The Ad5 12S growth factor induces F9 cell proliferation and differentiation.

The 12S gene of the E1A region of adenovirus induces the production of a growth factor that is necessary for the immortalization of primary epithelial cells. This growth factor is able to replace the strict serum requirement of F9 cells, a teratocarcinoma-derived embryonal carcinoma cell line. Furthermore, the growth factor induces a morphological alteration in the F9 cells such that they resemble visceral endoderm cells and express the surface antigens, SSEA-1 and SSEA-3, characteristic of these differentiated cells.