Figure 2.

Enhanced proliferative capacity of Ras^V12-expressing C/EBPβ^−/− MEFs. (A) Two independent populations of C/EBPβ^−/− MEFs were infected and selected as described in Figure 1A and were propagated on a 3T3 protocol for four passages. (B) Growth curves of C/EBPβ^−/− MEFs infected with empty vector or Ras^V12-expressing retrovirus, after passage 4. (C) Western blot analysis of p53, p19^ARF, and Ras in lysates prepared from the indicated MEFs at P1 and P4.