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Tectivirus

{{Short description|Family of viruses}}

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{{Use dmy dates|date=April 2017}}

{{Virusbox

| image = 1gw7.jpg

| image_caption = CryoEM model of Enterobacteria phage PRD1 capsid. PDB entry {{PDBe|1gw7}}{{cite journal|pmid=12219080|year=2002|last1=San Martín|first1=C|last2=Huiskonen|first2=JT|last3=Bamford|first3=JK|last4=Butcher|first4=SJ|last5=Fuller|first5=SD|last6=Bamford|first6=DH|last7=Burnett |first7=RM|title=Minor proteins, mobile arms and membrane-capsid interactions in the bacteriophage PRD1 capsid|volume=9|issue=10|pages=756–63|doi=10.1038/nsb837|journal=Nature Structural Biology|s2cid=32856328 }}

| taxon = Tectiviridae

| subdivision_ranks = Genera

| subdivision = See text

}}

Tectiviridae is a family of viruses with 12 species in five genera. Bacteria serve as natural hosts.{{cite web|title=Viral Zone|url=http://viralzone.expasy.org/all_by_species/579.html|publisher=ExPASy|access-date=15 June 2015}}{{cite web|title=Virus Taxonomy: 2024 Release|url=https://ictv.global/taxonomy|publisher=International Committee on Taxonomy of Viruses|access-date=24 March 2025}} Tectiviruses have no head-tail structure, but are capable of producing tail-like tubes of ~ 60×10 nm upon adsorption or after chloroform treatment. The name is derived from Latin tectus (meaning 'covered').{{cite web|url=https://talk.ictvonline.org/ictv-reports/ictv_9th_report/dsdna-viruses-2011/w/dsdna_viruses/133/tectiviridae|archive-url=https://web.archive.org/web/20190424161051/https://talk.ictvonline.org/ictv-reports/ictv_9th_report/dsdna-viruses-2011/w/dsdna_viruses/133/tectiviridae|url-status=dead|archive-date=24 April 2019|title=ICTV Ninth Report; 2009 Taxonomy Release: Tectiviridae|author=|website=ICTV|access-date=18 September 2020}}

Virology

File:Viruses.11.-2019-76-Fig-1b.png

The virions of Tectiviridae species are non-enveloped, icosahedral and display a pseudo T=25 symmetry. The capsid has two layers. The outer layer is a protein structure of 240 capsid proteins trimers, and the inner one is a proteinaceous lipid membrane which envelopes the virus genome. Apical spikes extending about 20 nanometers (nm) protrude from the icosahedrons vertices.{{cn|date=October 2022}}

The genome is a single molecule of linear double-stranded DNA of 15 kilobases in length, and has 30 open reading frames. It forms a tightly packed coil and encodes several structural proteins. It encodes about 30 proteins that are transcribed in operons. At least 9 structural proteins are present in the viron. The genome is about 66 megadaltons in weight and constitutes 14–15% of the virion by weight. Lipids constitute a further 15% by weight. Carbohydrates are not present.{{cn|date=October 2022}}

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by adsorption into the host cell. After adsorption to the host cell surface the virion extrudes a tail-tube structure through a vertex for genome delivery into the host. Replication follows the DNA strand displacement model. DNA-templated transcription is the method of transcription. Capsid proteins polymerize around a lipoprotein vesicle translocated in the cytoplasm by virion assembly factors.

Mature virons are released by lysis, which, in the case of PRD1, is achieved with the aid of virus-encoded lysis machinery consisting of four proteins: P15 (endolysin),{{cite journal|title=Gene XV of bacteriophage PRD1 encodes a lytic enzyme with muramidase activity|journal=Eur J Biochem|year=1994|volume=225|issue=1|pages=341–346|doi=10.1111/j.1432-1033.1994.00341.x|pmid=7925454|vauthors=Caldentey J, Hänninen AL, Bamford DH |doi-access=free}} P35 (holin),{{cite journal|title=Identification and mutational analysis of bacteriophage PRD1 holin protein P35|journal=J Bacteriol|year=2003|volume=185|issue=13|pages=3795–3803|doi=10.1128/JB.185.13.3795-3803.2003|pmid=12813073|vauthors=Rydman PS, Bamford DH |pmc=161566}} P36 and P37 (homologues of the Rz/Rz1 proteins of phage lambda).{{cite journal|title=Identification and functional analysis of the Rz/Rz1-like accessory lysis genes in the membrane-containing bacteriophage PRD1|journal=Mol Microbiol|year=2008|volume=68|issue=2|pages=492–503|doi=10.1111/j.1365-2958.2008.06165.x|pmid=18366440|vauthors=Krupovic M, Cvirkaite-Krupovic V, Bamford DH |doi-access=free}}

Taxonomy

Tectiviridae contains the following genera and species:

Other unassigned phages:[https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=2047787&lvl=3&lin=f&keep=1&srchmode=1&unlock Unclassified Tectiviridae]. NCBI Taxonomy.

References

{{Reflist}}

Further reading

  • [https://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.068.htm ICTVdB—The Universal Virus Database] ICTVdB Management (2006). 00.068. Tectiviridae. In: ICTVdB—The Universal Virus Database, version 3. Büchen-Osmond, C. (Ed), Columbia University, New York, USA
  • [https://web.archive.org/web/20070224232458/http://www.microbiologybytes.com/virology/VirusGroups.html Virus Taxonomy]: Eighth Report of the International Committee on Taxonomy of Viruses H.V. Van Regenmortel, D.H.L. Bishop, M. H. Van Regenmortel, Claude M. Fauquet (Eds)
  • [http://www.ictvdb.rothamsted.ac.uk/ICTVdB/68010000.htm 68.0.1. Tectivirus] {{Webarchive|url=https://web.archive.org/web/20070928130124/http://www.ictvdb.rothamsted.ac.uk/ICTVdB/68010000.htm |date=28 September 2007 }}

External links

  • [http://viralzone.expasy.org/all_by_species/579.html Viralzone: Tectivirus]
  • [http://ictvonline.org/virusTaxonomy.asp ICTV]

{{Baltimore classification}}

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Category:Bacteriophages