Gt(ROSA)26Sor^tm1(creB)Dwi

A cassette was constructed with the creB fragment of cre recombinase (codons 60-343) fused to an FKBP dimerization domain by an F2 linker and included a polyadenylation sequence. This cassette was cloned into a plasmid containing Gt(ROSA)26Sor homology sequences. The linearized plasmid was introduced into ES cells and by homologous recombination the creB sequence was inserted into the Gt(ROSA)26Sor locus. When crossed to mice expressing the creA sequence, the two fragments will dimerize in presence of AP20187 and a functional cre protein will be produced. (J:194841)