Gammaretrovirus

Gammaretrovirus is a genus of the Retroviridae family. It is a type of retrovirus that includes viruses which cause various types of cancer in animals. The name "gammaretrovirus" comes from the Greek letter gamma (γ), as these were the third group of retroviruses discovered.

Structure

Gammaretroviruses are enveloped viruses with spherical to pleomorphic shapes. The diameter of the virion is around 80-100 nm. The viral envelope is derived from the host cell membrane and contains viral glycoproteins. The capsid is spherical and contains two copies of positive-sense, single-stranded RNA.

Replication

The replication cycle of gammaretroviruses is similar to that of other retroviruses. The virus attaches to the host cell via the viral envelope proteins and the host cell receptor. This is followed by fusion of the viral and cellular membranes, allowing the viral capsid to enter the cell. The viral RNA is then reverse transcribed into DNA by the viral reverse transcriptase enzyme. This DNA is integrated into the host cell genome by the viral integrase enzyme. The integrated viral DNA is then transcribed and translated by the host cell machinery, producing new viral proteins and RNA. These are assembled into new virions which bud from the host cell, acquiring their envelope in the process.

Pathogenesis

Gammaretroviruses can cause various types of cancer in animals. This is usually due to the integration of the viral DNA into the host cell genome, which can disrupt the normal functioning of cellular genes and lead to uncontrolled cell growth. Some gammaretroviruses also carry oncogenes, which can directly contribute to the transformation of normal cells into cancer cells.

Examples

Examples of gammaretroviruses include the Murine leukemia virus (MLV), which causes leukemia in mice, and the Feline leukemia virus (FeLV), which causes leukemia in cats.

See also

• Retrovirus
• Oncovirus
• Murine leukemia virus
• Feline leukemia virus

Gammaretrovirus Resources
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