Bacteriophages are viruses adapted to living and replicating within bacteria. Because of their position, they don’t typically engage in gene-transfer with anything beyond other bacteriophages and its host bacteria.
Typically.
NewScientist (15 October 2016) reports on the detection of a gene in a virus from an arachnid, and, well, here it is:
[The virus named] WO, however, faces an unusual challenge: its targets are Wolbachia bacteria living in the cells of insects, spiders and some other animals. That means that for it to attack new targets, WO has to escape not only from its existing Wolbachia host, but also from the eukaryotic cell. The virus particles must then evade the eukaryote’s powerful immune system.
Many viruses of eukaryotic cells [i.e., non-bacterial cells] co-opt genes from their hosts to help them do this. To see if WO could do the same, microbiologists Sarah and Seth Bordenstein at Vanderbilt University in Nashville, Tennessee, sequenced its genome. They found several genes closely related to ones present in eukaryotes, including the gene for latrotoxin, the poison used by black widow spiders. It kills by poking holes in cell membranes, making it a plausible tool for a virus needing to escape from a eukaryotic cell (Nature Communications, DOI: 10.1038/ncomms13155).
Interesting. I wonder about the likelihood of the Wolbachia bacteria ever invading human hosts. And whether or not the virus makes enough latrotoxin to seriously damage the human host. A virus is very small, but it uses the machinery of the cell it has invaded to reproduce – and, in this case, produce the latrotoxin. Perhaps if enough viruses were active at the same time…
But Wolbachia is interesting for other reasons. The High-Tech Society is also on this subject and contributes an additional interesting tidbit:
Wolbachia is currently being studied as a way to repress the virus spreading capabilities of mosquitos, after studies showed that it prevents the spread of dengue and zika virus in infected mosquitoes. Being able to edit it before infecting mosquitoes would offer scientists more control over the effects, and more repression of viruses like Zika. WO also spreads freely among wolbachia, meaning that spreading it to even a small population could eventually result in large scale results.
