EB3 ES cells were targeted with a vector containing the Tet-off regulation cassette for the homeodomain transcription factor Ipf1 and EGFP expression. A floxed neo was removed via cre-mediated excision. EB3 cells carry one allele of Pou5f1 that has been inactivated by targeted integration of E14Tg2a ES cells with an IRESBSDpA selection cassette. (J:102833, J:103479)