... hafter the start of treatment with EGF, indicating thatEGF regulated the level of the Bcl-XLprotein at the transcriptional level. Next we determined the effect of ADR on the expression of Bcl-XL(Fig. ... proteins, is inducedthrough MAP kinase activation, allowing transactiva-tion of genes containing AP1-binding elements. How-ever, it is not known whether EGF is capable of protecting cells from ... transcription, were increased in response toEGF. Pretreatment of the cells with PD98059, an inhibitor of MAP kinasekinase, inhibited the EGF-induced c-Fos and c-Jun expression, AP1 DNAbinding, Bcl-XLexpression,...