Tg(Ctsk-cre/ERT2)4Hlk

The transgenic construct was generated by insertion of the mouse Ctsk sequence (-3429 to +52) into a cre/ERT2 expression plasmid. A purified 1.7 kb fragment of the original vector was microinjected into C57BL/6 (B6) or FVB fertilized oocytes. Seven B6 and 2 FVB founder mice were identified and crossed to C57BL/6 (FVB founders were crossed + 8 generations to B6) animals. Quantitative RT-PCR (QPCR) was performed on 8-10 week-old animals and showed cre/ERT2 mRNA expression was significant only in bone tissue. Founder #4 on the original B6 background and #284 on the FVB background were crossed to Rosa-lacz reporter animals. Beta-galactosidase staining was observed in long bones and calvaria of tamoxifen-treated 8-10 week old animals and in embryos from pregnant females treated with tamoxifen at E13.5. Line #4 was studied in greater detail. (J:186154)