RNA Editing Enhances DNA Repair

Researchers at the University of California, Davis, have found an RNA-editing reaction that may play a role in repairing DNA damaged by an inflammatory response (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1009231107). RNA-editing reactions can alter nucleotides and change the protein-coding properties of RNA molecules, and they are known to alter the function of some nervous system proteins. Sheila S. David, Peter A. Beal, and colleagues investigated the DNA repair enzyme NEIL1, which initiates repair of oxidized DNA bases. When an adenosine in NEIL1 messenger RNA gets deaminated to form inosine, the mRNA is subsequently translated to place an arginine instead of a lysine in the portion of NEIL1 that recognizes oxidized DNA bases. The amino acid switch affects which DNA lesions NEIL1 preferentially recognizes and the enzyme’s activity in excising oxidized bases. Because production of the RNA deamination enzyme is induced by an inflammatory response, the researchers propose that editing of the mRNA of NEIL1 may be a way that cells provide themselves with a broader range of DNA repair in response to the oxidative stress of inflammation.