creAB::NrdJ-1N consists of a portion of the P1cre recombinase (amino acid residues 1-250) fused to the NrdJ-1N split intein fragment. creAB::NrdJ-1N can be used as part of a bipartite split-Cre recombinase system in combination with NrdJ-1C::creC (FBrf0245663). The NrdJ-1N and NrdJ-1C split intein fragments form a complementary pair which show efficient protein trans-splicing and a lack of cross-reactivity with other split intein fragments (PMID:22753413). In the bipartite split system, a functional P1cre recombinase is only reconstituted at the intersection of the expression patterns of the creAB::NrdJ-1N and NrdJ-1C::creC split components, when trans-splicing between the NrdJ-1N and NrdJ-1C split intein fragments results in the 'creAB' and 'creC' fragments being fused into a single polypeptide (with the split intein fragments being excised during the trans-splicing reaction) (FBrf0245663). The reconstituted recombinase is expected to have the properties of the native P1cre recombinase, with compatible target sites corresponding to the wild-type loxP site and some of its derivatives. Recombination occurs between a pair of target sites oriented in the same direction; the 13bp repeats each act as binding sites for the recombinase, while the asymmetric 8bp spacer is the site of DNA strand exchange and determines the orientation of the target site (PMID:3856690).