Highly efficient RNA-guided base editing in mouse embryos.

Area of Science:

• Genetics
• Molecular Biology
• Gene Editing

Background:

• Base editors (BEs) are tools for precise DNA modification.
• BEs combine cytidine deaminase with CRISPR-Cas9 to convert cytidine to uridine.
• This enables targeted single-base-pair substitutions in eukaryotic genomes.

Purpose of the Study:

• To establish an efficient method for generating mice with targeted point mutations using base editors.
• To assess the efficiency of base editors in creating specific mutations in mouse zygotes.

Main Methods:

• Base editor (BE) mRNA or ribonucleoproteins targeting the Dmd or Tyr gene were delivered into mouse zygotes.
• Delivery methods included electroporation and microinjection.
• The efficiency of mutation generation in F0 mice was evaluated.

Main Results:

• Nonsense mutations were observed in F0 mice with an efficiency ranging from 44% to 57%.
• Allelic frequencies of these targeted mutations reached up to 100% in some cases.
• This demonstrates the high efficacy of the base editing approach in vivo.

Conclusions:

• Base editors provide an efficient strategy for introducing targeted point mutations in mice.
• This technique facilitates the rapid generation of genetically modified mouse models for research.
• The high efficiency and allelic frequency indicate the robustness of this gene editing method.