Temporal variation of c-fos proto-oncogene expression during osteoblast differentiation and osteogenesis in developing rat bone

✍ Scribed by M. Machwate; A. Jullienne; M. Moukhtar; Dr. P. J. Marie

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 958 KB
• Volume: 57
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240570108

✦ Synopsis

Abstract

To delineate the implication of c‐fos protooncogenic in the osteogenie process, we have investigated the temporal pattern of c‐fos mRNA expression in fetal and neonatal rat bone during intramembranous and endochondral bone formation. Northern blot analysis of mRNA extracted from calvaria and femur showed that expression of c‐fos, Histone H4, and osteocalcin mRNAs followed a temporal sequence during bone development. The levels of histone H4 mRNA, a marker of cell proliferation, were high at early stages of fetal development of calvaria and femur, and decreased until birth. In both the postnatal calvaria and femur, c‐fos mRNA levels increased transiently at birth and preceded a rise in osteocalcin transcripts, a marker of the mature osteoblast phenotype. The immunohistochemical analysis showed that c‐fos protein was expressed in osteoprogenitor cells in the perichondrium and periosteum, and not in mature osteoblasts which expressed markers of differentiated osteoblasts such as type‐I collagen, bone sialoprotein, and osteocalcin. Thus, the transient c‐fos proto‐oncogene expression during the postnatal life that precedes the osteocalcin expression may be involved in the transition from the precursor state to mature osteoblasts. These results suggest that c‐fos proto‐oncogene may play an important role in osteogenesis during rat postnatal life.