Fig. 6. Effect of Zeb1 mutation on expression of Zeb2 and Snail1/2 mRNAs, and TGF-β-dependent induction of vimentin and repression of E-cadherin mRNAs. (A) Real-time PCR analysis shows that TGF-β is unable to repress E-cadherin mRNA levels in Zeb1-null MEFs. Concentrations of TGF-β are shown. No E-cadherin mRNA was detected in wild-type cells (see also Fig. 8B below). (B) Real-time PCR was used to assess the effect of Zeb1 mutation on expression of other E-box-binding repressor mRNAs (Zeb2, Snail1 and Snail2) in MEFs. Results were normalized to β-actin and Gapdh mRNA, with similar results. (C) Real-time PCR analysis shows that basal vimentin mRNA expression is unaffected by Zeb1 mutation, but TGF-β induction is lost in Zeb1-null MEFs. (D) Real-time PCR shows that the basal plasminogen activator inhibitor 1 (PAI-1) mRNA level is unaffected by Zeb1 mutation, and it remains inducible by TGF-β in Zeb1-null MEFs.