Msx1^{tm2.1(cre/ERT2)Bero}

A targeting vector with the cre/ERT2 sequence, polyadenylation site, and an Frt-flanked neomycin cassette inserted into the ATG site of Msx1 in a plasmid was generated by homologous recombination in bacteria. The linearized targeting vector was electroporated into ES cells and targeted clones were used to generated chimeras. F1 offspring were crossed to Flp deleter mice to delete the neo marker. (J:173525, J:194129)