Fos^{tm2.1(icre/ERT2)Luo}

A targeting vector was designed to insert a 2A::iCreER::frt-neo-frt cassette into the translational stop site of the FBJ osteosarcoma oncogene locus (Fos) on chromosome 12. The viral 2A oligopeptide sequence mediates ribosomal skipping. The iCreER fusion gene used here has an improved/optimized variant of Cre recombinase (iCre) that is fused to a G400V/M543A/L544A triple mutation of the human estrogen receptor ligand binding domain (ER). TThe targeting construct was electroporated into 129;FVB-derived embryonic stem (ES) cells, and correctly targeted ES cells were injected into recipient blastocysts. Chimeric animals were bred to CD1 mice and/or germline-active GFP-FlpO transgenic mice (mixed genetic background including CD1) to delete the frt-flanked neo cassette. (J:101977, J:250613)