# Optical control of Cas9 activity through visible-light cleavable crRNAs

## TL;DR

This paper introduces a method to control Cas9 activity using visible light to cleave crRNAs, allowing precise and non-invasive genome editing.

## Contribution

The novel contribution is the development of visible-light cleavable crRNAs for spatial and temporal control of Cas9 activity.

## Key findings

- Visible-light cleavable crRNAs efficiently inhibit Cas9 activity in vitro.
- The method allows precise downregulation of Cas9 activity using visible light.
- This approach enables non-invasive and safe genome editing.

## Abstract

In this work, we present several visible-light cleavable crRNAs targeting two different genes for regulating Cas9 activity. The crRNAs contain a total of three different photocleavable linker (PL) which induce a bond break when irradiated with a suitable wavelength. Cleavage of the crRNAs efficiently inhibits Cas9 activity, as demonstrated by the in vitro Cas9 assay developed in this work. By using visible light, our approach will enable precise downregulation of Cas9 activity in terms of location and timing, thereby enabling non-invasive and harm free control over genome editing for safer application.

Visible-light-cleavable crRNAs enable precise and non-invasive deactivation of Cas9 activity for safer genome editing.