The Cre-lox system is used as a genetic tool to control site specific recombination events in genomic DNA.
The Cre protein (encoded by the locus originally named as "Causes recombination", with "Cyclization recombinase" being found in some references)[REF][REF] consists of 4 subunits and two domains: The larger carboxyl (C-terminal) domain, and smaller amino (N-terminal) domain.