Epidermal growth factor stimulates the phosphorylation of a specific nuclear protein in chick embryo epidermis

Summary Epidermal growth factor treatment of chick embryo epidermis in culture media or of chick embryos in vivo results in increased phosphorylation of a specific nuclear protein electrophoretically identical to the f 1 histone. This effect is produced by concentrations as low as 0.01 μg/ml though it is maximal at 4 μg/ml; it is apparent as early as 1/2 hour after treatment in vitro and it is maximal at 2–4 hours. The effect of epidermal growth factor is mimicked by dibutyryl cyclic AMP and 3-isobutyl-l-methylxanthine, but not by nerve growth factor.