Pandoraviridae

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Pandoraviridae
Pandoravirus virion.jpg
Pandoravirus virion
Virus classification
Group:
Group I (dsDNA)
Order:
Family:
Pandoraviridae
Genus:

Pandoraviridae is a proposed family of double-stranded DNA viruses that infect amoebae. There is only one genus in this family: Pandoravirus . Several species in this genus have been described, including Pandoravirus dulcis , Pandoravirus salinus and Pandoravirus yedoma . [1] [2]

Contents

History

The viruses were discovered in 2013. [1] [2]

Description

The viruses in this family are the second largest known virus (~1 micrometer) in capsid length, after Pithovirus (1.5 micrometer). [3] Pandoravirus has the largest viral genome known, containing double-stranded DNA of 1.9 to 2.5 megabase pairs. [4] [1]

Evolution

These viruses appear to be related to the phycodnaviruses. [5]

Related Research Articles

<span class="mw-page-title-main">DNA virus</span> Virus that has DNA as its genetic material

A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and those that have one strand of DNA in their genome, called single-stranded DNA (ssDNA) viruses. dsDNA viruses primarily belong to two realms: Duplodnaviria and Varidnaviria, and ssDNA viruses are almost exclusively assigned to the realm Monodnaviria, which also includes some dsDNA viruses. Additionally, many DNA viruses are unassigned to higher taxa. Reverse transcribing viruses, which have a DNA genome that is replicated through an RNA intermediate by a reverse transcriptase, are classified into the kingdom Pararnavirae in the realm Riboviria.

<span class="mw-page-title-main">Genome</span> All genetic material of an organism

In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA. The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences, and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplasts with a chloroplast genome.

<span class="mw-page-title-main">RNA virus</span> Subclass of viruses

An RNA virus is a virus—other than a retrovirus—that has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA (ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses include the common cold, influenza, SARS, MERS, COVID-19, Dengue virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles.

<span class="mw-page-title-main">Reverse transcriptase</span> Enzyme which generates DNA

A reverse transcriptase (RT) is an enzyme used to convert RNA genome to DNA, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. Contrary to a widely held belief, the process does not violate the flows of genetic information as described by the classical central dogma, as transfers of information from RNA to DNA are explicitly held possible.

<i>Mimivirus</i> Genus of viruses

Mimivirus is a genus of giant viruses, in the family Mimiviridae. Amoeba serve as their natural hosts. This genus contains a single identified species named Acanthamoeba polyphaga mimivirus (APMV). It also refers to a group of phylogenetically related large viruses.

<i>Poxviridae</i> Family of viruses

Poxviridae is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. There are currently 83 species in this family, divided among 22 genera, which are divided into two subfamilies. Diseases associated with this family include smallpox.

<span class="mw-page-title-main">Virophage</span> Viral parasites of giant viruses

Virophages are small, double-stranded DNA viral phages that require the co-infection of another virus. The co-infecting viruses are typically giant viruses. Virophages rely on the viral replication factory of the co-infecting giant virus for their own replication. One of the characteristics of virophages is that they have a parasitic relationship with the co-infecting virus. Their dependence upon the giant virus for replication often results in the deactivation of the giant viruses. The virophage may improve the recovery and survival of the host organism.

<span class="mw-page-title-main">Virus</span> Infectious agent that replicates in cells

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 11,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology.

<span class="mw-page-title-main">Largest organisms</span> List of largest organisms on Earth

This article lists the largest organisms for various types of life and mostly considers extant species, which found on Earth can be determined according to various aspects of an organism's size, such as: mass, volume, area, length, height, or even genome size. Some organisms group together to form a superorganism, but such are not classed as single large organisms. The Great Barrier Reef is the world's largest structure composed of living entities, stretching 2,000 km (1,200 mi) but contains many organisms of many types of species.

<span class="mw-page-title-main">Sputnik virophage</span> Subviral agent

Mimivirus-dependent virus Sputnik is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus. It is known as a virophage, in analogy to the term bacteriophage.

