# GFP-on mouse model for interrogation of in vivo gene editing

## TL;DR

This paper introduces a new mouse model that uses a fluorescent protein to quickly test how well gene editing tools work in living organisms.

## Contribution

The novel contribution is the development of the GFP-on mouse model for evaluating in vivo gene editing delivery vehicles.

## Key findings

- AAV9-ABE8e-sgRNA intravenous delivery in adult mice results in EGFP expression matching AAV9 tropism.
- Intrahepatic delivery in fetal mice restores EGFP expression in targeted organs for at least six months.
- The model enables high-throughput evaluation of gene editing tools and delivery methods.

## Abstract

Gene editing technologies have revolutionized therapies for numerous genetic diseases. However, in vivo gene editing hinges on identifying efficient delivery vehicles for editing in targeted cell types, a significant hurdle in fully realizing its therapeutic potential. A model system to rapidly evaluate systemic gene editing would advance the field. Here, we develop the GFP-on reporter mouse, which harbors a nonsense mutation in a genomic EGFP sequence correctable by adenine base editor (ABE) among other genome editors. The GFP-on system was validated using single and dual adeno-associated virus (AAV9) encoding ABE8e and sgRNA. Intravenous administration of AAV9-ABE8e-sgRNA into adult GFP-on mice results in EGFP expression consistent with the tropism of AAV9. Intrahepatic delivery of AAV9-ABE8e-sgRNA into GFP-on fetal mice restores EGFP expression in AAV9-targeted organs lasting at least six months post-treatment. The GFP-on model provides an ideal platform for high-throughput evaluation of emerging gene editing tools and delivery modalities.

In vivo gene editing hinges on identifying an ideal delivery vehicle from numerous candidates. Here, authors establish the GFP-on mouse model capable of translating successful adenine base editing to a fluorescent readout thus enabling the rapid evaluation of genome editing delivery vehicles.