A BAC clone spanning the Sftpc (SPC) and Nudt18 genomic regions of mouse chromosome 14 was modified to insert a reverse tetracycline transactivator sequence at the start ATG of the Sftpc locus. A second round of recombination was performed to insert a cre recombinase sequence under the control of the tetracycline responsive element (tetO) at the start ATG of the Nudt18 gene. Founder information was not available.