BMP Responsive Immortalized Reporter (BRITER) Cell Line

Generated in order to conduct high-thoroughput chemical and molecular genetic screening to identify a novel small molecule alternative activator of BMP signaling. The cells are immortalized tamoxifen inducible Bmp2; Bmp4 double conditional knockout murine (Bmp2c/c;Bmp4c/c; R26CreER neonatal mouse) calvarial osteoblast cells expressing a BMP Response Element(BRE)-dependent Firefly Luciferase (FFLuc) gene and an SV40 promoter/enhancer-dependent Renilla Luciferase (RRLuc) gene. FFLuc activity increases in response to BMP signaling activity while the RRLuc gene acts as an internal control to limit the number of false-positives resulting from non-specific activation of cellular processes, such as cell proliferation. In addition the sensitivity to exogenous BMP signaling can be intensified through the addition of 4-hydroxytamoxifen, which reduces the level of endogenous BMP signaling through the knockout of the Bmp2 and Bmp4 genes resulting in a specific and highly efficient reporter of BRE activation.