Schizotequatrovirus

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Schizotequatrovirus
Systematics
Classification : Viruses
Area : Duplodnaviria
Empire : Heunggongvirae
Phylum : Uroviricota
Class : Caudoviricetes
Order : Caudovirales
Family : Myoviridae
Subfamily : Tevenvirinae
Genre : Schizotequatrovirus
Taxonomic characteristics
Genome : dsDNA linear
Baltimore : Group 1
Symmetry : icosahedral, tailed
Cover : no
Scientific name
Schizotequatrovirus
Left
NCBI  Taxonomy: 1198137
ViralZone ( ExPASy , SIB): 2820

The genus Schizotequatrovirus (obsolete Schizot4virus or Schizot4likevirus ) includes viruses of the subfamily Tevenvirinae of the family Myoviridae in the order Caudovirales . Their natural hosts are bacteria , so they are bacteriophages (non-taxonomic classification). As of February 2020, there are species (species) recognized by the International Committee on Taxonomy of Viruses (ICTV) in this genus , including the type Vibrio virus KVP40

Systematics

The genus Schizotequatrovirus includes (as of the end of March 2020) the following unclassified representatives confirmed by the ICTV per Master Species List (MSL) 2018b v2 or listed by the US National Center for Biotechnology Information (NCBI):

Baltimore Group 1 : dsDNA

  • Genus: Schizotequatrovirus (obsolete Schizot4virus , Schizot4likevirus )
unclassified representatives:
  • Species: Vibrio phage 1.081.O._10N.286.52.C2
  • Species: Vibrio phage phi-Grn1
  • Species: Vibrio phage phi-ST2
  • Species: Vibrio phage ValB1 HC
  • Species: Vibrio phage VH1_2019
  • Species: Vibrio phage VH7D

construction

The virions (virus particles) of viruses of the genus Schizotequatrovirus are not enveloped and have a head and tail. The head is an elongated ellipsoid ( English prolate spheroid ) with a length of about 140  nm and a width of 70 nm. The tail is about 140 nm long, has 6 long end fibers (en. Terminal fibers ), 6 short spikes (peplomers ) and a small base plate. The tail is surrounded by a sheath that loosens when contracted and slides around the core of the tail.

The capsid has a symmetry with a triangulation number T = 13 Q = 21. The virions are not enveloped.

Genome

The genome is a single linear strand of dsDNA ; H. unsegmented (monopartite).

All three species have been fully sequenced. The genome length is between 244 and 248  kbp (kilobase pairs), the genome encodes 381 to 405 proteins . The complete genome, together with the complete genome for the (so far unclassified) Vibrio phage VH7D, is available from NCBI.

Propagation cycle

Virus replication is cytoplasmic (that is, it occurs in the cell plasma , not the nucleus ). The virions bind to the host cell using their terminal fibers. With the help of a viral exolysin (murein hydrolase), the cell wall of the bacterium is broken down to such an extent that the viral DNA is expelled into the host cytoplasm by contraction of the tail envelope. The method of transcription is DNA-assisted transcription. Once the viral genes have replicated, a procapsid (as a precursor of the capsid) is assembled and packaged. The tail is then also assembled and finally the mature virions are released by lysis of the bacterium (bursting with death).

The transmission occurs through passive diffusion .

history

According to the ICTV report 2010–11, the genus Schizot4likevirus was accepted as a new genus for the first time, at the same time as its type species Vibrio Phage KVP40 and the subfamily Tevenvirinae containing it . At the same time, the Vibrio phage nt-1 was moved from its previous classification T4-like viruses (later T4virus , now Tequatrovirus ) to this genus. In 2015 the genus was renamed Schizot4virus . With the Master Species List # 34, the genus was renamed again in 2019 (after Schizotequatrovirus ).

Individual evidence

  1. ↑ a b c d ICTV: ICTV Taxonomy history: Enterobacteria phage T4 , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
  2. ↑ a b c d e Viral Zone . ExPASy. Retrieved March 30, 2020.
  3. ↑ a b c ICTV Master Species List 2018b v2 MSL # 34v, March 2019
  4. ↑ ncbi. Schizotequatrovirus (genus)
  5. ↑ NCBI: unclassified Schizotequatrovirus
  6. ↑ ICTV Taxonomy history: Schizot4virus .
  7. ↑ NCBI: Vibrio phage ValKK3 (no rank)
  8. ↑ NCBI: Vibrio phage 1.081.O._10N.286.52.C2 (species)
  9. ↑ NCBI: Vibrio phage phi-Grn1 (species)
  10. ↑ NCBI: Vibrio phage phi-ST2 (species)
  11. ↑ NCBI: Vibrio phage ValB1 HC (species)
  12. ↑ NCBI: Vibrio phage VH1_2019 (species)
  13. ↑ NCBI: Vibrio phage VH7D (species)
  14. ↑ NCBI: Schizot4virus Complete Genomes . Retrieved March 30, 2020.
  15. ↑ ViralZone: Degradation of host peptidoglycans during virus entry , SIB ExPASy; see. also endolysins
  16. ↑ ICTV Proposal

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