Globuloviridae

Globuloviridae is a family of hyperthermophilic archaeal viruses. Crenarchaea of the genera Pyrobaculum and Thermoproteus (both in Thermoproteaceae) serve as natural hosts. There are four species in this family, assigned to a single genus, Alphaglobulovirus.^[1][2][3]

Globuloviridae
Virus classification
(unranked):	Virus
Family:	Globuloviridae
Genera
Alphaglobulovirus

Negative-contrast electron micrographs of virions of Pyrobaculum spherical virus (PSV, genus Alphaglobulovirus). (Left) Intact virions; arrows indicate spherical protrusions. (Right) Partially disrupted virions extruding disordered nucleoprotein core. The bars represent 100 nm. Modified from (Häring et al., 2004; provided by ICTV).

Taxonomy

The family contains one genus which contains four species:^[3][4]

• Alphaglobulovirus
  • Alphaglobulovirus cinderense, Thermoproteus tenax spherical virus 1
  • Alphaglobulovirus obsidianense, Pyrobaculum spherical virus
  • Alphaglobulovirus pozzuoliense, Pyrobaculum spherical virus 2
  • Alphaglobulovirus sileriense, Thermoproteus spherical piliferous virus 1

Structure

Virions in the Globuloviridae are spherical and enveloped. The diameter is around 100 nm.^[1][2]

Genome organization of Pyrobaculum spherical virus (PSV) showing location, sizes and direction of putative genes.

Genomes are linear dsDNA and non-segmented, around 20–30kb in length.^[1][2]

Genus	Structure	Symmetry	Capsid	Genomic arrangement	Genomic segmentation
Alphaglobulovirus	Spherical		Enveloped	Linear	Monopartite

Life cycle

Viral replication is cytoplasmic. DNA-templated transcription is the method of transcription. Pyrobaculum and Thermoproteus archaea 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
Alphaglobulovirus	Pyrobaculum and Thermoproteus archaea	None	Injection	Budding	Cytoplasm	Cytoplasm	Passive diffusion