Background: Ribozymes are small catalytic RNAs that possess the dual functions of sequence- specific RNA recognition and site- specific cleavage.

A second mechanism, which is operative at late times during viral replication, involves the site- specific cleavage of primary RNAs.

Hammerhead ribozymes are effective modulators of gene expression due to their simple structure, site- specific cleavage activity and catalytic potential.

V(D)J recombination is a highly regulated process, proceeding from a site- specific cleavage to an imprecise end joining.

V(D)J recombination proceeds from a site- specific cleavage to an imprecise end joining, via generation and resolution of recombination ends.

Selective inhibitors were applied to dissect the roles of the individual peptidases and to determine the peptidase- specific cleavage map of the hemoglobin molecule.

Analysis of aggrecanase specific cleavage patterns of a crude cartilage proteoglycan extract were used to validate some of the differences in peptide intensity identified.

Here, we review DSB repair mechanisms and site- specific cleavage systems that have provided insight into these mechanisms and led to the current gene editing revolution.

Results: Following AAV-mediated delivery of editing reagents to patient-derived primary human hepatocytes in vivo, OTC locus- specific cleavage was achieved at efficiencies of up to 72%.