Expression of the fibroblast growth factor 4 (FGF-4) gene is regulated by serum in Tera-2 embryonal carcinoma cells

Expression of the fibroblast growth factor 4 (FGF-4) gene is tightly regulated during mammalian development. Dysregulation of FGF-4 gene expression results in cell transformation and tumorigenesis. It is therefore pertinent to investigate the regulatory mechanisms which control expression of FGF-4. In an initial attempt to identify exogenous factors other than retinoic acid which might control FGF-4 expression, we have investigated the response of endogenous FGF-4 to serum in a number of embryonal carcinoma and embryonic stem cell lines. We have identified a human embryonal carcinoma cell line (Tera-2) in which the FGF-4 gene can be induced by serum. In Tera-2 cells made quiescent by serum deprivation, expression of the FGF-4 gene is repressed. Subsequent addition of serum reactivates FGF-LC expression and further addition of cycloheximide results in superinduction of mRNA suggesting that FGF-4 may be classified as an early response gene. It is suggested that this observation may be explained, at least in part, by the stage of differentiation of the Tera-2 cells.