The transgene contains the wild-type human BAC RP11-209M4, which contains SOST and the 3' end of MEOX. RT-PCR and quantitative PCR confirmed that all lines express human SOST in the mineralized bone of neonatal and adult mice (skull, rib, and femur) and in the adult kidney. No expression of human MEOX was detected. Three lines were generated (A, B, and an unnamed line). Founder line A was analyzed for expression.