Group Group I (dsDNA) Higher classification Caudovirales | Order Ligamenvirales Rank Family | |
Similar Fuselloviridae, Corticovirus, Tectivirus, Plasmaviridae, Leviviridae | ||
Lipothrixviridae is a family of viruses in the order Ligamenvirales. Thermophilic archaea in the kingdom Crenarchaeota serve as natural hosts. There are currently nine species in this family, divided among 4 genera.
Contents
Taxonomy
Group: dsDNA
The family consists of four genera: Alphalipothrixvirus, Betalipothrixvirus, Gammalipothrixvirus and Deltalipothrixvirus. They are classified into genera based on their genomic properties and on the diversity of their terminal appendages, which are involved in host cell recognition.
In the genus Gammalipothrixvirus claw-like structures are found at either end of the virion.
Members of the Lipothrixviridae share structural and genomic characteristics with viruses from the Rudiviridae family, which contains non-enveloped rod-shaped viruses. Viruses from the two families have linear dsDNA genomes and share up to nine genes. In addition, the filamentous particles of rudiviruses and lipothrixviruses are built from structurally similar, homologous major capsid proteins. Due to these shared properties viruses from the two families are classified into an order Ligamenvirales.
Virology
The viruses are enveloped and rod-shaped. The capsid varies considerably in length - 410-1950 nanometers (nm) - and is 24-38 nm in diameter. The envelope has a bilayer structure and includes glycolipids and phospholipids, the latter being specifically di-phytanyl tetraethers lipids. The phosphate residues of phospholipids are oriented towards the inside of the viron; the glycosyl residues of glycolipids are oriented towards the outside of the viron.
From either end of the viron are protrusions extending from the core through the envelope. The capsid itself is elongated and exhibits helical symmetry. The core itself is helical.
There are two major capsid proteins (MCP1 and MCP2). The basic MCP1 protein forms a core around which the genomic dsDNA is wrapped, whereas MCP2 interacts with the genome with its basic N-terminal region and the hydrophilic C-terminal domain is embedded into the lipid envelope Genomes are linear, around 56kb in length.
Life Cycle
Viral replication is cytoplasmic. Entry into the host cell is achieved by adsorption into the host cell. Dna templated transcription is the method of transcription. Archaea serve as the natural host. Transmission routes are passive diffusion.