scholarly journals Origin and Evolution of Eukaryotic Large Nucleo-Cytoplasmic DNA Viruses

Intervirology ◽  
2010 ◽  
Vol 53 (5) ◽  
pp. 284-292 ◽  
Author(s):  
Eugene V. Koonin ◽  
Natalya Yutin
Keyword(s):  
Dna Viruses ◽  
Origin And Evolution ◽  
Cytoplasmic Dna Viruses ◽  
Cytoplasmic Dna

scholarly journals Aggresomes Resemble Sites Specialized for Virus Assembly

2001 ◽  
Vol 153 (3) ◽  
pp. 449-456 ◽  
Author(s):  
Colin M. Heath ◽  
Miriam Windsor ◽  
Thomas Wileman
Keyword(s):  
Cellular Response ◽  
Virus Assembly ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Microtubule Organizing Center ◽  
Dna Viruses ◽  
Cytoplasmic Dna Viruses ◽  
Cell Biol ◽  
Cytoplasmic Dna ◽  
Organizing Center

The large cytoplasmic DNA viruses such as poxviruses, iridoviruses, and African swine fever virus (ASFV) assemble in discrete perinuclear foci called viral factories. Factories exclude host proteins, suggesting that they are novel subcellular structures induced by viruses. Novel perinuclear structures, called aggresomes are also formed by cells in response to misfolded protein (Johnston, J.A., C.L. Ward, and R.R. Kopito. 1998. J. Cell Biol. 143:1883–1898; García-Mata, R., Z. Bebök, E.J. Sorscher, and E.S. Sztul. 1999. J. Cell Biol. 146:1239–1254). In this study, we have investigated whether aggresomes and viral factories are related structures. Aggresomes were compared with viral factories produced by ASFV. Aggresomes and viral factories were located close to the microtubule organizing center and required an intact microtubular network for assembly. Both structures caused rearrangement of intermediate filaments and the collapse of vimentin into characteristic cages, and both recruited mitochondria and cellular chaperones. Given that ASFV factories resemble aggresomes, it is possible that a cellular response originally designed to reduce the toxicity of misfolded proteins is exploited by cytoplasmic DNA viruses to concentrate structural proteins at virus assembly sites.

scholarly journals Phylogeny of the Varidnaviria Morphogenesis Module: Congruence and Incongruence With the Tree of Life and Viral Taxonomy

2021 ◽  
Vol 12 ◽  
Author(s):  
Anthony C. Woo ◽  
Morgan Gaia ◽  
Julien Guglielmini ◽  
Violette Da Cunha ◽  
Patrick Forterre
Keyword(s):  
Evolutionary History ◽  
International Committee ◽  
Tree Of Life ◽  
Dna Viruses ◽  
Origin And Evolution ◽  
Double Stranded Dna ◽  
Domains Of Life ◽  
History Of ◽  
Recent Classification ◽  
Jelly Roll

Double-stranded DNA viruses of the realm Varidnaviria (formerly PRD1-adenovirus lineage) are characterized by homologous major capsid proteins (MCPs) containing one (kingdom: Helvetiavirae) or two β-barrel domains (kingdom: Bamfordvirae) known as the jelly roll folds. Most of them also share homologous packaging ATPases (pATPases). Remarkably, Varidnaviria infect hosts from the three domains of life, suggesting that these viruses could be very ancient and share a common ancestor. Here, we analyzed the evolutionary history of Varidnaviria based on single and concatenated phylogenies of their MCPs and pATPases. We excluded Adenoviridae from our analysis as their MCPs and pATPases are too divergent. Sphaerolipoviridae, the only family in the kingdom Helvetiavirae, exhibit a complex history: their MCPs are very divergent from those of other Varidnaviria, as expected, but their pATPases groups them with Bamfordvirae. In single and concatenated trees, Bamfordvirae infecting archaea were grouped with those infecting bacteria, in contradiction with the cellular tree of life, whereas those infecting eukaryotes were organized into three monophyletic groups: the Nucleocytoviricota phylum, formerly known as the Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs), Lavidaviridae (virophages) and Polintoviruses. Although our analysis mostly supports the recent classification proposed by the International Committee on Taxonomy of Viruses (ICTV), it also raises questions, such as the validity of the Adenoviridae and Helvetiavirae ranking. Based on our phylogeny, we discuss current hypotheses on the origin and evolution of Varidnaviria and suggest new ones to reconcile the viral and cellular trees.

scholarly journals Yaravirus: A novel 80-nm virus infectingAcanthamoeba castellanii

