Rhadinovirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Gammaherpesvirinae. Humans and other mammals serve as natural hosts. There are currently nine species in this genus including the type speciesSaimiriine gammaherpesvirus 2. Diseases associated with this genus include: Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease, caused by Human gammaherpesvirus 8, also known as Kaposi's sarcoma-associated herpesvirus. The term rhadino comes from the Latin fragile, referring to the tendency of the viral genome to break apart when it is isolated.
In general, rhadinoviruses infect lymphocytes and adherent cells, such as fibroblasts, epithelial cells, and endothelial cells and once infection occurs, it is, in general, lifelong. Rhandinoviruses infect a wide range of mammals, include humans. Rhadinoviruses have been found in New World monkeys such as the squirrel monkeys and in mice. More recently, both KSHV-like viruses and a new form of rhadinovirus called rhesus rhadinovirus have been discovered in Old World monkeys. These findings suggest that an additional human tumor virus related to KSHV may be found in humans.
Structure
Viruses in Rhadinovirus are enveloped, with icosahedral, spherical to pleomorphic, and round geometries, and T=16 symmetry. The diameter is around 150-200 nm. Genomes are linear and non-segmented, around 180kb in length. They are large double-stranded viruses that possess up to 100 genes in a single long chromosome, which is flanked by repetitive DNA sequences called terminal repeats.
Genus
Structure
Symmetry
Capsid
Genomic arrangement
Genomic segmentation
Rhadinovirus
Spherical pleomorphic
T=16
Enveloped
Linear
Monopartite
Life cycle
Viral replication is nuclear, and is lysogenic. Entry into the host cell is achieved by attachment of the viral glycoproteins to host receptors, which mediates endocytosis. Replication follows the dsDNA bidirectional replication model. DNA-templated transcription, with some alternative splicing mechanism is the method of transcription. Translation takes place by leaky scanning. The virus exits the host cell by nuclear egress, and budding. Humans and other mammals serve as natural hosts. Transmission routes are sexual, contact, and through saliva.
