Jm. Vanacker et al., Activation of the osteopontin promoter by the orphan nuclear receptor estrogen receptor related alpha, CELL GROWTH, 9(12), 1998, pp. 1007-1014
Estrogen receptor related alpha (ERR alpha) is an orphan nuclear receptor t
hat is closely related to the estrogen receptor. It is expressed in a varie
ty of adult and embryonic tissues (in particular, at the onset of ossificat
ion), as well as in several osteoblastic cell lines. ERR alpha acts as a si
te-specific, cell-specific transcriptional activator. Here, we show that ER
Ra transactivates the promoter of the mouse osteopontin (OPN) gene, the pro
duct of which is a marker of the late stages of osteoblastic differentiatio
n. This effect is cell specific and is exerted through derivatives of the E
RR alpha response element. Overexpression of ERRa in three different osteob
last-like cell lines results in an elevation of the amount of OPN-correspon
ding mRNA. Therefore, OPN is a target gene for ERR alpha, pointing to the r
ole of the latter in osteoblast differentiation.