2020 ◽  
Vol 117 (28) ◽  
pp. 16579-16586 ◽  
Author(s):  
Paulo V. M. Boratto ◽  
Graziele P. Oliveira ◽  
Talita B. Machado ◽  
Ana Cláudia S. P. Andrade ◽  
Jean-Pierre Baudoin ◽  
...  
Keyword(s):  
Major Capsid Protein ◽  
Amino Acid Level ◽  
Three Dimensional ◽  
Genomic Diversity ◽  
Phylogenetic Distance ◽  
Preliminary Assessment ◽  
Dna Viruses ◽  
Origin And Evolution ◽  
Viral Genomes ◽  
Jelly Roll

Here we report the discovery of Yaravirus, a lineage of amoebal virus with a puzzling origin and evolution. Yaravirus presents 80-nm-sized particles and a 44,924-bp dsDNA genome encoding for 74 predicted proteins. Yaravirus genome annotation showed that none of its genes matched with sequences of known organisms at the nucleotide level; at the amino acid level, six predicted proteins had distant matches in the nr database. Complimentary prediction of three-dimensional structures indicated possible function of 17 proteins in total. Furthermore, we were not able to retrieve viral genomes closely related to Yaravirus in 8,535 publicly available metagenomes spanning diverse habitats around the globe. The Yaravirus genome also contained six types of tRNAs that did not match commonly used codons. Proteomics revealed that Yaravirus particles contain 26 viral proteins, one of which potentially representing a divergent major capsid protein (MCP) with a predicted double jelly-roll domain. Structure-guided phylogeny of MCP suggests that Yaravirus groups together with the MCPs ofPleurochrysisendemic viruses. Yaravirus expands our knowledge of the diversity of DNA viruses. The phylogenetic distance between Yaravirus and all other viruses highlights our still preliminary assessment of the genomic diversity of eukaryotic viruses, reinforcing the need for the isolation of new viruses of protists.

scholarly journals DNA-PK is a DNA sensor for IRF-3-dependent innate immunity

eLife ◽  
2012 ◽  
Vol 1 ◽  
Author(s):  
Brian J Ferguson ◽  
Daniel S Mansur ◽  
Nicholas E Peters ◽  
Hongwei Ren ◽  
Geoffrey L Smith
Keyword(s):  
Innate Immunity ◽  
Virus Infection ◽  
Vaccine Development ◽  
Rna Virus ◽  
Severe Combined Immunodeficiency ◽  
Type I ◽  
Dna Sensor ◽  
Dna Viruses ◽  
Cytoplasmic Dna ◽  
Dependent Protein

Innate immunity is the first immunological defence against pathogens. During virus infection detection of nucleic acids is crucial for the inflammatory response. Here we identify DNA-dependent protein kinase (DNA-PK) as a DNA sensor that activates innate immunity. We show that DNA-PK acts as a pattern recognition receptor, binding cytoplasmic DNA and triggering the transcription of type I interferon (IFN), cytokine and chemokine genes in a manner dependent on IFN regulatory factor 3 (IRF-3), TANK-binding kinase 1 (TBK1) and stimulator of interferon genes (STING). Both cells and mice lacking DNA-PKcs show attenuated cytokine responses to both DNA and DNA viruses but not to RNA or RNA virus infection. DNA-PK has well-established functions in the DNA repair and V(D)J recombination, hence loss of DNA-PK leads to severe combined immunodeficiency (SCID). However, we now define a novel anti-microbial function for DNA-PK, a finding with implications for host defence, vaccine development and autoimmunity.

scholarly journals Genomic Sequence of Spodoptera frugiperda Ascovirus 1a, an Enveloped, Double-Stranded DNA Insect Virus That Manipulates Apoptosis for Viral Reproduction

2006 ◽  
Vol 80 (23) ◽  
pp. 11791-11805 ◽  
Author(s):  
Dennis K. Bideshi ◽  
Marie-Véronique Demattei ◽  
Florence Rouleux-Bonnin ◽  
Karine Stasiak ◽  
Yeping Tan ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Genomic Sequence ◽  
Open Reading Frames ◽  
The Novel ◽  
Fatty Acid Elongase ◽  
Dna Viruses ◽  
Origin And Evolution ◽  
Iridescent Virus ◽  
Double Stranded Dna ◽  
New Hosts

