FIG. 2.

Expression of eIF4E in stably transfected tetracycline-inducible NIH 3T3 cells. (Upper panel) Immunoblot analysis was performed on total protein (25 μg) from cells cultured for 24 h in the presence or absence of tetracycline. S2-6 cells are the parental cells, which express tTA upon induction. C1, C2, and C3 are stably transfected cell lines expressing eIF4E. The blot was probed first with a rabbit polyclonal anti-eIF4E antibody, followed by a mouse monoclonal anti-actin antibody. After probing with ¹²⁵I-labelled anti-rabbit and anti-mouse secondary antibodies, the amount of eIF4E expressed was quantitated with a Bas 2000 phosphorimager. Relative molecular masses for protein standards are indicated in kilodaltons to the right. (Lower panel) Quantitation of the results shown in the upper panel. eIF4E expression was normalized against actin levels and expressed as the ratio relative to the amount of eIF4E in S2-6 cells in the presence of tetracycline, which was set at 1. Values are the averages of three experiments, and the standard errors are shown.