Orthohepadnavirus
| Orthohepadnavirus | |
|---|---|
| |
| TEM micrograph showing Hepatitis B virus virions | |
Virus classification 
| |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Pararnavirae |
| Phylum: | Artverviricota |
| Class: | Revtraviricetes |
| Order: | Blubervirales |
| Family: | Hepadnaviridae |
| Genus: | Orthohepadnavirus |
| Species | |
| |
Orthohepadnavirus is a genus of viruses, in the family Hepadnaviridae. Humans and other mammals serve as natural hosts. There are currently 12 species in this genus including the type species Hepatitis B virus. Diseases associated with this genus include: hepatitis, hepatocellular carcinoma (chronic infections), and cirrhosis.The hepatitis B virus, which is a family of Orthohepadnavirus and has approximately 3000 nucleotides, is the smallest human virus genome. The hepatitis B virus contains a spherical lipid 42-47 nm in diameter. It has a partially double chain structure and circular genome. It contains an envelope that encompasses all of the nucleocapsid and small, medium, large viral envelope proteins that contain this genome. There are multiple life cycle steps. As a first step, it is fixed by binding to the receptor on the surface of hepatocytes[1][2]
Structure
Viruses in Orthohepadnavirus are enveloped, with spherical geometries, and T=4 symmetry. The diameter is around 42 nm. Genomes are circular, around 3.2kb in length. The genome codes for 7 proteins.[1]
| Genus | Structure | Symmetry | Capsid | Genomic arrangement | Genomic segmentation |
|---|---|---|---|---|---|
| Orthohepadnavirus | Icosahedral | T=4 | Non-enveloped | Circular | Monopartite |
Life cycle
Viral replication is nucleo-cytoplasmic. Replication follows the dsDNA(RT) replication model. DNA-templated transcription, specifically dsDNA(RT) transcription, with some alternative splicing mechanism is the method of transcription. Translation takes place by leaky scanning. The virus exits the host cell by budding, and nuclear pore export. Human and mammals serve as the natural host. Transmission routes are sexual, blood, and contact.[1]
| Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
|---|---|---|---|---|---|---|---|
| Orthohepadnavirus | Humans; mammals | Hepatocytes | Cell receptor endocytosis | Budding | Nucleus | Cytoplasm | Vertical: parental; sex; blood |
References
- ^ a b c "Viral Zone". ExPASy. Retrieved 15 June 2015.
- ^ ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.