Rhadinovirus

Die Gattung Rhadinovirus bildet eine Untergruppe der Unterfamilie der Gammaherpesviren (Gammaherpesvirinae). Diese wiederum gehören zur Familie der Herpesviren (Herpesviridae). Rhadinoviren sind bei verschiedenen Nagetieren (Wühler), Huftieren (Hauspferde, Gnus, Rinder) sowie Primaten isoliert worden. Das bisher einzige bekannte menschliche Rhadinovirus ist das Humane Herpesvirus 8 (offiziell Human gammaherpesvirus 8, HHV-8). HHV-8 verursacht beim Menschen das Kaposi-Sarkom und einen Teil der Fälle von Morbus Castleman. Wie andere Gammherpesviren infizierendie Rhadinoviren Lymphozyten, in denen sie auch persistieren. Rhadinoviren sind vielfach mit einer malignen Transformation und damit der Entstehung von Tumorerkrankungen assoziiert.

Rhadinoviren sind 150 bis 200 nm im Durchmesser groß, das ikosaedrische Kapsid (T=16) im Innern etwa 100–110 nm. Das Genom ist innerhalb des Kapsids auf einer dünnen, spindelähnlichen Core-Struktur aufgewickelt, nach der die Gattung ihren Namen erhielt (altgriechisch ῥαδινός = schlank, spitz zulaufend). Das Genom ist ca. 145.000–165.000 Bp groß. Zusätzlich beinhalten die Viruspartikel (Virionen) auch zelluläre und virale mRNA.

Systematik

Neben einer großen Zahl derzeit nicht klassifizierter Rhadinoviren oder assoziierter Viren bei verschiedensten Tierarten (Primaten, Delfinen, Flusspferd, Hasen, Echte Bandikutratte, Elefanten u. a.),^[2] sind folgende Vertreter als Spezies der Gattung definiert:^[3][4]

• Genus Rhadinovirus

• Spezies Humanes Herpesvirus 8 (en. Human gammaherpesvirus 8, HHV-8)
• Spezies Herpesvirus saimiri 2 (en. Saimiriine gammaherpesvirus 2, SaHV-2)
• Spezies Atelines Herpesvirus 2 (Klammeraffen-Herpesvirus 2, en. Ateline gammaherpesvirus 2)
• Spezies Atelines Herpesvirus 3 (Klammeraffen-Herpesvirus 3, en. Ateline gammaherpesvirus 3)
• Spezies Makaken-Herpesvirus 5 (Rhesusaffen-Rhadinovirus, Cercopithecines Herpesvirus 17, en. Macacine gammaherpesvirus 5, McHV5)
• Spezies Bovines Herpesvirus 4 (en. Bovine gammaherpesvirus 4, BoHV-4)
• Spezies Murides Herpesvirus 4 (en. Murid gammaherpesvirus 4, MuHV-4)

• Murine herpesvirus 68 (syn. Mouse herpesvirus 68)

• Spezies Murides Herpesvirus 7 (en. Wood mouse herpesvirus, offiziell Murid gammaherpesvirus 7, MuHV-8)
• Spezies Cricetides Herpesvirus 2 (Nagetier-Herpesvirus Peru, en. Cricetid gammaherpesvirus 2) – befällt Cricetidae

Einzelnachweise

1. ↑ ^{a b c d e} Human alphaherpesvirus 1. ICTV Taxonomy history; EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL #35)
2. ↑ zum Beispiel Rhesus Monkey Rhadinovirus (RRV), Yu et al. (2003)
3. ↑ Master Species List 2018a v1. ICTV, MSL including all taxa updates since the 2017 release. Fall 2018 (MSL #33)
4. ↑ ViralZone: Rhadinovirus. SIB Swiss Institute of Bioinformatics

Rhadinovirus (synonyms: Rhadinoviridae and gamma-2 herpesviruses) 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 12 species in this genus.^[1][2] Diseases associated with this genus include: Kaposi's sarcoma,^[1] primary effusion lymphoma and multicentric Castleman's disease, caused by Human gammaherpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV). The term rhadino comes from the Latin fragile, referring to the tendency of the viral genome to break apart when it is isolated.

Species

The genus consists of the following 12 species:^[2]

• Ateline gammaherpesvirus 2
• Ateline gammaherpesvirus 3
• Bovine gammaherpesvirus 4
• Cricetid gammaherpesvirus 2
• Human gammaherpesvirus 8
• Macacine gammaherpesvirus 5
• Macacine gammaherpesvirus 8
• Macacine gammaherpesvirus 11
• Macacine gammaherpesvirus 12
• Murid gammaherpesvirus 4
• Murid gammaherpesvirus 7
• Saimiriine gammaherpesvirus 2

Hosts

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. Rhadinoviruses infect a wide range of mammals, include humans. Rhadinoviruses have been found in New World monkeys such as the squirrel monkeys (herpesvirus saimiri) and in mice (Murid gammaherpesvirus 68). 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.^[1] 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.

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.^[1]

Notes

Rhadinoviruses are unique because they have mastered the ability to pirate cellular genes from their host cells and incorporate them into their genomes. For example, most rhadinoviruses have a copy of the cyclin gene, which regulates the ability of the cell to divide. These viruses tend to cause tumors when infection occurs outside of their native hosts or in the case of KSHV, in humans when the host is immunosuppressed due to AIDS, old age, or in the setting of organ transplantation.

References

Rhadinovirus eller gamma-2 herpesvirus er ei slekt av gammaherpesvirus som kan infisera pattedyr. Dei kan vera vanlege hjå hovudverten dei infiserer (hjå over 50 % av individa i ein populasjon), men utan at sjukdomsuttrykk hjå denne arten er kjende. Likevel er det kjent at dei kan valda kreftsjukdomar hjå andre artar. Menneskeviruset Kaposi-sarkom-assosiert herpesvirus kan derimot mellom anna valda den høvesvis sjeldne kreftsjukdomen Kaposi-sarkom hjå menneske. Det er mogeleg at andre rhadinovirus òg valdar sjeldne sjukdomar hjå hovudverten, og at desse sjukdomane ikkje er oppdaga av di dei er sjeldne.^[1]

Rhadinovirus vert delte inn i to grupper, rhadinovirus 1 (RV1) og rhadinovirus 2 (RV2).^[2] Dei kan ta opp gen frå vertsorganismen i genomet sitt.^[1]

Utanom mennesket er rhadinovirus kjende frå pattedyr som storfe, sau, hest, klatremus, vestapar og austapar.^[1][2]

Kjelder

Denne biologiartikkelen er ei spire. Du kan hjelpe Nynorsk Wikipedia gjennom å utvide han.