1.
Mouse Model for Optogenetic Genome Engineering.
Abstract:
Optogenetics, a technology to manipulate biological phenomena thorough light, has attracted much attention in neuroscience. Recently, the Magnet System, a photo-inducible protein dimerization system which can control the intracellular behavior of various biomolecules with high accuracy using light was developed. Furthermore, photoactivation systems for controlling biological phenomena are being developed by combining this technique with genome-editing technology (CRISPR/Cas9 System) or DNA recombination technology (Cre-loxP system). Herein, we review the history of optogenetics and the latest Magnet System technology and introduce our recently developed photoactivatable Cre knock-in mice with temporal-, spatial-, and cell-specific accuracy.
2.
Establishment of a tTA-dependent photoactivatable Cre recombinase knock-in mouse model for optogenetic genome engineering.
Abstract:
The Cre-loxP recombination system is widely used to generate genetically modified mice for biomedical research. Recently, a highly efficient photoactivatable Cre (PA-Cre) based on reassembly of split Cre fragments has been established. This technology enables efficient DNA recombination that is activated upon blue light illumination with spatiotemporal precision. In this study, we generated a tTA-dependent photoactivatable Cre-loxP recombinase knock-in mouse model (TRE-PA-Cre mice) using a CRISPR/Cas9 system. These mice were crossed with ROSA26-tdTomato mice (Cre reporter mouse) to visualize DNA recombination as marked by tdTomato expression. We demonstrated that external noninvasive LED blue light illumination allows efficient DNA recombination in the liver of TRE-PA-Cre:ROSA26-tdTomato mice transfected with tTA expression vectors using hydrodynamic tail vein injection. The TRE-PA-Cre mouse established here promises to be useful for optogenetic genome engineering in a noninvasive, spatiotemporal, and cell-type specific manner in vivo.
