ABSTRACT
Few cell lines have been used to investigate the involvement of c-Fos in differentiation. Furthermore, some data have been derived from organ culture experiments. The potential involvement of c-Fos in the differentiation of embryonal carcinoma (EC) cells was tested by transfection of different c-fos gene constructs into F9 EC cells. The First report about the expression of c-Fos in mice described it as restricted to the extraembryonic tissues and placenta in mouse development and to bone and skin in adult mice. In addition, c-Fos is expressed in the intestine, developing cartilage, and the spinal cord as well as in certain structures in the peripheral nervous system. If c-Fos is a key regulator in development, one would expect its activity to be dominant. The ultimate proof for the function of c-Fos in differentiation and development is the analysis of mice lacking c-Fos. The tissue culture experiments had previously indicated that c-Fos has a distinct function in differentiation.
