Retroviruses

Retroviruses are a family of viruses that are defined by their replication process, which involves the reverse transcription of their RNA into DNA. This process is facilitated by the viral enzyme reverse transcriptase. Retroviruses are enveloped viruses that can infect both vertebrate and invertebrate species.

Structure

Retroviruses are spherical in shape and are approximately 80-100 nanometers in diameter. They are composed of an outer envelope, a capsid, and two identical strands of RNA. The envelope is derived from the host cell membrane and contains viral glycoproteins, which are essential for the virus to bind to and enter host cells.

Replication

The replication cycle of retroviruses begins with the binding of the virus to a specific receptor on the host cell. This is followed by the fusion of the viral envelope with the cell membrane, allowing the viral capsid to enter the cell. The capsid is then uncoated, releasing the viral RNA and reverse transcriptase into the cell. The reverse transcriptase enzyme transcribes the viral RNA into DNA, which is then integrated into the host cell's genome by the viral enzyme integrase. The integrated viral DNA, known as a provirus, is transcribed and translated by the host cell's machinery to produce new viral proteins and RNA. These components are then assembled into new virus particles, which bud from the host cell and go on to infect other cells.

Classification

Retroviruses are classified into seven genera: Alpharetrovirus, Betaretrovirus, Gammaretrovirus, Deltaretrovirus, Epsilonretrovirus, Lentivirus, and Spumavirus. Each genus includes viruses that infect specific types of cells and cause distinct diseases.

Diseases

Retroviruses are associated with various diseases in humans and animals. The most well-known retrovirus in humans is the HIV, which causes AIDS. Other retroviruses, such as HTLV, can cause cancers and neurological diseases.

Treatment and Prevention

Treatment for retroviral infections primarily involves antiretroviral therapy, which includes drugs that inhibit the function of viral enzymes. Prevention strategies include vaccination, safe sex practices, and needle exchange programs.

See Also

• Virus
• RNA
• DNA
• Reverse transcriptase
• Integrase
• HIV
• AIDS
• HTLV

Retroviruses Resources
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