<p>(A) Western immunoblot analysis of the Dox-regulated Osx-expressing C2C12 cells. Osx expression is turned on in the absence of Dox. Beta-actin was used as a loading control. (B) MMP13 mRNA levels in a stable Tet-off C2C12 mesenchymal cell line. RNA was obtained from cultures treated with or without Doxycycline. Osx expression is induced in the absence of Doxycycline in this stable cell line. MMP13 mRNA levels were quantitated by real-time RT-PCR. The MMP13 RNA level obtained from the cells cultured with Dox was normalized to a value of 1. Values are presented as the mean ± S.D.</p
