FIGURE 5.

Increase in expression levels of p16^INK4a, p19^ARF, and p21^CIP1/WAF1 by oncogenic Ras. A–C, LSK cells transfected with Mock or N-RasE12 were cultured with rmSCF, rmIL-3, and rhEPO for 2 days. Total RNA was isolated from GFP⁺ cells, and the expression levels of p16^INK4a and p19^ARF were analyzed by semiquantitative RT-PCR (A). Immunofluorescence staining of p16^INK4a and p19^ARF localizations (red) in Hoechst 33342-stained nuclei of GFP⁺ cells are shown (magnification, 630×) (B). The expression levels of p21^CIP1/WAF1 were analyzed by real-time RT-PCR. The results are normalized to the levels of HPRT gene and shown as means ± S.D. (n = 3) (C).