Evidence of thousands of phages with DNA strands that should allow them to conduct gene editing on other viruses or bacteria has been discovered by researchers at the University of California, Berkeley, and the University of California, Los Angeles, in collaboration with a colleague from Vilnius University. Their work may be seen in the online edition of Cell.
Some members of this team found in 2012 that RNA may be used to instruct CRISPR-Cas9 to alter specific sections of DNA in other animals. Finding that many different kinds of bacteria employ CRISPR-Cas systems to fight off viral infections inspired their investigation. Bacteria can protect themselves from future infections from a specific strain of virus by using this technique to cut and remove DNA strands from the virus and store them in their own genomes.
Researchers have now discovered that certain viruses have comparable machinery, although until recently, this had been thought to be extremely unusual. This fresh effort was made by the academics to find out how common something really is.
A large amount of time was spent examining the genetic material of thousands of phages (bacteria-infecting viruses) for clues to the existence of a CRISPR system. More than 6,000 were located by the researchers, demonstrating that they are not exceedingly unusual.
The DNA fragments identified by the researchers were hypothesized to have been snatched from bacteria and to have been utilized in a process similar to that of conventional antibiotics in the defense against other phages and bacteria. They need to do further investigation to back up their assumptions. Meanwhile, by inspecting specific gene fragments in greater detail, scientists learned that not all systems were the same, with some appearing to be more compact and energy-efficient than others. Scientists who are already employing such systems to modify cells for human reasons may benefit from the discovery. It may also spark the development of novel applications of biotechnology, such as the use of phage-based systems for gene editing in situations where conventional methods are impractical due to their bulk.
Sources:
Basem Al-Shayeb et al. (2022). Diverse virus-encoded CRISPR-Cas systems include streamlined genome editors, Cell. DOI: 10.1016/j.cell.2022.10.020
https://phys.org/news/2022-11-thousands-phages-crispr-gene.html
