Pioneering The Development Of CRISPR-Guided Photooxidation Of Guanine For Guanine-To-Cytosine Conversion In Cellular DNA

Abstract

Adapted as an RNA-guided genome-editing system, CRISPR/Cas9 has served promising potential in the treatment of human genetic diseases. Specifically, enzymatic base editors can effectively catalyze single-nucleotide conversions in cellular DNA through the use of a catalytically-dead Cas9 and a deaminase. Current base editors primarily consist of cytosine and adenine base editors, which can create C-to-T and A-to-G conversions through deamination of the substrate, respectively. However, the use of enzyme-based approaches can give rise to exasperated levels of non-specific editing. Therefore, new base editors are needed to expand the mutagenic repertoire of current base editing technologies, as well as reduce off-target effects associated with current editors. For this, the photooxidation of guanine was explored as a method of achieving precise G-to-C conversions in the cellular genome. The development of the first chemical base editor could therefore allow for the utmost spatiotemporal precision, potentially alleviating the off-target effects associated with enzymatic editors.