Coumarin linker facilitates regulation of CRISPR/Cas9 activity using visible light

Photochemical control of CRISPR/Cas9 gene editing technology is an important tool for a variety biochemical applications. In the past, either photo-activation or photo-inactivation has been achieved using UV-light responsive chromophores, which are not ideal for in vivo applications. In this work, we describe a coumarin containing phosphoramidite that can be site-specifically incorporated into guide RNA using solid phase synthesis. It will facilitate regulation of Cas9-enabled nuclease activity using visible light. As a proof-of-concept, we synthesized guide RNA targeting the GFP gene. Regulation of nuclease activity was shown in solution, as well as in live GFP-expressing HEK293 cells.