RnMyRV3, and RnMBV1 were 6.8%, 1.2%, 0.3%, 13.0%, and 24.9%, respectively. Importantly, the vsRNA abundances and accumulation levels of viral RNA were not always correlated, and the origins of the vsRNAs were distinguishable among the five mycoviruses. These data corroborated diverse interactions between encapsidated dsRNA mycoviruses and RNA silencing. Moreover, a green fluorescent protein (GFP)-based sensor assay inR. necatrixrevealed that RnMBV1 infection induced silencing of the target sensor gene (GFP gene and the partial RnMBV1 sequence), suggesting that vsRNAs from RnMBV1 activated the RNA-induced silencing complex. Overall, this study provides insights into RNA silencing against encapsidated dsRNA mycoviruses.IMPORTANCEEncapsidated dsRNA fungal viruses (mycoviruses) are believed to replicate inside their virions; therefore, there is a question of whether they induce RNA silencing. Here, we investigated inductions of RNA silencing against encapsidated dsRNA mycoviruses (a partitivirus, a quadrivirus, a victorivirus, a mycoreovirus, and a megabirnavirus) inRosellinia necatrix. We revealed upregulation of RNA silencing-related genes inR. necatrixinfected with a mycoreovirus or a megabirnavirus but not with other viruses, which was consistent with the relatively high abundances of vsRNAs from the two mycoviruses. We also showed common and different molecular features and origins of the vsRNAs from the five mycoviruses. Furthermore, we demonstrated the activation of RNA-induced silencing complex by mycoviruses inR. necatrix. Taken together, our data provide insights into an RNA silencing pathway against encapsidated dsRNA mycoviruses which is differentially induced among encapsidated dsRNA mycoviruses; that is, diverse replication strategies exist among encapsidated dsRNA mycoviruses.

Replication of virus-like particles in Penicillium stoloniferum mycelia

1974 ◽  
Vol 20 (2) ◽  
pp. 113-117 ◽  
Author(s):  
R. W. Detroy ◽  
E. B. Lillehoj ◽  
C. W. Hesseltine
Keyword(s):  
Nucleic Acid ◽  
Rna Synthesis ◽  
Fungal Growth ◽  
Viral Rna ◽  
Direct Extraction ◽  
Viral Dsrna ◽  
Virus Like Particles ◽  
Absorption Determination ◽  
Penicillium Stoloniferum ◽  
Cellulose Column

Direct extraction of nucleic acid from mycelium of Penicillium stoloniferum yielded five viral double-stranded ribonucleic acid (dsRNA) components, transfer RNA (tRNA), and a deoxyribonuclease-sensitive fraction of deoxyribonucleic acid. Analysis of fungal cells from a submerged fermentation demonstrated detectable viral dsRNA and both types of virus-like particles (VLP) at 36 h with an increase in viral RNA synthesis for both VLP parallel to fungal growth up to 72 h followed by mycelial autolysis and loss of viral RNA. Replication of nucleic acid from VLP was measured by (i) incorporation of 14C-2-uracil into viral dsRNA, (ii) purification of viral dsRNA by cellulose column chromatography and subsequent ultraviolet absorption determination, and (iii) analysis of nucleic acid species by poly-acrylamide gel electrophoresis.

scholarly journals Comparison of Polymerase Subunits from Double-Stranded RNA Bacteriophages

2001 ◽  
Vol 75 (22) ◽  
pp. 11088-11095 ◽  
Author(s):  
Hongyan Yang ◽  
Eugene V. Makeyev ◽  
Dennis H. Bamford
Keyword(s):  
Molecular Basis ◽  
Rna Synthesis ◽  
Regulatory Mechanism ◽  
Biochemical Properties ◽  
Double Stranded Rna ◽  
The Family ◽  
Dsrna Viruses ◽  
Template Specificity

ABSTRACT The family Cystoviridae comprises several bacteriophages with double-stranded RNA (dsRNA) genomes. We have previously purified the catalytic polymerase subunit (Pol) of one of the Cystoviridae members, bacteriophage φ6, and shown that the protein can catalyze RNA synthesis in vitro. In this reaction, both bacteriophage-specific and heterologous RNAs can serve as templates, but those containing 3′ termini from the φ6 minus strands are favored. This provides a molecular basis for the observation that only plus strands, not minus strands, are transcribed from φ6 dsRNA segments in vivo. To test whether such a regulatory mechanism is also found in other dsRNA viruses, we purified recombinant Pol subunits from the φ6-related bacteriophages φ8 and φ13 and assayed their polymerase activities in vitro. The enzymes catalyze template-dependent RNA synthesis using both single-stranded-RNA (ssRNA) and dsRNA templates. However, they differ from each other as well as from φ6 Pol in certain biochemical properties. Notably, each polymerase demonstrates a distinct preference for ssRNAs bearing short 3′-terminal sequences from the virus-specific minus strands. This suggests that, in addition to other factors, RNA transcription inCystoviridae is controlled by the template specificity of the polymerase subunit.

Crystalloid Inclusions in Hepatocyte Mitochondria and Their Similarity to Cytoplasmic Crystalloids

1974 ◽  
Vol 32 ◽  
pp. 198-199
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Special Interest ◽  
Structural Variations ◽  
Mitochondrial Alterations ◽  
The Matrix ◽  
Crystalloid Inclusions ◽  
Liver Biopsies

Mitochondrial alterations were studied in 25 liver biopsies from patients with alcoholic liver disease. Of special interest were the morphologic resemblance of certain fine structural variations in mitochondria and crystalloid inclusions. Four types of alterations within mitochondria were found that seemed to relate to cytoplasmic crystalloids.Type 1 alteration consisted of localized groups of cristae, usually oriented in the long direction of the organelle (Fig. 1A). In this plane they appeared serrated at the periphery with blind endings in the matrix. Other sections revealed a system of equally-spaced diagonal lines lengthwise in the mitochondrion with cristae protruding from both ends (Fig. 1B). Profiles of this inclusion were not unlike tangential cuts of a crystalloid structure frequently seen in enlarged mitochondria described below.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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