What is ARCUS?

ARCUS is a next-generation genome editing platform derived from a natural genome editing enzyme called a homing endonuclease.

Homing endonucleases

Homing endonucleases are nature’s genome editing system. They are site-specific DNA-cutting enzymes encoded in the genomes of many eukaryotic species. Homing endonucleases have the unusual ability to precisely recognize long DNA sequences (12-40 base pairs) that are typically rare enough to occur only once in a complex genome. By targeting a double strand DNA break to a specific site in the genome of a cell, a homing endonuclease triggers the cell’s DNA repair pathways and stimulates homologous recombination. In nature, this results in gene conversion events in which the genome of the cell is modified in a very precise way, most frequently by the insertion of a foreign gene at the site of the DNA break. The ability to generate a single DNA break in a complex genome to achieve gene modification – without off-targeting – makes homing endonucleases the ideal starting material for a genome editing technology.


The backbone of the ARCUS technology is the ARC Nuclease – a fully synthetic enzyme that is very similar to a homing endonuclease but is modified to be a better starting point for the development of new gene editing reagents. ARC Nuclease shares many of the positive attributes of a homing endonuclease, such as small size and unparalleled sequence specificity, but it can more easily be evolved into a custom gene editing tool that recognizes a DNA sequence of our choosing. Each ARCUS reagent is optimized using a set of proprietary in silico and lab-based techniques to ensure maximum gene editing efficiency with minimum off-target activity.

What makes ARCUS unique in the world of genome editing?


Precision BioSciences owns ARCUS. Only a Precisioneer can make an ARCUS reagent.


ARCUS isn’t limited to deletions. ARCUS can be used to insert, delete or edit DNA.


ARCUS doesn’t miss its target. ARCUS doesn’t generate truly random DNA-breaks.


310 amino acids. 930 base pairs. ARCUS is compatible with essentially any delivery strategy.


Polypeptide. ARCUS is a single protein expressed from a single gene. There’s no need to deliver multiple parts.


Matched 4 base pair 3′ overhangs result in perfect, predictable removal of DNA.