Mutant/mutation
The mutant contains a diCre expression cassette containing the two genes Cre59-FKBP and Cre60-FRB placed on either side of the bidirectional eef1a promoter. This expression cassette has been introduced in the neutral p230p locus of wild type P. yoelii. This mutant does not contain a drug-selectable marker (SM). The hdhfr-yfcu SM, used to introduce the diCre cassette, has been removed by negative selection.

Protein (function)
The rapamycin-inducible Cre recombinase (DiCre) established for use in P. falciparum uses the rapamycin-binding FKBP12 and FRB proteins to dimerise the two enzyme halves. In the DiCre system, Cre is expressed in the form of two separate, enzymatically inactive polypeptides, each fused to a different rapamycin‐binding protein (either FKBP12 or FRB, the rapamycin‐binding domain of the FKBP12‐rapamycin‐associated protein mTOR).
Rapamycin‐induced heterodimerization of the two components restores recombinase activity (rapamycin‐mediated dimerization of two distinct, enzymatically inactive polypeptides approximately corresponding to the individual domains of Cre (residues Thr19–Asn59, called Cre59, and Asn60‐343, called Cre60) each fused to a different rapamycin‐binding protein (FKBP12 and FRB respectively) results in the reconstitution of Cre recombinase activity).

This site–specific recombinase recognises short, 34 bp sequences called loxP sites and catalyses the excision or inversion of the floxed (flanked by loxP) DNA segment.

Phenotype
Evidence for expression of FRB-fused Cre60 (FRB-Cre60) and FKBP12 was obtained by Western and IFA analysis using antibodies targeting both proteins.

Additional information
In the paper this transgenic line expressing DiCre has been used to introduce a second DNA construct that replaced the PKAc gene (cAMP-dependent protein kinase) of P. yoelii with a mutated PKAc gene that has a loxP sequence inserted between PKAc exon 1 and 2 (see mutant RMgm-5084).
Evidence is presented that (from the Abstract): 'The DiCre-loxP inducible knockout (iKO) system showed more than 80% excision efficacy of the target PKAc locus and more than 90% reduction of locus transcripts 24 hours (one cell cycle) after RAP administration in vivo. Using this developed system, cAMP-dependent protein kinase (PKAc) was inducibly disrupted and we found that PKAc-iKO parasites showed severe growth and erythrocyte invasion defects'. 

Other mutants