Fromanvirus

Fromanvirus (synonyms L5-like viruses, L5-like phages, L5likevirus) is a genus of viruses in the order Caudovirales, in the family Siphoviridae. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There are 59 species in this genus.

Taxonomy
The following species are recognized:


 * Mycobacterium virus Alma
 * Mycobacterium virus Arturo
 * Mycobacterium virus Astro
 * Mycobacterium virus Backyardigan
 * Mycobacterium virus Benedict
 * Mycobacterium virus Bethlehem
 * Mycobacterium virus Billknuckles
 * Mycobacterium virus BPBiebs31
 * Mycobacterium virus Bruns
 * Mycobacterium virus Bxb1
 * Mycobacterium virus Bxz2
 * Mycobacterium virus Che12
 * Mycobacterium virus Cuco
 * Mycobacterium virus D29
 * Mycobacterium virus Doom
 * Mycobacterium virus Ericb
 * Mycobacterium virus Euphoria
 * Mycobacterium virus George
 * Mycobacterium virus Gladiator
 * Mycobacterium virus Goose
 * Mycobacterium virus Hammer
 * Mycobacterium virus Heldan
 * Mycobacterium virus Jasper
 * Mycobacterium virus JC27
 * Mycobacterium virus Jeffabunny
 * Mycobacterium virus JHC117
 * Mycobacterium virus KBG
 * Mycobacterium virus Kssjeb
 * Mycobacterium virus Kugel
 * Mycobacterium virus L5
 * Mycobacterium virus Lesedi
 * Mycobacterium virus LHTSCC
 * Mycobacterium virus lockley
 * Mycobacterium virus Marcell
 * Mycobacterium virus Microwolf
 * Mycobacterium virus Mrgordo
 * Mycobacterium virus Museum
 * Mycobacterium virus Nepal
 * Mycobacterium virus Packman
 * Mycobacterium virus Peaches
 * Mycobacterium virus Perseus
 * Mycobacterium virus Pukovnik
 * Mycobacterium virus Rebeuca
 * Mycobacterium virus Redrock
 * Mycobacterium virus Ridgecb
 * Mycobacterium virus Rockstar
 * Mycobacterium virus Saintus
 * Mycobacterium virus Skipole
 * Mycobacterium virus Solon
 * Mycobacterium virus Switzer
 * Mycobacterium virus SWU1
 * Mycobacterium virus Tiger
 * Mycobacterium virus Timshel
 * Mycobacterium virus Trixie
 * Mycobacterium virus Turbido
 * Mycobacterium virus Twister
 * Mycobacterium virus U2
 * Mycobacterium virus Violet
 * Mycobacterium virus Wonder

Structure
Fromanviruses are nonenveloped, with a head and tail. The icosahedral head is about 60 nm in diameter, with covalently linked capsid proteins. The tail is long and flexible, at about 135 nm long, 8 nm wide, and has a terminal knob with one short tail fiber.

Genome
Bxb1, D29, and L5 and have been fully sequenced. They range between 49k and 53k nucleotides, with 79 to 90 proteins. Their complete genomes, and the genomes of many other species and unclassified viruses, are available via NCBI.

Life cycle
The virus attaches to the host cell's adhesion receptors using its terminal fiber, and ejects the viral DNA into the host cytoplasm via long flexible tail ejection system. Viral replication is cytoplasmic. Replication follows the replicative transposition model. 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
According to ICTV's 1996 report, the genus L5likevirus was first accepted under the name L5-like phages, assigned only to family Siphoviridae. The whole family was moved to the newly created order Caudovirales in 1998, and the genus was renamed to L5-like viruses in ICTV's seventh report in 1999. In 2012, the genus was renamed again, this time to L5likevirus. The genus was later renamed to Fromanvirus.