tequatrovirus tequatrovirus tequatrovirus is a genus of viruses in the order caudovirales, in the family myoviridae, in the subfamily tevenvirinae. gram-negative bacteria serve as the natural host, with transmission achieved through passive diffusion. there are 75 species in this genus. tequatrovirus virus classification (unranked): virus realm: duplodnaviria kingdom: heunggongvirae phylum: uroviricota class: caudoviricetes order: caudovirales family: myoviridae subfamily: tevenvirinae genus: tequatrovirus species see text synonyms t4virus taxonomy the following species are assigned to the genus: citrobacter virus crrp10 citrobacter virus phizz6 citrobacter virus phizz23 enterobacteria virus aplg8 enterobacteria virus gizh enterobacteria virus ime340 enterobacteria virus kha5h enterobacteria virus rb18 enterobacteria virus rb27 enterobacteria virus t6 escherichia virus ar1 escherichia virus areg1 escherichia virus c40 escherichia virus cf2 escherichia virus dalca escherichia virus e112 escherichia virus ec121 escherichia virus ecml134 escherichia virus ecnp1 escherichia virus eco4 escherichia virus ecomf1 escherichia virus f2 escherichia virus ffieco06 escherichia virus g8 escherichia virus g28 escherichia virus g50 escherichia virus g4498 escherichia virus g4507 escherichia virus g9062 escherichia virus hy01 escherichia virus hy03 escherichia virus ime09 escherichia virus ime537 escherichia virus kaw1e185 escherichia virus kit03 escherichia virus lutter escherichia virus nbeco003 escherichia virus nbg2 escherichia virus oe5505 escherichia virus ozark escherichia virus pd112 escherichia virus pe37 escherichia virus pp01 escherichia virus rb3 escherichia virus rb14 escherichia virus rb32 escherichia virus slur03 escherichia virus slur04 escherichia virus t2 escherichia virus t4 escherichia virus teqdroes escherichia virus teqhad escherichia virus teqskov escherichia virus yueel01 salmonella virus sg1 salmonella virus snuabm-01 serratia virus phizz30 shigella virus cm8 shigella virus jk45 shigella virus pss1 shigella virus sf21 shigella virus sf22 shigella virus sf23 shigella virus sf24 shigella virus sh7 shigella virus shbml501 shigella virus shbml-50-1 shigella virus shfl2 shigella virus shfml11 shigella virus shfml26 yersinia virus d1 yersinia virus fps-2 yersinia virus pst yersinia virus pyps2t yersinia virus zn18 structure tequatrovirus species are nonenveloped, with a head and tail. the head is a prolate spheroid approximately 120 nm in length and 86 nm in width, with an elongated icosahedral symmetry (t=13, q=21) composed of 152 total capsomers. the tail has six long terminal fibers, six short spikes, and a small base plate. the tail is enclosed in a sheath, which loosens and slides around the tail core upon contraction. genusstructuresymmetrycapsidgenomic arrangementgenomic segmentation tequatrovirushead-tailt=13 q=21non-envelopedlinearmonopartite genome genomes are linear, around 169kb in length. the genome codes for 300 proteins. some species have been fully sequenced and are available from ictv. they range between 159k and 235k nucleotides, with 242 to 292 proteins. the complete genomes are available from the national center for biotechnology information, along with the complete genomes for dozens of other similar, unclassified virus strains. life cycle viral replication is cytoplasmic. the virus attaches to the host cell using its terminal fibers, and uses viral exolysin to degrade the cell wall enough to eject the viral dna into the host cytoplasm via contraction of its tail sheath. dna-templated transcription is the method of transcription. the virus exits the host cell by lysis, and holin/endolysin/spanin proteins. once the viral genes have been replicated, the procapsid is assembled and packed. the tail is then assembled and the mature virions are released via lysis. gram-negative bacteria serve as the natural host. transmission routes are passive diffusion. genushost detailstissue tropismentry detailsrelease detailsreplication siteassembly sitetransmission tequatrovirusbacteria: gram negativenoneinjectionlysiscytoplasmcytoplasmpassive diffusion history the ictv's first report (1971) included the genus t-even phages, unassigned to an order, family, or subfamily. the genus was renamed in 1976 to t-even phage group, moved into the newly created family myoviridae in 1981. in 1993, it was renamed again to t4-like phages, and was moved into the newly created order caudovirales in 1998. the next year (1999), it was renamed to t4-like viruses. once more, the genus was moved into the newly created subfamily tevenvirinae in 2010-11, renamed to t4likevirus in 2012, and renamed again to t4virus in 2015. the proposals before 1993, and from 1998 are unavailable online. the other proposals are available here: 1993, 1999, 2010, 2012.