<i>Cafeteria roenbergensis virus</i> Species of virus

Cafeteria roenbergensis virus (CroV) is a giant virus that infects the marine bicosoecid flagellate Cafeteria roenbergensis, a member of the microzooplankton community.

A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum Nucleocytoviricota.

<i>Megavirus</i> Genus of viruses

Megavirus is a viral genus, phylogenetically related to Acanthamoeba polyphaga mimivirus (APMV). In colloquial speech, Megavirus chilensis is more commonly referred to as just "Megavirus". Until the discovery of pandoraviruses in 2013, it had the largest capsid diameter of all known viruses, as well as the largest and most complex genome among all known viruses.

<span class="mw-page-title-main">Mavirus</span> Genus of viruses

Mavirus is a genus of double stranded DNA virus that can infect the marine phagotrophic flagellate Cafeteria roenbergensis, but only in the presence of the giant CroV virus. The genus contains only one species, Cafeteriavirus-dependent mavirus. Mavirus can integrate into the genome of cells of C. roenbergensis, and thereby confer immunity to the population

<i>Pandoravirus</i> Genus of giant virus possessing a large double-stranded DNA genome

Pandoravirus is a proposed genus of giant virus, first discovered in 2013. It is the third largest in physical size of any known viral genus, behind Pithovirus and Megaklothovirus. Pandoraviruses have double stranded DNA genomes, with the largest genome size of any known viral genus.

<i>Alphapithovirus</i> Genus of viruses

Alphapithovirus, first described in a 2014 paper, is a genus of giant virus known from two species, Alphapithovirus sibericum, which infects amoebas and Alphapithovirus massiliense. It is a DNA based virus and is a member of the nucleocytoplasmic large DNA viruses clade. The 2014 discovery was made when a viable specimen was found in a 30,000-year-old ice core harvested from permafrost in Siberia, Russia.

Polintons are large DNA transposons which contain genes with homology to viral proteins and which are often found in eukaryotic genomes. They were first discovered in the mid-2000s and are the largest and most complex known DNA transposons. Polintons encode up to 10 individual proteins and derive their name from two key proteins, a DNA polymerase and a retroviral-like integrase.

<span class="mw-page-title-main">Marine viruses</span> Viruses found in marine environments

Marine viruses are defined by their habitat as viruses that are found in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Viruses are small infectious agents that can only replicate inside the living cells of a host organism, because they need the replication machinery of the host to do so. They can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.

Nucleocytoviricota is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix -viricota for virus phylum. These viruses are referred to as nucleocytoplasmic because they are often able to replicate in both the host's cell nucleus and cytoplasm.

Virosphere was coined to refer to all those places in which viruses are found or which are affected by viruses. However, more recently virosphere has also been used to refer to the pool of viruses that occurs in all hosts and all environments, as well as viruses associated with specific types of hosts, type of genome or ecological niche.

References

  1. 1 2 3 Yong, Ed (18 July 2013). "Giant viruses open Pandora's box". Nature. doi:10.1038/nature.2013.13410. S2CID   88440241.
  2. 1 2 Nadège Philippe; Matthieu Legendre; Gabriel Doutre; et al. (July 2013). "Pandoraviruses: Amoeba Viruses with Genomes Up to 2.5 Mb Reaching That of Parasitic Eukaryotes" (PDF). Science. 341 (6143): 281–6. Bibcode:2013Sci...341..281P. doi:10.1126/science.1239181. PMID   23869018. S2CID   16877147.
  3. Sirucek, Stefan (3 March 2014). "Ancient "Giant Virus" Revived From Siberian Permafrost". National Geographic. Archived from the original on 4 March 2014.
  4. Brumfiel, Geoff (18 July 2013). "World's Biggest Virus May Have Ancient Roots". National Public Radio. Retrieved 18 July 2013.
  5. Yutin N, Koonin EV (2013). "Pandoraviruses are highly derived phycodnaviruses". Biol. Direct. 8: 25. doi: 10.1186/1745-6150-8-25 . PMC   3924356 . PMID   24148757.