T5likevirus

T5likevirus (synonyms T5-like phages, T5-like viruses) is a genus of viruses in the family Siphoviridae, unassigned to a sub-family. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are currently eight species in this genus, including the type species Enterobacteria phage T5.^[1][2][3]

Taxonomy

Species:

• Enterobacteria phage T5 (type species)
• Escherichia phage Akfv33
• Escherichia phage Bf23
• Escherichia phage Eps7
• Escherichia phage H8
• Escherichia phage T5
• Salmonella phage Spc35
• Vibrio phage 149 (type IV)

Structure

T5likeviruses are nonenveloped, with a head and tail. The head is icosahedral (T=13) and is about 90 nm in diameter. The tail is about 180nbsp;nm long, 9nbsp;nm wide. It has three long, kinked terminal fibers around 120nbsp;nm in length, and a single straight central fiber attached to a conical tip.^[1]

Genome

The type species, Enterobacteria phage T5, and several other species have been fully sequenced. The genomes range between roughly 108-121 thousand nucleotides, with about 140 to 170 predicted open reading frames. The complete genomes, as well as two other similar, unclassified genomes are available here.^[3][4]

Life cycle

The virus attaches to the host cell's adhesion receptors using its terminal fibers, and degrades the cell wall using viral exolysin enough to eject the viral DNA into the host cytoplasm via long flexible tail ejection system. 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.^[1]

History

According to ICTV's 1996 report, the genus T5likevirus was first accepted under the name T5-like phages, assigned only to family Siphoviridae. The whole family was moved to order Caudovirales in 1998, and the genus was renamed to T5-like viruses in ICTV's 7th Report in 1999. In 2012, it was renamed again to T5likevirus.^[2]

References