Alpharetrovirus

Alpharetrovirus is a genus of the Retroviridae family. It is a type of retrovirus that is characterized by its ability to cause cancer in birds. The name "Alpharetrovirus" is derived from the Greek letter alpha, which is used to denote the first in a series, reflecting the fact that these were the first retroviruses to be discovered.

Characteristics

Alpharetroviruses are enveloped viruses with spherical to pleomorphic morphology. The diameter of the virions is around 80-100 nm. The genome of these viruses is not segmented and contains a single molecule of linear, positive-sense, single-stranded RNA.

Replication Cycle

The replication cycle of Alpharetroviruses involves several steps. First, the virus attaches to the host cell using its envelope proteins. This is followed by fusion of the viral and cellular membranes, allowing the virus to enter the cell. Once inside, the viral RNA is reverse transcribed into DNA by the viral enzyme reverse transcriptase. This DNA is then integrated into the host cell's genome, where it can be transcribed and translated to produce new viral proteins and RNA. The new virions are assembled and released from the cell to infect other cells.

Pathogenesis

Alpharetroviruses are known to cause various types of cancer in birds, including leukemia, lymphoma, and sarcoma. The mechanism by which these viruses cause cancer involves the integration of their DNA into the host cell's genome. This can lead to the activation of oncogenes or the inactivation of tumor suppressor genes, resulting in uncontrolled cell growth and the formation of a tumor.

Examples

Some examples of Alpharetroviruses include Rous sarcoma virus, which causes sarcoma in chickens, and Avian leukosis virus, which causes leukemia in birds.

See Also

• Retrovirus
• Oncovirus
• Rous sarcoma virus
• Avian leukosis virus