Satelliittivirus

Satelliittivirus is a classification of subviral agents that require the presence of a helper virus for replication. These distinct RNA molecules are not able to produce their own proteins and thus depend entirely on the replication machinery of a co-infecting virus, known as the helper virus. Satelliittiviruses themselves are infectious but their infectivity is contingent upon the presence of the helper virus in the same host cell. Their genomes are typically small and encode only a limited number of proteins, if any. The replication of a satelliittivirus genome is carried out by the RNA-dependent RNA polymerase of the helper virus. The satelliittivirus genome is then encapsidated by proteins provided by the helper virus, or in some cases, by a specific satelliittivirus-encoded coat protein that is synthesized using helper virus resources. These agents are found in a wide range of hosts, including plants, animals, and fungi. While they do not independently cause disease, they can often influence or exacerbate the symptoms caused by their helper virus. For instance, some satelliittiviruses can lead to more severe disease manifestations when infecting plants alongside their specific helper viruses. The study of satelliittiviruses provides insights into viral evolution and the complex interactions between different viral entities within a host.