Base editing both DNA strands in distinct editing windows with small CRISPR-associated effector Cas12f1

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• CRISPR-associated (Cas) base editors enable targeted DNA base conversions without double-strand breaks.
• Cas proteins are key components of CRISPR systems, facilitating precise genome editing.

Purpose of the Study:

• To develop novel, miniature base editors using the CRISPR-Cas12f1 protein.
• To characterize the base editing activity and profile of these new Cas12f1-based editors.

Main Methods:

• Engineered chimeric base editors by fusing catalytically inactive dCas12f1 with cytosine or adenine deaminases.
• Performed systematic base editing analyses on a target plasmid sequence in *Escherichia coli*.

Main Results:

• Demonstrated efficient base editing using the small Cas12f1 base editors.
• Observed efficient editing on both the target DNA strand and the displaced non-target strand, a unique profile not seen with other base editors.

Conclusions:

• Developed novel, miniature CRISPR-Cas12f1 base editors with a unique editing profile.
• These AsCas12f1 base editors represent a valuable addition to the CRISPR-Cas genome editing toolbox due to their small size and distinct editing capabilities.