scholarly journals Unique viruses that infect Archaea related to eukaryotes

2021 ◽  
Author(s):  
Ian M Rambo ◽  
Valerie De Anda ◽  
Marguerite V Langwig ◽  
Brett J Baker
Keyword(s):  
Transcriptional Regulation ◽  
Deep Sea ◽  
Structural Proteins ◽  
Genome Replication ◽  
Dna Viruses ◽  
Viral Genomes ◽  
Archaeal Viruses ◽  
Hydrothermal Sediments ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Globally Distributed

Asgard archaea are newly described microbes that are related to eukaryotes. Asgards are diverse and globally distributed, however, their viruses have not been described. Here we characterize seven viral genomes that infected Lokiarchaeota, Helarchaeota, and Thorarchaeota in deep-sea hydrothermal sediments. These viruses code for structural proteins similar to those in Caudovirales, as well as proteins distinct from those described in archaeal viruses. They also have genes common in eukaryotic nucleocytoplasmic large DNA viruses (NCLDVs), and are predicted to be capable of semi-autonomous genome replication, repair, epigenetic modifications, and transcriptional regulation. Moreover, Helarchaeota viruses may hijack host ubiquitin systems similar to eukaryotic viruses. This first glimpse of Asgard viruses reveals they have features of both prokaryotic and eukaryotic viruses, and provides insights into their roles in the ecology and evolution of these globally distributed microbes.

scholarly journals Unique viruses that infect Archaea related to eukaryotes

2021 ◽  
Author(s):  
Ian Rambo ◽  
Valerie De Anda ◽  
Marguerite Langwig ◽  
Brett Baker
Keyword(s):  
Deep Sea ◽  
Structural Proteins ◽  
Genome Replication ◽  
Dna Viruses ◽  
Viral Genomes ◽  
Double Stranded Dna ◽  
Archaeal Viruses ◽  
Hydrothermal Sediments ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Globally Distributed

Abstract Asgard archaea are globally distributed, newly described microbes related to eukaryotes. Despite their importance, Asgard viruses have not been described. Here we characterize seven double-stranded DNA (dsDNA) viral genomes that infected Lokiarchaeota, Helarchaeota, and Thorarchaeota in deep-sea hydrothermal sediments. These viruses code for Caudovirales-like structural proteins, as well as proteins distinct from those described in archaeal viruses. They contain genes common in eukaryotic nucleocytoplasmic large DNA viruses (NCLDVs), and appear to be capable of semi-autonomous genome replication, repair, epigenetic modifications, and transcriptional regulation. Moreover, Helarchaeota viruses may hijack host ubiquitin systems similar to eukaryotic viruses. Recovery of these Asgard viral genomes reveals they contain features of both prokaryotic and eukaryotic viruses, and provides insights into their roles in the ecology and evolution of their hosts.

scholarly journals Hitchhiking of Viral Genomes on Cellular Chromosomes

2019 ◽  
Vol 6 (1) ◽  
pp. 275-296 ◽  
Author(s):  
Tami L. Coursey ◽  
Alison A. McBride
Keyword(s):  
Viral Genome ◽  
Viral Infections ◽  
Genome Replication ◽  
Mitotic Chromosomes ◽  
Dna Viruses ◽  
Viral Genomes ◽  
Barr Virus ◽  
Dividing Cells ◽  
Viral Genome Replication ◽  
Epstein Barr

Persistent viral infections require a host cell reservoir that maintains functional copies of the viral genome. To this end, several DNA viruses maintain their genomes as extrachromosomal DNA minichromosomes in actively dividing cells. These viruses typically encode a viral protein that binds specifically to viral DNA genomes and tethers them to host mitotic chromosomes, thus enabling the viral genomes to hitchhike or piggyback into daughter cells. Viruses that use this tethering mechanism include papillomaviruses and the gammaherpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. This review describes the advantages and consequences of persistent extrachromosomal viral genome replication.

scholarly journals Virus Genomes from Deep Sea Sediments Expand the Ocean Megavirome and Support Independent Origins of Viral Gigantism

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Disa Bäckström ◽  
Natalya Yutin ◽  
Steffen L. Jørgensen ◽  
Jennah Dharamshi ◽  
Felix Homa ◽  
...  
Keyword(s):  
Deep Sea ◽  
Genomic Diversity ◽  
Genome Comparison ◽  
Phylogenomic Analysis ◽  
Dna Viruses ◽  
Deep Sea Sediments ◽  
Giant Viruses ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Loki’S Castle ◽  
Virus Genomes

