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.[1][2][3]
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.[1]
Genus
Structure
Symmetry
Capsid
Genomic arrangement
Genomic segmentation
Fromanvirus
Head-Tail
T=7
Non-enveloped
Linear
Monopartite
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.[3]
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.[1]
Genus
Host details
Tissue tropism
Entry details
Release details
Replication site
Assembly site
Transmission
Fromanvirus
Bacteria
None
Injection
Lysis
Cytoplasm
Cytoplasm
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.[2] The genus was later renamed to Fromanvirus.
