Ameloblastin upstream region contains structural elements regulating transcriptional activity in a stromal cell line derived from bone marrow.

Ameloblastin (AMBN) was originally described as a tooth-specific extracellular matrix protein, but current data have shown that AMBN is present in many different tissues of mesenchymal origin. The identification of regulatory elements in the promoter region of the Ambn gene would assist in identifying potential mesenchymal-specific transcriptional factors. In this study we subcloned a 3,788-bp region upstream (and a 54-bp region downstream) of the mouse Ambn transcriptional start site into a LacZ reporter construct and called this construct 3788-Ambn-lacZ. In silico analysis of the 3,788-bp Ambn promoter region identified 50 potential cis-regulatory elements, 29 of which are known to be functional in cell populations of mesenchymal origin. The reporter construct was activated in transfected bone marrow cells, and the promoter activity was induced in cell cultures following addition of recombinant AMBN, interferon-γ, serotonin, or dexamethasone. We discuss the relative significance of the potential cis-acting gene-regulatory elements of Ambn in relation to bone morphogenesis. Knowledge of Ambn gene-regulatory elements will be of importance when developing strategies for bone repair and replacement in a clinical surgical setting.