: The enzyme reverse transcriptase "back-transcribes" the viral RNA into a double-stranded DNA copy.
Retroviruses are a unique family of viruses that have fundamentally changed our understanding of genetics, evolution, and medicine. Unlike most living organisms that store genetic information as DNA, retroviruses carry their genetic blueprint as . Their name refers to their "backward" replication process: they use a specialized enzyme called reverse transcriptase to convert their RNA into DNA once they infect a host cell. The Replication Cycle: Rewriting the Host’s Code Retrovirus
The hallmark of a retrovirus is its ability to integrate its own genetic material permanently into the host's genome. This process occurs in several distinct stages: Their name refers to their "backward" replication process:
: The host cell's machinery mistakenly treats the provirus as one of its own genes, producing viral mRNA and proteins. These components assemble into new, immature viral particles that bud off from the cell. These components assemble into new, immature viral particles
: Finally, a protease enzyme cleaves the viral proteins into their functional forms, maturing the virus so it can infect new cells. Human Health and Diseases
Retroviruses are responsible for several significant human diseases. The most well-known is , which attacks the immune system's T-cells and can lead to AIDS . Other notable human retroviruses include:
: Another enzyme, integrase , carries this viral DNA into the cell's nucleus and "clips" it into the host's own DNA. At this stage, the integrated viral DNA is known as a provirus .