Sputnik virophage

Sputnik virophage is a type of virophage that was discovered in 2008. It is associated with the Mamavirus, a variant of the Acanthamoeba polyphaga Mimivirus (APMV), which is itself a large virus that infects amoebae. The discovery of Sputnik virophage has added complexity to the understanding of viral evolution and interactions, highlighting the existence of viruses that can parasitize other viruses.

Discovery

Sputnik was discovered in a water cooling tower in Paris, France. It was found to co-infect Acanthamoeba cells along with the Mamavirus. The presence of Sputnik virophage was shown to impair the replication of the Mamavirus, thereby acting as a "virus of a virus".

Characteristics

Sputnik virophage measures approximately 50 nm in diameter and contains a circular double-stranded DNA genome. Its genome encodes for 21 proteins, several of which are involved in virus particle formation and DNA manipulation. Unlike most viruses that infect eukaryotic cells, Sputnik relies on the machinery of its host virus, Mamavirus, for replication, making it a unique example of a parasitic virus.

Impact on Host Virus

The infection of Mamavirus by Sputnik virophage leads to a decrease in the production of Mamavirus particles and an increase in the production of defective Mamavirus particles. This interaction not only affects the replication efficiency of the host virus but also suggests a form of viral interference, where the virophage can influence the outcome of co-infections in the amoeba host.

Ecological and Evolutionary Significance

The discovery of Sputnik virophage has implications for understanding viral ecology and evolution. It supports the idea that virophages can play a role in controlling the population dynamics of other viruses, potentially influencing the structure of viral communities. Furthermore, the study of Sputnik and other virophages can provide insights into the mechanisms of viral parasitism and the evolutionary relationships between viruses.

Research and Applications

Research on Sputnik virophage and its interactions with host viruses is ongoing. Studies are focused on understanding the molecular mechanisms underlying virophage-host interactions, the impact of virophages on viral evolution, and the potential use of virophages in controlling harmful viral infections.

See Also

• Virus
• Mimivirus
• Virophage
• Acanthamoeba polyphaga