Virus Editor
Scientists have developed a system for editing the genomes of bacteriophage viruses
American molecular biologists were able to adapt the popular CRISPR/Cas13 genomic editor to work with the genome of bacteriophage viruses. This makes it possible to make point changes to their genes and create new variations of viral drugs for bacterial infections, according to the journal Nature Microbiology (Guan et al., Bacteriophage genome engineering with CRISPR–Cas13a).
"We have adapted the CRISPR/Cas13 RNA editor to work with the genome of these bacterial pathogens," the experts said.
The CRISPR/Cas9 system is a kind of genetic "antivirus", it is able to find and destroy traces of viral DNA in the genome of a microbe. Her discovery led to the creation of many genomic editors based on CRISPR/Cas9 and similar cellular systems capable of editing not only DNA molecules, but also RNA.
A team of scientists led by Joseph Bondi-Denomi, associate professor at the University of California at San Francisco, was able to adapt one of the versions of this genomic editor, CRISPR/Cas13, to work with the genome of bacteriophage viruses. This is what researchers call the varieties of viruses that attack only microbes and do not pose a threat to humans.
Bacteriophages are often considered by scientists as a possible replacement for antibiotics. But this is prevented by the fact that microbes quickly mutate and become protected from many broad-acting bacteriophage viruses. Researchers have developed an approach that allows this problem to be circumvented by making point modifications to the DNA of these viruses.
According to scientists, this system makes changes not to the DNA of the virus itself, but to its RNA copies, which are used to produce new viral particles inside infected microbes. Thus, experts bypass the protective systems of bacteriophages, which prevent the bacterial "antivirus" from recognizing the virus genome and destroying it.
To do this, they modified the structure of the Cas13 enzyme in such a way that it did not destroy the entire copy of the viral genome, but removed from the chain only a part that coincided in structure with one of the short RNA templates. Scientists have tested the work of this system on bacteriophages OMKO1, PKZ and PaMx41, which affect Pseudomonas aeruginosa and are often used in the fight against "invulnerable" to antibiotics variations of this microbe.
Subsequent experiments by scientists showed that a modified version of the Cas13 enzyme was able to embed several foreign DNA sites into the genome of the bacteriophages OMKO1, PKZ and PaMx41, which caused these viruses to glow or produce different proteins.
According to scientists, such successes will be able to accelerate the development of medicines based on genetically modified bacteriophages.
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