ABSTRACT Ascoviruses (family Ascoviridae) are double-stranded DNA viruses with circular genomes that attack lepidopterans, where they produce large, enveloped virions, 150 by 400 nm, and cause a chronic, fatal disease with a cytopathology resembling that of apoptosis. After infection, host cell DNA is degraded, the nucleus fragments, and the cell then cleaves into large virion-containing vesicles. These vesicles and virions circulate in the hemolymph, where they are acquired by parasitic wasps during oviposition and subsequently transmitted to new hosts. To develop a better understanding of ascovirus biology, we sequenced the genome of the type species Spodoptera frugiperda ascovirus 1a (SfAV-1a). The genome consisted of 156,922 bp, with a G+C ratio of 49.2%, and contained 123 putative open reading frames coding for a variety of enzymes and virion structural proteins, of which tentative functions were assigned to 44. Among the most interesting enzymes, due to their potential role in apoptosis and viral vesicle formation, were a caspase, a cathepsin B, several kinases, E3 ubiquitin ligases, and especially several enzymes involved in lipid metabolism, including a fatty acid elongase, a sphingomyelinase, a phosphate acyltransferase, and a patatin-like phospholipase. Comparison of SfAV-1a proteins with those of other viruses showed that 10% were orthologs of Chilo iridescent virus proteins, the highest correspondence with any virus, providing further evidence that ascoviruses evolved from a lepidopteran iridovirus. The SfAV-1a genome sequence will facilitate the determination of how ascoviruses manipulate apoptosis to generate the novel virion-containing vesicles characteristic of these viruses and enable study of their origin and evolution.

scholarly journals The genomes of nucleocytoplasmic large DNA viruses: viral evolution writ large

2021 ◽  
Vol 7 (9) ◽  
Author(s):  
Heli A. M. Mönttinen ◽  
Cedric Bicep ◽  
Tom A. Williams ◽  
Robert P. Hirt
Keyword(s):  
De Novo ◽  
Viral Evolution ◽  
Gene Duplications ◽  
Protein Coding ◽  
Dna Viruses ◽  
Genomic Plasticity ◽  
Origin And Evolution ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Coding Capacity ◽  
Capacity Characteristic

The nucleocytoplasmic large DNA viruses (NCLDVs) are a diverse group that currently contain the largest known virions and genomes, also called giant viruses. The first giant virus was isolated and described nearly 20 years ago. Their genome sizes were larger than for any other known virus at the time and it contained a number of genes that had not been previously described in any virus. The origin and evolution of these unusually complex viruses has been puzzling, and various mechanisms have been put forward to explain how some NCLDVs could have reached genome sizes and coding capacity overlapping with those of cellular microbes. Here we critically discuss the evidence and arguments on this topic. We have also updated and systematically reanalysed protein families of the NCLDVs to further study their origin and evolution. Our analyses further highlight the small number of widely shared genes and extreme genomic plasticity among NCLDVs that are shaped via combinations of gene duplications, deletions, lateral gene transfers and de novo creation of protein-coding genes. The dramatic expansions of the genome size and protein-coding gene capacity characteristic of some NCLDVs is now increasingly understood to be driven by environmental factors rather than reflecting relationships to an ancient common ancestor among a hypothetical cellular lineage. Thus, the evolution of NCLDVs is writ large viral, and their origin, like all other viral lineages, remains unknown.

Electron microscopy of endocardial cell populations

1978 ◽  
Vol 36 (2) ◽  
pp. 486-487
Author(s):  
T. G. Sarphie ◽  
C. R. Comer ◽  
D. J. Allen
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Cellular Transformation ◽  
Cell Populations ◽  
Cell Surfaces ◽  
Kb Cells ◽  
Dna Viruses ◽  
Cell Cycles ◽  
Ultrastructural Studies ◽  
Endocardial Cell

Previous ultrastructural studies have characterized surface morphology during norma cell cycles in an attempt to associate specific changes with specific metabolic processes occurring within the cell. It is now known that during the synthetic ("S") stage of the cycle, when DNA and other nuclear components are synthesized, a cel undergoes a doubling in volume that is accompanied by an increase in surface area whereby its plasma membrane is elaborated into a variety of processes originally referred to as microvilli. In addition, changes in the normal distribution of glycoproteins and polysaccharides derived from cell surfaces have been reported as depreciating after cellular transformation by RNA or DNA viruses and have been associated with the state of growth, irregardless of the rate of proliferation. More specifically, examination of the surface carbohydrate content of synchronous KB cells were shown to be markedly reduced as the cell population approached division Comparison of hamster kidney fibroblasts inhibited by vinblastin sulfate while in metaphase with those not in metaphase demonstrated an appreciable decrease in surface carbohydrate in the former.

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