Synthetic far-red light-mediated CRISPR-dCas9 device for inducing functional neuronal differentiation

Significance We have developed an optogenetic far-red light (FRL)-activated CRISPR-dCas9 system (FACE) that is orthogonal, fine-tunable, reversible, and has robust endogenous gene-activation profiles upon stimulation with FRL, with deep tissue penetration capacity, low brightness, short illumination time, and negligible phototoxicity. The FACE device is biocompatible and meets the criteria for safe medical application in humans, providing a robust differentiation strategy for mass production of functional neural cells from induced pluripotent stem cells simply by utilizing a beam of FRL. This optogenetic device has expanded the optogenetic toolkit for precise mammalian genome engineering in many areas of basic and translational research that require precise spatiotemporal control of cellular behavior, which may in turn boost the clinical progress of optogenetics-based precision therapy.