CRISPR editor can also be used for RNA editing

Research into RNA editing could enable treatments for genetic diseases. Researchers at Montana State University have shown how the CRISPR technique can also be used to edit RNA. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a type of immune system bacteria use to recognise and fight viruses. This system has been used for years to cut and edit DNA, but the deployment of similar technology for RNA is new. A CRISPR protein called Cas9 is used to edit DNA, while a different CRISPR system is needed for RNA; the researchers tried a subsystem known as type III.

"In our previous work, we used CRISPR type III to edit viral RNA in a test tube, but we wondered if we could program RNA manipulation in a living human cell," said co-author Artem Nemudryi. The scientists therefore programmed CRISPR type III proteins to cut out the RNA containing the mutation that causes cystic fibrosis and restore cell function. The cell eventually pieced the cut RNA back together in a way that removed the mutation.

Why edit the RNA if it is a temporary molecule, whereas editing the template DNA would resolve the situation once and for all? Manipulating the "template", i.e. editing the DNA, could in some cases cause undesirable and potentially irreversible side changes. Because RNA is a temporary copy, any edits made are essentially reversible and carry much less risk.

Source: Anna Nemudraia et al, Repair of CRISPR-guided RNA breaks enables site-specific RNA excision in human cells, Science (2024). DOI: 10.1126/science.adk5518