An HA-tagged Ptch1 sequence from C57BL/6 was modified to encode the Threonine to Asparagine sustitution at amino acid residue 1267 which is found in FVB/N strains. Residue 1267 is found in a conserved region of the cytoplasmic domain near the C-terminus. The modified sequence was placed under the control of the human KRT14 promoter. At least four founder lines were produced (numbers 6, 7, 8, 10). (J:118622)