FIGURE 3.
p38γ is essential for ras-induced senescence, phosphorylation of p53 at Ser33, and induction of p21WAF1 expression. A, BJ cells transduced with shGFP or shp38γ-550 or -1023 and Ha-RasV12 (Ras) or vector (WH) were subjected to Western blot analysis detecting the indicated proteins. Cells were lysed on day 8 post-Ras transduction at PD36. B, the population doublings of BJ cells transduced with shGFP or shp38γ-550 or -1023 and Ha-RasV12 or vector were followed over a period of 12 (left panel) or 23 (right panel) days, starting at day 5 post-Ras transduction at PD36 (top panel) or PD35 (bottom panel). Values are mean ± S.D. for duplicates. C, BJ cell lines (described in B) were stained for the SA-β-gal senescence marker on day 17 post-Ras transduction. Values are mean ± S.D. for duplicates.