ABSTRACT The nucleocytoplasmic large DNA viruses (NCLDV) of eukaryotes (proposed order, “Megavirales”) include the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Marseilleviridae, and Mimiviridae, as well as still unclassified pithoviruses, pandoraviruses, molliviruses, and faustoviruses. Several of these virus groups include giant viruses, with genome and particle sizes exceeding those of many bacterial and archaeal cells. We explored the diversity of the NCLDV in deep sea sediments from the Loki’s Castle hydrothermal vent area. Using metagenomics, we reconstructed 23 high-quality genomic bins of novel NCLDV, 15 of which are related to pithoviruses, 5 to marseilleviruses, 1 to iridoviruses, and 2 to klosneuviruses. Some of the identified pithovirus-like and marseillevirus-like genomes belong to deep branches in the phylogenetic tree of core NCLDV genes, substantially expanding the diversity and phylogenetic depth of the respective groups. The discovered viruses, including putative giant members of the family Marseilleviridae, have a broad range of apparent genome sizes, in agreement with the multiple, independent origins of gigantism in different branches of the NCLDV. Phylogenomic analysis reaffirms the monophyly of the pithovirus-iridovirus-marseillevirus branch of the NCLDV. Similarly to other giant viruses, the pithovirus-like viruses from Loki’s Castle encode translation systems components. Phylogenetic analysis of these genes indicates a greater bacterial contribution than had been detected previously. Genome comparison suggests extensive gene exchange between members of the pithovirus-like viruses and Mimiviridae. Further exploration of the genomic diversity of Megavirales in additional sediment samples is expected to yield new insights into the evolution of giant viruses and the composition of the ocean megavirome. IMPORTANCE Genomics and evolution of giant viruses are two of the most vigorously developing areas of virus research. Lately, metagenomics has become the main source of new virus genomes. Here we describe a metagenomic analysis of the genomes of large and giant viruses from deep sea sediments. The assembled new virus genomes substantially expand the known diversity of the nucleocytoplasmic large DNA viruses of eukaryotes. The results support the concept of independent evolution of giant viruses from smaller ancestors in different virus branches.

scholarly journals Pleomorphic archaeal viruses: the family Pleolipoviridae is expanding by seven new species

2020 ◽  
Vol 165 (11) ◽  
pp. 2723-2731 ◽  
Author(s):  
Tatiana A. Demina ◽  
Hanna M. Oksanen
Keyword(s):  
New Species ◽  
Membrane Vesicles ◽  
Virus Species ◽  
Virus Taxonomy ◽  
Dna Viruses ◽  
Dna Molecule ◽  
Double Stranded Dna ◽  
Archaeal Viruses ◽  
The Family ◽  
Globally Distributed

AbstractEstablished in 2016, the family Pleolipoviridae comprises globally distributed archaeal viruses that produce pleomorphic particles. Pseudo-spherical enveloped virions of pleolipoviruses are membrane vesicles carrying a nucleic acid cargo. The cargo can be either a single-stranded or double-stranded DNA molecule, making this group the first family introduced in the 10th Report on Virus Taxonomy including both single-stranded and double-stranded DNA viruses. The length of the genomes is approximately 7–17 kilobase pairs, or kilonucleotides in the case of single-stranded molecules. The genomes are circular single-stranded DNA, circular double-stranded DNA, or linear double-stranded DNA molecules. Currently, eight virus species and seven proposed species are classified in three genera: Alphapleolipovirus (five species), Betapleolipovirus (nine species), and Gammapleolipovirus (one species). Here, we summarize the updated taxonomy of the family Pleolipoviridae to reflect recent advances in this field, with the focus on seven newly proposed species in the genus Betapleolipovirus: Betapleolipovirus HHPV3, HHPV4, HRPV9, HRPV10, HRPV11, HRPV12, and SNJ2.

scholarly journals Identification of an l-Rhamnose Synthetic Pathway in Two Nucleocytoplasmic Large DNA Viruses

2010 ◽  
Vol 84 (17) ◽  
pp. 8829-8838 ◽  
Author(s):  
Madhu Parakkottil Chothi ◽  
Garry A. Duncan ◽  
Andrea Armirotti ◽  
Chantal Abergel ◽  
James R. Gurnon ◽  
...  
Keyword(s):  
Posttranslational Modification ◽  
Structural Proteins ◽  
Acanthamoeba Polyphaga ◽  
Dna Viruses ◽  
Green Algal ◽  
Late Genes ◽  
Reductase Gene ◽  
Algal Host ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Additional Support

