Fig. 1. JunB-expressing MEFs show premature entry into senescence. (A) Western blot analysis of JunB expression levels in wild-type (WT) and jB-Tg MEFs. The results from independent MEF lines of each genotype are shown. (B) Proliferation curves of WT and jB-Tg MEFs. The results from three independent MEF lines of each genotype are shown. (C) Senescence-associated β-galactosidase activity in passage 2, 4 and 6 WT and jB-Tg MEFs.