American scientists, along with colleagues from Russia, have confirmed that a bacterial protein, which was previously assumed to be capable of editing RNA (ribonucleic acid), can in fact be used as a tool for modifying the genome, similar to the CRISPR / Cas9 technology. The article was published in the journal Science.
About half of all bacteria have a kind of analogue of the immune system, called CRISPR / Cas9, which protects them from viruses. The system consists of genes that encode the Cas proteins that cut foreign genes, as well as of short repetitive DNA sequences separated by unique regions - spacers. Spacers encode various types of guide RNA, a molecule that recognizes specific viral gene sequences and directs Cas to render them harmless.
There are many types of CRISPR / Cas9, which are characterized by different Cas9 proteins. Previously, scientists described the C2c2 protein, which does not contain regions that perform a nuclease function, in other words, cut DNA. The researchers suggested that the protein targets RNA.
A series of experiments have proven that C2c2 is indeed capable of cleaving single-stranded RNA. This ability of the protein allows the CRISPR system to be used to knockout - suppress functions - of bacterial messenger RNA, which transfers information from genes to ribosomes, where proteins are synthesized on its basis. Scientists tested the ability of C2c2 to bind to specific regions of E. coli (Escherichia coli) RNA and showed that the protein not only binds to RNA, but also disrupts its sequence.
According to the authors of the work, most likely there are other systems targeting RNA. In the future, scientists plan to develop customizable molecular tools for manipulating viral, bacterial and even human RNA.