What is a homing endonuclease?

Homing endonucleases (often called ‘meganucleases’) comprise a large family of natural enzymes that recognize and cut long DNA sequences.  They are unique in nature in their ability to discriminate a single site within a large genome.  One example of a natural meganuclease is the I-CreI protein from Chlamydomonas algae.  This enzyme recognizes and cleaves a 22bp DNA sequence (shown) in the chloroplast chromosome.

The Precision BioSciences DNE approach maintains the natural function of these homing endonucleases and simply directs it to new locations by re-engineering the DNA-recognition properties of the enzyme.

Jurica, et al. (1998), Mol. Cell 2:469-476