Bone morphogenetic proteins (BMP-2 and BMP-3) induce the late phase expression of the proto-oncogene c- fos in murine osteoblastic MC3T3-E1 cells

Abstract

Here we report that bone morphogenetic proteins 2 and 3 (BMP-2 and BMP-3) induced marked expression of c- fos mRNA in a biphasic manner, i.e. the late phase (48 to 60 h) as well as the immediate-early phase (0.5 h), in murine osteoblastic MC3T3-El cells in vitro. The BMP-induced late phase c- fos gene expression was temporally associated with the onset of marked expression of the genes for osteocalcin and alkaline phosphatase, differentiation markers of mature osteoblasts. In contrast, none of TGF-β1, 10% FBS, IGF-I and IGF-II, which induced only the immediate-early c- fos mRNA expression, stimulated the expression of osteocalcin and alkaline phosphatase genes. These data suggest that in osteoblasts BMP-2 and BMP-3 induce the late phase expression of c- fos, which may play a role in transcriptional activation of the genes involved in differentiation of osteoblasts.