ABSTRACT Nucleocytoplasmic large DNA viruses (NCLDVs) are characterized by large genomes that often encode proteins not commonly found in viruses. Two species in this group are Acanthocystis turfacea chlorella virus 1 (ATCV-1) (family Phycodnaviridae, genus Chlorovirus) and Acanthamoeba polyphaga mimivirus (family Mimiviridae), commonly known as mimivirus. ATCV-1 and other chlorovirus members encode enzymes involved in the synthesis and glycosylation of their structural proteins. In this study, we identified and characterized three enzymes responsible for the synthesis of the sugar l-rhamnose: two UDP-d-glucose 4,6-dehydratases (UGDs) encoded by ATCV-1 and mimivirus and a bifunctional UDP-4-keto-6-deoxy-d-glucose epimerase/reductase (UGER) from mimivirus. Phylogenetic analysis indicated that ATCV-1 probably acquired its UGD gene via a recent horizontal gene transfer (HGT) from a green algal host, while an earlier HGT event involving the complete pathway (UGD and UGER) probably occurred between a protozoan ancestor and mimivirus. While ATCV-1 lacks an epimerase/reductase gene, its Chlorella host may encode this enzyme. Both UGDs and UGER are expressed as late genes, which is consistent with their role in posttranslational modification of capsid proteins. The data in this study provide additional support for the hypothesis that chloroviruses, and maybe mimivirus, encode most, if not all, of the glycosylation machinery involved in the synthesis of specific glycan structures essential for virus replication and infection.

scholarly journals Comparative Analysis of Transcriptional Regulation Patterns: Understanding the Gene Expression Profile in Nucleocytoviricota

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 935
Author(s):  
Fernanda Gil de Souza ◽  
Jônatas Santos Abrahão ◽  
Rodrigo Araújo Lima Rodrigues
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Evolutionary History ◽  
Dna Viruses ◽  
Lack Of Information ◽  
Multiplication Cycle ◽  
Giant Viruses ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Transcriptional Process ◽  
Evolutionary Aspects

The nucleocytoplasmic large DNA viruses (NCLDV) possess unique characteristics that have drawn the attention of the scientific community, and they are now classified in the phylum Nucleocytoviricota. They are characterized by sharing many genes and have their own transcriptional apparatus, which provides certain independence from their host’s machinery. Thus, the presence of a robust transcriptional apparatus has raised much discussion about the evolutionary aspects of these viruses and their genomes. Understanding the transcriptional process in NCLDV would provide information regarding their evolutionary history and a better comprehension of the biology of these viruses and their interaction with hosts. In this work, we reviewed NCLDV transcription and performed a comparative functional analysis of the groups of genes expressed at different times of infection of representatives of six different viral families of giant viruses. With this analysis, it was possible to observe a temporal profile of their gene expression and set of genes activated in specific phases throughout the multiplication cycle as a common characteristic of this group. Due to the lack of information regarding the transcriptional regulation process of this group of pathogens, we sought to provide information that contributes to and opens up the field for transcriptional studies of other viruses belonging to Nucleocytoviricota.

scholarly journals Virus genomes from deep sea sediments expand the ocean megavirome and support independent origins of viral gigantism

2018 ◽  
Author(s):  
Disa Bäckström ◽  
Natalya Yutin ◽  
Steffen L. Jørgensen ◽  
Jennah Dharamshi ◽  
Felix Homa ◽  
...  
Keyword(s):  
Deep Sea ◽  
Genomic Diversity ◽  
Genome Comparison ◽  
Phylogenomic Analysis ◽  
Dna Viruses ◽  
Deep Sea Sediments ◽  
Giant Viruses ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Loki’S Castle ◽  
Virus Genomes

AbstractThe Nucleocytoplasmic Large DNA Viruses (NCLDV) of eukaryotes (proposed order ”Megavirales”) include the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Marseilleviridae, and Mimiviridae, as well as still unclassified Pithoviruses, Pandoraviruses, Molliviruses and Faustoviruses. Several of these virus groups include giant viruses, with genome and particle sizes exceeding those of many bacterial and archaeal cells. We explored the diversity of the NCLDV in deep-sea sediments from the Loki’s Castle hydrothermal vent area. Using metagenomics, we reconstructed 23 high quality genomic bins of novel NCLDV, 15 of which are closest related to Pithoviruses, 5 to Marseilleviruses, 1 to Iridoviruses, and 2 to Klosneuviruses. Some of the identified Pitho-like and Marseille-like genomes belong to deep branches in the phylogenetic tree of core NCLDV genes, substantially expanding the diversity and phylogenetic depth of the respective groups. The discovered viruses have a broad range of apparent genome sizes including putative giant members of the family Marseilleviridae, in agreement with multiple, independent origins of gigantism in different branches of the NCLDV. Phylogenomic analysis reaffirms the monophyly of the Pitho-Irido-Marseille branch of NCLDV. Similarly to other giant viruses, the Pitho-like viruses from Loki’s Castle encode translation systems components. Phylogenetic analysis of these genes indicates a greater bacterial contribution than detected previously. Genome comparison suggests extensive gene exchange between members of the Pitho-like viruses and Mimiviridae. Further exploration of the genomic diversity of “Megavirales” in additional sediment samples is expected to yield new insights into the evolution of giant viruses and the composition of the ocean megavirome.ImportanceGenomics and evolution of giant viruses is one of the most vigorously developing areas of virus research. Lately, metagenomics has become the main source of new virus genomes. Here we describe a metagenomic analysis of the genomes of large and giant viruses from deep sea sediments. The assembled new virus genomes substantially expand the known diveristy of the Nucleo-Cytoplasmic Large DNA Viruses of eukaryotes. The results support the concept of independent evolution of giant viruses from smaller ancestors in different virus branches.

