The construct contains cDNA of demethylation deficient Kdm2b under the control of the CMV promoter fused with the tet-responsive element (tetO) which was co-electroporated into KH2 embryonic stem cells along with a plasmid expressing Flpe recombinase to allow FRT/Flpase-mediated single copy site-specific integration into the locus. (J:232437)