B6.129P2-Gt(ROSA)26Sor^tm3Nik/J

These 5172 3-state Cre-sensitive (5172 3SCS) mice contain a construct designed to insert (from 5' to 3') a floxed-STOP cassette, tdTomato open reading frame (ORF), and a floxed-internal ribosome entry site (IRES) fused to an enhanced green fluorescent protein (GFP) ORF. The IRES-eGFP element was flanked by 5172 mutant loxP sites (which recombine at 30% the efficiency of wildtype loxP sites). This vector was inserted into the Gt(ROSA)26Sor locus allowing for widespread expression. These 5172 3SCS mice are of general use for detecting cells that have expressed the Cre recombinase, for Cre recombinase-based lineage marking experiments, and in particular for applications in which it is useful to discriminate cells that differ in how much Cre recombinase they have expressed.Cre recombinase-dependent excision of IRES-GFP in the 5172 3SCS strain occurs at approximately three times the efficiency it does in the 3373 3SCS strain.