FIGURE 9.

p38 MAPK signaling is needed for Arf induction by ectopically expressed RAS, but inhibition of TβrI does not. Representative Western blot for the indicated proteins using lysates from wild type MEFs, exposed to the indicated chemical inhibitors at the time of transduction using Gfp- or H-RAS^V12-expressing retrovirus. Lysates were collected 48 h after transduction. Fluorescence microscopy detection of Gfp from the murine stem cell virus-based vectors showed no differences in transduction efficiency across the samples.