A fragment (-9624 - +4439) of the mouse Dmp1 gene containing a 9624 bp promoter region, the 95 bp exon 1, 4326 bp intron 1 and 17 bp of initial non-coding region of exon 2 was cloned into a vector in front of the cre/ERT2 cDNA. The linearized vector was injected into B6C3F1 pronuclei. 14 pups that were positive for cre integration were identified and six independent founders were crossed to wild-type B6 mice. Two founders demonstrated penetrant excision of the STOP cassette when crossed to Rosa26-lacZ reporter mice, and were analyzed in greater detail. The two transgenic founder lines (D77 and 0022) were identified to have tamoxifen-inducible Cre recombinase activity in both osteocytes and mature osteoblasts. The two lines were similar with the only difference that line D77 had greater expression in mature osteoblasts.