Cre-mediated recombination between Gt(ROSA)26Sortm6(ACTB-EGFP*,-tdTomato)Luo and Gt(ROSA)26Sortm7(ACTB-EGFP*)Luo produces this allele. The allele has the CMV enhancer/chicken beta-actin core promoter (pCA) upstream of the recombined "MADM TT" cassette inserted into the Gt(ROSA)26Sor locus. The "MADM TT" cassette has an ATG start codon, a beta-globin intronic sequence (containing a frt-flanked region of two lox site variants [lox2272 and lox5171] followed by a single loxP site), an ATG-less tdTomato sequence (nucleotides 3-1548 including stop codon) tagged with three copies of the Myc epitope at its C-terminus, and an SV40 T-antigen poly(A) signal. (J:181830)