FIGURE 5.
Mutant Ras causes superinduction of ZEB1 in Ras-TKO MEFs, but it represses ZEB1 in wild-type MEFs (Ras-MEF). Two levels of ZEB1 knockdown were used to assess the importance of ZEB1 induction in Ras-TKO MEFs. A, real-time PCR showing that ZEB1 is superinduced by Ras in Ras-TKO MEFs. Ras-TKO ZEB1 shRNA-1 and Ras-TKO ZEB1 shRNA-2 show two different levels of lentiviral ZEB1 shRNA knockdown of ZEB1 in Ras-TKO MEFs. B, real-time PCR showing that knockdown of ZEB1 in Ras-TKO MEFs to the level seen in WT MEFs (Ras-TKO ZEB1 shRNA-1) leads to rapid induction of E-cadherin (E-Cad) and cdk inhibitor mRNAs, whereas knockdown ZEB1 only to reverse Ras superinduction (Ras-TKO ZEB1 shRNA-2) does not. Ras-TKO ZEB1 shRNA-1 MEFs were prior to passage, and Ras-TKO ZEB1 shRNA-2 were at passage 2. C, real-time PCR showing Ras-mediated repression of ZEB1 and induction of p16 and p21 in wild-type (WT) MEFs. Error bars, S.D.