Bodo saltans virus

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"Bodo saltans virus"
Systematics
Classification : Viruses
Area : Varidnaviria
Empire : Bamfordvirae
Phylum : Nucleocytoviricota
Class : Megaviricetes
Order : Impersonal
Family : Mimiviridae
Subfamily : " Klosneuvirinae " / " Aquavirinae " / "Megavirinae"
Genre : " Toilet new virus " ?
Type : "Bodo saltans virus"
Taxonomic characteristics
Symmetry : icosahedral
Scientific name
"Bodo Saltans Virus"
Short name
BsV
Left
NCBI  Taxonomy: 2024608

" Bodo saltans virus " ( BsV , English " Bodo saltans virus ) " is a proposed species of giant viruses in the phylum Nucleocytoviricota ( Nucleocytoplasmic large DNA viruses , NCDLV ) of the family Mimiviridae and possibly in the genus " Klosneuvirus ", or at least the subfamily " Klosneuvirinae ". This was discovered in a freshwater pond in British Columbia . The natural host of BsV is the species Bodo saltans , a protozoan that is one of the kinetoplastids . Most of the other members of the Mimiviridae known to date infect amoeba of the genus Ancanthamoeba instead .

As of March 2019, the species has not yet been confirmed by the International Committee on Taxonomy of Viruses (ICTV).

description

The virus particles (virions) of BsV are similar to those of the mimiviruses and replicate in cytoplasmic virus factories in a manner typical for Mimiviridae . They have a diameter of approx. 300  nm .

The genome of BsV is linear and consists of double-stranded DNA (dsDNA). It is 1,385,869 base pairs in length . The GC content is 25.3%. According to the research, the genome of 1227 should open reading frame ( english open reading frames , ORFs) are predicted and 1,207 proteins encoded . Homology to known eukaryotic sequences was found in 27% of these encoded proteins, and in more than half there are no identifiable matches. The encoded proteins are involved in DNA replication and repair, RNA synthesis and modification. There are also translation proteins and capsid proteins .

Unlike other known giant viruses, there are no genes for tRNAs . Since BsV does not encode any enzymes involved in protein synthesis, the virus must use host tRNAs for this purpose.

Genes encoding a membrane fusion system could be derived from the eukaryotic host by horizontal gene transfer . These could enable the virions to enter the host cell.

Mobile genetic elements are abundant, including self-splicing proteins (so-called inteins ), as well as ribozyming sequences that can splice out of the RNA. Such mobile genetic elements had never been found in other giant viruses before.

There are 148 copies of a protein that may be involved in fighting host defenses. According to the authors, this gene has been duplicated repeatedly because a larger amount was needed for the virus to replicate well in the host cells. A similar amplification of genes encoding an antagonist of an immune protein of the host was also observed in the genome of the vaccinia virus (also an NCLDV from the family of the Poxviridae ).

Systematics

The closest relatives of BSV include the in Klosterneuburg found Klosneuviren " Klosneuvirus " systems (COS), " Hokovirus " (HokV), " Catovirus " (CATV) and " Indivirus " (PERSONALIS). With them BSV belongs to the family as accepted by ICTV family mimiviridae . In detail, the family relationships are still under discussion. Usually, BsV is combined with the four genera found in Klosterneuburg, and possibly others, to form a proposed subfamily " Klosneuvirinae ".

Most of the time there is a closer relationship between the toilet viruses and the mimiviruses than with the cafeteria viruses . Contrary to this, some authors see a closer relationship between the toilet viruses and the cafeteria viruses and “ Namo virus ” and therefore propose a common subfamily “ Aquavirinae ” of these two clades.

While the NCBI sees the “ Bodo saltans virus ” (BsV) as a species in the genus “ Klosneuvirus ”, Disa Bäckström et al. (2019), Fig. 3, a system of toilet new viruses with the " Catovirus " as the closest relative of BsV among the four original toilet new viruses. Cladograms for the internal systematics of the toilet new viruses can be found under Klos new virus §Systematics .

Deeg et al. (2018) understand the toilet new viruses as subtaxons of an extended subfamily " Megavirinae ", which includes all conventional Mimiviridae , and to which the candidates formerly assigned to the Phycodnaviridae (with the " OLPG ", "Organic Lake Phycodnavirus Group" group) as a subfamily " Mesomimivirinae “form a sister taxon within an extensive family Mimiviridae .

Individual evidence

  1. ↑ a b c d e ICTV: ICTV Master Species List 2019.v1 , New MSL including all taxa updates since the 2018b release, March 2020 (MSL # 35)
  2. ↑ a b NCBI : Bodo saltans virus (species), date of access: August 2, 2019
  3. ↑ a b c d e f g h i C.M. Deeg, ECT Chow, CA Suttle: The kinetoplastid-infecting Bodo saltans virus (BsV), a window into the most abundant giant viruses in the sea . In: eLife . 7, 2018, p. E33014. doi : 10.7554 / eLife.33014 .
  4. ↑ a b c d e f Vincent Racaniello, David Tuller, Gertrud U. Rey: Bodo saltans virus, an abundant giant aquatic Mimivirus , on: virology blog, December 28, 2017
  5. ↑ ICTV: ICTV Master Species List 2018b.v2 MSL # 34v, March 2019
  6. ↑ David M. Needham, Alexandra Z. Worden et al .: A distinct lineage of giant viruses brings a rhodopsin photosystem to unicellular marine predators , in: PNAS, 23 September 2019, doi: 10.1073 / pnas.1907517116 , ISSN 0027-8424 , here: Supplement 1 (xlsx)
  7. ↑ Vincent Racaniello, Alan Dove, Rich Condit, Kathy Spindler: Pox has got a squeeze-box, seals are gonna sneeze all night , on: This Week in Virology, September 2, 2008
  8. ↑ Frederik Schulz, Natalya Yutin, Natalia N. Ivanova, Davi R. Ortega, Tae Kwon Lee, Julia Vierheilig, Holger Daims, Matthias Horn, Michael Wagner, Grant J. Jensen, Nikos C. Kyrpides, Eugene V. Koonin, Tanja Woyke : Giant viruses with an expanded complement of translation system components . In: Science . tape 356 , no. 6333 , April 7, 2017, ISSN  0036-8075 , p. 82-85 , doi : 10.1126 / science.aal4657 , PMID 28386012 .
  9. ↑ Center national de la recherche scientifique: List of the main “giant” viruses known as of today , Université Aix Marseille, April 18, 2018.
  10. ↑ Center national de la recherche scientifique: List of the main “giant” viruses known as of today (March 2019) , Université Aix Marseille, March 2019.
  11. ↑ Disa Bäckström, Natalya Yutin, Steffen L. Jørgensen, Jennah Dharamshi, Felix Homa, Katarzyna Zaremba-Niedwiedzka, Anja Spang, Yuri I. Wolf, Eugene V. Koonin, Thijs J. G. Ettema; Richard P. Novick (Ed.): Virus Genomes from Deep Sea Sediments Expand the Ocean Megavirome and Support Independent Origins of Viral Gigantism , in: mBio Vol. 10 No. 2 2019, doi: 10.1128 / mBio.02497-18