Group Group I (dsDNA) Family Myoviridae Rank Genus | Order Caudovirales Subfamily Spounavirinae | |
People also search for Spounavirinae, Spounalikevirus | ||
Twortlikevirus is a genus of viruses in the order Caudovirales, in the family Myoviridae, in the subfamily Spounavirinae. Bacteria serve as natural hosts. There are currently five species in this genus, including the type species Staphylococcus phage Twort.
Contents
Taxonomy
Group: dsDNA
Structure
Viruses in this genus are nonenveloped, with a head and tail. The head is approximately 84 nm to 94 nm in diameter and T=16 symmetry. The tail is around 140 nm to 219 nm long, has 6 long terminal fibers, 6 short spikes, globular structures at the tip, and a double base plate. The tail is enclosed in a sheath, which loosens and slides around the tail core upon contraction.
Life cycle
Viral replication is cytoplasmic. The virus attaches to the host cell using its tail fibers, and ejects the viral DNA into the host cytoplasm via contraction of its tail sheath. DNA-templated transcription is the method of transcription. 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. Bacteria serve as the natural host. Transmission routes are passive diffusion.
History
The genus Twortlikevirus was first accepted as a new genus, at the same time as all five of its contained species as well as its containing sub-family Peduovirinae, in ICTV's 2010–11 report. The new genus was proposed in 2009.
Genome
Genomes are linear, around 130-140kb in length. The genome codes for 190 to 215 proteins. Four of the five viruses' genomes have been fully sequenced and are available on NCBI's website (the only exception being Listeria phage P100). They range between 130k and 149k nucleotides, with 190 to 233 proteins. All four complete genomes, as well as several additional "unclassified" virus genomes, are available online.