A 5 kb Krt15 promoter fragment was inserted into a vector containing the cre/ERT2 (Cre/ER(G)T2) cassette. The construct was microinjected into oocytes and eight founder lines were obtained. 3 lines were found to exhibit specific cre nuclear staining patterns and recombined reporter patterns (in offspring of crosses) in hair follicles after tamoxifen administration. A high expressing line, line C, was established. (J:175633)