Tg(Six2-EGFP/cre)1Amc

The 181 kb C57BL/6J mouse bacterial artificial chromosome (BAC) RPCI23-311C1, containing the entire Six2 locus (and other genes), was modified by targeting a Tet-off-eGFPCre into the ATG start site of the Six2 locus. This inserted a Tet-off cassette (tetracycline-regulated transactivator (tTA), 2xpolyA signal, tetracycline-responsive element (TRE or tetO with CMV min promoter) followed by an Enhanced Greed Fluorescent Protein/Cre Recombinase (EGFP/Cre) fusion protein coding sequence, (SV40 polyA signal), and frt-flanked kanamycin cassette. The targeted BAC sequences were further modified using FLP recombination to remove the selection cassette and linearized to remove its original vector backbone. The resulting modified BAC was microinjected into CD-1 zygotes. Sequence updates published after this transgene was created revealed an upstream Six2 ATG start site that is in-frame with the tTA; thus an apparent and unintended fusion was created with the tTA (80 amino acids potentially added) that renders transgene expression unaffected by tetracycline/doxycycline administration. (J:148455)