Igs7^{tm1(tetO-tdTomato,-Cdkn1a)Rdiez}

The targeting vector is designed with, from 5' to 3', an FRT3 site, two copies of chicken beta-globin HS4 insulator element (to reduce reporter gene expression in the absence of transactivators), a Tet-response element/promoter (TRE tight, composed of seven TetO repeats and a minimal CMV promoter), a loxP-flanked red fluorescent protein variant (tdTomato) acting as a STOP cassette with 2 polyadenylation sequences (synthetic pA and hGHpA), cyclin-dependent kinase inhibitor 1A (P21) (Cdkn1a) open reading frame, a BGH polyA, a woodchuck virus RNA stabilizing sequence (WPRE), two copies of chicken beta-globin HS4 insulator element, an AttB site, a PGK-5'hygro cassette, an RNA splice donor and a FRT5 site. G4 embryonic stem cells previously targeted with FRT3::AttB::PGK-neoR-polyA::FRT5::splice acceptor::3'hygro cassette::SV40 polyA:AttP in Igs7, were transfected with the replacement vector and Flp recombinase vector for recombinase-mediated cassette exchange (RCME). (J:290413)