An RNA virus that infects mosquitos has been newly discovered. The catch? It separately packages its 5 genomic segments into different virions. Amazingly, the virus tentatively named Guiaco Culex (GCXV), is not the only virus that employs this replication technique. In fact, there are many known plant and fungi viruses, known as multicomponent viruses, that package their segments separately. It is one of the many diverse replication strategies of RNA viruses, and although there is strong evidence that segmentation helps with differential gene expression, it is not well understood why a virus would package its segments separately, since this likely hinders efficient viral transmission.
In order to produce the full infection cycle in multicomponent viruses, all or most segments must be present, although researchers believe that infection by a subset of the segments is enough to induce viral transcription and replication. In the case of GCXV, its likely that 4/5 segments are necessary for infection and transmission, and the fifth segment codes for a nonstructural protein.
GCXV is the first multicomponent animal virus discovered, and it is also the only known enveloped multicomponent virus. It seems to be distantly related to flaviviridae. Hopefully with the discovery of this novel animal virus research into multicomponent viruses will increase, and someday we will understand what is going on with these viruses.
Read the study here:
Ladner, J. T., Wiley, M. R., Bietzel, B., August, A. J., & Dupuis, A. P., II. (2016, September 14). A Multicomponent Animal Virus Isolated from Mosquitoes. Cell Host & Microbe, 20(3), 357-367.
And the NPR article here:
Elisa Hofmeister ‘18