Betaretrovirus

Betaretrovirus is a genus of the Retroviridae family. They are enveloped viruses with a positive-sense, single-stranded RNA genome. The RNA genome is reverse transcribed into DNA, which is integrated into the host cell genome. Betaretroviruses are known to cause diseases in mammals, including humans.

Structure

Betaretroviruses are spherical in shape, with a diameter of approximately 100 nm. They have a lipid envelope derived from the host cell membrane, which contains viral glycoproteins. Inside the envelope is the capsid, which contains two copies of the RNA genome and the viral enzymes reverse transcriptase and integrase.

Replication

The replication cycle of betaretroviruses begins with the binding of the viral glycoproteins to specific receptors on the host cell surface. This is followed by fusion of the viral envelope with the cell membrane, allowing the capsid to enter the cell. The capsid is uncoated, and the RNA genome is reverse transcribed into DNA by the viral reverse transcriptase. The resulting DNA is integrated into the host cell genome by the viral integrase. The integrated DNA, known as a provirus, is transcribed and translated by the host cell machinery to produce new viral proteins and RNA genomes. The new viruses are assembled and bud from the cell, acquiring their envelope from the cell membrane.

Pathogenesis

Betaretroviruses can cause diseases in mammals, including humans. The most well-known betaretrovirus is the Mouse Mammary Tumor Virus (MMTV), which causes mammary tumors in mice. In humans, betaretroviruses have been associated with breast cancer and primary biliary cirrhosis, although the evidence is not conclusive.

See also

• Retrovirus
• Oncovirus
• Mouse Mammary Tumor Virus

References

Betaretrovirus Resources
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