The construct containing the following components (5' to 3') was inserted into the locus: a splice acceptor sequence, improved transactivator (rtTA*M2) with a poladenylation sequence, floxed neo/ura selection cassette, a second polyadenylation site, and tetO driven GFP with a human growth hormone polyadenylation sequence. Cre-mediated recombination removed the neo/ura cassette. (J:165820)