scholarly journals vConTACT: an iVirus tool to classify double-stranded DNA viruses that infectArchaeaandBacteria

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3243 ◽  
Author(s):  
Benjamin Bolduc ◽  
Ho Bin Jang ◽  
Guilhem Doulcier ◽  
Zhi-Qiang You ◽  
Simon Roux ◽  
...  
Keyword(s):  
Sequence Space ◽  
Dna Viruses ◽  
Viral Genomes ◽  
Double Stranded Dna ◽  
Microbial Ecosystems ◽  
Archaeal Viruses ◽  
Predictive Understanding ◽  
Taxonomic Assignments ◽  
User Friendly

Taxonomic classification of archaeal and bacterial viruses is challenging, yet also fundamental for developing a predictive understanding of microbial ecosystems. Recent identification of hundreds of thousands of new viral genomes and genome fragments, whose hosts remain unknown, requires a paradigm shift away from traditional classification approaches and towards the use of genomes for taxonomy. Here we revisited the use of genomes and their protein content as a means for developing a viral taxonomy for bacterial and archaeal viruses. A network-based analytic was evaluated and benchmarked against authority-accepted taxonomic assignments and found to be largely concordant. Exceptions were manually examined and found to represent areas of viral genome ‘sequence space’ that are under-sampled or prone to excessive genetic exchange. While both cases are poorly resolved by genome-based taxonomic approaches, the former will improve as viral sequence space is better sampled and the latter are uncommon. Finally, given the largely robust taxonomic capabilities of this approach, we sought to enable researchers to easily and systematically classify new viruses. Thus, we established a tool, vConTACT, as an app at iVirus, where it operates as a fast, highly scalable, user-friendly app within the free and powerful CyVerse cyberinfrastructure.

scholarly journals Latest Advances of Virology Research Using CRISPR/Cas9-Based Gene-Editing Technology and Its Application to Vaccine Development

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 779
Author(s):  
Man Teng ◽  
Yongxiu Yao ◽  
Venugopal Nair ◽  
Jun Luo
Keyword(s):  
Biological Sciences ◽  
Gene Therapy ◽  
Genetic Engineering ◽  
Gene Function ◽  
Viral Genome ◽  
Gene Editing ◽  
Vaccine Development ◽  
Future Prospects ◽  
Dna Viruses ◽  
Viral Genomes

In recent years, the CRISPR/Cas9-based gene-editing techniques have been well developed and applied widely in several aspects of research in the biological sciences, in many species, including humans, animals, plants, and even in viruses. Modification of the viral genome is crucial for revealing gene function, virus pathogenesis, gene therapy, genetic engineering, and vaccine development. Herein, we have provided a brief review of the different technologies for the modification of the viral genomes. Particularly, we have focused on the recently developed CRISPR/Cas9-based gene-editing system, detailing its origin, functional principles, and touching on its latest achievements in virology research and applications in vaccine development, especially in large DNA viruses of humans and animals. Future prospects of CRISPR/Cas9-based gene-editing technology in virology research, including the potential shortcomings, are also discussed.

scholarly journals Effects of Temperature and Pressure on Sulfate Reduction and Anaerobic Oxidation of Methane in Hydrothermal Sediments of Guaymas Basin

2004 ◽  
Vol 70 (2) ◽  
pp. 1231-1233 ◽  
Author(s):  
Jens Kallmeyer ◽  
Antje Boetius
Keyword(s):  
Sulfate Reduction ◽  
Deep Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Guaymas Basin ◽  
Oxidation Of Methane ◽  
Hydrothermal Sediments ◽  
Deep Sea Sediments ◽  
Effects Of Temperature ◽  
Temperature And Pressure

ABSTRACT Rates of sulfate reduction (SR) and anaerobic oxidation of methane (AOM) in hydrothermal deep-sea sediments from Guaymas Basin were measured at temperatures of 5 to 200°C and pressures of 1 × 105, 2.2 × 107, and 4.5 × 107 Pa. A maximum SR of several micromoles per cubic centimeter per day was found at between 60 and 95°C and 2.2 × 107 and 4.5 × 107 Pa. Maximal AOM was observed at 35 to 90°C but generally accounted for less than 5% of SR.

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