Abstract
Bone morphogenetic proteins-2 and -4 (BMPs-2 and -4) are transforming growth factor beta-related proteins that can induce bone formation in vivo. We observed that the level of endogenous BMP-2 mRNA increased an average of 11-fold on differentiation of F9 embryonal carcinoma cells into parietal endoderm after treatment with retinoic acid (RA) and cAMP, whereas the message for the closely related BMP-4 decreased 12-fold after this treatment. Therefore, the effects of exogenous recombinant BMP-2 protein on the RA-induced differentiation of F9 embryonal carcinoma cells were investigated. BMP-2 addition altered the growth and morphology of RA-treated but not untreated cells. Moreover, the abundance of several messages was affected by exogenous BMP-2 treatment. Notably, the BMP-2 and -4 messages themselves were reduced by the addition of exogenous BMP-2. The observations suggest that RA, which is known to affect bone morphogenesis, may regulate the osteoinductive proteins, BMP-2 and -4. Furthermore, BMP-2 and -4 may be involved in preimplantation embryogenesis.