A bacterial artificial chromosome (BAC) library (CHORI) was used to obtain a BAC (#RP23-27F7) containing the entire mouse parathyroid hormone-like peptide (Pthlh) gene. This BAC was modified to replace the native start codon of the Pthlh gene with a cre/ERT2 fusion gene (Cre recombinase fused to a human estrogen receptor ligand-binding domain), followed by an SV40 polyadenylation sequence. (J:266751)